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Current Findings Regarding Zirconia Implants
Abstract
Purpose:
The present article aims to analyze the available clinical data on the survival and success rate of dental zirconia implants (ZI).
Material and method:
Studies (2006-2011) listed in the bibliography were obtained by using the key words "zirconia, zirconium, implants, dental, clinical" and combinations of these in different databases and on the internet. These articles served as a basis for the article.
Results:
A total of 17 clinical studies were found, involving 1,675 implants and 1,274 patients. In 16 studies, one-piece implant systems were investigated. The survival rates for ZI range from 74-98% after 12-56 months, with success rates between 79.6-91.6% 6-12 months after prosthetic restoration. However, the design of most of the studies show considerable shortcomings, and only low evidence level.
Conclusion:
The small number of studies and the limited period of observation permit only a qualified statement on the clinical success of ZI. The results available to date indicate that ZI are inferior to titanium implants (TI) with regard to survival and success rates. Well-conducted long-term studies are urgently needed to permit a meaningful assessment of the survival or success rates of ZI and a statement concerning their application as an alternative to TI.
... Modern implant dentistry began in the 1950s when Per-Ingvar Brånemark, a Swedish professor, stumbled upon a phenomenon he called "osseointegration" [3]. The success of endosseous implants is directly related to osseointegration: a process of implant-bone interaction that ultimately leads to bone-to-implant anchorage, which is crucial for the long-term success of the implant [4]. ...
... The success of endosseous implants is directly related to osseointegration: a process of implant-bone interaction that ultimately leads to bone-to-implant anchorage, which is crucial for the long-term success of the implant [4]. The first patient was successfully treated in 1965, using a titanium screw implant [3]. Since then, millions of patients worldwide have been treated with dental implants, with titanium having established itself as the preferred material [3,5,6]. ...
... The first patient was successfully treated in 1965, using a titanium screw implant [3]. Since then, millions of patients worldwide have been treated with dental implants, with titanium having established itself as the preferred material [3,5,6]. ...
Background: This study compared the in vitro response of a mouse pre-osteoblast cell line on a novel sandblasted zirconia surface with that of titanium. Material and Methods: The MC3T3-E1 subclone 4 osteoblast precursor cell line was cultured on either sandblasted titanium (SBCpTi) or sandblasted zirconia (SBY-TZP). The surface topography was analysed by three-dimensional laser microscopy and scanning electron microscope. The wettability of the discs was also assessed. The cellular response was quantified by assessing the morphology (day 1), proliferation (day 1, 3, 5, 7, 9), viability (day 1, 9), and migration (0, 6, 24 h) assays. Results: The sandblasting surface treatment in both titanium and zirconia increased the surface roughness by rendering a defined surface topography with titanium showing more apparent nano-topography. The wettability of the two surfaces showed no significant difference. The zirconia surface resulted in improved cellular spreading and a significantly increased rate of migration compared to titanium. However, the cellular proliferation and viability noted in our experiments were not significantly different on the zirconia and titanium surfaces. Conclusions: The novel, roughened zirconia surface elicited cellular responses comparable to, or exceeding that, of titanium. Therefore, this novel zirconia surface may be an acceptable substitute for titanium as a dental implant material.
... Zir has proven to have similar PLOS biological properties and similar short-term survival rate compared to the conventional titanium alloy, Ti-6Al-4V, implants (Ti). [1][2][3] Beside esthetics, Zir as a restorative material has proven to be superior to other ceramic materials [3][4][5][6][7][8] in terms of mechanical and biological properties including high fracture toughness, high elastic modulus, low thermal conductivity, as well as low dental plaque affinity. One-piece Zir dental implants have been shown to have clinically acceptable mechanical properties even for a reduced diameter implant design. ...
... [22] With esthetic consideration, Zir implant has been indicated in different types of clinical scenarios including healed sockets, immediate implant placement, as well as immediate loading protocol. [1,3,6,9] Note also that anterior edentulous site often has reduced bone width resulting in more challenge in implant placement and in long term maintaining peri-implant bone. [23,24] This study applied FEA to examine the effects of different clinical scenarios that had not been studied biomechanically. ...
... Zir dental implants have recently been introduced and advocated for the esthetic zone. [1,3,6] This study was one of the first to apply FEA models to represent the use of a Zir single implant in three common clinical scenarios in the esthetic zone; the healed socket or edentulous area (HS model), in the reduced bone width area (RB model), and in the extraction socket with grafting (EG model). Since the modulus of elasticity of Zir is approximately twice that of Ti, it was hypothesized that the stress/strain distribution might have been different. ...
This study evaluated the von Mises stress (MPa) and equivalent strain occurring around monolithic yttria-zirconia (Zir) implant using three clinically simulated finite element analysis (FEA) models for a missing maxillary central incisor. Two unidentified patients’ cone-beam computed tomography (CBCT) datasets with and without right maxillary central incisor were used to create the FEA models. Three different FEA models were made with bone structures that represent a healed socket (HS), reduced bone width edentulous site (RB), and immediate extraction socket with graft (EG). A one-piece abutment-implant fixture mimicking Straumann Standard Plus tissue level RN 4.1 X 11.8mm, for titanium alloy (Ti) and Zir were modeled. 178 N oblique load and 200 N vertical load were used to simulate occlusal loading. Von Mises stress and equivalent strain values for around each implant model were measured. Within the HS and RB models the labial-cervical region in the cortical bone exhibited highest stress, with Zir having statistically significant lower stress-strain means than Ti in both labial and palatal aspects. For the EG model the labial-cervical area had no statistically significant difference between Ti and Zir; however, Zir performed better than Ti against the graft. FEA models suggest that Ti, a more elastic material than Zir, contributes to the transduction of more overall forces to the socket compared to Zir. Thus, compared to Ti implants, Zir implants may be less prone to peri-implant bone overloading and subsequent bone loss in high stress areas especially in the labial-cervical region of the cortical bone. Zir implants respond to occlusal loading differently than Ti implants. Zir implants may be more favorable in non-grafted edentulous or immediate extraction with grafting.
... 9 Çelik seramik olarak adlandırılan itriyum-stabilize tetragonal zirkonya polikristal (Yttria-stabilized tetragonal zirconia polycrystal (YTZP) metal seramik materyal özellikleri yüksek eğilme direnci (900-1200 MPa), düşük elastik modülüsü (200 GPa) ve sertlik (1200 vickers sertlik) ile mekanik ve estetik olarak güçlü bir materyaldir. 4,10,11 Zirkonyada, 200 o C sıcaklıkta su buharında spontan olarak metastabil olan tetragonal fazdan monoklinik faza geçiş olmaktadır. Buna bağlı olarak da zirkonyanın dayanıklılığı, yoğunluğu ve doygunluğu azalmaktadır. ...
... 2009 yılında zirkonya implantlara ait kısa dönem veriler olmakla birlikte uzun dönem veriler olmadığı için rutin kullanımlarının önerilmediği belirtilmesine rağmen daha sonraki yıllarda zirkonya implantlar ile ilgili pek çok çalışma yapılmıştır. 9,10,[12][13][14] Bu derlemenin amacı, zirkonya implantların avantaj ve dezavantajları, titanyum implantlar ile karşılaştırılması, ticari zirkonya implant sistemleri, zirkonya implantlar üzerine yapılan son çalışmalar ile ilgili bilgiler verilerek güncel gelişmelerin anlatılmasına yöneliktir. ...
... Zirkonya seramiklerin asitleme işlemlerine dayanıklı olmasından dolayı asitle pürüzlendirme etkili olmamakla birlikte son yıllarda deneysel olarak asitle pürüzlendirme yapılan zirkonya seramiklerin kullanımı vurgulanmaktadır. 10 Yüzey işlemlerinde kumlama (air abrasion), cam partiküler infiltrasyonu, zirkonya partikülleri ile pürüzlendirme, nanoteknoloji, lazer teknolojisi ve plazma sprey tekniği uygulanmaktadır. 3,35,36 100 adet Ceraroot (Iceberg, Spain) zirkonya implant iki farklı yüzey modifikasyonu ile 1 yıllık takip sonucunda 2 adet implant on beş gün sonra başarısız olmuş ancak % 98 gibi yüksek bir başarı gözlenmiştir. ...
... Therefore, 11 review studies were selected for assessment. [46][47][48][49][50][51][52][53][54][55] However, 2 review studies were further eliminated since they were classified as low-quality reviews (Supplementary Table 3, available online). 51,52 The characteristics and outcome summary of the 9 reviews finally selected are reported in Supplementary Table 4 (available online) and Table 2, respectively. ...
... The included participants and implants ranged from 231 53 to 1274 50 and 398 46 to 1948, 47 respectively, excluding the oldest study, which included 0 participants (Supplementary Table 4, available online). 54 Seven of the 9 reviews included were conducted by clinicians and scientists based in Germany and Switzerland. ...
... 54 Seven of the 9 reviews included were conducted by clinicians and scientists based in Germany and Switzerland. 46,48,50,[53][54][55][56] The number of databases used in the reviews ranged from 1 54,56 to 4, 53 mean of 2.67 (Supplementary Table 4, available online). The average number of clinical studies included in the reviews was 12.2. ...
Statement of problem. The clinical effectiveness of zirconia implants as an alternative to titanium implants is still controversial.
Purpose. The purpose of this analysis was to identify and evaluate systematic reviews reporting on the clinical outcomes of zirconia implants for oral rehabilitation.
Material and methods. An electronic search was undertaken on MEDLINE, Embase, and the Cochrane Oral Health Reviews databases up to December 24, 2018, without language restriction. Eligible reviews were screened and assessed. The eligibility criteria were systematic reviews or meta-analyses, implant survival rate, implant success, marginal bone loss, peri-implant soft tissue status, and biologic and functional complications of zirconia implants. Two review authors
independently evaluated the quality assessment of the secondary studies by applying the Assessing the Methodological Quality of Systematic Reviews (AMSTAR) tool.
Results. Nine reviews fulfilled the inclusion criteria and were evaluated. Seven reviews were classified as moderate and 2 as high quality. The overall AMSTAR’s quality of these reports was moderate. In the primary studies contained in these reviews, zirconia implant clinical outcomes were found to be similar or inferior to those for titanium implants. The few primary clinical studies contained in these reviews were not homogeneous among each other, presented poor methodology, and only offered promising short-term outcomes due to the lack of long-term follow-ups.
Conclusions. Based on this meta-review, in spite of short-term promising results of zirconia implants, evidence with long term is lacking.
(Cite as: Afrashtehfar KI, Del Fabbro M. Clinical performance of zirconia implants: A meta-review. J Prosthet Dent. 2020 Mar;123(3):419-426. doi: 10.1016/j.prosdent.2019.05.017)
... However, despite the superior corrosion resistance of titanium, research has shown that after the insertion of titanium dental implants, deposits of fine titanium particles can migrate with the blood into tissues of internal organs, including the lungs and bones. This may trigger an inflammatory response that could play a contributing role in the development of peri-implantitis defects [3]. ...
... While the vast majority of dental implants today are still made from titanium, we know that other metals such as niobium may also obtain osseointegration and that some ceramic materials have shown adequate implant stability [4]. In recent years, zirconia has gained great clinical interest as a non-metal alternative implant material due to its esthetically superior white-colored surface [5], reduced potential to adhere to microorganisms [6], and excellent biocompatibility [3]. In fact, animal studies have shown that zirconia implants have evidenced-based osseointegration similar to that of titanium implants [7]. ...
Wettability is recognized as an important property of implant surfaces for ensuring improved biological responses. However, limited information exists on how bone grafting procedures including materials influence the hydrophilic behavior of implant surfaces. This in vitro study aimed to investigate the influence of two bovine grafting materials after hydration on the wettability of four different disk surfaces: commercially pure titanium (CP-Ti), titanium–zirconium dioxide (TiZrO2-Cerid®), zirconia (SDS®), and niobium. Wettability tests were performed on each of the four implant surfaces with a solution of 0.9% sodium chloride after mixture with W-boneTM (Group A) or Bio-Oss® (Group B) or 0.9% sodium chloride alone (Group C). In total, 360 contact angle measurements were completed with n = 30 per group. Statistical analysis was performed using a one-way analysis with variance (ANOVA) test with a significant mean difference at the 0.05 level. For pure titanium, Group A demonstrated increased hydrophilicity compared to Group B. Both TiZrO2 and zirconia showed significant differences for Groups A, B and C, exhibiting a decrease in hydrophilicity after the use of bovine grafting materials compared to titanium surfaces. Niobium remained consistently hydrophobic. In summary, this study revealed that bovine grafting materials may diminish the hydrophilicity of zirconia surfaces and exert varied effects on titanium and niobium. These findings contribute to the understanding of implant surface interactions with grafting materials, offering insights for optimizing biological responses in implantology.
... In case of zirconia synthesis, stabilization of the product is the main target that can be achieved using additives/dopants along with higher temperatures. However, the toxicity and/or strength degradation with time limits the use of zirconia in biomedical applications (Mamivand et al., 2013;Nishihara et al., 2019;Depprich et al., 2014). Most of the research related to zirconia stabilization is based on organic solvents and/or acids (Hua et al., 2006). ...
... For as-synthesized zirconia samples only 510 cm − 1 active vibration was observed in the low frequency region [ Fig. 4(a)]. It is due to characteristic vibration spectra of metastable t-ZrO 2 (Depprich et al., 2014). Several vibrational peaks were observed for aged zirconia samples [ Fig. 4(b-c)]. ...
