Article

In Vitro Biofilm Formation On Titanium And Zirconia Implant Surfaces

Authors:
  • University Center for Dental Medicine Basel (UZB), University of Basel
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Abstract

Background: It has been hypothesized that zirconia might have a reduced bacterial adhesion compared to titanium; however, results from experimental studies are rather controversial. The aim of the present study was to compare biofilm formation on zirconia and titanium implant surfaces using an in vitro 3-species biofilm and human plaque samples. Methods: Experimental disks made of titanium (Ti-M, Ti-SLA) or zirconia (ZrO2-M, ZrO2-ZLA) with a machined or a sandblasted and acid-etched surface topography were produced. Applying an in vitro 3-species biofilm or human plaque samples for bacterial adhesion to each type of disk after 72 hours of incubation was assessed using an anaerobic flow chamber model. Results: Zirconia showed statistically significant reduction in 3-species biofilm thickness compared to titanium (ZrO2-M: 8.41µm; ZrO2-ZLA: 17.47µm; Ti-M: 13.12µm; Ti-SLA: 21.97µm); however, no differences were found regarding 3-species-biofilm mass and metabolism. Human plaque analysis showed optical density values of 0.06 and 0.08 for ZrO2-M and ZrO2-ZLA, and values of 0.1 and 0.13 for Ti-M and Ti-SLA, respectively; indicating statistically significant reduction in human biofilm mass on zirconia compared to titanium. Additionally, zirconia revealed statistically significant reduction in human plaque thickness (ZrO2-M: 9.04µm; ZrO2-ZLA: 13.83µm; Ti-M: 13.42µm; Ti-SLA: 21.3µm) but a similar human plaque metabolism compared to titanium. Conclusion: Zirconia implant surfaces showed statistically significant reduction in human plaque biofilm formation after 72 hours of incubation in an experimental anaerobic flow chamber model compared to titanium implant surfaces.

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... Mit der Entwicklung und Verbesserung von Biomaterialien hat die Anwendung von Keramik in der restaurativen Zahnmedizin eine Renaissance erlebt [41]. In diesem Zusammenhang hat sich die Verwendung von dentalen Implantaten aus Zirkonoxid zu einer Alternative von Titanimplantaten entwickelt [42,43]. ...
... In Bezug auf biologische Reaktionen haben In-vivo-und In-vitro-Studien gezeigt, dass Implantate aus Zirkondioxid eine geringe Affinität zu bakterieller Plaque haben [44], dass es selten periimplantäre entzündliche Infiltrate gibt und dass sie eine gute Weichgewebsintegration [43,45] und Osseointegration [46] ...
... Zirkondioxid hat außerdem eine Reihe vielversprechender physikalischer und mechanischer Eigenschaften, darunter eine niedrige Wärmeleitfähigkeit, eine hohe Biegefestigkeit (900-1200 MPa), eine angemessene Bruchfestigkeit sowie eine hohe Verschleiß-und Korrosionsbeständigkeit[45,47]. Trotz der vielversprechenden und günstigen Eigenschaften dieses Biomaterials ist jedoch weitere Grundlagen-und klinische Forschung erfor-derlich, um Langzeitergebnisse zu generieren sowie technische und biologische Komplikationen im Zusammenhang mit ihrer Verwendung zu bewerten[41,43, 45].In Kooperation mit dem Biomaterialien-Labor der Abteilung für orale Pathologie an der zahnmedizinischen Fakultät der Universität Buenos Aires wurde eine deskriptive Pilotstudie durchgeführt, um die Reaktion der menschlichen Mundschleimhaut auf Zirkonoxidimplantate zu bewerten[48].Die Ergebnisse wurde 2018 auf der 96 th General Session & Exhibition der International Association for Dental Research (IADR) in London vorgestellt. Zu die-Zeramex T, Dentalpoint AG, Zürich, Schweiz) bei der Implantatfreilegung 3 bis 4 Monate nach Insertion gewonnen und analysiert (▶ Abb. 1). ...
... Im Vergleich zu anderen Keramiken, beispielsweise Aluminiumoxid, hat Zirkonoxid deutlich bessere biomechanische Eigenschaften [7,8]. Diese verbesserten mechanischen Eigenschaften sind dafür verantwortlich, dass ZrO 2 -Implantate den Kaukräften in der Mundhöhle standhalten können [9]. Ein wichtiger Begriff in diesem Zusammenhang ist die sogenannte Phasentransformation von Zirkonoxid. ...
... [1,5,6,7]. Tribologie ist die Wissenschaft von den Mechanismen des Verschleißes durch Reibung von interagierenden Oberflächen, die sich in relativer Bewegung befinden [6,7,8,9,10]. Die kombinierte Wirkung der mechanischen, biochemischen und elektrochemischen Faktoren ist als Tribokorrosion bekannt; wenn Tribokorrosion in einer biologischen Umgebung auftritt, wird sie als Biotribokorrosion bezeichnet [11,12,13]. ...
... Eine geringere Plaque-Akkumulation an der Zirkonoxidoberfläche wird ebenfalls diskutiert, wobei die Datenlage hier nicht eindeutig ist [9,10]. Es scheint aber, dass Zirkonoxid eine bessere Weichgewebesituation als Titan ermöglicht. ...
... Furthermore, reports prove zirconia to have an advantage in terms of biological properties with soft peri-implant tissues thereby modulating fibers and cell attachment and behavior with greater effectiveness and biocompatibility [16,17]. Along with the properties mentioned above, zirconia has a low surface energy [18,19], therefore it retains very low amounts of plaque and consequently has less bacterial colonization on its surface. In a study, Kunrath et al. showed by comparing surfaces with different morphologies which were exposed to the bacterium Staphylococcus epidermidis that there was less bacterial adhesion on ZrO2 surfaces [18]. ...
... In a study, Kunrath et al. showed by comparing surfaces with different morphologies which were exposed to the bacterium Staphylococcus epidermidis that there was less bacterial adhesion on ZrO2 surfaces [18]. Moreover, Roehling et al., revealed a significant reduction in the formation of oral biofilm on zirconia surfaces after 72 hours [19]. ...
... Rough surfaces have historically shown greater potential for adherence of osteoprogenitor cells, inducing faster osseointegration in intraosseous devices, both in ZrO2 and in Ti [103]. However, the same characteristic is seen with regards to bacterial adhesion on surfaces inserted subgingivally or supragingivally [18,19]. Degidi et al. published an interesting study in humans where they found that the gingival inflammatory markers were high around titanium caps compared to the zirconium oxide ones [104]. ...
Article
Full-text available
Background: Dental components manufactured with zirconia (ZrO2) represent a significant percentage of the implant prosthetic market in dentistry. However, during the last few years, we have observed robust clinical and pre-clinical scientific investigations on zirconia both as a prosthetic and an implantable material. At the same time, we have witnessed consistent technical and manufacturing updates with regards to the applications of zirconia which appear to gradually clarify points which until recently were not well understood. Methods: This critical review evaluated the "state of the art" in relation to applications of this biomaterial in dental components and its interactions with oral tissues. Results: The physico-chemical and structural properties as well as the current surface treatment methodologies for ZrO2 were explored. A critical investigation of the cellular response to this biomaterial was completed and the clinical implications discussed. Finally, surface treatments of ZrO2 demonstrate that excellent osseointegration is possible and provide encouraging prospects for rapid bone adhesion. Furthermore, sophisticated surface treatment techniques and technologies are providing impressive oral soft tissue cell responses thus leading to superior biological seal. Conclusions: Dental devices manufactured from ZrO2 are structurally and chemically stable with biocompatibility levels allowing for safe and long-term function in the oral environment.
... Literature comparing titanium to zirconia regarding biofilm formation is still inconclusive (Hanawa, 2020;Roehling et al., 2017;Wassmann et al., 2017;Zeller et al., 2020). This might be due to varying surface roughness of the specimens between tested materials (John et al., 2016;Zeller et al., 2020). ...
... Streptococcus sanguinis (DSM 20068), Fusobacterium nucleatum (ATCC 10953), and Porphyromonas gingivalis (DSM 20709) were used to test the in vitro biofilm formation after 72 h on the specimens (Astasov-Frauenhoffer et al., 2014Roehling et al., 2017). A 10 µl inoculum of S. sanguinis (stored in 50% glycerol at −80°C) was suspended in 10 ml Schaedler broth (BBL, Becton Dickinson) and incubated aerobically at 37°C for 24 h. ...
... Standard deviation was below 20% for all groups, indicating a high reproducibility of the outcomes. The roughest zirconia surface Z14 that was sandblasted, etched, and heat-treated revealed the highest biofilm formation, confirming previous findings about surface roughness being the key factor for biofilm formation in various models (Anami et al., 2012;Aykent et al., 2010;Glauser et al., 2017;Roehling et al., 2017). In the current in vitro model, little biofilm formation was ob- surfaces (Roehling et al., 2017). ...
Article
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Objectives: To determine if the surface treatment of zirconia affects biofilm formation in an in vitro three-species biofilm model and in situ. Material and methods: Zirconia surfaces considered for the transmucosal portion of a zirconia implant were compared with polished pure titanium grade 4 (Tp). Discs 13 mm in diameter of either polished (Zp), polished and heat-treated (Zpt), machined (Zm), machined and heat-treated (Zmt) and sandblasted, etched and heat-treated (Z14) zirconia were fabricated. Surface roughness and wettability of specimens was measured. Biofilm formation was evaluated by safranin staining and scanning electron microscopy (SEM) using a three-species model, and intraorally with 16 volunteers carrying oral splints in two independent experiments. Relative biofilm formation was compared with Kruskal-Wallis followed by Bonferroni post-hoc test (α=0.05). Results: In vitro biofilm formation with optical density values on Zp (0.14±0.01), Zpt (0.14±0.02), Zm (0.13±0.01) and Zmt (0.13±0.01) was significantly lower than on Tp (0.21±0.05) and Z14 (0.20±0.04) (p<0.05). In situ biofilm formation was significantly higher on Z14 (0.56±0.45) (p<0.05), while no significant differences in optical density were observed among Zp (0.25±0.20), Zm (0.36±0.34) and Tp (0.28±0.22). SEM analysis supported quantitative findings. Conclusions: In the in vitro three-species biofilm model differences in material and surface roughness affected biofilm formation. In situ biofilm formation was mainly affected by the surface roughness of the specimens. Polishing of zirconia is recommended to reduce biofilm formation while heat-treatment has no significant effect.
... The use of ZrO 2 in PHB implants positively influences radiological contrast [24]. Besides this positive property, an antibacterial activity of ZrO 2 has also been reported [25][26][27][28]. For example, one study investigated the antimicrobial activity of ZrO 2 nanoparticles and zirconium complexes, and while ZrO 2 inhibited the growth of Escherichia coli, zirconium complexes exhibited activity against both Gram-positive and Gram-negative bacteria [25]. ...
... Compared with PHB + GP, PHBzr + GP pins exhibited a significantly lower CFU count after prolonged incubation. Some recent studies reported antimicrobial activity for ZrO 2 [25][26][27][28], which explain the observed results. ZrO 2 was not primarily added to pins for antimicrobial reasons in the present study, but rather to make implants more visible using x-rays. ...