Pr and Co co-doped BiFeO3 multiferroics of the following composition BiCoxPrxFe1-2xO3, where (x = 0.00, 0.05, 0.10, 0.15, 0.20 and 0.25) were prepared via sol-gel route. XRD, FTIR, SEM, VSM and VNA were used to evaluate the structural, phase, morphological and electromagnetic properties of Pr and Co co-doped multiferroics. All the undoped and Pr–Co co-doped multiferroics were of single rhombohedral phased whereas at higher concentration the orthorhombic structure was present. FTIR analysis exhibited the presence of orthorhombic phase. SEM images revealed that the grains of Pr and Co doped multiferroics are circular and elliptical in shape. Dielectric and electromagnetic properties were analysed using VNA from 1 to 6 GHz. Dielectric constant, dielectric loss factor, electric modulus, relative permeability, loss tangent, ac conductivity, and Q factor were determined from the toroidal shaped multiferroics. The double doping of Pr and Co multiferroics at x = 0.15 unveiled higher dielectric constant, ac conductivity and other related electromagnetic properties as compared to doped and undoped multiferroics. Pr and Co doped multiferroics also disclosed higher Q factor values at 2.65 GHz. Thin substrate as absorber and square shape resonator of Pr–Co co-doped BiFeO3 multiferroics at x = 0.15 were simulated using FDTD method. The first resonance absorption peak with a very high Q-factor was achieved at 1.2 GHz whereas the second absorption peak was attained at 2.4 GHz respectively. The absorptivity was also analysed corresponding to the different angles of incident for both TE- and TM-modes. Therefore, Pr–Co co-doped multiferroics have potential applications in the absorption and resonator devices in GHz regime.
... In case of zirconia synthesis, stabilization of the product is the main target that can be achieved using additives/dopants along with higher temperatures. However, the toxicity and/or strength degradation with time limits the use of zirconia in biomedical applications (Mamivand et al., 2013;Nishihara et al., 2019;Depprich et al., 2014). Most of the research related to zirconia stabilization is based on organic solvents and/or acids (Hua et al., 2006). ...
... For as-synthesized zirconia samples only 510 cm − 1 active vibration was observed in the low frequency region [ Fig. 4(a)]. It is due to characteristic vibration spectra of metastable t-ZrO 2 (Depprich et al., 2014). Several vibrational peaks were observed for aged zirconia samples [ Fig. 4(b-c)]. ...
It is well known that long term stability in zirconia has been a problem because of the structural alteration from stabilized tetragonal zirconia to monoclinic that leads to fracture in implants. Microwave (MW) assisted sol-gel synthesis is employed in the present work to prepare stabilize zirconia nanoparticles. ZrOCl2.8H2O is used as a precursor whereas de-ionized water is used as a solvent. Power of microwave radiations is varied in the range of 100–1000W. Zirconia nanoparticles have been characterized under as-synthesized, 6- and 12-months’ room temperature (RT) aged conditions. Metastable phase (MP) of zirconia, appearing under as-synthesized conditions, transforms to phase pure tetragonal zirconia (t-ZrO2) after RT aging that was prepared with MW powers of 100, 200 and 700–1000W. Whereas, MP transforms to mixed tetragonal-monoclinic phases at microwave powers of 300–600W after RT aging. XPS results show presence of oxygen-deficient state of ZrO2 lattice along with surface defects contributing towards the tetragonal zirconia phase under all conditions. Value of dielectric constant (i.e. ∼11–12 at log f = 4.0), hardness (∼1376 HV) and fracture toughness observed under all conditions are well in agreement to be used for biological implants. Disks of aged t-ZrO2 nanoparticles are checked for their biodegradation test by dipping in simulated body fluid for several weeks. ZrO2, with 26 weeks of immersion, shows small loss in hardness and weight. Stabilized tetragonal zirconia shows strong anti-oxidant activity. Stabilized ZrO2 nanoparticles presented strong antibacterial activity against both gram positive (S. aureus, Bacillus) and gram negative (E. coli) bacteria. Thus, structural and mechanical stability of zirconia (checked after 6 and 12 months) make this material highly beneficial for long term use in biomedical applications.
... This review aims to present and discuss the data available from preclinical studies on osseointegration of zirconia implants placed in the jawbone with a focus on bone-to-implant contact (BIC). For clinical data on zirconia dental implants, readers are referred to recent reviews (Cionca et al. 2017, Depprich et al. 2014, Elnayef et al. 2017, Hashim et al. 2016, Pieralli et al. 2017. Although important to the long-term success of dental implants, soft tissue integration of zirconia will not be discussed in this review (for reviews, see Linkevicius & Vaitelis 2015, Sanz-Martin et al. 2018, Sculean et al. 2014). ...
... A review analyzing 17 studies published between 2006 and 2011 showed that the survival rates for zirconia dental implants ranged from 74% -98% after 12 -56 months, with success rates between 79.6% -91.6% 6 to 12 months after prosthetic restoration (Depprich et al. 2014). The authors concluded that the design of most of the studies showed considerable shortcomings and only a low level of evidence, and that zirconia implants are inferior to titanium implants with regard to survival and success rates. ...
Background: Due to its advantageous physical, biological, and esthetic proper-ties as well as its resistance to corrosion, zirconia as a biomaterial to replace missing tooth roots has been the focus of great interest and may become a reli-able alternative to titanium implants.Aim: To present and discuss the preclini- cal data available on osseointegration of zirconia implants placed in the jawbone.Results: A great number of preclinical studies on zirconia implants with histo-logic and histomorphometric data are available. Zirconia implants were tested with different implant dimensions and designs, different surface treatments (e.g. machined, sandblasted, acid-etched, alkaline-etched, fusion-sputtered, selective infiltration-etched, powder injection molding, laser-treated, plasma-treated, microgrooved), in different species (i.e., rabbit, monkey, sheep, miniature pig, rat, dog) and different anatomical locations (i.e. tibia, femur, pelvis, maxilla, mandible), under different loading conditions, and with different observation periods (i.e. 1–56 weeks). Taken together, the bone-to-implant (BIC) values reported in the literature for zirconia implants placed in the jawbone range from 18% to 89% with many values in the order of 50%–75%. All in all, most preclinical studies and reviews concluded that the BIC values did not reveal statistically significant differences between zirconia and titanium implants. Furthermore, most studies and most reviews come to the conclusion that modified zirconia surfaces have higher BIC values than machined ones.Conclusions: Most preclinical studies and reviews conclude that zirconia and titanium implants have similar BIC values. Nevertheless, the survival and success rates of zirconia implants documented in clinical studies are dependent on the implant type/system and somewhat inferior to those of titanium implants. More solid, long-term clinical data on zirconia implants are needed and differences between implant systems and surgical procedures need to be evaluated.
Keywords: Zirconia, dental implant, osseointegration, bone-to-implant contact
... They exhibit enhanced toughness and fracture resistance owing to allotropy, which leads to phase transformation toughening mechanisms [10]. In addition to their exceptional esthetic characteristics, zirconia implants exhibit biocompatibility comparable to titanium implants and reduced plaque affinity [11]. ...
Objective
This study analyzed clinical parameters to assess whether dental implant material is a risk factor for peri-implantitis.
Methods
A literature search was performed on PubMed Central, Cochrane, PubMed/MEDLINE, Embase, and Scopus. The PICO strategy involved healthy patient, partially or fully edentulous, receiving at least one dental implant; zirconia or titanium dental implants; comparison involving assessment of whether there were differences in the risk of peri-implantitis among different materials used for dental implants; clinical parameters. Quality assessment was performed using the modified Jadad scale.
Results
Nineteen articles met the inclusion criteria. BoP did not have statistically significant differences comparing zirconia and titanium implants or natural teeth. MBL had diversified results; sometimes, it was higher in zirconia implants than titanium; otherwise, there was no significant difference. Comparing implants with natural teeth, MBL was lower in titanium implants over prolonged observation periods, and greater severity was found in the zirconia group. Notably, natural teeth had minimal bone loss. Zirconia implants demonstrated reduced plaque accumulation and minimal microbial contamination compared to titanium implants and control teeth. The quality assessment was considered poor to low in 9 studies and good to excellent in 10. The development of peri-implantitis was influenced by several patient-specific and clinical factors, underscoring the need to adopt a comprehensive and personalized approach to implant dentistry and peri-implantitis prevention.
Conclusion
It was not possible to draft any solid conclusion for the relationship between implant material and peri-implantitis.
... 85 Additionally, several clinical studies supported the positive outcomes of using zirconia implants in terms of implant stability and survival rates. [86][87][88] Taking into account the findings from various laboratory, animal model, and clinical studies, it can be concluded that both zirconia and the traditional gold standard material, titanium, exhibit similar levels of osseointegration. However, in certain significant cases, zirconia was found to perform even better than titanium. ...
... The literature supports that more inflammation is found in titanium implants, which can be represented initially by the BoP and, consequently, MBL [23]. This fact was proved by studies using zirconia implants, showing reduced activation of local inflammatory response and bone resorption compared with titanium [24,25]. ...
Objective: The goal of this systematic review and meta-analysis was to assess whether there were clinically relevant differences in the treatment of edentulous areas comparing zirconia (Zr) and titanium (Ti) dental implants. The null hypothesis is that no differences can be observed in terms of the clinical parameters; the positive hypothesis I is that Zr implants have generally better results compared to Ti implants; and the positive hypothesis II is that Ti implants have a generally superior result than Zr implants. Methods: This review work was registered on the PROSPERO platform, and its development was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) statement. The electronic search process was conducted on three databases (PubMed/Scopus/Web of Science), including randomized controlled trials (RCTs) from the past 10 years (up to April 2024). Identified articles were analyzed and included/excluded based on pre-defined selection and exclusion criteria. The quality assessment and risk of bias were evaluated using a Cochrane risk-of-bias assessment tool specifically designed for randomized trials (RoB2). A meta-analysis was conducted to correlate different treatment options based on the described outcomes; a random-effects model was used in the analysis of the variables. The analysis of heterogeneity was conducted by means of Cochran’s Q-test and Higgins’ I² statistic. Results: Six RCTs were enrolled; 152 patients (90 males and 62 females) and 448 implants (267 Zr and 181 Ti) were included. Dental implant placement involved both the maxillary and mandibular arches. The implant sites showed heterogeneity in receiving Zr and Ti dental implants; in particular, 22 dental implants were placed in the mid-palatal region and 426 dental implants in the alveolar region (255 were in Zr and 171 in Ti). Regarding the success rate, it was better for Zr but with no statistical difference (p > 0.05); bleeding on probing had slight differences between Ti with 0.34% ± 0.42 and Zr with 0.26% ± 0.36 (p > 0.05); plaque score showed 0.46 ± 0.47 for Ti compared to 0.44 ± 0.49 for Zr (p > 0.05); no statistically significant difference was observed for pink esthetic score (PES). Statistically significant results were found for survival rate, which favored Ti implants (77.6%) compared to Zr (70.3%) (p < 0.05), and for marginal bone loss, which showed less loss in Ti implants (0.18 mm ± 0.47) compared to 0.42 mm ± 0.40 in Zr at 12 months (p < 0.001). Conclusions: The present systematic review and meta-analysis identified the positive hypothesis I and rejected the null and positive hypothesis II; it was possible to conclude that Ti dental implants have a better survival rate and less marginal bone loss than Zr dental implants after 1-year follow-up.
... Installing dental implants has become routine in the oral rehabilitation of partially or completely edentulous patients. In recent years, implants made of titanium and zirconia alloy with a micro-rough surface have been studied in detail as alternative materials to replace lost dental elements and have shown to be biologically well tolerated and exhibit adequate osseointegration [1][2][3][4][5][6]. ...
The present case describes the clinical and radiographic results of 24 months of two-piece injection-molded zirconia implants with immediate loading, as well as the aesthetic and functional planning performed in the anterior maxilla. Case presentation: A 36-year-old female patient was referred to a dental school due to dissatisfaction with the aesthetics of her smile and the absence of dental elements 22 and 24. Prosthetic rehabilitation of the anterior maxilla was performed, including implant-supported prosthesis with zirconia implants and ceramic veneers, using a digital workflow. The patient was followed up for 24 months, with good clinical and radiographic results. Conclusions: The aesthetic and functional rehabilitation performed in the patient's maxilla, with veneers and ceramic crowns, was successful and contributed to the patient's psychological and emotional well-being, in addition to restoring occlusal stability, through the orientation of the canine and the adequate protrusion of the anterior teeth.
... Following their introduction in the early 2000s, zirconia implants attracted significant interest, particularly for rehabilitations in the aesthetic zone [18]. Apart from their superior aesthetic properties, zirconia implants also display similar biocompatibility to titanium implants, lower affinity to plaque and low modulus of elasticity [19,20]. The biomechanical properties of zirconia implants have been assessed in numerous experiments, and overall, their early failure rates seem generally higher compared with titanium implants. ...
Objective
This systematic review assessed the available evidence on the survival and success rate of zirconia and titanium implants. As secondary outcomes, aesthetic, radiographic and clinical parameters, as well as biological and mechanical complications, were considered.
Materials and methods
A systematic search was performed up to March 2022 to identify CCTs/RCTs comparing zirconia and titanium implants with a minimum of 12 months of follow-up. Meta-analysis was performed when ≥ 2 articles with similar characteristics were retrieved.
Results
Four published articles with two RCTs (2 different patient populations) with 100 zirconia and 99 titanium implants that were followed up over 12–80 months were selected out of the 6040 articles. A non-statistically significant difference between zirconia and titanium implant survival at 12 months was suggested (P = 0.0938). The success rates were 57.5–93.3% and 57.1–100% for zirconia and titanium implants, respectively. The pink aesthetic score (PES) was higher for zirconia (10.33 ± 2.06 to 11.38 ± 0.92) compared to titanium implants (8.14 ± 3.58 to 11.56 ± 1.0).
Conclusion
Based on the 2 RCTs retrieved in the literature, similar survival rates were reported for zirconia and titanium implants in the short term (12 months of follow-up). Future RCTs are warranted to evaluate the long-term outcomes of zirconia implants.
Clinical relevance
Zirconia implants may be the procedure of choice, particularly in the aesthetic zone, since they show a similar survival and success rate as titanium implants on a short-term follow-up.
Trial registration
Systematic review registration number—CRD42021288704 (PROSPERO).
... Due to good biocompatibility, ceramic osseosubstituting materials have become widely used in practical medicine [6]. The presence of zirconium in ceramics significantly improves mechanical properties of the material [7,8], without having toxic effect on preosteoblasts and improving the reaction of osteoblasts [9,10]. Addition of lanthanum has a significant effect on corrosion resistance of the material, moreover, it has an inhibitory effect on the formation of osteoclasts [11,12]. ...
Creation of new ceramic materials for the bone augmentation purposes that combine the absence of cytotoxicity, high strength and osseointegration characteristics is an urgent modern task. In this work, the cytocompatibility of ceramic materials based on lanthanum zirconate (La2Zr2O7) was determined to assess the prospects for their use as implants and components of human joint endoprostheses. The effect of ceramic materials based on undoped and alkali-earth (Ca, Sr) doped La2Zr2O7 on the viability and proliferative activity of human cells was evaluated. The release of elements into the culture medium was also evaluated.
... 6,7 However, ZrO 2 has been observed to accumulate less plaque, 7,8 and no metal color can be seen when exposed through the tissue. 9,10 Furthermore, Depprich et al 11 observed that ZrO 2 dental implants displayed a 74% to 98% implant survival rate over 12 to 56 months and 79.6% to 91.6% success rates over 6 to 12 months. Later, according to the meta-analysis results from Elnayef et al, 12 ZrO 2 implants showed a 91.5% survival rate and a 91.6% success rate over a 42.37-month mean follow-up period, reporting that this may be a good alternative to Ti implants, specifically in the anterior esthetic areas with a thin tissue biotype. ...
Purpose:
To demonstrate the likelihood of the polyetheretherketone (PEEK), zirconia (ZrO2), and titanium (Ti) disks to support proliferation and hemidesmosome formation of gingival cells.
Materials and methods:
Water contact angle was performed on each material, and surface roughness (Ra) was measured. Scanning electron microscopy and x-ray photoelectron spectroscopy were used. Later, oral keratinocyte cells were cultured on disks, and metabolic activity and expression of hemidesmosome markers, integrin α6 and β4, in relation to the biomaterial disks at 1, 3, and 5 days of cell culture were quantified. Tissue culture polystyrene was used as the control. Statistical analysis was performed with analysis of variance (ANOVA) with Tukey post hoc comparison test. A P value of < .05 was considered statistically significant.
Results:
The water contact angle ranged from 70.2 degrees (Ti) to a maximum of hydrophobicity of 93.3 degrees (PEEK). Ra was highest on ZrO2, followed by PEEK. Ti showed the most keratinocyte metabolic activity at 1, 3, and 5 culture periods. Contrarily, ZrO2 and PEEK disks had lower keratinocyte metabolic activity at all observation times, with no statistical differences between both groups. Integrin α6 and β4 expression was highest on TCPS and ZrO2 compared to Ti and PEEK.
Conclusion:
Keratinocytes proliferated faster on Ti than on ZrO2 and PEEK substrates, and expression of hemidesmosome formation markers, integrin α6 and β4, were higher on ZrO2 than either Ti or PEEK. Int J Oral Maxillofac Implants 2023;38:496-502. doi: 10.11607/jomi.9894.
... The study was conducted on one-piece zirconia implants, as these currently hold the predominant position among ceramic implants. Due to the wider range of technical and biological complications, intense research is currently being conducted on two-piece ceramic implants [1,40,44,45]. However, the presented solution for an excess-free cementing process offers the option to use one-piece zirconia implants in well-managed clinical situations. ...
The aim of this study was to find a suitable material combination to avoid cement excess in the marginal region of one-piece zirconia implant-supported restorations by means of a hybrid crown consisting of a meso- and a suprastructure. One-piece zirconia implants (n = 120) were embedded in epoxy resin. Microfilled resin composite mesostructures (n = 60), designed as caps, were bonded on the implant abutment with a primer only. A molar crown was constructed and cemented with a resin cement on top of the mesostructure as a suprastructure out of feldspar ceramic (n = 12), lithium-disilicate (n = 24), or zirconia (n = 24). Fracture load (n = 6) and retention force (n = 6) were measured immediately after storage in distilled water at 37 °C for 24 h, as well as after an additional exposure to artificial aging in a chewing simulator and simultaneous thermal cycling. For the measurement of the fracture load, monolithic crowns made of the employed restorative materials and identical in shape to the hybrid crowns served as controls (n = 6 each). Fracture load values for feldspar ceramic and lithium-disilicate hybrid crowns were slightly higher than those for the respective monolithic crowns at baseline and after aging, which was statistically significant only for feldspar crowns after aging. In contrast, fracture load values for zirconia monolithic crowns were higher than those for zirconia hybrid crowns, which was only statistically significant after aging. Artificial aging reduced the fracture load of feldspar and lithium-disilicate crowns both for hybrid and monolithic crowns. The effect was only statistically significant for lithium disilicate hybrid crowns. The fracture load for hybrid and monolithic zirconia crowns was increased by artificial aging without reaching statistical significance. The retention force of lithium-disilicate and zirconia hybrid crowns was not affected by artificial aging. Taking into account retention force and fracture load, lithium-disilicate hybrid crowns showed promising results.
... 272,273 The studies revealed that roughened surface of the zirconia is favoring osseointegration to bone. 274 Some studies indicated that the use of alumina with zirconia tends to increase biocompatibility. 275 7.6. ...
This review focuses on the advancements in additive manufacturing techniques that are utilized for fabricating bioceramic scaffolds and their characterizations leading to bone tissue regeneration. Bioscaffolds are made by mimicking the human bone structure, material composition, and properties. Calcium phosphate apatite materials are the most commonly used scaffold materials as they closely resemble live bone in their inorganic composition. The functionally graded scaffolds are fabricated by utilizing the right choice of the 3D printing method and material combinations to achieve the requirement of the bioscaffold. To tailor the physical, mechanical, and biological properties of the scaffold, certain materials are reinforced, doped, or coated to incorporate the functionality. The biomechanical loading conditions that involve flexion, torsion, and tension exerted on the implanted scaffold are discussed. The finite element analysis (FEA) technique is used to investigate the mechanical property of the scaffold before fabrication. This helps in reducing the actual number of samples used for testing. The FEA simulated results and the experimental result are compared. This review also highlights some of the challenges associated while processing the scaffold such as shrinkage, mechanical instability, cytotoxicity, and printability. In the end, the new materials that are evolved for tissue engineering applications are compiled and discussed.
... Zirconia is presently a widely used material owing to several advantages, including excellent biocompatibility, mechanical properties, and aesthetics, making it a good alternative to titanium [2]. e zirconia used in dentistry is an yttria-stabilized tetragonal polycrystal (Y-TZP), a tetragonal single phase stabilized by adding Y 2 0 3 , which has excellent physical properties such as fracture toughness, flexural strength, and hardness [3]. When external stress is applied to the zirconia and a crack develops, a phase transition from tetragonal to monoclinic occurs and a part of the fracture energy is absorbed. ...
Purpose. Loosening and fracture of abutment screws are one of the most common complications in implant-retained fixed prostheses. Thus, applying the proper tightening torque to the abutment screw is important for preventing the loosening effect of the abutment screw and ensuring the stability of the implant fixture-abutment connection. Therefore, in this study, we aimed to investigate the effect of the tightening torque of the abutment screw on the stability of the fixture-abutment connection in a two-piece zirconia implant system using finite element analysis (FEA). Materials and Methods. The two-piece zirconia implant structures used in this study were designed using the CATIA program. The abutment screws with tightening torques of 25 (TT-25), 35 (TT-35), and 45 (TT-45) N·cm were assumed to fix the abutment and fixture. Vertical (200 N) and oblique (100 N) loads were applied to the finite element model generated for FEA simulation, and the stress levels and distributions were investigated. Results. The TT-45 group exhibited the highest von Mises stress in the abutment and fixture, followed by the TT-35 and TT-25 groups. The von Mises and minimal principal stresses of the abutment screw were also highest in the TT-45 group, followed by the TT-35 and TT-25 groups. In all three groups, the area with the highest stress concentration was located at the point of contact with the bottom of the screw head. Furthermore, the TT-25 group showed the highest safety factor value. The TT-35 group showed a safety factor value similar to the safe minimum standard, while the TT-45 group showed a lower safety factor value. Conclusion. When a torque of 35 N cm was applied to the two-piece zirconia implant system, it showed a maximum stress value close to 660 MPa (75% of the yield strength of the Ti-6Al-4V alloy), which is the optimal preload recommended for abutment screws.
... Additionally, implants made of zirconium dioxide could be superior compared to titanium implants in terms of bacterial adhesion and may lead to lower levels of inflammation mediators in peri-implant tissues resulting in an improved esthetic outcome [17][18][19][20]. Due to the limited numbers of patients and implants, studies on ceramic implants are frequently lacking validity in terms of survival and success rates [21]. Currently, no studies exist on immediately placed and immediately loaded ceramic implants and investigations on this topic would be of particular scientific interest [22]. ...
Background
There is limited evidence for the use of zirconium dioxide implants in immediate implant placement as well as for related immediate loading protocols. The aim of this retrospective study was to investigate the survival rate, success and patient satisfaction of immediately placed zirconia implants compared to delayed placed implants.
Methods
The study included 58 partially edentulous patients who were treated between 2013 and 2015 with immediate and delayed transgingival healing zirconium dioxide implants (SDS, Kreuzlingen/ Switzerland). In addition to survival and success rate, marginal bone loss was assessed using radiographs and soft tissue was evaluated using Pink Esthetic Score. Oral health-related quality of life was investigated prospectively using a modified OHIP questionnaire.
Results
The cumulative survival rate of all implants included was 92% with 88% classified as full success. No significant difference was found between the bone levels of immediately and delayed placed and immediately and delayed loaded implants. The mean Pink Esthetic Score after final prosthetic rehabilitation was 12.2/14 points indicating excellent esthetic clinical results. Analysis of the OHIP questionnaire showed a mean value of 0.54/100 points reflecting a high patient satisfaction.
Conclusions
Immediate and delayed placed as well as loaded zirconium dioxide implants showed excellent results regarding implant success and survival in this study. Zirconium dioxide implants may ensure excellent esthetic results and high patient satisfaction.
... In addition, Zr implants show a 74-98% implant survival rate over 12 to 56 months and a 79.6-91.6% success rate over 6 to 12 months [13]. ...
The purpose of this clinical series was to evaluate the clinical and radiographic outcomes of 20 zirconia dental implants, with a minimum follow-up of two years. Patients with at least one zirconia dental implant were included, with a mean follow-up of 34.05 months. The patient complaints such as pain and foreign body sensation, as well as clinical parameters including peri-implant infections with suppuration, implant mobility, gingival index (GI), modified plaque index (mPI), modified sulcus bleeding index (mBI), probing depth (PD) and radiological distance between the implant shoulder to the closest mesial and distal bone-to-implant contact (BIC), were assessed. All zirconia implants were successfully integrated without any pain or foreign body sensation. No mobility was detected in any of the 20 implants. Clinical examination revealed a mean PD of 2.56 mm and a radiological mean distance between the implant shoulder and the initial site of visible bone-to-implant contact (BIC) of 1.44 mm. In addition, GI, mPI and mBI indicated minimal to no inflammation. Results obtained from this series suggest that one-piece zirconia dental implants achieve good clinical and radiographic outcomes over a mean follow-up of 34 months and may be deemed a good option in patients with favorable bone conditions.
... Zirconia is highly biocompatible and possess good stability properties. However, some studies revealed long-term outcomes may be inferior to those of comparable studies that investigated titanium implants [3][4][5]. ...
The influence of UV light and non-thermal plasma on the osseointegration of yttria-stabilized zirconia implants (Y-TZP) comparing the two methods is unclear. The aim of this study was to show the influence of these methods on the osseointegration of dental zirconia implants in an animal model. A total of 54 implants were either untreated, treated with UV light (UV), or non-thermal oxygen plasma for 12 min and inserted into the parietal bones of six domestic pigs. The animals were sacrificed after a healing interval of two, four, and nine weeks. The degree of osseointegration was determined using histomorphometric determination of bone-to-implant contact values (BIC) and the bone-to-implant contact values within the retentive parts of the implants (BAFO). BIC values decreased in all groups after four weeks of healing and re-increased after nine weeks in all groups. BAFO increased significantly over time in all groups. However, there were no statistically significant differences in BIC and BAFO values between the control group and the test groups and over time. Clinical studies may follow to confirm the influence of cold plasma and UV light on the healing and survival of zirconia implants.
... This is especially important in cases in which the patient presents a thin peri-implant soft tissue or when mucosa recession may occur over time. [20][21][22] Also, an irritation-free attachment of zirconia implants and abutments with peri-implant soft tissues has been demonstrated, as well as a comparable or even better soft tissue healing response around these when compared to titanium devices. 11,23 A prospective clinical study found that most patients treated with 2-piece zirconia implants presented low plaque and bleeding indices, indicating healthy periimplant soft tissues in up to 6 years, which according to the authors might be explained by zirconia's low affinity with plaque and reduced inflammatory infiltrate. ...
This case report describes the treatment of two patients who presented with single edentulous sites in the region of upper premolars and were rehabilitated through the placement of injection‐molded 2‐piece zirconia implants and immediate single crowns. Three months after surgery, definitive prostheses were confectioned through digital workflow. Both patients were followed for 12 months during which clinical and radiographic implant success were observed, concerning implant stability, absence of peri‐implantitis signs, complete implant osseointegration, good marginal bone‐level maintenance, and excellent soft tissue esthetics. No biological or mechanical complications were observed within this period. The clinical cases suggest that treatment with injection‐molded 2‐piece zirconia implants and zirconia abutments is a successful and reliable alternative for single‐unit immediate rehabilitation, with predictable results in the short‐term concerning.
... введение Процесс взаимодействия имплантата и воспринимающего костного ложа сложен и зависит от витальных функций кости в зоне дефекта, площади контакта имплантата с костью, а также от совместимости остеозамещающего материала с окружающей тканью по физико-химическим, биологическим и механическим свойствам [1,2,3]. На сегодняшний день керамика на основе соединений циркония успешно применяется в стоматологии в качестве облицовочного материала и как основа для изготовления зубных протезов [4,5]. Также этот вид керамики нашел применение в оперативной травматологии и ортопедии для изготовления компонентов пар трения, демонстрируя лучшую износостойкость по сравнению с другими материалами [6]. ...