Article
Full-text available
Purpose: The aim of this study was to evaluate the antimicrobial efficacy of adding a gentamicin palmitate (GP) coating and zirconium dioxide (ZrO2) to biodegradable poly(3-hydroxybutyrate) (PHB) to reduce biofilm formation. Methods: Cylindrical pins with and without a coating were incubated in Müller-Hinton broth inoculated with 2105 colony-forming units (CFU) mL-1 of Staphylococcus aureus for 2 or 7 days, then sonicated to disrupt biofilms. Pure PHB (PHB+GP) and PHB pins with ZrO2 added (PHBzr+GP) were coated with GP and compared with PHB pins lacking a coating (PHB). Cells (CFU) were counted to quantify the number of bacteria in the biofilm and a cell proliferation assay was employed to evaluate metabolic activity, and scanning electron microscopy (SEM) was performed to visualize the structure of the biofilm. Results: After 2 days of incubation there were significantly more cells in biofilms on PHB pins than PHB+GP and PHBzr+GP pins (p<0.0001), and cells in the sonication fluid obtained from GP-coated pins exhibited significantly lower metabolic activity than cells from uncoated PHB pins (p<0.0001). After 7 days of incubation metabolic activity was lowest for PHBzr+GP, with significant differences between PHB and PHBzr+GP (p=0.001). SEM revealed more cells attached to the surface, and more structured biofilms, on pins without a coating. Conclusion: Coating pins with GP significantly reduced early biofilm formation on PHB implants. This could lower the potential risk of surgical site infections when using PHB implants. Addition of ZrO2 might further enhance the antibacterial properties. Such modification of the implant material should therefore be considered when developing new biodegradable PHB implants.
... Microbiota can be identified 30 minutes after implant installation and within two weeks, with an established community similar to that found around natural teeth in the same mouth [11]. Roehling et al. [12] believe that a reduced bacterial adhesion on implant surfaces might be clinically associated with a reduced risk or incidence of peri-implant infections. Several factors affect this process, e.g., bacterial properties and material surface characteristics. ...
... The characterization of machined and etched surfaces with atomic force microscopy (AFM) and the ability of different bacteria to form a biofilm on these surfaces has been largely analyzed in literature [13][14][15][16][17]. However, there is not a total consensus about this topic in literature, and contrasting results have been shown [12,16]. Streptococcus oralis is an initial colonizer in human plaque. ...
Article
Full-text available
This work aimed to compare the capability of Streptococcus oralis to adhere to a novel surface, double-etched titanium (DAE), in respect to machined and single-etched titanium. The secondary outcome was to establish which topographical features could affect the interaction between the implant surface and bacteria. The samples’ superficial features were characterized using scanning electron microscopy (SEM) and energy dispersive x-ray spectrometry (EDS), and the wetting properties were tested through sessile methods. The novel surface, the double-etched titanium (DAE), was also analyzed with atomic force microscopy (AFM). S. oralis was inoculated on discs previously incubated in saliva, and then the colony-forming units (CFUs), biomass, and cellular viability were measured at 24 and 48h. SEM observation showed that DAE was characterized by higher porosity and Oxygen (%) in the superficial layer and the measurement of the wetting properties showed higher hydrophilicity. AFM confirmed the presence of a higher superficial nano-roughness. Microbiological analysis showed that DAE discs, coated by pellicle’s proteins, were characterized by significantly lower CFUs at 24 and 48 h with respect to the other two groups. In particular, a significant inverse relationship was shown between the CFUs at 48 h and the values of the wetted area and a direct correlation with the water contact angle. The biomass at 24 h was slightly lower on DAE, but results were not significant concerning the other groups, both at 24 and 48 h. The DAE treatment not only modifies the superficial topography and increased hydrophilicity, but it also increases the Oxygen percentage in the superficial layer, which could contribute to the inhibition of S. oralis adhesion. DAE can be considered a promising treatment for titanium implants to counteract a colonization pioneer microorganism, such as S. oralis.
... Thus, zirconia implants have similar osteointegration with their titanium counterparts, at least in the early healing stage [216]. Moreover, zirconia implants are associated with less biofilm formation than titanium implants, decreasing the risk of peri-implantitis [217]. However, the disadvantage of low-temperature degradation of Zirconia needs to be noted when choosing the implant design [218]. ...
... [213]. However, it is interesting to note that the cell proliferation of osteoblasts on machined titanium surfaces is significantly greater than that on machined zirconia [219], while machined zirconia-based surfaces had a statistically significant decrease in biofilm thickness compared to machined titanium [217]. ...
Article
Full-text available
Implant surface design has evolved to meet oral rehabilitation challenges in both healthy and compromised bone. For example, to conquer the most common dental implant-related complications, peri-implantitis, and subsequent implant loss, implant surfaces have been modified to introduce desired properties to a dental implant and thus increase the implant success rate and expand their indications. Until now, a diversity of implant surface modifications, including different physical, chemical, and biological techniques, have been applied to a broad range of materials, such as titanium, zirconia, and polyether ether ketone, to achieve these goals. Ideal modifications enhance the interaction between the implant’s surface and its surrounding bone which will facilitate osseointegration while minimizing the bacterial colonization to reduce the risk of biofilm formation. This review article aims to comprehensively discuss currently available implant surface modifications commonly used in implantology in terms of their impact on osseointegration and biofilm formation, which is critical for clinicians to choose the most suitable materials to improve the success and survival of implantation.
... Another indication is patients with metal allergies and chronic diseases resulting from this allergy. Further, owing to the lower bacteria accumulation propriety of zirconia implants, this ceramic might be a preferred material for patients with a history of peri-implantitis [7,[18][19][20][21][22][23]. ...
... The researchers found that zirconia showed a reduction in biofilm thickness and mass compared with titanium, but similar biofilm metabolism was found. These results suggest that zirconia implants can form less plaque, leading to less peri-implant inflammation than titanium implants [20]. Considering the bacterial adhesion in zirconia, the Grossner-Schreiber group [22] found that bacterial counts were higher with titanium discs than zirconia, while Scarano et al. [23] showed that bacterial adhesion was significantly higher with pure titanium surfaces as compared with zirconium oxide surfaces, as data also supported by Sadid-Zadeh and collaborators find [87]. ...
Article
Full-text available
This review aims to discuss the advantages and disadvantages of zirconia implants compared with titanium implants. Moreover, it intends to review the relevant available long-term literature of these two materials regarding osteointegration, soft-tissue, microbiota, and peri-implantitis, focusing on clinical results. Briefly, titanium implants are a reliable alternative for missing teeth; however, they are not incapable of failure. In an attempt to provide an alternative implant material, implants made from ceramic-derivate products were developed. Owing to its optimal osseointegration competence, biocompatibility, and esthetic proprieties, zirconium dioxide (ZrO2), also known as zirconia, has gained popularity among researchers and clinicians, being a metal-free alternative for titanium implants with its main use in the anterior esthetic zones. This type of implant may present similar osseointegration as those noted on titanium implants with a greater soft-tissue response. Furthermore, this material does not show corrosion as its titanium analog, and it is less susceptible to bacterial adhesion. Lastly, even presenting a similar inflammatory response to titanium, zirconia implants offer less biofilm formation, suggesting less susceptibility to peri-implantitis. However, it is a relatively new material that has been commercially available for a decade; consequently, the literature still lacks studies with long follow-up periods.
... Traditionally, metal-ceramic crowns and metal abutments have been used for years as restorative materials in prosthetic rehabilitations in this scenario, sometimes leading to compromised esthetic results and adverse tissue reactions due to metal corrosion, which facilitated soft tissue inflammation and bone loss, leading to some degree of damage over time. 1 More recently, ceramic abutments have been introduced and gained popularity because of their better esthetic results (avoiding the grayish aspect through gingival tissue) 2 and better biologic properties due to lower biofilm adhesion and absence of corrosion. 3,4 These abutments have been developed in the hybrid form, associating a metal base to attach to the implant, which decreases the number of catastrophic ceramic fractures in the implant connection area due to the limited abutment thickness in place. 5 More recently, polyether ether ketone (PEEK) has been employed for dental prosthetic rehabilitations as an alternative to ceramic and metallic materials. ...
Article
Purpose: The aim of this study was to inspect the mechanical fatigue behavior of an implant-supported restorative system using polyether ether ketone (PEEK) and yttria partially stabilized zirconia polycrystals (YZ) as materials for customized definitive implant-supported hybrid abutments, supporting two types of all-ceramic restorations: translucent zirconia (TZ) and lithium disilicate (LD) monolithic crowns. Materials and methods: Forty Morse taper implants were included in epoxy resin. Titanium intermediary abutments were placed, and the specimens were randomly allocated into four groups (n = 10) according to the customized hybrid abutment material (PEEK or YZ) and the monolithic crowns (TZ or LD) representing a maxillary central incisor crown. The specimens were subjected to a mechanical fatigue test (step-stress analysis) by means of an initial 200-N load for 5,000 cycles and subsequent increase of 50 N (step-size) at each 10,000 cycles, until failure occurred. The load at failure and number of cycles until failure were recorded; survival probabilities and specimen displacement were calculated for each step. The failure pattern was evaluated, and the Weibull modulus was obtained for each condition. Results: Fatigue of both types of crowns was not influenced by the abutment material (LD-PEEK = LD-YZ; TZ-PEEK = TZ-YZ). In the PEEK abutment, the values obtained in the LD and TZ crowns showed no statistical difference; however, in the YZ abutment, the TZ crown presented a load at failure value that was statistically higher than that for LD. Failure pattern analysis revealed a higher prevalence of crown fracture for LD groups, while screw/implant platform fractures were shown for TZ groups. Conclusion: YZ and PEEK hybrid abutments promoted similar fatigue levels regardless of the crown materials, TZ crowns promoted a higher fatigue level than LD ones when associated with YZ abutments, and LD crowns promoted a similar fatigue level to TZ ones when associated with PEEK custom abutments. Higher prevalence of crown fractures was shown for LD and screw/implant platform fractures for TZ groups.
... After an in situ exposure of 8 h, the least biofilm accumulation was associated with the largest hydrophobicity on glazed feldspar ceramic surfaces closely followed by highly polished surfaces [171]. Zirconia implant surfaces showed in vitro statistically significantly less bio-film formation after 72 h of incubation in an experimental anaerobic flow chamber model as compared with titanium implant surfaces [172]. This was confirmed in in situ studies [173,174]. ...
Chapter
Biofilm formation depends on many factors, one of them being the surface (substrate) on which the biofilm is formed, and dental restorative materials are such substrates. Biofilms play a crucial role for caries formation and inflammation of gingival, periodontal, or mucosal tissues next to restorations. Even general health problems such as systemic infections in immunocompromised patients may result from biofilms on dental materials (e.g., on dentures). Furthermore, biofilms may change material or surface properties. Biofilms on restorative materials have been investigated by several in vitro, in situ, and in vivo methods measuring a large number of different endpoints. Basically, datasets obtained from different methodological approaches are most suitable for final assessments. While surface properties like wettability or surface free energy (SFE) influence biofilm formation to a certain extent, the most relevant surface properties are material roughness followed by surface chemistry. The pellicle, which is formed rapidly on restorations after in vivo exposure, masks or levels off the influence of surface properties like wettability or SFE on biofilm formation. The prevention of biofilm formation is mainly based on general oral hygiene regimens. Furthermore, optimal polishing of restorative materials is instrumental. Several antimicrobial substances have been incorporated into restorative materials, which act by being released or as surface repellents. However, the optimal biofilm-preventive restorative material has not been found so far. New approaches in this context should aim at: (1) better understanding the role of the biofilm matrix (extracellular polymeric substance), and (2) implementing ecology-based approaches for the modification of dysbiotic disease-associated biofilms.
... Zirconia has gained outstanding popularity in recent years and is recommended as a dental material for implant because of its good biocompatibility (Zhang and Lawn, 2018), superior mechanical properties (Turon-Vinas and Anglada, 2018), low plaque affinity (Roehling et al., 2017), and excellent esthetic outcomes (Tabatabaian, 2019). Over the past years, research and development of dental implant biomaterials has focused on osseointegration. ...