Background . The ceramic based on lanthanum zirconate is characterized by optimal mechanical characteristics, low corrosion potential and the absence of cytotoxicity. Thus, the possibility of its use as bone substituting material is currently studied. The purpose of the study was to determine the mechanical, morphological and x-ray spectral characteristics of bone tissue after implantation of ceramic material based on lanthanum zirconate. Materials and methods . The experiment was conducted on 27 female guinea pigs of a single line, divided into 3 groups of 9 animals each. In the main group (LZ), lanthanum zirconate rods were implanted. In the comparison group (b-TCP), fixation was performed with b-tricalcium phosphate rods. In the native control group (NC) no surgical procedures were performed. A fracture was created in distal metadiaphysis area of femur using open osteoclasia. Animals were hatched 4, 10, and 25 weeks after the start of the experiment. Bone tissue features were studied in the perifocal region. The following methods were used: uniaxial compression, scanning electron microscopy (SEM), energy dispersive x-ray microanalysis (EDxMA). The statistical analysis was performed using the Mann-Whitney test. Results . The architectonics of the newly formed bone in the LZ group appeared as a developed lacunar tubular network. The structural components of the extracellular matrix were oriented along the bone functional load vectors. The Ca/P ratio in the periimplant region of the bone in the LZ group was significantly higher than in the b-TCP and NC groups. This may indicate a high strength of the newly formed bone. Mechanical testing showed that the strength and performance of the system of “lanthanum zirconate – bone” under uniaxial compression exceeded the similar indicators in the b-TCP group. Conclusion . The synthesized new material based on lanthanum zirconate seems promising for use in traumatology and orthopedics. Although, additional studies are needed to optimize these implants integration into bone tissue.
... Zirconia's extensive use has been attributed to its excellent mechanical properties; including high flexural strength (900-1200 MPa) and fracture toughness, high modulus of elasticity, as well as resistance to both corrosion and wear (Norbert Cionca, Hashim, & Mombelli, 2017). Moreover, animal studies have demonstrated this material's high capacity of osseointegration, with bone-implant contact (BIC) and removal torque similar to titanium's (Depprich et al., 2012;Manzano, Herrero, & Montero, 2014). In vitro experiments have further shown that microbial biofilm is less adherent to zirconia surfaces, and thus trigger a lower amount of inflammatory infiltrate in the surrounding tissues (Degidi et al., 2006;Nascimento et al., 2014). ...
Objectives
The aim of this prospective clinical trial was to present the 6‐year outcomes of a two‐piece yttria‐stabilized tetragonal zirconia polycrystals (Y‐TZP) implant system in partially edentulous patients.
Material and methods
Forty‐nine two‐piece zirconia implants were placed in 32 patients systemically healthy. Zirconia abutments were connected with adhesive resin cement. Single‐unit full‐ceramic crowns were cemented. The cases have been followed for an average of 82.2 ± 5.86 months after loading (range 74.93‐92.26 months).
Results
24 participants with 39 implants were available for examination 6 years after loading. The cumulative implant survival rate was 83%. On an implant‐level, the cumulative mechanical complication rate was 17.5%, the cumulative technical complication rate was 13%, the biological complication rate was 8%. After 6 years, subjects reported good satisfaction with the treatment: 3.7 ± 4.4 on a visual analog scale (VAS) from 0 to 100 mm.
Conclusions
Within the limitations of this prospective case series study, two‐piece zirconia implants could offer an alternative for treatment of single edentulous spaces in the posterior region. The major complication on the long‐term of this pioneering system was the abutment fracture, however due to the versatility of a two‐piece implant system, replacement of the broken parts was possible.
... [16] Zirconia in dental implants A study investigated the survival and achievement of zirconia dental implants in light of the accessible clinical information from case reports, forthcoming and review clinical examinations, and randomized multicenter research studies. [17] These investigations, aside from one, [18] detailed the utilization of single piece zirconia implants. The follow-up period of 5 years revealed 74%-98% survival rate and achievement rates in the vicinity of 79.6% and 91.6% following 6 years of prosthetic rebuilding. ...
Titanium and its alloys are mainly used in manufacturing dental implants. The fact that titanium implants are immunologically very effective, new methods are being experimented to achieve utmost success rate as a biomaterial. One fundamental indicator for clinical achievement of implant is the decision of composition decided for the implant with the objective to improve osseointegration. The main objective of this study was to explore literature on dental materials used for implants, contrast them with titanium dental implants, with the aim to improve osseointegration and mechanical quality using Ti–Ga–Si dental implant.
... 2,5,[12][13][14] Early studies using zirconia implants point toward good biocompatibility properties along with reduced activation of local inflammatory response and bone resorption compared with titanium. [15][16][17] Dental implant technology is a fast-moving area in dentistry, exhibiting a plethora of new clinical studies with longer follow-ups. Emerging studies on ceramic implants enable better evaluation of the clinical performance of zirconia alongside the traditional use of titanium. ...
Purpose:
The purpose of this study was to provide sufficient information on the clinical outcome of zirconia implants, mainly observing the survival rate and marginal bone loss (MBL), with a minimum follow-up of 12 months, to verify the adoption of ceramics as a rational possibility for dental implants.
Materials and methods:
A systematic electronic search through the PubMed (MEDLINE) and EMBASE databases was performed by two independent reviewers to identify clinical studies published between January 2005 and April 2019 containing a minimum of 10 patients per study and 12 months of follow-up after functional loading. References from the selected articles were manually reviewed for further studies.
Results:
From the initial 1,225 articles retrieved, 19 met all the inclusion criteria. The marginal bone remodeling accounted for mean losses of 0.8 mm (95% CI: 0.60 to 1.00 mm) and 1.01 mm (95% CI: 0.72 to 1.29 mm) at 1 year and 2 years postloading, respectively. The failure rate of 6.8% was calculated for a mean follow-up period of 2.75 years, where the prevalence of early failure, late failure, and implant fracture was 3.4%, 1.7%, and 1.7%, respectively. The meta-analysis associated with the survival rate of one- and two-piece zirconia dental implants was hindered due to the lack of confidence interval or standard deviation information in most of the included articles.
Conclusion:
Zirconia implants presented MBL values consistent with the standard in the global consensus, high survival rates, and considerable clinical results at short-term observation periods following prosthetic delivery.
... The growing demand of better esthetics and non-metallic materials has brought zirconia as an alternative to titanium implants due to its inert nature, excellent biocompatibility, and transformation toughening mechanism to prevent crack propagation [1][2][3][4][5]. On comparing the mechanical aspect, titanium used for dental implants has about 20-30 times higher fracture toughness and is also more ductile than zirconia [6]. ...
Objectives
Previous studies have shown that the fracture toughness of ceramics can be determined from the fractal dimensions (D) of their fracture surfaces and that the surface should be leveled to obtain an accurate D measurement. This study was to determine the effects of leveling operations and distance from the failure origin on the D values.
Methods
Twelve clinically failed zirconia implants from four different manufacturers: Axis Biodental (n = 7), Z-Systems (n = 3), Straumann (n = 1), and Swiss Dental Solutions (n = 1) were obtained from one of the authors and thoroughly cleaned. Epoxy replicas were made of three locations along the crack path in the center region of each fracture surface (near origin (O), hackle (H), and near compression curl (CC)) using a light body polyvinyl siloxane impression material. Surfaces were scanned in ScanAsyst mode with a scan size of 5 μm × 5 μm and a scan rate of 0.592 Hz using the atomic force microscope. The surface scans were then leveled using 1st order flattening operation in the AFM analysis software. The height data before and after the operation were imported into a custom MathCAD script, and FRACTALS software was used to determine the D value by Minkowski Cover algorithm, which was shown previously to be the algorithm with the highest precision. A Wilcoxon signed-rank test, two-way repeated-measures ANOVA, and one-way repeated-measures ANOVA were performed as detailed below.
Results
The data were not normally distributed (S-W p ≤ 0.05), so a non-parametric repeated measures test (Wilcoxon signed-rank test) was selected. The median D values before and after leveling were 2.161 and 2.174, respectively. There was a significant difference before and after leveling (p < 0.001). The two-way repeated-measures ANOVA showed no significant difference among the D values for different implant brands (p = 0.66) and scanning locations on the fracture surface (p = 0.83). After eliminating the implant brand as a factor, the data passed normality and equal variance tests (S-W p = 0.88, BF p = 0.15). The mean D values and standard deviations from the three locations (O, H, CC) were 2.183 ± 0.031, 2.179 ± 0.024, and 2.175 ± 0.018, respectively. One-way repeated measures ANOVA showed no significant effect of scanning location (p = 0.74).
Significance
The leveling operation successfully removed the tilt without decreasing surface tortuosity, as it increased the D values significantly. The fractal dimension was the same at the three locations on the fracture surfaces. This means that hackle and compression curl regions can be used to determine fracture toughness when the failure origin has been lost.
... However a frequent fracture incidence was reported impeding their wide use (8). Currently, zirconia is the material of choice for ceramic dental implants, offering adequate mechanical and physical properties compared to Ti implants (9). Yttriumstabilized tetragonal polycrystalline zirconia (Y-TZP) dental implants were shown to promote osseointegration, produce an excellent soft tissue response, low plaque affinity, and can have a natural tooth-like color (10). ...
Introduction: Dental implants are currently one of the main pillars of restorative dentistry. Titanium and its alloys were and still are the gold standard for dental implant materials. However, Titanium is not a perfect material thus the search for a more ideal material is ongoing. Zirconia and Polyetheretherketone are two viable alternatives to titanium as dental implant materials. These two materials show different mechanical and biological behavior in vitro and in vivo. Objectives: Evaluation of mechanical performance and bioactivity of Polyetheretherketone as an implant material following controlled biomimetic simulations. Zirconia was used as a comparable implant material. Materials and Methods: Microbars of Polyetheretherketone and yttrium-stabilized tetragonal polycrystalline zirconia were prepared using precision cutter under water cooling and used for biomimetic assessment of the following properties: Flexural strength and elastic modulus for unaged and aged microbars using cyclic loading, Vickers Microhardness and In vitro Bioactivity using simulated body fluid. Results: Biomimetic mechanical evaluation displayed significance decrease of flexural strength and elastic modulus values for both unaged and aged Polyetheretherketone compared to zirconia. No significance was detected for Polyetheretherketone after aging. While, zirconia showed significant decrease of flexural strength and elastic modulus values after aging. There was also a significant decrease in microhardness values of Polyetheretherketone corresponding to zirconia. In vitro Bioactivity showed the higher affinity of zirconia to bone formation compared to Polyetheretherketone. Conclusions: Polyetheretherketone could be recommended as a promising alternative to titanium and zirconia as a dental implant material. [Youssef M. Kassem and Dawlat Mostafa. Biomimetic Evaluation of Polyetheretherketone as a Promising Implant Material: In vitro study. J Am Sci 2019;15(2):21-30]. ISSN 1545-1003 (print); ISSN 2375-7264 (online).
... However a frequent fracture incidence was reported impeding their wide use (8). Currently, zirconia is the material of choice for ceramic dental implants, offering adequate mechanical and physical properties to overcome the drawbacks of Ti implants (9). ...
... 2 Furthermore, it is known that zirconia, besides its tooth-like color, possesses favorable biological properties such as low thermal conductivity, low affinity to plaque, and high biocompatibility. [3][4][5] In the past decades, conventional dental implants made from titanium have been widely investigated in different clinical settings, indications, and regions. To date, dental implants from titanium can be regarded as a reliable and long term, stable treatment option to replace missing teeth and attach dentures in case of tooth loss. ...
Background
Dental implants made of zirconia ceramics experienced a renaissance in the past years. However, there is still a lack in reliable long‐term clinical data.
Purpose
Aim of the present prospective clinical study was to analyze the dental implants made from zirconia, regarding their clinical performance compared to natural teeth (control).
Materials and Methods
Eighty‐three zirconia implants in 28 adults were analyzed after 7.8 years of integration. Approximal plaque index (API), sulcus bleeding index (SBI), probing pocket depth (PPD), probing attachment level (PAL), and creeping or recession (CR/REC) of the mucosa/gingiva were analyzed. Changes in the marginal bone level (MBL) have been determined by comparing radiographs recorded immediately after implant placement and at the follow‐up investigation. Furthermore, the pink esthetic score (PES), Periotest values (PTV), microbial colonization of the implant/dental sulcus fluid, and patient satisfaction were assessed.
Results
The survival rate of zirconia implants was 100%, however one implant presented a profound peri‐implantitis, resistant to therapies. No statistical significance was observed between implants and teeth regarding SBI and PAL. Statistical significance was detected regarding API and CR/REC with significantly less plaque accumulation and recession in the study group. Significantly higher values for PPD were obvious in the zirconia implant group. PES of 9 ± 2.7 indicate a rather average esthetic result. Analysis of MBL revealed a mean peri‐implant bone resorption of 1.2 mm. Microbial analysis revealed a nonstatistically significant higher colonization of bacteria in the study group, whereas single bacteria species were detected in statistically significant higher amounts.
Conclusion
The investigated one‐piece zirconia dental implants presented favorable long‐term clinical results, comparable to natural teeth (SBI and PAL), and, regarding adhesion of plaque and creeping attachment (CR/REC), even superior. The microbial investigation revealed a shift in peri‐implant colonization around zirconia implants over years, mainly without clinical effect on peri‐implantitis.
... A guidance paper to the use of fractography in failure analysis of brittle materials has recently been published [5]. Zirconia implants have been brought to the dental market as a viable alternative to titanium implants initially to fulfill a demand from patients for non-metallic materials [8]. Thanks to its high biocompatibility, mechanical properties and interesting transformation toughening mechanisms under the application of a stress, zirconia is currently the structural ceramic used for dental biomedical applications [9][10][11][12]. ...