Article
Full-text available
Zirconia exhibits excellent biocompatibility and is widely used as dental implant materials in prosthodontics. Over the past years, research and development of dental implant biomaterials has focused on osseointegration, but few reports exist regarding the role of the immune environment on cellular responses to these materials. The present study investigates the effect of different nanostructured zirconia surface topographies on macrophage phenotypes and their influence on gingival fibroblast behavior. Three different nanostructured zirconia surfaces are characterized using scanning electron microscopy, atomic force microscopy, and water contact angle. Blank-machined zirconia (BMZ) surfaces were superior to RAW264.7 cell proliferation and adhesion. RAW264.7 seeded on all nanostructured zirconia surfaces polarized toward both inflammatory M1 and anti-inflammatory M2 macrophages with more M2 macrophage phenotype on BMZ surfaces. Meanwhile, conditioned media (CM) from RAW264.7 culture on three nanostructured zirconia surfaces inhibited cell apoptosis to human gingival fibroblasts (HGFs) but promoted HGF proliferation and secretion. Under modulation of RAW264.7 culture, HGFs cultured on BMZ surfaces significantly secreted more extracellular matrix with a higher expression of collagen-I (COL-I), vinculin (VCL), and fibronectin (FN) than those coated on self-glazed zirconia (CSGZ) and self-glazed zirconia (SGZ) surfaces. After being coated with a nano zirconia film, CSGZ surfaces showed certain changes in cell proliferation, adhesion, and protein production compared with SGZ surfaces. These findings will provide an overview of manipulating surface topography to modulate macrophage phenotypes in order to create an effective macrophage immune response and reinforce soft tissue integration.
... Die Verwendung von keramischen Implantaten verringert das Risiko aufgrund einer korrosions-und abriebstabileren Oberfläche [4] und einer geringeren mikrobiellen Belagsadhäsion am Implantatdurchtritt zur Mukosa [6,7]. Die Stabilität von Keramikimplantaten, insbesondere aus ATZ-Keramik, sind für die klinische Anwendung inzwischen wissenschaftlich gut geprüft und mit der von Titanimplantaten vergleichbar [8]. ...
Article
Die Verwendung von dauerhaft einzugliedernden Fremdmaterialien sollte bei Patienten mit Autoimmunerkrankungen und defizitärem Immunzustand aufgrund der kompromittierten Immunitätslage und der gestörten Immuntoleranz mit besonderer Vorsicht und Bevorzugung von biologisch verträglicheren Werkstoffen, sowohl beim Implantat als auch bei den prothetischen Aufbaustrukturen, erfolgen. Durch Tribokorrosion von der Implantatoberfläche ins Gewebe abgegebene Partikel als auch mögliche Sensibilisierungsreaktionen gegen Metalle aus Legierungen des Zahnersatzes können die defizitären Toleranz- und Abwehrkompetenzen negativ triggern und zur dauerhaften Verschlechterung der immunitären Konstellation beitragen [5]. Die Verwendung von keramischen Implantaten verringert das Risiko aufgrund einer korrosions- und abriebstabileren Oberfläche [4] und einer geringeren mikrobiellen Belagsadhäsion am Implantatdurchtritt zur Mukosa [6, 7]. Die Stabilität von Keramikimplantaten, insbesondere aus ATZ-Keramik, sind für die klinische Anwendung inzwischen wissenschaftlich gut geprüft und mit der von Titanimplantaten vergleichbar [8].
... The result suggested that not only surface roughness or surface hydrophilicity might be important factors for biofilm formation, but also material composition-metals compared to ceramics-suggesting a reduced disposition for peri-implant plaque and subsequent potential peri-implant infections on zirconia compared to titanium implant surfaces. (44,88) ...
... The surface degradation of commercial Ti, Zr, and ZrO 2 caused by bacterial adhesion (in particular, the Streptococcus species) has been discussed in several papers in the literature [111][112][113] concluding more recently that dental implant surfaces of TiZr and ZrO 2 are not more susceptible to colonization than commercially pure Ti implants [114,115]. ...
Article
Full-text available
This review article was developed based on the scientometric analysis of the evaluated studies conducted on titanium−zirconium (TixZr) alloys from 2000 to the present. The scientometric data obtained helped us to identify the most researched topics and these topics were further analyzed and discussed. An increasing number of researchers are considering TixZr alloys as opposed to the traditional ones because these alloys present improved mechanical properties and in some cases improved corrosion resistance and biocompatibility. Due to the natural layer of oxides formed on these alloys, multiple surface modification methods can be applied to solve some of the challenges faced in the field of implantable materials. A significant number of studies are now focusing on surface modifications at the nanometer scale or various coatings for improved corrosion resistance and biological interactions. Although not yet commercially available, a TiZr alloy with a nanostructured surface and embedded biologically active substances, such as antibiotics or coated with hydroxyapatite, may become a future option.
... This topic is discussed widely in the dental implant community [3][4][5][6][7][8]. Additionally, some investigations showed that zirconia ceramics are less prone to bacterial attachment and peri-implant infection [9][10][11][12][13][14][15][16][17][18], although this positive effect was not shown in all investigations [19][20][21][22]. Whether an advantage with respect to bacterial adhesion/ peri-implant infection is attributable to the zirconia implant has to be questioned since the (ceramic) prosthetic reconstruction (abutment, crown) is in contact with the oral environment. ...
Article
Full-text available
The goal of the present review is to update the reader on the scientific background of zirconia ceramic implants. Clinical investigations using zirconia ceramic implants over the last couple of years have brought up some new developments and questions. Can we be confident in placing zirconia ceramic implants given the recently published data? Is there a difference in the application of one- and two-piece implants? Systematic reviews on preclinical investigations of zirconia implants revealed that one-piece zirconia implants (> 4 mm) are sufficiently stable for clinical use. The same is true for some clinically available two-piece implant systems. Osseointegration and soft tissue integration are, according to the reviews, similar between titanium and zirconia implants with similar surface topographies. Regarding the clinical outcome, a meta-review exists evaluating systematic reviews. The findings of the systematic reviews and the meta-review are that there are good short-term clinical results for one-piece zirconia implants. However, the data for two-piece implants is not robust. In certain applications (single tooth restorations and small bridges), the results of zirconia implants are comparable with titanium implants in short-term studies. Some mid-term investigations support the short-term results. However, according to the current scientific data available, zirconia implants cannot yet be considered an alternative to titanium implants because there are many areas where there is a lack of clinical studies on zirconia implants. Currently, they are an addendum to the titanium implant armamentarium for situations where they are useful (patient request, known hypersensitivity to titanium, or questions of esthetics when titanium might appear inappropriate for a certain situation/condition), but long-term studies are needed. Without a doubt, there is a need for two-piece zirconia implants, but limited research exists to support their clinical use at the moment.
... Traditional Protocol The implant placement process can also be done in one step. In such a case, this protocol is called immediate loading [7]. The immediate loading method reduces the healing time and implant loading time. ...
Article
Full-text available
Today, an artificial tooth root called a dental implant is used to replace lost tooth function. Treatment with dental implants is considered an effective and safe method. However, in some cases, the use of dental implants had some failures. The success of dental implants is influenced by several biomechanical factors such as loading type, used material properties, shape and geometry of implants, quality and quantity of bone around implants, surgical method, lack of rapid and proper implant surface's integration with the jaw bone, etc. The main purpose of functional design is to investigate and control the stress distribution on dental implants to optimize their performance. Finite element analysis allows researchers to predict the stress distribution in the bone implant without the risk and cost of implant placement. In this study, the stresses created in the 3A.P.H.5 dental implant's titanium fixture and screw due to the change in abutment angles tolerance have been investigated. The results show that although the fixture and the screw's load and conditions are the same in different cases, the change of the abutment angle and the change in the stress amount also made a difference in the location of maximum stress. The 21-degree abutment puts the fixture in a more critical condition and increases the chance of early plasticization compared to other states. The results also showed that increasing the abutment angle to 24 degrees reduces the stress in the screw, but decreasing the angle to 21 degrees leads to increased screw stress and brings it closer to the fracture.
... The medium TSB was replaced with a fresh medium plus saliva. They were then incubated at 37 • C in CO 2 to form a mature biofilm and planktonic cells were removed under sterile conditions [26,27]. Finally, the medium TSB was replaced with fresh medium plus saliva and incubated at 37 • C for 24 h in CO 2 . ...
Article
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The aim of this in vitro study was to compare three disinfection protocols of biofilm-coated machined (MAC) and acid etched (SLA) commercial pure Grade 4 Titanium disks. Samples were infected with a vial of polymicrobial biofilm to simulate peri-implantitis in vitro. Seventeen MAC and twenty SLA titanium disks were randomly assigned to: (1) glycine powder air-flow (GYPAP) for 1 min; (2) a local delivered triple paste antibiotic composed by a gel mixture with ciprofloxacin, metronidazole, and clarithromycin (3MIX) for 1 h; and (3) a combination of both (GYPAP + 3MIX). Biocompatibility of the titanium disks after each treatment protocol was assessed by measurement of adhesion and growth of adipose-derived mesenchymal stem cells (ASCs) after 24 and 72 h. A confocal laser scanning microscope (CLSM) assessed the antibacterial effect of each treatment. Data of the antibacterial efficacy and cell viability were presented as mean with standard deviation and calculated by one-way ANOVA with multiple comparisons via Bonferroni tests. Results were considered significant with p < 0.05. The higher cell viability was achieved by the 3MIX and GYPAP combination on the SLA surfaces after 72 h. CLSM analysis showed a mean ratio of dead bacteria statistically higher in the 3MIX + GYPAP group compared with the GYPAP and 3MIX subgroups (p < 0.05). In conclusion, data showed that the combination of GYPAP and 3MIX could be preferred to the other protocols, especially in presence of SLA titanium surface.
... 11-14 3 yttria-stabilized zirconia (3Y-TZP) has been introduced as an alternative ceramic material for dental implants due to its aesthetic and mechanical properties associated with a significant decrease in the adhesion of oral biofilms. [15][16][17][18][19][20][21] Apart from the base material, alterations in the implant surface significantly influence the success of osseointegration and soft tissue adhesion. 7,22,23 More specifically, the most important surface properties are topography, roughness, and wettability. ...
Article
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Yttria‐stabilized zirconia (YSZ) is being proposed as an alternative material to Titanium for dental implants due to its aesthetic and biocompatibility properties. However, is it yet to define the optimal surface treatment to improve YSZ bioactivy. Texturization is a promising approach, but the biological role of patterned YSZ surfaces in cell cultures is yet to be determined. Thus, cellular behavior of osteoblasts and fibroblasts in contact with groove‐texturized YSZ surfaces was investigated. YSZ discs were groove‐textured by conventional milling and Nd:YAG laser. All samples including control were sandblasted and acid‐etched. Human osteoblasts and fibroblasts were cultured on discs for 14 days. Morphology and cellular adhesion were observed. Cell viability, interleukin‐1β, osteopontin, collagen type I prodution, alkaline phosphatase activity, and interleukin‐8 were measured. YSZ texturization by conventional milling improved osteoblasts viability and differentiation when compared to laser texturization. Fibroblasts behavior did not seem to be influenced by the texturing technique. Compared to sandblasting and acid etching currently used as gold standard for zirconia dental implants no superiority of macrotexturization was found.
... Zirconia can be used in patients with titanium allergy and shows it has advantages over titanium for use in oral areas where aesthetics require the use of a material with a color similar to that of natural teeth [5][6][7]. In addition, compared to titanium implants, zirconia has excellent biocompatibility and shows a lower adhesion of bacteria, thereby reducing the risk of peri-implantitis [8][9][10][11][12]. ...
Article
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Plasma treatment on a zirconia surface prevents bacterial contamination and maintains osteoblast activity. To assess the degree of adhesion of Porphyromonas gingivalis on a zirconia surface after non-thermal plasma (NTP) treatment, specimens were treated with plasma for 60, 300, and 600 s, after which P. gingivalis was inoculated onto the surface and incubated for 48 h. To assess osteoblast activity after NTP treatment, osteoblasts (MC3T3-E1) were dispensed onto the specimens contaminated with P. gingivalis immediately after NTP for 60 and 120 s, followed by incubation for 48, 72, and 96 h. P. gingivalis was cultured after 60 s of NTP treatment of zirconia. The NTP and control groups showed no significant difference (p = 0.91), but adhesion was significantly increased following NTP treatment for 300 s or longer (300, 600 s groups) (p < 0.05). After NTP treatment of P. gingivalis-contaminated zirconia, osteoblast activity significantly increased at 72 and 96 h (I60 and I120 s group) in the groups treated with plasma (p < 0.017). Application of NTP to dental zirconia implants for 60 s not only inhibits the proliferation of P. gingivalis, which causes peri-implantitis but also increases osseointegration on zirconia surfaces contaminated with P. gingivalis.
... Zirconia implants have a proven performance record lower than that of titanium implants. The survival rate for one-piece immediate zirconia implants is so low (85%) they are contraindicated [11]. Overall, zirconia implants are to be used in select cases only, where the above indications are implicit. ...
Chapter
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Materials science can be overwhelming for many dentists. Implant dentistry is a significant industry, and understanding the materials science can be complex. This chapter aims to demystify the main topics related to implants, including their materials, designs, and surfaces, and provide clinically relevant knowledge. A dental implant and its crown may be made up of many different materials. The term ‘implant bulk material’ refers to the main material the bulk of the actual dental implant is manufactured from. With regards to implant bulk materials, titanium and its alloys remain the gold standard in implant dentistry. Zirconia implants have a proven performance record lower than that of titanium implants. Tests on implants made of polyetheretherketone have been reported. The chapter provides a summary of the most important and clinically relevant knowledge on implant body shapes, and thread patterns, and implant connections.
... The chemical and surface morphological characterization reported herein demonstrated that the surfaces of both implant types displayed a comparable wettability and predominately hydrophobic character. Furthermore, both implant surfaces displayed similar overall morphology with a combined micro-roughness and macro-roughness that is typical for implants treated by a combination of sandblasting and acid etching [36]. With regard to both characterizations, i.e., the analysis of surface topography as well as to the histomorphometric analysis of osseointegration, the results reported herein are consistent with results of similar studies that have compared sandblasted and acid-etched zirconia and titanium implants [37]. ...
Article
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Objectives: This study compared the osseointegrative potential of a novel injection molded zirconia dental implant (Neodent Zi ceramic implant, test) and a commercially available titanium implant (Neodent Alvim implant, control) in terms of histomorphometrically derived bone-to-implant contact (BIC), first bone-to-implant contact (fBIC), and the ratio of bone area to total area (BATA) around the implant. Materials and methods: A total of 36 implants, 18 per individual test device, were implanted in a split-mouth arrangement in either side of the edentulous and fully healed mandible of 6 minipigs. Histomorphometric analysis of BIC, fBIC, and BATA were performed 8 weeks post implantation and subjected to statistical non-inferiority testing. Surface characteristics of both implant types were compared in terms of contact angle, surface topography, and elemental composition. Results: BIC, fBIC, and coronal BATA values of test and control implants were statistically comparable and non-inferior. BIC values of 77.8 ± 6.9% vs. 80.7 ± 6.9% (p = 0.095) were measured for the test and control groups. fBIC lingual values were - 238 ± 328 μm compared with - 414 ± 511 μm (p = 0.121) while buccal values were - 429 ± 648 μm and - 588 ± 550 μm (p = 0.230) for the test and control devices, respectively. BATA in the apical segment was significantly higher in the test group compared with the control group (67.2 ± 11.8% vs. 59.1 ± 11.4%) (p = 0.0103). Surface topographies of both implant types were comparable. Surface chemical analysis indicated the presence of carbonaceous adsorbates which correlated with a comparable and predominantly hydrophobic character of the implants. Conclusion: The results demonstrate that the investigated zirconia implants, when compared with a commercially available titanium implant, show equivalent and non-inferior bone integration, bone formation, and alveolar bone level maintenance. This qualifies the investigated zirconia implant as a potential candidate for clinical development. Clinical relevance: This study investigated the osseointegration of a novel zirconia 2-piece dental implant prototype intended for clinical development. With the aim of translating this prototype into clinical development preclinical models, procedures and materials within this study have been selected as close to clinical practice and human physiological conditions as possible.
... On titanium implant surfaces, it was demonstrated that an R a value of 0.2 µm and below did not influence the quantity of bacterial adhesion [36]. For example, it has been suggested that rougher surfaces support bacterial colonization [37,38], although the results are conflicting. Early biofilm formation by Streptococcus mutans has also been shown to be reduced on conventionally polished surfaces when compared to surfaces polished with a simplified protocol which removed less material from the surface, and hence it was concluded that polishing did not necessarily reduce oral bacterial colonisation [39]. ...
Article
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The topographic features of surfaces are known to affect bacterial retention on a surface, but the precise mechanisms of this phenomenon are little understood. Four coccal-shaped bacteria, Staphylococcus sciuri, Streptococcus pyogenes, Micrococcus luteus, and Staphylococcus aureus, that organise in different cellular groupings (grape-like clusters, tetrad-arranging clusters, short chains, and diploid arrangement, respectively) were used. These differently grouped cells were used to determine how surface topography affected their distribution, density, dispersion, and clustering when retained on titanium surfaces with defined topographies. Titanium-coated surfaces that were smooth and had grooved features of 1.02 µm-wide, 0.21 µm-deep grooves, and 0.59 µm-wide, 0.17 µm-deep grooves were used. The average contact angle of the surfaces was 91°. All bacterial species were overall of a hydrophobic nature, although M. luteus was the least hydrophobic. It was demonstrated that the 1.02 µm-wide featured surface most affected Strep. pyogenes and S. sciuri, and hence the surfaces with the larger surface features most affected the cells with smaller dimensions. The 0.59 µm featured surface only affected the density of the bacteria, and it may be suggested that the surfaces with the smaller features reduced bacterial retention. These results demonstrate that the size of the topographical surface features affect the distribution, density, dispersion, and clustering of bacteria across surfaces, and this is related to the cellular organisation of the bacterial species. The results from this work inform how surface topographical and bacterial properties affect the distribution, density, dispersion, and clustering of bacterial retention.
... Yttria-stabilized polycrystalline tetragonal zirconia (Y-TZP) has been widely used in dental implants due to its esthetic and mechanical results [7,8] and has also been associated with a significant reduction in the formation of oral biofilms [9][10][11][12][13]. Zirconia implants, as stated in recent systematic and critical reviews, are described as a promising alternative to Titanium implants, for showing similar results in the clinical parameter of direct contact surface between bone and implant, as well as for adequate chewing load dissipation [14][15][16][17]. ...
Article
Full-text available
The aim of this study was to evaluate gingival fibroblasts and human osteoblasts’ response to textured Nd:YAG laser microgrooves, with different dimensions, on zirconia implant surfaces. A total of 60 zirconia disks (8 mm in diameter and 2 mm in thickness) were produced and divided between four study groups (N = 15): three laser-textured (widths between 125.07 ± 5.29 μm and 45.36 ± 2.37 μm and depth values from 50.54 ± 2.48 μm to 23.01 ± 3.79 μm) and a control group without laser treatment. Human osteoblasts and gingival fibroblasts were cultured on these surfaces for 14 days. FEG-SEM (Field Emission Gun–Scanning Electron Microscope) images showed cellular adhesion at 24 h, with comparable morphology in all samples for both cell types. A similar cell spreading within the grooves and in the space between them was observed. Cell viability increased over time in all study groups; however, no differences were found between them. Additionally, proliferation, ALP (Alkaline phosphatase) activity, collagen type I, osteopontin and interleukin levels were not significantly different between any of the study groups for any of the cell types. Analysis of variance to compare parameters effect did not reveal statistically significant differences when comparing all groups in the different tests performed. The results obtained revealed similar cell behavior based on cell viability and differentiation on different microtopographic laser grooves, compared to a microtopography only established by sandblasting and acid-etching protocol, the reference surface treatment on zirconia dental implants.
... 13,14 In some studies, one-piece zirconia implants showed good tissue response and a satisfactory degree of biocompatibility. [15][16][17] In 3-year follow-up studies on the success and survival of onepiece zirconia implants, survival rates ranged from 97.5% to 98.5%, which are almost identical to those of titanium implants. 18,19 However, from the perspective of reconstructing lost teeth, one-piece zirconia implants have somewhat less prosthetic flexibility than two-piece zirconia implants. ...
Article
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.
... 3,4 Yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) ceramics have exhibited a huge market potential in the field of dental restoration, which is ascribed to their high chemical stability, favorable histocompatibility, excellent mechanical properties and similar color with human teeth. [5][6][7][8] However, the biofilm formed around the Y-TZP ceramics implant will affect the osseointegration ability of the implants, and even lead to implant failure, which severely limits its widespread application in dental implant field. [9][10][11] In recent years, most researchers have prepared bioactive coatings on the surface of Y-TZP ceramics attempting to improve their osseointegration, but the extremely poor bonding strength between the coating and Y-TZP implant affected the service life of the implant material. ...
Article
Yttria‐stabilized tetragonal zirconia polycrystal (Y‐TZP) ceramics with outstanding mechanical properties and aesthetic origins is expected to be used in dental implant application. However, tetragonal zirconia ceramics are not bioactive, which affect the osseointegration and reliability as dental implant materials. Herein, in this study, Y‐TZP ceramics were modified by grain‐boundary activation via coating a bioactive glass (BG) sol with different content on the crystal surfaces of zirconia powder and followed by being gelled, dried, granulated, low‐temperature treated, molded and sintered at 1450 ℃ for 3 h in air. The effects of BG content on the morphology, phase compositions, mechanical properties, in vitro mineralization ability, cell biological properties of the bioactivity modified Y‐TZP ceramics were evaluated. The BG additive did not affect the tetragonal‐monoclinic phase transformation of ZrO2. However, the addition of BG decreased the flexural strength of the modified Y‐TZP ceramics compared to that of Y‐TZP. The in vitro mineralization results showed that a homogeneous apatite layer was produced on the surface of the Y‐TZP ceramics when they were immersed in the simulated body fluid (SBF) for 21 days. The cell response results indicated that the bioactive surface modification of Y‐TZP ceramics could promote the cell adhesion, propagation and osteogenic differentiation performance. Thus, our research results suggest that the highly bioactive Y‐TZP ceramics could be a potential candidate for dental implant material. This article is protected by copyright. All rights reserved
... Not only were biofilms, imaged using CSM, structurally similar, but the composition of the bacterial community, analyzed by qPCR, also did not show appreciable differences. In another study of dental plaque formation in a flow chamber under anaerobic conditions (341), zirconia surfaces showed a statistically significant reduction in bacterial adhesion after 3 days of incubation compared to titanium surfaces. Nevertheless, differences between zirconia and titanium surfaces with regard to biofilm formation are still under debate. ...
Article
The spread of biofilms on medical implants represents one of the principal triggers of persistent and chronic infections in clinical settings, and it has been the subject of many studies in the past few years, with most of them focused on prosthetic joint infections. We review here recent works on biofilm formation and microbial colonization on a large variety of indwelling devices, ranging from heart valves and pacemakers to urological and breast implants and from biliary stents and endoscopic tubes to contact lenses and dental and neurosurgical implants.
... Local or systemic cytotoxic effects, as well as adverse reactions, have not been observed with zirconia implants [69]. In addition, poor bacterial adhesion is reported on zirconia surfaces compared to titanium surfaces in vitro [70] and in vivo [71], contributing to the health and maintenance of peri-implant tissues. ...