Objectives:
To provide fractographic analysis of clinically fractured zirconia implants recovered with their cemented crown. To calculate bending moments, corresponding stress and crack onset location on the implant's fracture surface using a mathematical model integrating spatial coordinates of the crown-implant part and occlusal loading obtained from 2D and 3D images.
Methods:
15 fractured zirconia implants parts (11 posterior and 4 anterior) with their all- ceramic crowns still cemented on it were recovered. The implants were first generations from four manufacturers (AXIS Biodental, Z-Systems, Straumann, Swiss Dental Solutions). The time-to-failure varied between 2weeks and 9years. Fractography was performed identifying the failure origin and characteristic surface crack features. From 2D and 3D digital images of the crown-implant part, spatial coordinates anchoring the crown's occlusal contacts with the implant's central axis and reference plane were integrated in a mathematical model spreadsheet. Loads of 500 N in total were selectively distributed over identified occlusal contacts from wear patterns. The resultant bending and torsion moments, corresponding shear, tensile, maximum principal stress and von Mises stress were calculated. The fracture crack onset location on the implant's fracture surface was given by an angular position with respect to an occlusal reference and compared with the location of the fracture origin identified from fractographic analysis.
Results:
Implants fractured from the periphery of the smaller inner diameter between two threads at the bone-entrance level except for one implant which failed half-way within the bone. The porous coating (AXIS Biodental) and the large grit alumina sandblasting (Z-System) created surface defects directly related to the fracture origin. The model spreadsheet showed how occlusal loading with respect to the implant's central axis affects bending moments and crack onset. Dominant loads distributed on contacts with important wear pattern provided a calculated crack onset location in good agreement with the fractographic findings of the fracture origin.
Significance:
Recovered broken zirconia implant parts with their restorative crowns can provide not only information regarding the failure origin using fractography but also knowledge regarding occlusal crown loading with respect to the implant's axis. The mathematical model was helpful in showing how occlusal loading affects the location of the fracture initiation site on clinical zirconia implant fracture cases.
... It has been shown that in the interpretation of CBCT images, artifacts adjacent to Ti implants are a common finding that may hinder the correct interpretation of the peri-implant situation ( Two implant systems made from different materials, that is titanium and zirconium dioxide were tested in this study. Titanium has been established as the preferred metal for dental implants owing to its unique mechanical properties as well as its high resistance to corrosion (Depprich et al., 2014). Lately, zirconium dioxide got more popular as a biocompatible and aesthetical alternative because of its biophysical properties and white color. ...
Objective
To test the accuracy of measurement of interproximal peri‐implant bone defects at titanium (Ti) and zirconium dioxide (ZrO2) implants by digital periapical radiography (PR) and cone beam computed tomography (CBCT).
Material and Methods
A total of 18 models, each containing one Ti and one ZrO2 implant, were cast in dental stone. Six models each were allocated to following defect groups: A ‐ no peri‐implant defect, B ‐ 1 mm width defect, C ‐ 1.5 mm width defect. The defect width was measured with a digital sliding caliper. Subsequently, the models were scanned by means of PR and CBCT. Three examiners assessed the defect width on PR and CBCT. Wilcoxon signed‐rank test and Wilcoxon rank sum test were applied to detect differences between imaging techniques and implant types.
Results
For PR the deviation of the defect width measurement (mm) for groups A, B and C amounted to 0.01±0.03, ‐0.02±0.06 and ‐0.00±0.04 at Ti and 0.05±0.02, 0.01±0.03 and 0.09±0.03 at ZrO2 implants. The corresponding values (mm) for CBCT reached 0.10±0.11, 0.26± 0.05 and 0.24±0.08 at Ti and 1.07±0.06, 0.64±0.37 and 0.54±0.17 at ZrO2 implants. Except for Ti with defect A, measurements in PR were significantly more accurate in comparison to CBCT (p≤0.05). Both methods generally yielded more accurate measurements for Ti than for ZrO2.
Conclusions
The assessment of interproximal peri‐implant defect width at Ti and ZrO2 implants was more accurate in PR in comparison to CBCT. Measurements in CBCT always led to an overestimation of the defect width, reaching clinical relevance for ZrO2 implants.
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Objective
To describe the clinical and radiographic performance and survival rate of a new two-piece ceramic implant system after at least 12 months of follow-up.
Materials and methods
Sixty-five implants were placed and followed up for at least 12 months (12.3 ± 1.5), in 50 patients. The implants were installed both in fresh extraction sockets and in healed sites and received provisional restoration when the clinical insertion torque was greater than 35Ncm. The primary results describe the survival rate of these implants. Clinical performance was evaluated through the evaluation of the Pink Esthetic Score (PES) and the degree of satisfaction of the patients. Bone loss was measured through radiographic measurements of the marginal bone loss in the mesial (MBLM) and distal (MBLD) sites.
Results
The survival rate was 98.5%. The average MBLM was 0.24 mm (± 0.53) and the MBLD was 0.27 mm (± 0.57). A statistical difference was observed only when comparing immediate implants with delayed ones (MBLM – p = 0.046 and MBLD - p = 0.028) and when they received immediate provisionalization or not (MBLM - p = 0.009 and MBLD - p = 0.040). The PES before the intervention (T0) was 13.4 (± 0.8) and the PES at T2 (12-month follow-up) was 12.9 (± 1.5) (p = 1.14).
Conclusion
The new two-piece ceramic implant used in the present study showed predictable and reliable results, similar to those found with titanium implants after one year of follow-up.
Clinical relevance
These implants can be used as an alternative to titanium implants in terms of the marginal bone loss and the degree of patient satisfaction.
The purpose of this study was to analyze the biomechanical properties of implants made of different materials to replace missing teeth by using three-dimensional finite element analysis and provide a theoretic basis for clinical application. CBCT data was imported into the Mimics and 3-Matic to construct the three-dimensional finite element model of a missing tooth restored by an implant. Then, the model was imported into the Marc Mentat. Based on the variations of the implant materials (titanium, titanium–zirconia, zirconia and poly (ether-ether-ketone) (PEEK)) and bone densities (high and low), a total of eight models were created. An axial load of 150 N was applied to the crown of the implant to simulate the actual occlusal situation. Both the maximum values of stresses in the cortical bone and implant were observed in the Zr-low model. The maximum displacements of the implants were also within the normal range except for the PEEK models. The cancellous bone strains were mainly distributed in the apical area of the implant, and the maximum value (3225 μstrain) was found in PEEK-low model. Under the premise of the same implant material, the relevant data from various indices in low-density bone models were larger than that in high-density bone models. From the biomechanical point of view, zirconia, titanium and titanium–zirconia were all acceptable implant materials for replacing missing teeth and possessed excellent mechanical properties, while the application of PEEK material needs to be further optimized and modified.
Dental implant fittings are often made of a variety of materials. Titanium alloys, zirconium, PEEK, composite materials, 3D-printed materials, and biodegradable materials are a few of the most recent implant materials. A great deal of research is being done on implant surface coating materials, such as nanostructured materials and bioactive coatings, to improve the osseointegration of the implant with the bone.
Nano-zirconia, also known as nanocrystalline zirconia or zirconia nanoparticles, is a versatile material with numerous applications in various fields, including catalysis, sensors, energy storage, and biomedical engineering. This review manuscript explores the synthesis methods of nano-zirconia, focusing on the sol-gel method, precipitation method, hydrothermal method, flame spray pyrolysis, and template-assisted synthesis. Each method is discussed in detail, highlighting its advantages and disadvantages. The selection of a synthesis approach depends on factors such as desired properties, scalability, cost, and equipment availability. Furthermore, the study examines specific dental applications where nano-zirconia materials find utility. In dental implantology, nano-zirconia implants have shown promising results in terms of osseointegration, with comparable or superior performance to titanium implants. Surface modifications, such as bioactive coatings, have been explored to enhance osseointegration and long-term success. Additionally, nano-zirconia ceramics have been utilized in dental prostheses, such as crowns, due to their biocompatibility and exceptional strength. Studies have evaluated the mechanical properties and translucency of different zirconia compositions for dental restorations. Moreover, improvements in the sol-gel process have led to the development of zirconia-silica glass ceramics with enhanced aesthetics and corrosion resistance. Lastly, the impact of professional tooth cleaning on zirconia dental prostheses has been investigated, providing insights into surface properties and bacterial adherence. Overall, nano-zirconia materials offer great potential in various dental applications, and their synthesis methods can be tailored to obtain desired properties for specific uses. Further research and optimization are required to fully explore and exploit the capabilities of nano-zirconia in dental settings.
Objectives:
Long-term follow-up observations of zirconia implants are rare. This study aimed at evaluating the clinical performance of two-piece zirconia implants in the posterior jaws over 9 years.
Materials and methods:
Sixty partially edentulous patients were treated with two-piece zirconia implants. In eight no primary stability could be achieved. Fifty-two patients received the final restoration (i.e. cemented fibreglass abutments and all-ceramic crowns). After 2 years, 2 implants failed and 4 dropouts were recorded. The remaining 46 patients with one target implant each were recalled at 9 years. Besides implant survival, clinical parameters at the implant level (plaque index-PI, bleeding on probing-BOP, probing depth-PD, mucosal recession-MR) were recorded and compared with previously collected data. Mechanical and technical complications were assessed.
Results:
Thirty patients responded. The mean observation period was of 111.1±2.2 months. One implant was lost. Data recorded from the remaining 29 implants were analysed. PI values increased overtime. Mean BOP and PD remained unchanged during follow-up. No additional cases of peri-implantitis were recorded over the 10 diagnosed during the first 2 years of follow-up. No significant changes in mean MR values were detected over time, with 65% of the all included implants exhibiting no recession at 9 years and all the others, but one, a maximum MR of 1mm. Three technical and 6 mechanical complications occurred in 7 patients between 2- and 9-years (6.9% and 20.7%, respectively, at patient level).
Conclusion:
Within the limitations of the present study, a high survival rate was registered. Albeit frequent mechanical and technical complications, two-piece zirconia implants could represent a valid solution for the replacement of single teeth in the posterior jaws.
The field of Implantology is a relatively new niche when viewed against the entire history of medical disciplines. This newer approach affords such an advantage in therapeutic and cosmetic modalities that it has rapidly become the trending topic of study amongst researchers and clinicians. The field of Dental Implantology alone has evolved into a booming hub of commerce and analysis to an extent that it has generated a revenue of approximately 4.6 billion USD. Why did a fledgling topic evolve so rapidly into a hallmark area of clinical query and application? To address that question, one must delve into the structure and function of an implant and its trending applications.
Purpose:
Zirconia has exceptional biocompatibility and good mechanical properties in clinical situations. However, finite element analysis (FEA) studies on the biomechanical stability of two-piece zirconia implant systems are limited. Therefore, the aim of this study was to compare the biomechanical properties of the two-piece zirconia and titanium implants using FEA.
Materials and methods:
Two groups of finite element (FE) models, the zirconia (Zircon) and titanium (Titan) models, were generated for the exam. Oblique (175 N) and vertical (175 N) loads were applied to the FE model generated for FEA simulation, and the stress levels and distributions were investigated.
Results:
In oblique loading, von Mises stress values were the highest in the abutment of the Zircon model. The von Mises stress values of the Titan model for the abutment screw and implant fixture were slightly higher than those of the Zircon model. Minimum principal stress in the cortical bone was higher in the Titan model than Zircon model under oblique and vertical loading. Under both vertical and oblique loads, stress concentrations in the implant components and bone occurred in the same area. Because the material itself has high stiffness and elastic modulus, the Zircon model exhibited a higher von Mises stress value in the abutments than the Titan model, but at a level lower than the fracture strength of the material.
Conclusion:
Owing to the good esthetics and stress controllability of the Zircon model, it can be considered for clinical use.
The aim of this in-vitro study was to evaluate the fracture strength of a two-piece ceramic implant system after hydrothermal aging and mechanical loading.
For this purpose, three series consisting of eight two-piece zirconia implants (Y-TZP) were either mechanically fatigued (ZM, 107 chewing cycles), or hydrothermally aged (Z85, in water with 85° C) or simultaneously mechanically loaded and hydrothermally aged (ZM85, 107 chewing cycles, 85° C). Untreated ceramic and titanium implants of a similar design served as references (V3 and TK). The Y-TZP implants were manufactured by cold injection molding (CIM). In a preliminary experiment it was determined whether the embedding height of the samples had a significant influence on the fracture strength of the implants. Eight ceramic implants were embedded with the shoulder 1 mm (group V1) or 3 mm (group V3) above the margin of the sample holder. It was shown that the embedding height had no significant influence on the fracture strength of the ceramic implants. Consequently, all implants of the main experimental groups were embedded according to ISO 14801 3 mm above the margin of the holder in prefabricated PEEK holders in dual-polymerizing acrylic resin. All implants were loaded to fracture in the static load test in a universal testing machine (Zwick, Z010 / TN2S, Ulm, Germany). The statistical analysis of the data was performed using the software STATA 14. T-tests were used for pairwise comparisons of the groups in order to analyse the bending moment. The level of significance was set at p= 0.05. In addition, a linear regression analysis with the independent parameters material, hydrothermal aging, mechanical loading and the combination of both loads was performed.
Compared to untreated control groups loading/aging resulted in significantly increased fracture strength/bending moments (Z85: 1134 N/623.9 Ncm, ZM85: 877 N/482.4 Ncm and ZM: 1008 N/554.6 Ncm compared to the control group V3: 660 N/362.7 Ncm; TM: 998 N/548.9 Ncm compared to the control group TK: 846 N/465.4 Ncm). No statistically significant difference in the bending moments within the ceramic test groups could be observed. When comparing the unloaded ceramic and titanium groups (V3 versus TK), significantly higher values were found for the titanium implants.
Within the limits of this investigation, the examined implant system seems to be suitable for clinical use.
As a metal-free counterpart to titanium, zirconia-based ceramic implants have emerged as a charming alternative in the dental sector in recent years. If you compare the two materials with each other, they correlate excellently in terms of biocompatibility and osseointegration. Nevertheless, ceramic implants account for only about 5% of all implants manufactured on the world market. Many users are critical of the non-metallic material because of its would be lack of mechanical stability and its ageing behaviour. But are these prejudices justified, and could the worldwide share of ceramic implants increase further in the coming years? This article compares the latest studies and gives an overview of the advantages and disadvantages of zirconium dioxide-based implants.