Article
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Purpose of Review Graphene is introduced in dentistry as a material to be used in the fabrication or coating of dental implants due to its biocompatibility, ability to physically interact with biomolecules and very high surface area. This review highlights the current knowledge on the general properties of graphene, potential benefits especially when used in zirconia-based implants, as composite materials and coatings. Recent Findings The literature reviewed showed a growing body of evidence supporting the use of graphene-based material, associated with titanium or zirconia as a coating or composite material that helps in cell viability, differentiation and proliferation, improving the bioactivity, osseointegration, physical, chemical and mechanical properties particularly zirconia. Graphene-based materials present great potential for biomedical applications especially when used in the form of nanostructured biological coatings that can be obtained through reproducible and economical processes. Summary The use of graphene as a composite implant material or coating may have great potential for osseointegration and bone regeneration, providing that, features including hydrophilicity, protein adsorption capacity, oxygen content and effect of external parameters such as temperature, pH and ionic strength need further elucidations before they can be implemented as a coating or composite material for dental implants.
Article
Die Implantattherapie bei älteren Menschen bedarf einer gezielten Planung. Dabei spielt die Unterscheidung zwischen dem dritten oder vierten Lebensabschnitt für die Behandlungsplanung und die anschließende zahnärztliche Betreuung eine wichtige Rolle, da diese Patientengruppen sich fundamental voneinander unterscheiden. Für Menschen des dritten Lebensabschnitts steht das gesamte Spektrum der zahnärztlichen Implantologie zur Verfügung, allerdings müssen chronische Erkrankungen, Medikation und manuelle Geschicklichkeit beachtet werden. Da dentale Implantate meist deutlich länger als 20 Jahre im Mund verbleiben, muss prospektiv die zukünftige Abnahme der biologischen, sozialen und psychischen Funktionen bei der Planung berücksichtigt werden. Im vierten Lebensabschnitt ist das Leben von der Abhängigkeit bei den Aktivitäten des täglichen Lebens (ADL), Multimorbidität, Polypharmazie und Institutionalisierung bestimmt. Es gibt fast keine wissenschaftliche Evidenz zur Implantattherapie dieser Patientengruppe. Die wenigen vorhandenen Studien zeigen eine sehr hohe Implantatüberlebensrate und es gibt Hinweise auf verringerte akute peri-implantäre Entzündungsreaktionen. Gerade Patienten in der vierten Lebensphase könnten am meisten vom funktionellen Gewinn einer implantatstabiliserten Totalprothese profitieren, wenn die muskulären Fähigkeiten zur Stabilisierung einer Prothese nachlassen. Allerdings müssen die Handhabung, Nachsorge und tägliche Pflege gesichert werden, bevor mit einer solchen Therapie im Sinne des Nichtschadensgebots begonnen wird. Menschen im palliativen Kontext weisen zunehmend Implantate auf, die für die Betroffenen und die Pflegenden vor große Herausforderungen stellen können. Hier müssen die Implan-tatprothesen rechtzeitig „rückgebaut“ werden, um Schmerzen und Infektionen zu vermeiden.
Conference Paper
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Fabrication of dental restorations made of zirconia-based biomaterials with enhanced mechanical and tribological properties together with customized surface topography and microstructure for promoting enamel adhesion and cell proliferation while hindering bacterial spreading is a very challenging task to accomplish through conventional machining operations. In fact, traditional milling processes of sintered ceramics are typically labor-intensive, therefore expensive and time-consuming, and these aspects can be further exasperated when microsized features are required. On the other hand, unconventional techniques such as laser milling can represent a suitable solution to produce miniaturized individualized structures on advanced ceramics since it is a non-contact thermal process that ensures the elimination of cutting forces and allows hard and brittle materials to be machined without the need for special equipment which requires high investments and long processing times. In this context, this study aims to investigate the capability of a nanosecond pulsed fiber laser to machine samples made of yttria-stabilized zirconia through a systematic experimental approach in order to identify the most suitable process operational parameters combinations that ensure the obtainment of specific surface topographies while minimizing the machining time. The milling process is carried out by using a 30 W Q-switched Yb:YAG fiber laser by controlling laser beam scan speed, scan strategy and hatch distance and following a multi-level factorial design-based experimentation. The adoption of the laser technology to machine yttria-stabilized zirconia results in a high-repeatable, accurate and time-saving process allowing easy control of the process outcomes.
Article
Orthodontic Titanium implants are the most employed and well investigated in literature. In fact, thanks to its mechanical properties and biocompatibility with the human bone, this material represents one of the best solutions to improve the osseointegration process and implant life. In recent years, the attention was shifted to soft tissue integration which has led to a new solution in terms of implant design and material. According to recent researches, metal-free implants, like Zirconia implant, can improve the biological width and accelerate the osseointegration process. Beyond the advantage in biological terms, the use of Zirconia leads to a different mechanical behaviour concerning Titanium, in particular on the cortical bone. In this work, the effect that the material change have on the stress distribution around the cortical bone has been analyzed through a Finite Element Analysis (FEA). According to literature of recent years, dental prosthesis of this study has been tested using a compression load applied to the post surface with three different inclinations. The simulation results show that the stress evaluated for Zirconia implant are more distributed around the cortical bone while the stress evaluated for the Titanium implant is extended more over the whole implant. These results confirm that the use of Zirconia could improve the osseointegration process and guarantee a longer life of the implant.
Article
Background Peri‐implant tissue condition can result from prosthodontic, surgical and bacteriological factors. Purpose This study investigated the effects of prosthodontic factors on peri‐implant tissue. Materials and Methods Subjects were 140 patients with 310 implants from Osaka University Dental Hospital. Prosthodontic factors examined were the connection type, the suprastructure retention type, the material of the abutment and the mesiodistal and buccolingual prosthetic form of the superstructure as emergence angle. The objective variables were the modified bleeding index (mBI) and marginal bone level (MBL). Statistical analysis was used as a generalized estimation equation. Results The taper joint had a significantly smaller MBL than the butt joint (P < .001). There was no significant difference in mBI and MBL between cement and screw retaining. Zirconium and titanium resulted in a significantly smaller mBI than gold alloy (zirconium/gold alloy: P = .037, titanium / gold alloy: P = .021), but there was no significant difference in the MBL. Both mBI and MBL tended to be smaller when the emergence angle was around 20° to 40°, although this difference was not significant. Conclusion As a result of multivariate analysis, our findings suggest that to reduce MBL from the perspective of prosthodontic factors it is preferable to use an implant with a taper joint connection positioned with an emergence angle of 20° to 40°.
Article
Objectives To analyze the soft tissue morphology under healthy and experimental mucositis conditions comparing zirconia and titanium implants. Methods Forty‐two patients with two adjacent missing teeth received one zirconia (Zr) and one titanium (Ti) implant, with the mesial and distal position randomized. At 3 months, half of the patients were instructed to continue (healthy; h) and the other half to omit (experimental mucositis; m) oral hygiene around the implants for 3 weeks. Clinical parameters were evaluated before and after the experimental phase and a soft tissue biopsy was harvested. Mixed model analyses were performed to analyze the data. Results The plaque control record increased significantly for the two mucositis groups, reaching 68.3±31.9% (mean±standard deviation) for Zr‐m and 75.0±29.4% for Ti‐m (p<0.0001), being also significantly lower for Zr‐m than for Ti‐m. Bleeding on probing remained stable in group Zr‐m and amounted to 21.7±23.6%, but increased significantly in group Ti‐m (p=0.040), measuring 32.5±27.8%. The number of inflammatory cells and the length of the junctional epithelium did not significantly differ between the groups. Conclusion Both implants rendered similar outcomes under healthy conditions. Lower plaque and bleeding scores were detected for zirconia implants under experimental mucositis conditions. Histologically, only minimal differences were observed.
Article
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The aim of this study was to compare the clinical properties of tooth-colored computer-aided design/computer-aided manufacturing (CAD/CAM) materials for the fabrication of a 3-unit fixed dental prostheses (FDPs) in the same clinical scenario. A 53-year-old female patient was supplied with a 3-unit FDP to replace a second premolar in the upper jaw. Restorations were fabricated from 3 mol%, 4 mol%, and 5 mol% yttrium oxide zirconia, zirconia with translucency gradient, indirect composite resin, polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). Milling time, weight, and radiopacity were investigated. Esthetics were examined following the US Public Health Service criteria (USPHS). The milling time for zirconia was twice as high as for the indirect composite resin, PEEK, or PEKK. The latter materials had a weight of 2 g each, while zirconia restorations yielded 5 g. Zirconia presented intense radiopacity. PEEK and PEKK required veneering and an opaquer was applied to the PEKK framework. All FDPs showed acceptable esthetics. PEEK and PEKK restorations were featured by a grayish shimmering. A variety of CAD/CAM materials are available to fabricate 3-unit FDPs with esthetically acceptable results. In the esthetic zone, PEEK and PEKK require veneering and an opaquer might be applied. Milling time, weight, and radiopacity were relatively high for zirconia FDPs.
Article
Objective: To investigate the effect of porous surface morphology of zirconia on the proliferation and differentiation of osteoblasts. Methods: According to different manufacturing and pore-forming methods, the zirconia specimens were divided into 4 groups, including milled sintering group (M-Ctrl), milled porous group (M-Porous), 3D printed sintering group (3D-Ctrl) and 3D printed porous group (3D-Porous). The surface micromorphology, surface roughness, contact angle and surface elements of specimens in each group were detected by scanning electron microscope (SEM), 3D laser microscope, contact angle measuring device and energy-dispersion X-ray analysis, respectively. MC3T3-E1 cells were cultured on 4 groups of zirconia discs. The cell morphology of MC3T3-E1 cells on zirconia discs was eva-luated on 1 and 7 days by SEM. The cell proliferation was detected on 1, 3 and 5 days by cell counting kit-8 (CCK-8). After osteogenic induction for 14 days, the relative mRNA expression of alkaline phosphatase (ALP), type Ⅰ collagen (Colla1), Runt-related transcription factor-2 (Runx2) and osteocalcin (OCN) in MC3T3-E1 cells were detected by real-time quantitative polymerase chain reaction. Results: The pore size [(419.72±6.99) μm] and pore depth [(560.38±8.55) μm] of 3D-Porous group were significantly larger than the pore size [(300.55±155.65) μm] and pore depth [(69.97±31.38) μm] of M-Porous group (P < 0.05). The surface of 3D-Porous group appeared with more regular round pores than that of M-Porous group. The contact angles of all the groups were less than 90°. The contact angles of 3D-Ctrl (73.83°±5.34°) and M-Porous group (72.7°±2.72°) were the largest, with no significant difference between them (P>0.05). Cells adhered inside the pores in M-Porous and 3D-Porous groups, and the proliferation activities of them were significantly higher than those of M-Ctrl and 3D-Ctrl groups after 3 and 5 days' culture (P < 0.05). After 14 days' incubation, ALP, Colla1, Runx2 and OCN mRNA expression in 3D-Porous groups were significantly lower than those of M-Ctrl and 3D-Ctrl groups (P < 0.05). Colla1, Runx2 and OCN mRNA expressions in M-Porous group were higher than those of 3D-Porous group (P < 0.05). Conclusion: The porous surface morphology of zirconia can promote the proliferation and adhesion but inhibit the differentiation of MC3T3-E1 cells.