Tumor region automated segmentation from the digitized hematoxylin and eosin stained histology image is a fundamental step for efficient tumor quantification and biomarker interrogation. In this study, we presented an automated deep learning-based tumor segmentation model for automated tumor extent delineation in whole slide tissue images of p16-positive oropharyngeal squamous cell carcinomas (n = 248). The employed ResNet model was trained using images with coarse annotations (i.e., polygon-style bounding box annotations). The model was trained using n = 194 images and validated using n = 49 images. Another cohort of five whole slide images was used as independent test purpose. The experimental result demonstrated that satisfactory segmentation results could be achieved, an accuracy of about 90% in both of the validation and test cohorts, even when using non-exhaustive tumor annotations for training the model. Such an accurate and efficient tumor detection model could be used for early detection of disease and the prediction of aggressiveness in oropharyngeal squamous cell carcinomas, which could improve the patients’ survival to manage their therapeutic strategies appropriately.
Dental implants have become an integral part of orofacial rehabilitation. In addition to their use for tooth replacement, they have become important in maxillofacial prosthetic rehabilitation. Head and neck cancers often require ablative surgery that includes the maxilla and mandible. The use of dental implants to support prostheses replacing portions of the jaws and facial skeleton has given individuals with this disease functionality, aesthetics, and emotional support that have never before been possible. Digital technology has further provided opportunities in the planning and execution of maxillofacial rehabilitation using dental implants. This allows the use of advanced surgical and prosthetic techniques with an improved result for the patients.
Polyether-ether-ketone (PEEK) has emerged in Implant Dentistry with a series of short-time applications and as a promising material to substitute definitive dental implants. Several strategies have been investigated to diminish biofilm formation on the PEEK surface aiming to decrease the possibility of related infections. Therefore, a comprehensive review was carried out in order to compare PEEK with materials widely used nowadays in Implant Dentistry, such as titanium and zirconia, placing emphasis on studies investigating its ability to grant or prevent biofilm formation. Most studies failed to reveal significant antimicrobial activity in pure PEEK, while several studies described new strategies to reduce biofilm formation and bacterial colonization on this material. Those include the PEEK sulfonation process, incorporation of therapeutic and bioactive agents in PEEK matrix or on PEEK surface, PEEK coatings and incorporation of reinforcement agents, in order to produce nanocomposites or blends. The two most analyzed surface properties were contact angle and roughness, while the most studied bacteria were Escherichia coli and Staphylococcus aureus. Despite PEEK's susceptibility to biofilm formation, a great number of strategies discussed in this study were able to improve its antibiofilm and antimicrobial properties.
The paper presents the results of experimental studies of the adhesion strength at a static load on the gap of dental cement joints of an individual milled transdental implant with solid tissues of the tooth root. The samples consisted of a composition composed of a conical-shaped structure (similar to a transdental implant made of titanium alloy and zirconium dioxide) inserted into the canal of a natural tooth stump and fixed in it with cement gluing. The experiments were performed on previously removed teeth with a resected root tip in the amount of 78 units. As a result of the study, cements were identified that ensure the highest adhesive strength of the joint "individual transdental implant-dental cement-stump of an extracted tooth" in the specimen. For the root fixation of titanium alloy implants, composite Multilink-N cement is recommended, and for zirconium dioxide implants, Fuji-1 glass ionomer cement is recommended. At the second stage, the effect of artificial surface roughness of the implant on the adhesion properties of the cement joint implant-tooth was investigated. To this end, before conducting experiments on the extrusion of the pins, the samples surfaces were sandblasted with aluminum oxide granules of 50, 150, 250 microns in size. Cements were used for fixation, which showed the highest adhesive characteristics at the previous stage. It turned out that an increase in the roughness size in the range of 50-250 μm improves the adhesion parameters of the cement joint implant-tooth for all tested cements. The presence of implant roughness allows one to withstand a significantly greater load compared to a smooth implant, and an increase in the implant surface roughness value from 50 to 250 μm also significantly (almost 2.5 times) increases the load.
Zirconia (ZrO2) is an emerging alternative to titanium for dental implant systems due to its material properties including high mechanical strength and chemical stability. However, oral environmental factors such as bacterial adhesion and mechanical fatigue may trigger low-temperature degradation of ZrO2, leading to reduced mechanical strength and potential implant fracture. Although failure modes of ZrO2 in orthopedic applications have been studied, they have yet to be thoroughly investigated in the context of dental implant systems. Thus, the goal of the present study was to assess the surface of ZrO2 dental implants for signs of degradation after exposure to oral bacteria and in combination with mechanical fatigue. ZrO2 dental implants were subjected to 30-day immersion in (i) early- or (ii) late-colonizing oral bacteria, or (iii) were mechanically loaded for 2 x 10⁶ cycles with oral bacteria in circulation. Optical microscopy, Raman microscopy, and X-ray photoelectron spectroscopy (XPS) were used to evaluate the surface morphology, phase composition, and chemical composition, respectively. Post-immersion, all implants exhibited minimal changes in surface features, and all loaded-implants survived cyclic fatigue tests. All implants had <1% monoclinic phase at the collar, junction, and screw regions, excluding the screw threads which was significantly higher but <10%. XPS revealed an increase in carbon- and nitrogen-based organic debris on the implants exposed to early colonizers as compared to those immersed in late colonizers or synergistically with mechanical loading. Within the limitations of the present study, ZrO2 is a suitable alternative material for dental implant systems based on its ability to resist both physical and chemical degradation imposed by oral bacteria and applied cyclic loads.
Objectives:
To evaluate whether zirconia implants demonstrate differences in hard and soft tissue integration compared to titanium implants in preclinical studies.
Material and methods:
In March 2017, electronic (MEDLINE, EMBASE) and hand search was performed to identify preclinical studies comparing zirconia and titanium implants. Primary outcomes were bone-to-implant contact (BIC) and removal torque out (RTQ), respectively, push-in (PI) measurements. Secondary outcomes included biologic width (BW) dimensions.
Results:
A total of 37 studies were included for data extraction after screening of 91 from 1,231 selected titles. Thirty-seven experimental studies using six different species were identified. The follow-up periods ranged between 0.4 and 56 weeks. For titanium, mean values of 59.1% (95% CI: 53.3 - 64.8), 102.6 Ncm (95% CI: 81.5 - 123.6), and 25.1 N (95% CI: 20.2 - 30.0) for BIC, RTQ, and PI were estimated, respectively. The mean values for zirconia were 55.9% (95% CI: 51.6 - 60.1), 71.5 Ncm (95% CI: 51.1 - 91.9), and 22.0 N (95% CI: 13.2 - 30.7) for corresponding parameters. Confounding factors such as animal species, implant material, loading protocol, and study or loading duration significantly influenced the outcomes. Similar qualitative soft tissue integration was reported for zirconia and titanium implants. However, faster maturation processes of epithelial and connective tissues around zirconia implants were assumed. Quantitatively, similar BW dimensions were evaluated for titanium (3.5 mm; 95% CI: 2.9 - 4.2) and zirconia (3.2 mm; 95% CI: 2.7 - 3.7), whereas the loading protocol significantly influenced the outcomes.
Conclusions:
Zirconia and titanium implants demonstrate a similar soft and hard tissue integration capacity. However, titanium tended to show a faster initial osseointegration process compared to zirconia. Importantly, not only material characteristics but predominantly animal species and study protocols can significantly influence the outcomes.
Bis heute liegen nur wenig Daten über die mechanische Stabilität von zweiteiligen Keramikimplantaten aus ATZ Keramik vor. Daher war es das Ziel dieser in-vitro-Studie gewesen, den Einfluss der thermomechanischen Belastung in einer Kaumaschine im Hinblick auf die maximale Bruchfestigkeit eines zweiteiligen Keramikimplantatsystems zu untersuchen. Als Referenz dienten zwei klinisch erfolgreiche Implantatsysteme aus einer TiZr-Legierung und aus Titan. Diese drei Implantatgruppen, die jeweils aus 16 Implantaten bestanden, wurden jeweils in zwei gleich große Untergruppen aufgeteilt: ZB (Keramikimplantat belastet), ZU (Keramikimplantat unbelastet), RB (TiZr-Legierung belastet), RU (TiZr-Legierung unbelastet), TB (Titan belastet) und TU (Titan unbelastet). Die Untergruppen ZB, RB und TB wurden einer thermomechanischen Belastung im Kausimulator mit 10 Millionen Zyklen unterzogen. Hierbei wurde die Gruppe ZB einer hydrothermalen Alterung im +85 °C heißen Wasserbad ausgesetzt. Die Wasserbadtemperatur betrug bei den Gruppen RB und TB circa +20 °C. Die anderen Gruppen wurden direkt dem statischen Bruchtest zugeführt (ZU, RU und TU). Ein Implantat pro Untergruppe wurde nicht gebrochen und zur mikroskopischen Abutmentspaltanalyse herangezogen. Zusätzlich wurden von vier ausgewählten Bruchfragmenten des Keramikimplantats metallografische Längsschliffe angefertigt und mikroskopisch analysiert. Alle Implantate überlebten die Belastungsphase im Kausimulator. Für den statischen Bruchtest ergaben sich folgende mittleren Drehmomente: ZB: 6138 Nmm, ZU: 6135 Nmm, RB: 7346 Nmm, RU: 7559 Nmm, TB: 6727 Nmm, TU: 6830 Nmm. Es wurde kein signifikanter Drehmomentunterschied zwischen den belasteten und unbelasteten Keramikimplantaten (p = 0,727) sowie zwischen den Keramik- und zweiteiligen Titanimplantaten (p = 0,086) festgestellt. Ein signifikanter Drehmomentunterschied wurde zwischen den Keramikimplantaten und Implantaten aus einer TiZr-Legierung beobachtet (p = 0,002). Die Fragmentlängsschliffe wiesen oberflächliche Schraubenhalsschäden auf der Belastungsseite auf. Es kann innerhalb der Grenzen dieser Untersuchung geschlussfolgert werden, dass die thermomechanische Belastung keinen negativen Einfluss auf die Bruchfestigkeit des zweiteiligen Keramikimplantats hatte. Das zweiteilige Keramikimplantat scheint bezüglich der Stabilität für den klinischen Einsatz geeignet zu sein.
In der vorliegenden Arbeit wird über die Ergebnisse einer Langzeit-Verlaufsstudie berichtet. Sie untersuchte bei 1342 Patienten 2304 enossale Implantate verschiedener Implantatsysteme (Bonefit. Bränemark, Frialit-2, IMZ, ITI-Hohlzylinder, TPS und Tübinger Implantat), die im Zeitraum von 1975 bis Frühjahr 1993 in der Poliklinik für Zahnärztliche Chirurgie und Pctrodontologie der Universität Tübingen konsekutiv inseriert und im Rahmen des Sonderforschungsbereiches 175 Jmplantologie" nachkontrolliert, dokumentiert und ausgewertet wurden. Mit Verweildaueranalysen nach Kaplan-Meier wird für jedes Implantatsystem das Liegedauerverhalten bei ausschließlicher Betrachtung des Implantat-Verlustes untersucht. Zum Vergleich werden Verweildaueranalysen nach Cutler-Ederer unter Berücksichtigung klinischer und röntgenologischer Nachkontrollparameter dargestellt. Bei einigen Implantatsystemen zeigt sieb ein deutliches Mißverhältnis zwischen klinischen und röntgenologischen Nachkontrollen mit pathologischem Befund zum Kriterium ..Implantat in situ öder Implantatverlust". Unter Berücksichtigung dieser pathologischen Befunde müssen mehr Implantate als Mißerfolge gewertet werden als tatsächlich Implantate zu Verlust gingen. Diese Betrachtung des Mißerfolges erlaubt eine differenziertere und kritische Beurteilung der vorgestellten Systeme.
The aim of this work was to clinically and radiographically evaluate survival and success rate of zirconia dental implants positioned in premolar area during a follow-up period of at least 12 months up to 24 months.
Sixteen patients were treated with 26 zirconia implants. All implants received immediate temporary restorations and 6 months after surgery were definitively restored. Twelve to 14 months after implant insertion, a clinical-radiographical evaluation was performed in order to estimate peri-implant tissues health and peri-implant marginal bone loss.
The survival rate was 96.16%. The success rate was 91.6%.
Because of the limited number of implants, conclusions may not be considered significant even if results are encouraging. Further scientific information regarding clinical use of zirconia dental implants are needed, as well as prospective long-term clinical studies in order to understand if zirconia implants may represent a valid alternative to titanium implants.
The aim of this study was to present authors' two-year clinical experience with Yttrium-stabilized zirconium dioxide implants placed in native bone or regenerated bone.
Yttrium-stabilized zirconium dioxide implants made of brezirkon (whiteSKY, Bredent medical, Senden, Germany) were used for the treatment of edentulous ridge rehabilitation in the Dental Clinic of the University of Milan (Head of the Department, Prof. F. Santoro). Zirconium dioxide is a highly resistant ceramic material obtained by cleaning zirconium dioxide and zirconium silicate. The implant used in the clinical study featured a conical one piece implant with double cylindrical thread with a sandblasted rough surface. The prosthetic section was smooth.
Forty-six implants have been inserted in 18 patients from January 2007 to January 2009, the follow-up period was comprised between 6 and 24 months. The overall success rate was 89%; the success rate in native bone was 97% and 74% in augmented bone. It can be stated that the success rate is comparable to titanium fixtures.
It would be logical to use a ceramic material for the esthetic regions; zirconium dioxide is particularly suitable since it features tissue friendliness and resistance comparable to titanium. The good mechanical properties, possibility of easy fabrication of the prosthetic restoration and the good integration into the tissue and the esthetics provide perfect preconditions for yttrium-stabilized zirconium dioxide to become the most commonly used material in implant dentistry.
This report demonstrates the clinical use of a modified, truly anatomic, root-analogue zirconia implant for immediate replacement of a two-rooted, left first mandibular molar. A 50-year-old female patient with chronic apical periodontitis of the left mandibulary first molar was referred and the tooth was extracted. The mesial root had to be removed surgically due to a root fracture. A truly anatomical, root identical, roughened zirconia implant modified by macro-retentions was manufactured and placed into the extraction socket by tapping 7 days later. After 4 months a composite crown was cemented in place. No complications occurred during the healing period. A good functional and aesthetic result was achieved with minimal bone resorption and soft tissue recession at 30 months follow-up. This report describes the successful clinical use of an immediate, single stage, truly anatomical root-analogue zirconia implant for replacement of a two-rooted tooth. Significant modifications such as macro-retentions yielded primary stability and excellent osseointegration. This novel approach is minimally invasive, respects the underlying anatomy, aids socket prevention, is time- and cost-saving with good patient acceptance as there is no need for bone drilling, sinus lift, bone augmentation or other traumatic procedures.
Ceramic biomaterials have gained widespread use in arthroprostheses joints. Ceramic oxides including alumina as á -corundum Al2 O3 and zirconia, as yttria-stabilised zirconia polycrystals, were used in large number of patients, especially in the manufacture of ball heads for hip replacements. The experience and the feedbacks gathered in more than 30-year clinical use of alumina, and 15-year use of zirconia are reviewed. The results of in vitro and in vivo studies on the biocompatibility of alumina and zirconia ceramics are analyzed as well as the studies on carcinogenicity. (Journal of Applied Biomaterials & Biomechanics 2003; 1: 19-32).
To evaluate whether immediate non-occlusal loading of single zirconia implants could reduce early failures when compared to immediate occlusal loading.
Forty partially edentulous patients who received one single zirconia implant (Z-Systems) at least 10 mm long and 3.25 mm wide inserted with a torque of at least 35 Ncm were randomised to immediate occlusal or non-occlusal loading groups. All patients received provisional acrylic crowns the same day of implant placement. Provisional crowns were replaced after 4 to 5 months by definitive full ceramic crowns. Outcome measures were implant success, any complications and peri-implant marginal bone levels.
One year after loading, no patients had dropped out. Five implants (12.5%) failed early: three occlusally loaded and two non-occlusally loaded. Three complications occurred, all after delivery of the definitive crowns: one crown fractured (occlusal loading), one had to be remade after debridement because of hyperplastic tissues (occlusal loading), and one crown decemented (nonocclusal loading). These differences were not statistically significant. Both groups gradually lost periimplant bone in a highly statistically significant way. One year after loading, patients subjected to non-occlusal loading lost an average of 0.7 mm of peri-implant bone versus 0.9 mm in the occlusal group. This difference in bone loss between groups was not statistically significant. There was an association between immediate post-extractive implants and implant failures (P=0.01). Four of the 10 immediate post-extractive implants (40%) failed versus one out of 30 delayed implants (3%).
The results of this study do not provide a conclusive answer to whether immediate non-occlusal loading may decrease implant failures. Immediately loaded zirconia implants placed in post-extractive sites had high failure rates.
Titanium and titanium alloys are widely used for fabrication of dental implants. Because of potential immunologic and possible esthetic compromises with titanium implants, novel implant technologies are being developed. However, these novel technologies must maintain the characteristics that provide titanium implants with their high success rates. Zirconia implants were introduced into dental implantology as an alternative to titanium implants. Zirconia seems to be a suitable implant material because of its toothlike color, mechanical properties, biocompatibility, and low plaque affinity. The aim of this study is to review clinical and research articles conducted on zirconia dental implants, compare them with titanium dental implants, and provide information on zirconia dental implant osseointegration and mechanical strength. Zirconia dental implants have the potential to become alternative dental implants to titanium dental implants, but they are not yet in routine clinical use.
The multipiece nature of different implant systems is problematic for a number of reasons. The greatest challenge is bacterial colonization of the implant and of the surrounding tissue, because of the implant/abutment and abutment/crown interfaces, as well as the micromovements of the individual components of the implant. A possibility of eliminating microgaps between the individual components of the implant on the one hand and avoiding micromovements on the other is described in this paper.
This study evaluated non-submerged, root-analogue zirconia implants with two different surfaces for immediate single-rooted tooth replacement in 18 patients. After tooth extraction the root was laser scanned and one-piece root analogue zirconia dental implants with one of two different surfaces were manufactured. In group A (n=6) the implant surface was roughened by sandblasting only, in group B (n=12) additional macroretentions limited to the interdental space, to avoid fracture of the thin buccal cortex, were designed prior to laser scanning. Implants were placed in the socket 1-8 days after extraction by tapping and restored with a composite crown 3-5 months later. Implant survival, level of marginal bone and adverse soft tissue changes were recorded. No complications occurred during the healing period. In group A, all implants were lost within 2 months, with an unaltered extraction socket. In group B, overall survival rate was 92% for implants that were functional for 1-33 months. Excellent aesthetic and functional results were achieved with the composite crown with minimal bone resorption and soft tissue recession. Significant modifications, such as macroretentions seem to indicate that primary stability and excellent osseointegration of immediate root-analogue zirconia implants can be achieved, while preventing unaesthetic bone resorption.
Titanium and titanium alloys are widely used for fabrication of dental implants. Since the material composition and the surface topography of a biomaterial play a fundamental role in osseointegration, various chemical and physical surface modifications have been developed to improve osseous healing. Zirconia-based implants were introduced into dental implantology as an alternative to titanium implants. Zirconia seems to be a suitable implant material because of its tooth-like colour, its mechanical properties and its biocompatibility. As the osseointegration of zirconia implants has not been extensively investigated, the aim of this study was to compare the osseous healing of zirconia implants with titanium implants which have a roughened surface but otherwise similar implant geometries.
Forty-eight zirconia and titanium implants were introduced into the tibia of 12 minipigs. After 1, 4 or 12 weeks, animals were sacrificed and specimens containing the implants were examined in terms of histological and ultrastructural techniques.
Histological results showed direct bone contact on the zirconia and titanium surfaces. Bone implant contact as measured by histomorphometry was slightly better on titanium than on zirconia surfaces. However, a statistically significant difference between the two groups was not observed.
The results demonstrated that zirconia implants with modified surfaces result in an osseointegration which is comparable with that of titanium implants.
The successful use of zirconia ceramics in orthopedic surgery led to a demand for dental zirconium-based implant systems. Because of its excellent biomechanical characteristics, biocompatibility, and bright tooth-like color, zirconia (zirconium dioxide, ZrO2) has the potential to become a substitute for titanium as dental implant material. The present study aimed at investigating the osseointegration of zirconia implants with modified ablative surface at an ultrastructural level.
A total of 24 zirconia implants with modified ablative surfaces and 24 titanium implants all of similar shape and surface structure were inserted into the tibia of 12 Göttinger minipigs. Block biopsies were harvested 1 week, 4 weeks or 12 weeks (four animals each) after surgery. Scanning electron microscopy (SEM) analysis was performed at the bone implant interface.
Remarkable bone attachment was already seen after 1 week which increased further to intimate bone contact after 4 weeks, observed on both zirconia and titanium implant surfaces. After 12 weeks, osseointegration without interposition of an interfacial layer was detected. At the ultrastructural level, there was no obvious difference between the osseointegration of zirconia implants with modified ablative surfaces and titanium implants with a similar surface topography.
The results of this study indicate similar osseointegration of zirconia and titanium implants at the ultrastructural level.
Criteria for the evaluation of dental implant success are proposed. These criteria are applied in an assessment of the long-term efficacy of currently used dental implants including the subperiosteal implant, the vitreous carbon implant, the blade-vent implant, the single-crystal sapphire implant, the Tübingen implant, the TCP-implant, the TPS-screw, the ITI hollow-cylinder implant, the IMZ dental implant, the Core-Vent titanium alloy implant, the transosteal mandibular staple bone plate, and the Brånemark osseointegrated titanium implant. An attempt has been made to standardize the basis for comments on each type of implant.
The infiltration of saliva into the multi-metallic structures on titanium implants brings different types of alloys into temporary or permanent contact. In this way a galvanic cell is established as a result of their potential difference. The galvanic cell phenomenon is compounded by another type of corrosion resulting from the geometry of the assembly: localized crevice corrosion. Fifteen galvanic couples (Ti/gold-based alloys, Ti/palladium-based alloy and Ti/non-precious alloys) were studied. Various electrochemical parameters (Ecorr, Ecommon, Ecouple corr, Ecrevice, icorr, icouple corr and Tafel slopes) were analysed. The galvanic currents measured are of the same order of magnitude (except Ti/stainless steel). They remain low. Application of the mixed-potential theory shows that titanium in coupling with the alloys studied will be under either cathodic or anodic control. According to the results obtained, an alloy that is potentially usable for superstructures in a galvanic coupling with titanium must fulfil a certain number of parameters: in a coupling, titanium must have a weak anodic polarization; the current generated by the galvanic cell must also be weak; the crevice potential must be markedly higher than the common potential.
49 patients participated in a prospective study of treatment of total or partial edentulism with fixed prosthodontics supported by Biocerama sapphire implants. 15 patients were treated for maxillary or mandibular edentulism, and 7 for a missing maxillary anterior tooth. The remaining 27 patients, with Applegate‐Kennedy Class I‐IV residual dentitions, were treated with fixed bridges supported by free‐standing implants, or bridges supported by teeth and implants. Implant success, prosthesis stability, radiographic marginal bone level as well as parameters for peri‐implant health were evaluated. The study began in 1982, and clinical treatment of the last patients was completed in 1988, i.e., a follow‐up period ranging from 7 to 13 years. Of the patients treated for total mandibular edentulism, one implant fractured after 6 years in situ. The bone implant score (BIS) values for those implants were at the time for the bridge cementation 63.5±1.4 and at 1, 2, 3 and 5 year follow‐ups 62.1±1.4, 61.9±1.5, 61.5±1.6, and 60.95±1.3, respectively. The success rate was loo%, 100% and 97.7% for the mandible at 3, 5 and 10 years, respectively. Of the 7 edentulous patients treated with maxillary fixed bridges, 6 implants in 1 patient had to be removed after 1 year in service. Another 2 patients lost all their implants, 6 each, after 36 months. 6 implants in the 4th patient did not fulfil the criteria for success and were rated as failures at the four year follow‐up. The success rate was thus 58.1 %, 44.2% and 44.2% for the maxilla at 3, 5 and 10 year follow‐ups, respectively. Of the 7 patients in whom single missing teeth were replaced, 1 implant in the pre‐molar region was lost during the 1st year post‐operatively, but no other complications or changes in BIS were observed. Of the 27 patients treated for partial edentulism (56 implants total) 1 implant, of a 4‐unit free standing maxillary bridge fractured after 6 years and was later replaced. There were no statistically significant differences in BIS changes for the implants when used as abutments for partial maxillary or mandibular edentulism. The cumulative success rates for the implants in the partially maxilla were 96.3, 92.6 and 92.6 at the 3,5 and 10 years respectively and 100% in the mandible over the whole period.
Résumé
49 patients ont participéà cette étude prospective de traitement d'édentation partielle ou totale avec des prothèses inamovibles posées sur des implants en saphir Bioceramo®. 15 patients ont été traités pour leur édentation totale supérieure ou inférieure, et sept pour une dent antéro‐supérieure manquante. Les 27 atients restants avec des dentitions résiduelles de classe 1 à IV d'Applegate‐Kennedy, one été traités aved des bridges placés sur implants ou sur implants et dents. Le succès de l'implant, la stabilité prothétique, le niveau osseux marginal radiographique ainsi que les paramètres de la santé parodontale ont étéévalués. Cette étude a démarré en 1982 et le traitement clinique des derniers patients s'est terminé en 1988 c. à ‐d. qu'il y a eu une période de suivi de 7 à 13 années. Chez les patients traités pour édentation complète inférieure un implant a été fracturé aprés 6 années in‐situ. Les valeurs du score osseux autour de l'implant (BIS) pour ces implants étaient au moment du placement du bridge de 63.5±1.4 et après 1, 2, 3 et 5 ans respectivement de 62.1±1.4, 61.9±1.5, 61.5±1.6 et 60.95±1.3. Le taux de succès était respectivement de 100%, 100% et 97,7% pour la mandibule après 3, 5 et 10 annèes. Chez les 7 patients édentés traité pour des bridges au niveau de maxillaire, 6 implants chez un patient ont du être enlevés après une année. 2 des patients ont perdu tous leurs implants, chacun 6 après 36 mois. 6 implants chez le 4ème patient n'ont pas rempli les critères du succès et ont été considérés comme un échec après l'examen de la 4ème année. Le taux de succès était respectivement de 51,8%, 44,2% et 44,2% pour le maxillaire lors des examens après 3, 5 et 10 années. Chez les 7 patients ches qui des dents solitaire ont été remplacées, un implant dans la région prémolaire a été perdu durant la première annèe suivant la chirugie mais aucune autre complication ou variation dans le BIS n'ont pu être mis en évidence. Des 27 patients traitiés pour édentation partielle (56 implants au total) un implant faisant partie d'un bridge supérieure de 4 unités s'est fractureé après 6 ans et a été remplacé par la suite. II n'y avait aucune différence statistiquement significative dans les variations BIS entre les implants lorsqu'ils ont été utilisés comme pilier pour 1′édentation partielle supŕieure ou inférieure. Les taux de succès pour ces implants placés dans le maxillaire étaient respectivement de 96,3, 92,6 et 92,6 aprés 3, 5 et 10 ans et de 100% dans la mandibule après cette période.