Article
Statement of problem Although luting space is related to the marginal fit of indirect restorations, information on its influence on the marginal fit and tensile strength of zirconia abutments bonded to titanium bases is lacking. Purpose The purpose of this in vitro study was to evaluate the influence of luting space on the marginal discrepancy and tensile strength of zirconia abutments bonded to a titanium base after dynamic loading. Material and methods Ninety implant replicas were embedded in resin blocks to attach 4-mm-high titanium luting bases. Zirconia abutments (Ceramill Zolid FX) were fabricated with different internal luting spaces: 25 μm (G25), 50 μm (G50), or 75 μm (G75). The zirconia abutments were cemented on the titanium bases by using a resin cement (Panavia F 2.0) under a constant load of 20 N. The marginal discrepancy and internal fit of 10 random specimens from each group were evaluated with a stereoscopic microscope at ×50 magnification. The remaining specimens were submitted to the tensile strength test in which half were evaluated after dynamic loading (1.2 million cycles of 200 N at 3.8 Hz) in a mechanical fatigue machine. The tensile strength test was performed using a pullout apparatus coupled to a universal testing machine at a crosshead speed of 0.5 mm/min. The mode of failure was determined by observation at ×50 magnification under a stereomicroscope and classified into adhesive or mixed. The groups were compared by using 2-way ANOVA and the Tukey HSD test (α=.05). Results Increase in the luting space did not influence the marginal discrepancy (P>.05). All zirconia abutments exhibited lower pullout strength after fatigue simulation (P<.05). G75 demonstrated lower tensile strength than G25 and G50 before and after loading (P<.05). Most failures were adhesive at the zirconia-cement interface. Conclusions The increase of the luting space to 75 μm did not influence marginal discrepancy; however, it reduced the tensile strength of a zirconia abutment bonded to a titanium base.
Article
The aim of this study was to analyse the effect of zirconia and titanium surfaces on biofilm formation and host-derived parameters. Studies comparing zirconia and titanium surfaces were selected up to September 1, 2019. The outcome measures were surface roughness, contact angle, bacterial count, bacterial adherence, biofilm thickness, bacterial distribution, and specifically investigated biofilm and specific host-derived immunological parameters. Random-effects meta-analyses of in vitro and in vivo studies were conducted. A total of 39 studies were included for data extraction. In the systematic review data, 10 studies stated that zirconia accumulated less initial oral biofilm parameters, 16 investigations showed negligible inter-material differences, and only one study showed that zirconia attracted the most biofilm. However, in the meta-analysis, the bacterial coverage was found to be significantly superior for zirconia surfaces (P < 0.00001); the other outcome measures did not show any statistically significant differences between zirconia and titanium for the remaining parameters and the studies presented a substantial degree of heterogeneity. Overall, on the basis of the meta-analysis, the current data situation does not allow a clear preference for the use of zirconia or titanium.
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Treatment of wastewater prior to release in water bodies is an imperative need of the current time to address the global water crises. Thus, consortium MCSt-1 was designed for an effective wastewater treatment based on its cellulolytic, proteolytic, lipolytic, phenol and sodium dodecyl sulfate degrading activities along with effective nutrient removal capacity. Performance of the designed consortium was assayed using two differently configured lab-scale bioreactors as subjected to immobilization on two different matrices (pebbles and nylon mesh). Consortium MCSt-1 proficiently removes soluble chemical oxygen demand, nitrate, ammonia and phosphorus with 83%, 67%, 76%, and 62% removal efficiency, respectively. The immobilization on a mesh is recommended as it exhibited better biofilm formation, hence results in significant organic load and nutrient removal. The functional potential of the consortium MCSt-1 explored through genome characterization and reveal the presence of genes responsible for phosphorus metabolism and removal (pst operon and ppk), ammonia assimilation (amt), and nitrate; nitrite reductase (nar, nir, nor). Additionally, consortium members also annotated with the phenol, catechol and benzoate degradation, stress response, heavy metal and antibiotics resistance genes. Hence, the designed consortium MCSt-1 can withstand the harsh condition of treatment plants and serves as the best solution for enhancing wastewater treatment efficiency.
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Dental implants have been used as far back as 2000BC, and since then have developed into highly sophisticated solutions for tooth replacement. It is becoming increasingly important for the materials used in dental implants to exhibit and maintain favorable long-term mechanical, biological and more recently, aesthetic properties. This review aims to assess the biomaterials used in modern dental implants, introducing their properties, and concentrating on modifications to improve these biomaterials. Focus is drawn to the prominent biomaterials, titanium (Ti) and zirconia due to their prevalence in implant dentistry. Additionally, novel coatings and materials with potential use as viable improvements or alternatives are reviewed. An effective dental biomaterial should osseointegrate, maintain structural integrity, resist corrosion and infection, and not cause systemic toxicity or cytotoxicity. Current materials such as bioactive glass offer protection against biofilm formation, and when combined with a titanium–zirconium (TiZr) alloy, provide a reliable combination of properties to represent a competitive alternative. Further long-term clinical studies are needed to inform the development of next-generation materials.
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Porous polymer materials derived from poly(ethylene glycol dimethacrylate) (poly‐EGDMA) and antibiotic containing polylactide (PLA) are obtained for the first time. Porous poly‐EGDMA monoliths with a system of open interconnected pores are synthesized by a visible light‐induced radical polymerization of EGDMA in the presence of 70 wt% of porogenic agent, e.g., 1‐butanol, 1‐hexanol, 1‐octanol, or cyclohexanol. The porosity of the obtained polymers is 75–78%. A modal pore size depends on the nature of the porogen and varies from 0.5 µm (cyclohexanol) to 12 µm (1‐butanol). The polymer matrix made with 1‐butanol features the presence of pores ranging from 1 to 100 µm. The pore surface of poly‐EGDMA matrices is inlayered with poly‐D,L‐lactide (Mn 23 × 10³ Da, PDI 1.31). The PLA‐modified poly‐EGDMA retains a porous structure that is similar to the initial poly‐EGDMA but with improved strength characteristics. The presence of antibiotic containing PLA ensures a high and continuous antibacterial activity of the hybrid polymeric material for 7 days. The nontoxicity of all the porous matrices studied makes them promising for clinical tests as osteoplastic materials.
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As dental implants have become one of the main treatment options for patients with tooth loss, the number of patients with peri-implant diseases has increased. Similar to periodontal diseases, peri-implant diseases have been associated with dental plaque formation on implants. Unconventional approaches have been reported to remove plaque from infected implants, but none of these methods can completely and permanently solve the problem of bacterial invasion. Fortunately, the constant development of antibacterial implant materials is a promising solution to this situation. In this review, the development and study of different antibacterial strategies for dental implant materials for the prevention of peri-implantitis are summarized. We hope that by highlighting the advantages and limitations of these antimicrobial strategies, we can assist in the continued development of oral implant materials.
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The contribution of polymers or plastics in our day-to-day life are limitless. Be it medical field, domestic life, corporate world or in living organism, everywhere the polymers have enormous applications. So, the properties of these polymers have been a major concern. The roles of contaminants and additives present in the polymers with changing the polymeric structures and their properties need to be study briefly. The present study represents how polymers are used in every material of our daily life and how the presence of contaminants in polymers affects the human life. Detrimental and beneficial effects of various contaminants on different polymeric structures have been a major concerned. The surface area of polymeric material plays an important role in contamination study. The factors which control the rate of absorption of contaminants in polymeric materials have been discussed here briefly. Various kinds of additives in different polymeric structures have significant roles in controlling the attachment of contaminants. So, the factors which control the absorption of contaminants in polymers and affecting their properties have been discussed briefly.
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Titanium implants have always been regarded as one of the gold standard treatments for orthopedic applications, but they still face challenges such as pain, bacterial infections, insufficient osseointegration, immune rejection, and difficulty in personalizing treatment in the clinic. These challenges may lead to the patients having to undergo a painful second operation, along with increased economic burden, but the use of drugs is actively solving these problems. The use of systemic drug delivery systems through oral, intravenous, and intramuscular injection of various drugs with different pharmacological properties has effectively reduced the levels of inflammation, lowered the risk of endophytic bacterial infection, and regulated the progress of bone tumor cells, processing and regulating the balance of bone metabolism around the titanium implants. However, due to the limitations of systemic drug delivery systems—such as pharmacokinetics, and the characteristics of bone tissue in the event of different forms of trauma or disease—sometimes the expected effect cannot be achieved. Meanwhile, titanium implants loaded with drugs for local administration have gradually attracted the attention of many researchers. This article reviews the latest developments in local drug delivery systems in recent years, detailing how various types of drugs cooperate with titanium implants to enhance antibacterial, antitumor, and osseointegration effects. Additionally, we summarize the improved technology of titanium implants for drug loading and the control of drug release, along with molecular mechanisms of bone regeneration and vascularization. Finally, we lay out some future prospects in this field.
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Objectives Oral bacterial adhesion on dental implant materials has been extensively studied using in vitro systems but has yielded results restricted to in vitro growth patterns due to limitations in species selection, sustained fastidious anaerobe growth, and mixed culture longevity. The aim of this study was to develop an oral bacterial biofilm model consisting of colonizers representative of the oral microbiome exhibiting temporal shifts characteristic of plaque development and maturation in vivo. Methods Streptococcus oralis, Actinomyces naeslundii, Aggregatibacter actinomycetemcomitans, Veillonella parvula, Fusobacterium nucleatum, and Porphyromonas gingivalis were grown in monoculture prior to combination in mixed culture. Commercially pure titanium (cpTi) and yttria-stabilized zirconia (ZrO2) disks with polished, acid-etched, or sandblasted surfaces were prepared to evaluate oral bacterial adhesion. After 6 h, 1, 3, 7, 14 and 21 days, genomic DNA from planktonic and adherent bacteria was isolated. Quantitative polymerase chain reaction (qPCR) was used to enumerate the amount and proportion of each species. Results Early-colonizing S. oralis and A. actinomycetemcomitans, dominated after 6 h prior to secondary colonization by F. nucleatum and V. parvula in planktonic (1 day) and sessile (3 days) form. A. naeslundii maintained relatively low but stable bacterial counts throughout testing. After 14 days, late-colonizing P. gingivalis became established in mixed culture and persisted, becoming the dominant species after 21 days. The composition of adherent bacteria across all substrates was statistically similar at all timepoints with notable exceptions including lower S. oralis bacterial counts on polished cpTi (3 days). Significance Within the present model’s limitations, multispecies oral bacterial attachment is similar on surface-treated cpTi and ZrO2.
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Zirconium-based implants have gained popularity in the dental implant field owing to their corrosion resistance and biocompatibility, attributed to the formation of a native zirconia (ZrO2) film. However, enhanced bioactivity and local therapy from such implants are desirable to enable the earlier establishment and improved long-term maintenance of implant integration, especially in compromised patient conditions. As a result, surface modification of zirconium-based implants have been performed using various physical, chemical and biological techniques at the macro-, micro-, and nano-scales. In this extensive review, we discuss and detail the development of Zr implants covering the spectrum from past and present advancements to future perspectives, arriving at the next generation of highly bioactive and therapeutic nano-engineered Zr-based implants. The review provides in-depth knowledge of the bioactive/therapeutic value of surface modification of Zr implants in dental implant applications focusing on clinical translation.
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Implant therapy in older people requires specific planning. The distinction between the third and fourth stages of life plays an important role in treatment planning and subsequent dental care, as these patient groups differ fundamentally from each other. For people in the third stage of life, the entire spectrum of dental implantology is available, but chronic diseases, medication, and manual dexterity must be taken into account. Because dental implants usually remain in the mouth for much longer than 20 years, future decline in biologic, social, and psychologic functions must be prospectively considered in planning. In the fourth stage of life, life is dominated by dependence in activities of daily living (ADL), multimorbidity, polypharmacy, and institutionalization. There is almost no scientific evidence on implant therapy for this patient group. The few existing studies show a very high implant survival rate, and there is evidence of reduced acute peri-implant inflammatory reactions. It is patients in the fourth stage of life who could benefit most from the functional gain of an implant-stabilized total prosthesis when the muscular abilities to stabilize a prosthesis decline. However, handling, follow-up, and daily care must be ensured before such therapy is started in the spirit of the no-harm principle. People in palliative contexts increasingly have implants that can pose significant challenges for both patients and caregivers. In this case, the implant prostheses must be “dismantled” in good time in order to avoid pain and infections. © 2021 Quintessence Publishing Company, Ltd. All Rights Reserved.
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Various types of zirconia are widely used for the fabrication of dental implant superstructures and fixtures. Zirconia–alumina composites, such as ATZ and NanoZR, are adequate for implant fixtures because they have excellent mechanical strength in spite of insufficient esthetic properties. On the other hand, yttria-stabilized zirconia has been used for implant superstructures because of sufficient esthetic properties. They are classified to 12 types with yttria content, monochromatic/polychromatic, uniform/hybrid composition, and monolayer/multilayer. Zirconia with a higher yttria content has higher translucency and lower mechanical strength. Fracture strength of superstructures strongly depends on the strength on the occlusal contact region. It suggests that adequate zirconia should be selected as the superstructure crown, depending on whether strength or esthetics is prioritized. Low temperature degradation of zirconia decreases with yttria content, but even 3Y zirconia has a sufficient durability in oral condition. Although zirconia is the hardest dental materials, zirconia restorative rarely subjects the antagonist teeth to occlusal wear when it is mirror polished. Furthermore, zirconia has less bacterial adhesion and better soft tissue adhesion when it is mirror polished. This indicates that zirconia has advantageous for implant superstructures. As implant fixtures, zirconia is required for surface modification to obtain osseointegration to bone. Various surface treatments, such as roughening, surface activation, and coating, has been developed and improved. It is concluded that an adequately selected zirconia is a suitable material as implant superstructures and fixtures because of mechanically, esthetically, and biologically excellent properties.
Article
Objectives This study aimed to assess the independent influence of grooves and pores texturized by milling on gold-standard zirconia implant surfaces. Methods Milled groove and pore textured with equivalent width, depth, and spacing on zirconia discs were produced using press and sintering techniques. All samples were sandblasted and acid-etched (SBAE), and untextured discs were used as controls. Osteoblasts and fibroblasts were cultured on discs for 14 days. Field emission gun-scanning electron microscopy (FEG-SEM) was used to observe cellular adhesion and morphology. Cell viability and proliferation assays were performed. Additionally, alkaline phosphatase activity, collagen type I, and osteopontin were evaluated at pre-defined time points. Results are presented as mean and standard deviation (SD), group comparisons were tested using one-way ANOVA (Tukey’s post-hoc), and significance was set at P <0.05. Results FEG-SEM images revealed cellular adhesion at 24 h in all samples with differences in distribution. Although both cell lines showed increased cell viability and differentiation cell markers such as collagen and osteopontin over time, statistically significant differences between groups were found in none of the quantitative study variables (P >0.05). Conclusion The results suggest similar cellular behavior between different patterns with similar dimensions and between them and microtopography by SBAE protocol currently used as the gold-standard for zirconia dental implants. The addition of pore and groove microtextures to the gold-standard zirconia dental implant surfaces treated with SBAE does not seem to be an asset in the cellular behavior of the hard and soft tissue cells.
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Background: The mechanism of action of adjuvant antibiotic therapy in the treatment of peri-implantitis is not well understood. The aim of this study is to investigate antibiotic susceptibility of an in vitro biofilm by isothermal microcalorimetry (IMC). Methods: Titanium disks containing a 72-hour three-species biofilm (Streptococcus sanguinis DSM20068, Fusobacterium nucleatum ATCC10953, and Porphyromonas gingivalis DSM20709) were placed in a series of IMC ampoules with nutrient agar supplemented with increasing concentrations of amoxicillin, metronidazole, or their combination and incubated anaerobically for 10 days. Lag time and maximum growth rate were determined from continuous heat-flow recordings of metabolic activity. To validate the IMC biofilm results, adherent S. sanguinis and P. gingivalis were incubated anaerobically in medium supplemented with antibiotics at 37°C for 24 hours, and their vitality was determined by live/dead staining, conventional culturing, and IMC. Results: In all biofilm samples incubated with antibiotics, a prolonged lag phase was observed compared with controls (P <0.05). Maximum growth rate was significantly lower for samples treated with either amoxicillin or metronidazole compared with controls (P <0.05). Combining the antibiotics did not improve this effect. Concentrations exceeding 10 times the minimum inhibitory concentration completely inhibited the growth of adherent S. sanguinis and P. gingivalis, whereas lower concentrations resulted in only a delay in the lag phase. A poor correlation was observed between live/dead staining and conventional culturing. Conclusions: IMC gives new evidence about antibiotic effects on oral biofilms and is more informative than conventional culture and live/dead assays. The combination of antibiotics was found to be more efficient than metronidazole alone; however, only minor differences in growth inhibition were detected compared with amoxicillin alone.
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Several parameters have been described for determining the success or failure of dental implants. The surface properties of transgingival implant components have had a great impact on the long-term success of dental implants. The purpose of this study was to compare the tendency of two periodontal pathogens to adhere to and colonize zirconia abutments and titanium alloys both in hard surfaces and soft tissues. Twelve patients participated in this study. Three months after implant placement, the abutments were connected. Five weeks following the abutment connections, the abutments were removed, probing depth measurements were recorded, and gingival biopsies were performed. The abutments and gingival biopsies taken from the buccal gingiva were analyzed using real-time polymerase chain reaction to compare the DNA copy numbers of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and total bacteria. The surface free energy of the abutments was calculated using the sessile water drop method before replacement. Data analyses used the Mann Whitney U-test, and P-values below 0.05 find statistical significance. The present study showed no statistically significant differences between the DNA copy numbers of A. actinomycetemcomitans, P. gingivalis, and total bacteria for both the titanium and zirconia abutments and the biopsies taken from their buccal gingiva. The differences between the free surface energy of the abutments had no influence on the microbiological findings. Zirconia surfaces have comparable properties to titanium alloy surfaces and may be suitable and safe materials for the long-term success of dental implants.
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The aim of this in vitro study was to investigate the adhesion of initial colonizer, Streptococcus sanguis, on resin, titanium and zirconia under the same surface polishing condition. Specimens were prepared from Z-250, cp-Ti and 3Y-TZP and polished with 1 µm diamond paste. After coating with saliva, each specimen was incubated with Streptococcus sanguis. Scanning electron microscope, crystal violet staining and measurement of fluorescence intensity resulting from resazurin reduction were performed for quantifying the bacterial adhesion. Surface of resin composite was significantly rougher than that of titanium and zirconia, although all tested specimens are classified as smooth. The resin specimens showed lower value of contact angle compared with titanium and zirconia specimens, and had hydrophilic surfaces. The result of scanning electron microscopy demonstrated that bound bacteria were more abundant on resin in comparison with titanium and zirconia. When total biofilm mass determined by crystal violet, absorbance value of resin was significantly higher than that of titanium or zirconia. The result of relative fluorescence intensities also demonstrated that the highest fluorescence intensity was found on the surface of resin. Absorbance value and fluorescence intensity on titanium was not significantly different from those on zirconia. Resin specimens showed the roughest surface and have a significantly higher susceptibility to adhere Streptococcus sanguis than titanium and zirconia when surfaces of each specimen were polished under same condition. There was no significant difference in bacteria adhesion between titanium and zirconia in vitro.
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The grofit package was developed to fit many growth curves obtained under different conditions in order to derive a conclusive dose-response curve, for instance for a compound that potentially affects growth. grofit fits data to different parametric models and in addition provides a model free spline method to circumvent systematic errors that might occur within application of parametric methods. This amendment increases the reliability of the characteristic parameters (e.g.,lag phase, maximal growth rate, stationary phase) derived from a single growth curve. By relating obtained parameters to the respective condition (e.g.,concentration of a compound) a dose response curve can be derived that enables the calculation of descriptive pharma-/toxicological values like half maximum effective concentration (EC50). Bootstrap and cross-validation techniques are used for estimating confidence intervals of all derived parameters.
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The microbial colonization of new ceramic materials developed for abutment manufacturing was assessed. The materials used in these experiments were disks of 'as-fired' and 'rectified' ceramic material made of tetragonal zirconia polycrystals stabilized with yttrium (Y-TZP) and commercially pure grade 2 titanium (Ti) with corresponding eluates. They were tested in vitro with the following bacteria: Streptococcus mutans, S. sanguis, Actinomyces viscosus, A. naeslundii, and Porphyromonas gingivalis. Proliferation was evaluated on plates by inhibitory halos around pits, previously inoculated with eluates obtained from the materials. Bacterial adhesion on materials was quantified by spectrophotometric evaluation of the slime production by the same bacteria. Moreover, early bacterial adhesion was evaluated in human volunteers and observed with SEM. No inhibition of bacterial proliferation using eluates was observed. In vitro as-fired and rectified Y-TZP showed significantly more adherent S. mutans than did Ti disks, while S. sanguis seemed to adhere easily to Ti specimens. No differences were noted for Actinomyces spp and P. gingivalis. In vivo Y-TZP accumulated fewer bacteria than Ti in terms of the total number of bacteria and presence of potential putative pathogens such as rods. No differences were observed between rectified and as-fired Y-TZP. Overall, Y-TZP accumulates fewer bacteria than Ti. Y-TZP may be considered as a promising material for abutment manufacturing.
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Little is known about the mechanisms of bacterial interaction with implant materials in the oral cavity. A correlation between plaque accumulation and progressive bone loss around implants has been reported. Bacterial adhesion shows a direct positive correlation with surface roughness. Other surface characteristics also seem to be extremely important with regard to plaque formation. Different adhesion affinities of bacteria have been reported for different materials. The aim of this study was to characterize the percentage of surface covered by bacteria on commercially pure titanium and zirconium oxide disks. Ten patients participated in this study. A removable acrylic device was adapted to the molar-premolar region, and commercially pure titanium (control) and zirconium oxide (test) disks were glued to the buccal aspect of each device. The surface roughness of titanium and test specimens was similar. After 24 hours, all disks were removed and processed for scanning electron microscopy, for the evaluation of the portion of surface covered by bacteria. In control specimens, the area covered by bacteria was 19.3% +/- 2.9; in test specimens, the area was 12.1% +/- 1.96. The disk surface covered by bacteria on test specimens was significantly lower than that of control specimens (P = 0.0001). Our results demonstrate that zirconium oxide may be a suitable material for manufacturing implant abutments with a low colonization potential.
Article
Objectives: The aim of the current study was the evaluation of biofilm development on different implant surfaces. Material and methods: Initial biofilm formation was investigated on five different implant surfaces, machined titanium (MTi), modified machined acid-etched titanium (modMATi), machined titanium zirconium (MTiZr), modified machined and acid-etched titanium zirconium (modMATiZr) and sandblasted large grid and acid-etched titanium zirconium surface (SLATiZr) for 24 and 48 h. Biocompatibility was tested after tooth brushing of the samples via cell viability testing with human gingival fibroblasts. Results: After 24 h of biofilm collection, mean plaque surface was detected in the following descending order: After 24 h: MTiZr > MTi > SLATiZr > modMATiZr > modMATi. Both M surfaces showed significant higher biofilm formation than the other groups. After 48 h: MTiZr > MTi > SLATiZr > modMATiZr > modMATi. After tooth brushing: SLATiZr > modMATi > modMATiZr > MTi > MTiZr. All native samples depicted significant higher cell viability than their corresponding surfaces after biofilm removal procedure. Conclusions: The TiZr groups especially the modMATiZr group showed slower and less biofilm formation. In combination with the good biocompatibility, both modMA surfaces seem to be interesting candidates for surfaces in transgingival implant design.