Resumen
49 pacientes participaron en un estudio prospectivo de tratamiento de edentulismo parcial o total con prótesis fija soporta da por implantes de zafiro de Bioceram®. 15 pacientes fueron tratados por edentulismo maxilar o mandibular, y siete por ausencia de un diente anterior maxilar. Los restantes 27 pacientes, con denticiones residuales Clase I‐IV de Applegate‐Kennedy, fueron tratados con puentes fijos soportados por implantes exclusivamente, o por puentes soportados por dientes e implantes. Se evaluaron el éxito de los implantes, la estabilidad de la prótesis, el nivel radiográfico del hueso marginal, además de los parámetros para la salud periimplantar. El estudio empezó en 1982, y el tratamiento clínico de los últimos pacientes fue completado en 1988, i.e., un periodo de seguimiento de entre siete a trece años. De los pacientes tratados por endentulismo total mandibular un implante se fractureó después de seis años in situ. Los valores de la relación hueso implante (BIS) para esos implantes fueron en el momento de la cementación del puente de 63.5±1.4 y en los seguimientos de 1, 2, 3 y 5 años de 62.1±1.4, 61.9±1.5, 61.5±1.6 y 60.95±1.3 respectivamente. El índice de éxito fue del 100%, 100% y 97.7% para la mandíbula a los 3, 5 y 10 años respectivamente. De los 7 pacientes edéntulos tratados con puentes fijos maxilares, tuvieron que retirarse 6 implantes en un paciente después de un año en servicio. Otros 2 pacientes perdieron todos sus implantes, 6 cada uno, después de 36 meses. Seis implantes en el cuarto paciente no completaron los criterios para ser considerados un éxito, y fueron considerados como fracaso en el cuarto año de seguimiento. El índice de éxito fue por lo tanto del 58.1%, 44.2% y 44.2% para el maxilar a los 3, 5 y 10 años de seguimiento respectivamente. De los siete pacientes en los cuales un solo diente ausente fue reemplazado, se perdió un implante en la región premolar en el primer año tras la operación, pero no se observaron otras complicaciones o cambios en el BIS. De los 27 pacientes tratados por edentulismo parcial (56 implantes en total) un implante, de un puente maxilar de cuatro unidades se fractureó después de seis años y fue posteriormente reemplazado. No hubo diferencias estadísticamente significativas en los cambios de BIS para los implantes cuando se usaron como pilares para edentulismo parcial maxilar o mandibular. Los indices de éxito acumulativo para los implantes en el maxilar parcialmente edéntulo fueron del 96.3, 92.6 y 92.6 a los 3, 5 y 10 años respectivamente, y del 100% en la mandíbula durante todo del periodo.
Zusammenfassung
Neunundvierzig Patienten nahmen an einer prospektiven Untersuchung über die Versorgung von teilweise oder total zahnlosen Kiefern mittels festsitzenden Rekonstruktionen, welche auf Bioceram® Sapphireimplantaten verankert wurden, teil. Fünfzehn Patienten wurden wegen totaler Zahnlosigkeit entweder im Ober‐ oder im Unterkiefer behandelt, bei sieben Patienten fehlte ein Frontzahn. Die übrigen 27 Patienten mit Applegate‐Kennedy‐Klasse I‐IV Restbezahnung wurden mittels festsitzenden Brücken auf Implantaten oder Brücken auf Zähnen und Implantaten versorgt. Die Implantaterfolgsrate, die Stabilität der Rekonstruktionen, die radiologische marginale Knochenhöhe sowie Parameter der periimplantären Gesundheit wurden ausgewertet. Die Untersuchung begann 1982 und die aktive Behandlung des letzten Patienten wurde 1988 abgeschlossen, d.h. die Nachuntersuchungsperiode variierte von 7 bis 13 Jahren. Bei den Patienten, die wegen totaler Zahnlosigkeit im Unterkiefer behandelt wurden, frakturierte ein Implantat nach einer Verweildauer von 6 Jahren. Die Knochen‐Implantat‐Messwerte (BIS) betrugen für diese Implantate zur Zeit der Brückenzementierung 63.5±1.4, nach 1 Jahr 62.1±1.4, nach 2 Jahren 61.9±1.5, nach 3 Jahren 61.5±1.6 beziehungsweise 60.95±1.3 nach 10 Jahren. Die Erfolgsrate betrug 100% nach 3 Jahren, 100% nach fünf Jahren beziehungs‐weise 97.7% nach 10 Jahren. Von den 7 zahnlosen Patienten, welche mit fixen Brücken im Oberkiefer versorgt wurden, mussten bei 1 Patienten 6 Implantate nach 1 Jahr entfernt werden. Zwei weitere Patienten verloren alle ihre Implantate, jeder 6 Stück, nach 36 Monaten. Sechs Implantate im vierten Patienten erfüllten die Erfolgskriterien nicht und wurden bei der Nachkontrolle nach 4 Jahren als Misserfolg eingestuft. Daher betrug die Erfolgsrate in der Maxilla nach 3 Jahren 58.1%, nach 5 Jahren 44.2% und nach 10 Jahren 44.2%. Bei den sieben Patienten, in welchen einzelne fehlende Zähne ersetzt wurden, ging im ersten Jahr postoperativ ein Implantat in der Prämolarenregion verloren, aber danach traten keine weiteren Komplikationen oder Aenderungen im BIS auf. Bei den 27 Patienten, welche wegen partieller Zahnlosigkeit behandelt wurden (insgesamt 56 Implantate) frakturierte ein Implantat einer viergliedrigen Brücke im Oberkiefer nach 6 Jahren und wurde später ersetzt. Es bestanden keine statistisch signifikanten Unterschiede in BIS‐Veränderungen für Implantate, welche als Pfeiler für die Versorgung einer partiellen Zahnlosigkeit im Ober‐ oder im Unterkiefer eingesetzt wurden. Die kummulative Erfolgsrate für Implantate im teilbezahnten Oberkiefer betrug nach 3 Jahren 96.3%, nach 5 Jahren 92.6% und nach 10 Jahren 92.6% und sie betrug im Unterkiefer während der gesamten Beobachtungszeit 100%.
The purpose of the present study was the macroscopic and microscopic failure analysis of fractured zirconia dental implants.
Thirteen fractured one-piece zirconia implants (Z-Look3) out of 170 inserted implants with an average in situ period of 36.75±5.34 months (range from 20 to 56 months, median 38 months) were prepared for macroscopic and microscopic (scanning electron microscopy [SEM]) failure analysis. These 170 implants were inserted in 79 patients. The patient histories were compared with fracture incidences to identify the reasons for the failure of the implants.
Twelve of these fractured implants had a diameter of 3.25 mm and one implant had a diameter of 4 mm. All fractured implants were located in the anterior side of the maxilla and mandibula. The patient with the fracture of the 4 mm diameter implant was adversely affected by strong bruxism. By failure analysis (SEM), it could be demonstrated that in all cases, mechanical overloading caused the fracture of the implants. Inhomogeneities and internal defects of the ceramic material could be excluded, but notches and scratches due to sandblasting of the surface led to local stress concentrations that led to the mentioned mechanical overloading by bending loads.
The present study identified a fracture rate of nearly 10% within a follow-up period of 36.75 months after prosthetic loading. Ninety-two per cent of the fractured implants were so-called diameter reduced implants (diameter 3.25 mm). These diameter reduced implants cannot be recommended for further clinical use. Improvement of the ceramic material and modification of the implant geometry has to be carried out to reduce the failure rate of small-sized ceramic implants. Nevertheless, due to the lack of appropriate laboratory testing, only clinical studies will demonstrate clearly whether and how far the failure rate can be reduced.
An investigation was conducted to evaluate the clinical and histologic results of bone and soft tissue healing around a two-piece zirconia dental implant in a human model. A healthy female patient requiring tooth replacement with dental implants received a two-piece zirconia implant together with conventional titanium implants to be implemented in a prosthesis. Clinical and radiographic evaluations at 6 months revealed stable osseointegrated zirconia and titanium dental implants. Light microscopy and backscatter scanning electron microscopic analyses confirmed the biocompatibility and achievement of osseointegration, in addition to maintenance of the crestal bone level. The findings suggest that the bone-to-implant contact with a zirconia implant surface is sufficient to provide clinical and histologic evidence of osseointegration. The biopsied two-piece zirconia dental implant with platform switching demonstrated osseointegration occlusal to the implant-abutment junction, eliminating the significance of the microgap.
The aim of this systematic literature review was to investigate the survival rates of teeth, implants, and double crown-retained removable dental prostheses (RDPs). Materials and
A systematic review of the literature published from January 1973 through May 2010 was conducted using electronic databases and hand-searching to assess the clinical outcomes of teeth, implants, and double crown-retained RDPs.
This review yielded 512 articles, which were narrowed down to 11. The included studies demonstrated tooth survival rates between 60.6% and 95.3% after an observation period of 4 to 10 years. The survival rates of RDPs supported by teeth ranged between 90.0% and 95.1% after 4 and 5.3 years, respectively. The survival rates of implants supporting prostheses in the mandible were between 97% and 100% after an observation period between 3 and 10.4 years. The survival rates of implant-retained RDPs in the mandible ranged between 95% and 100% after 9 and 10.4 years. Teeth and implants supporting prostheses in the maxilla, as well as the RDPs themselves, demonstrated a survival rate of 100% after 3.2 years.
The current literature does not provide sufficient information regarding the long-term outcome of double crown-retained RDPs. Further studies based on a higher level of evidence are needed to validate the outcomes of this treatment modality.
This case report describes the full-mouth oral rehabilitation of a titanium allergic patient. The patient was a young female with amelogenesis imperfecta who had generalized massive tooth destruction. All teeth in the mouth were extracted and 15 CeraRoot acid-etched (ICE surface) implants were placed (seven implants in the maxilla and eight implants in the mandible). No immediate temporaries were placed. Temporaries were placed 3 months after surgery, and left in function for 2 months. The case was finally restored with zirconium oxide bridges and ceramic veneering (three bridges in the maxilla and another three in the mandible). The 3-year follow-up showed good stability of soft tissues and bone level. Zirconium oxide implants and restorations might be an alternative for the oral rehabilitation of titanium allergic patients.
The aim of this study was to evaluate the 5-year success rate of zirconia (ZrO2) implants with three different kinds of surfaces.
One-piece zirconia dental implants (CeraRoot) with three different roughened surfaces were designed and manufactured for this study: coated, uncoated, and acid-etched. Five different implant designs were manufactured. Standard or flapless surgical procedures were used for implant placement. Simultaneous bone augmentation or sinus elevation was performed when bone height or width was insufficient. Definitive all-ceramic restorations were placed 4 months after implant placement (8 months or more for implants when bone augmentation or sinus elevation was performed). The implants were followed up to 5 years (mean, 3.40 +/- 0.21).
In all, 831 implants were placed in 378 patients with a mean age of 48 years. The overall implant success rate after 5 years of follow-up was 95% (92.77% for uncoated implants, 93.57% for coated implants, and 97.60% for acid-etched implants). The success rate of the acid-etched surface group was significantly better than that of the other two.
From this midterm investigation, it can be concluded that zirconia dental implants with roughened surfaces might be a viable alternative for tooth replacement. Further follow-up is needed to evaluate the long-term success rates of the implant surfaces studied.
Expectations regarding esthetics in dentistry are growing and research in the field of all ceramic materials for restoration of natural dentition and dental implants has intensified. Although the crown that covers the abutment of an implant may be esthetically optimal, the possibility exists that the grayish color of the titanium implant shines through the thin peri-implant mucosa and, because of the short peri-implant tissue recessions, impairs the entire esthetic result. To improve the esthetic aspect of dental implants, a ceramic material, zirconia, was introduced. We present a case in which a zirconia implant and an all-ceramic crown system were used for the maxillary anterior region and followed for 12 months.
The aim of this systematic review was to screen the literature in order to locate animal and clinical data on bone-implant contact (BIC) and clinical survival/success that would help to answer the question 'Are ceramic implants a viable alternative to titanium implants?'
A literature search was performed in the following databases: (1) the Cochrane Oral Health Group's Trials Register, (2) the Cochrane Central Register of Controlled Trials (CENTRAL), (3) MEDLINE (Ovid), and (4) PubMed. To evaluate biocompatibility, animal investigations were scrutinized regarding the amount of BIC and to assess implant longevity clinical data were evaluated.
The PubMed search yielded 349 titles and the Cochrane/MEDLINE search yielded 881 titles. Based upon abstract screening and discarding duplicates from both searches, 100 full-text articles were obtained and subjected to additional evaluation. A further publication was included based on the manual search. The selection process resulted in the final sample of 25 studies. No (randomized) controlled clinical trials regarding the outcome of zirconia and alumina ceramic implants could be found. The systematic review identified histological animal studies showing similar BIC between alumina, zirconia and titanium. Clinical investigations using different alumina oral implants up to 10 years showed survival/success rates in the range of 23 to 98% for different indications. The included zirconia implant studies presented a survival rate from 84% after 21 months to 98% after 1 year.
No difference was found in the rate of osseointegration between the different implant materials in animal experiments. Only cohort investigations were located with questionable scientific value. Alumina implants did not perform satisfactorily and therefore, based on this review, are not a viable alternative to titanium implants. Currently, the scientific clinical data for ceramic implants in general and for zirconia implants in particular are not sufficient to recommend ceramic implants for routine clinical use. Zirconia, however, may have the potential to be a successful implant material, although this is as yet unsupported by clinical investigations.
Ceramics have been used in dentistry and medicine for many years. Today, one of the most popular ceramics is zirconia because of its outstanding mechanical properties, which make it suitable for many indications formerly reserved for metals. Zirconia-based ceramics have been used for many years as the core for single crowns and long-span fixed prostheses. Zirconia-based ceramics have also been used as implants for hip replacements and finger, toe, and wrist joints. Recently, some articles in the dental literature suggest the possible use of zirconia implants for tooth replacement. The present case report illustrates the results that can be achieved using rough-surface zirconia implants in an esthetically demanding case. The 28-year-old male patient required replacement of the maxillary central incisors. Two rough-surface zirconia implants (CeraRoot) were used to immediately replace the extracted teeth. Immediate provisional restorations were placed for a period of 3 months until the final all-ceramic restorations were cemented. Zirconia implants may be a good alternative for tooth replacement, especially in esthetically demanding cases. More studies are needed to evaluate the long-term results of zirconia dental implants with different surfaces.