Article
Objective: The aim of the present study was to analyze biofilm formation on four different titanium-based surfaces (machined titanium zirconium (TiZr) alloy, M; machined, acid-etched TiZr alloy, modMA; machined, sandblasted, acid-etched TiZr alloy, modSLA; and micro-grooved titanium aluminum vanadium alloy, TAV MG) in an experimental human model. Material and methods: Custom-made discs were mounted in individual intraoral splint housings and worn by 16 volunteers for 24 h. The safranin staining assay, isothermal microcalorimetry (IMC), and SEM were applied before and after surface cleaning. Results: The hydrophilic surfaces modMA and modSLA with greater surface micro-roughness exhibited significantly more biofilm than the hydrophobic surfaces TAV MG and M. The standardized cleaning procedure substantially reduced the biofilm mass on all surfaces. After cleaning, the IMC analyses demonstrated a longer lag time of the growth curve on TAV MG compared to modSLA. Inter- and intraindividual variations in biofilm formation on the titanium discs were evident throughout the study. Conclusions: Surface hydrophilicity and roughness enhanced biofilm formation in vivo, whereas surface topography was the most influential factor that determined surface cleanability. While the grooved surface retained larger amounts of initial biofilm, the machined surface was easier to clean, but proliferation indicated by increased metabolic activity (growth rate) in IMC occurred despite mechanical biofilm removal.
Article
Objectives The impact of implant surfaces in dental biofilm development is presently unknown. The aim of this investigation was to assess in vitro the development of a complex biofilm model on titanium and zirconium implant surfaces, and to compare it with the same biofilm formed on hydroxyapatite surface. Methods Six standard reference strains were used to develop an in vitro biofilm over sterile titanium, zirconium and hydroxyapatite discs, coated with saliva within the wells of pre-sterilized polystyrene tissue culture plates. The selected species used represent initial (Streptococcus oralis and Actinomyces naeslundii), early (Veillonella parvula), secondary (Fusobacterium nucleatum) and late colonizers (Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans). The developed biofilms (growth time 1 to 120 h) were studied with confocal laser scanning microscopy using a vital fluorescence technique and with low-temperature scanning electron microscopy. The number (colony forming units/biofilm) and kinetics of the bacteria within the biofilm were studied with quantitative PCR (qPCR). As outcome variables, the biofilm thickness, the percentage of cell vitality and the number of bacteria were compared using the analysis of variance. Results The bacteria adhered and matured within the biofilm over the three surfaces with similar dynamics. Different surfaces, however, demonstrated differences both in the thickness, deposition of the extracellular polysaccharide matrix as well as in the organization of the bacterial cells. Significance While the formation and dynamics of an in vitro biofilm model was similar irrespective of the surface of inoculation (hydroxyapatite, titanium or zirconium), there were significant differences in regards to the biofilm thickness and three-dimensional structure.
Article
Purpose: Dental implants generally provide good results as replacements for missing teeth, but a few patients experience implant failure. The aim of this retrospective study was to analyze the characteristics and causes of implant failures in hopes of reducing future failures. Materials and methods: Patients who received one or more implants at the Dental Hospital of Yonsei University College of Dentistry between February 1991 and May 2009 were included in this study. Data including age, sex, medical history, habits (eg, smoking and drinking), bone quality, primary stability, implant size, implant surface, additional surgical procedures, prosthetic type, clinical symptoms, implant failure date, and causes of implant failure were obtained through a chart review. Follow-up radiographs were compared to those obtained at baseline. The Pearson chi-square test and Fisher exact test were used to evaluate the correlations between risk factors and implant failure. Results: In total, 879 patients received 2,796 implants; 150 implants in 91 patients had failed. Early and late implant failures occurred with 86 (57.3%) and 64 (42.7%) implants, respectively. The main causes of early and late implant failures were inflammation (47%) and overloading (53%), respectively. When the cause of early implant failure was inflammation, the failure rate was significantly higher for implants in the anterior maxilla; implants with poor primary stability, a machined surface, or a length exceeding 15 mm; and implants placed with a reconstructive procedure and two-stage surgery. When late implant failure was caused by overloading, the failure rate was significantly higher for implants with a machined surface, placed with a reconstructive procedure and/or two-stage surgery, and supporting telescopic dentures. Conclusion: Within the limitations of this study, the major causes of implant failure are inflammation and overloading, and they differ between early and late implant failures.
Article
To histologically and immunologically assess experimental peri-implant mucositis at surface enhanced modified (mod) hydrophilic titanium implants. In a split-mouth design (n=6 foxhounds), 4 different implants were inserted on each side of the maxilla: 3 titanium-zirconium alloy implants (TiZr) with either modSLA (sand-blasted, acid etched and chemically modified), modMA (machined, acid etched and chemically modified), or M (machined) surfaces in the transmucosal portion, and one titanium implant with a machined transmucosal portion (TiM). Experimental mucositis was induced at one randomly assigned side (NPC), while the contralateral maxillary side received mechanical plaque removal 3 times per week (PC). At 16 weeks, tissue biopsies were processed for histological (primary outcome: apical extension of the inflammatory cell infiltrate measured from the mucosal margin - PM-aICT) and immunohistochemical (CD68 antigen reactivity) analyses. Peri-implant sulcus fluid (PISF) was analysed for interleukin (IL)-1β, IL-8, matrix metalloproteinase (MMP)-8, and myeloperoxidase (MPO). Mean PM-aICT values varied between 1.86 (TiZrmodSLA) and 3.40 mm (TiM) in the UPC group, and between 0.88 (TiZrmodSLA) and 2.08 mm (TiZrM) in the PC group. Mean CD68, IL-1β, IL-8, MMP-8, and MPO values were equally distributed between mod- and control implants in both NPC and PC groups. The progression of experimental mucositis was comparable at all implant surfaces investigated. This article is protected by copyright. All rights reserved.
Article
Over the last 10 years use of isothermal microcalorimetry in the biological and biomedical field has been a increasing. Several biomedical applications such as detection and characterization of pathogens, drug testing, parasitology, and tissue engineering have been investigated. Similarly in environmental science isothermal microcalorimetry has been shown to provide insight in soil science or in geomicrobiology. Often it is useful to convert the isothermal microcalorimetry data into biologically meaningful data such as growth rate, lag phase, or maximum growth. In this study we review not only the various approaches used for such conversion but we also carefully look at the advantages, the drawbacks and underlying assumption of each approach. Understanding of these assumptions is a critical point into applying the right model to the right portion of the microcalorimetric data.
Article
Peri-implant mucositis and peri-implantitis are a raising issue in dental implantology. Peri-implant infections are mainly caused by the formation of biofilm. Different surface textures exhibit various conditions for biofilm formation resulting in several speed of maturation and development. On three different titanium implant surfaces, machined-surface (M), sandblasted large grit, and acid-etched surface (SLA) and machined-modified acid-etched surface (mod MA) initial biofilms were collected. Plaque formation was investigated by erythrosine staining and energy-dispersive X-ray spectroscopy (EDX). For testing the biocompatibility of these plaque-settled surfaces, autoclaved specimens were settled with human gingival fibroblasts, and cell viability was tested. The mean initial plaque surface was detected in the following descending order: M > SLA > mod MA. The differences between these groups were significant. The highest cell viability was detected in the M groups, whereas mod MA and SLA showed comparable results. The results of initial biofilm formation were proved by EDX. Within the limitations of this study, conclusion can be made that mod MA surface shows significant slower initial biofilm formation which could be an advantage in initial transgingival healing process and also an easement for oral hygiene of patients because maturation of plaque is retarded, and immature biofilms are easier to remove.
Article
Objective: Microorganisms harboring the oral cavity, mainly those related to periodontal diseases, are the most potential etiologic factor of failure in long-term implant treatment. The material used for abutment components may influence the adhesion and colonization of microbial species. The aim of this in vivo investigation was to evaluate the biofilm formation on machined (MPT) or cast titanium (CPT) and zirconia abutments (Zc). Methods: Six healthy subjects were enrolled in this randomized crossover clinical investigation. The study was conducted in three phases according to abutment surface evaluated. Each subject used an individual oral splint containing four disks of the same tested substrate, two located in the anterior and two in the posterior region, totalizing 12 specimens for subject. Participants were asked to use the removable intraoral splint during 24 h. DNA checkerboard hybridization method was used to identify and quantify 38 bacterial species colonizing formed biofilm on the abutment substrates. Results: Pathogens and non-pathogens species were found colonizing the three substrates surfaces. Fusobacterium nucleatum, Neisseria mucosa, Porphyromonas aeruginosa, Peptostreptococcus anaerobios, Staphylococcus aureus, Streptococcus gordonii, Streptococcus parasanguinis, and Tanerella forsythia were the only species with no significant differences over the tested materials (P > 0.05). All the other target species presented significant differences sought by Friedman test (P < 0.0001). Conclusions: There was a significant difference in the total bacterial count between the three groups. CPT presented the higher mean counts, followed by MPT and Zc. CPT group also showed a higher mean incidence of species than MPT and Zc. The anterior or posterior region of disks placement did not show significant differences in relation to bacterial adhesion.
Article
To analyze the tissue reactions following ligature removal in experimental periodontitis and peri-implantitis in dogs. Four implants with similar geometry and with two different surface characteristics (turned/TiUnite Nobel BioCare AB, Göteborg) were placed pair-wise in a randomized order in the right side of the mandible 3 months after tooth extraction in 5 dogs. Experimental peri-implantitis and periodontitis were initiated 3 months later by ligature placement around implants and mandibular premolars and plaque formation. The ligatures were removed after 10 weeks, and block biopsies were obtained and prepared for histological analysis 6 months later. It was demonstrated that the amount of bone loss that occurred during the period following ligature removal was significantly larger at implants with a modified surface than at implants with a turned surface and at teeth. The histological analysis revealed that peri-implantitis sites exhibited inflammatory cell infiltrates that were larger, extended closer to the bone crest and contained larger proportions of neutrophil granulocytes and osteoclasts than in periodontitis. It is suggested that lesions produced in experimental periodontitis, and peri-implantitis are different and that implant surface characteristics influence the inflammatory process in experimental peri-implantitis and the magnitude of the resulting tissue destruction.
Article
The purpose of this study was to investigate a three-species in vitro biofilm with peri-implantitis-related bacteria for its variability and metabolic activity. Streptococcus sanguinis, Fusobacterium nucleatum, and Porphyromonas gingivalis were suspended in simulated body fluid containing 0.2% glucose to form biofilms on polished, protein-coated implant-grade titanium disks over 72 h using a flow chamber system. Thereafter, biofilm-coated disks were characterized by scanning electron microscopy and fluorescence in situ hybridization/confocal laser scanning microscopy. To assess metabolic activity within the biofilms, their heat flow was recorded for 480 h at 37 °C by IMC. The microscopic methods revealed that the total number of bacteria in the biofilms varied slightly among specimens (2.59 × 10(4) ± 0.67 × 10(4) cells mm(-2) ), whereas all three species were found constantly with unchanged proportions (S. sanguinis 41.3 ± 4.8%, F. nucleatum 17.7 ± 2.1%, and P. gingivalis 41.0 ± 4.9%). IMC revealed minor differences in time-to-peak heat flow (20.6 ± 4.5 h), a trend consistent with the small variation in bacterial species proportions as shown by microscopy. Peak heat flow (35.8 ± 42.6 μW), mean heat flow (13.1 ± 22.0 μW), and total heat over 480 h (23.5 ± 37.2 J) showed very high variation. These IMC results may be attributed to differences in the initial cell counts and relative proportions of the three species, their distribution and embedment in exopolysaccharide matrix on the test specimens. The present results provide new insights into variability and dynamics of biofilms on titanium disks, aspects that should be explored in future studies of dental surfaces.
Article
The prerequisite for glasses and glass-ceramics to bond to living bone is the formation of biologically active bonelike apatite on their surfaces in the body. Our previous study showed that a silica gel prepared by hydrolysis and polycon- densation of tetraethoxysilane in aqueous solution containing poly(ethy1ene glycol) induces apatite nucleation on its surface in a simulated body fluid. In the present study, the effects of heat treatment of silica gel on its catalytic effects in apatite nucleation was investigated in a simulated body fluid. I t was found that apatite forms on the surfaces of silica gels heat-treated below 8OO°C, but not on those heat-treated above 900°C. The volume of nanometer-range pores in the gel remarkably decreased by heat treatment above 900°C. The concentration of silanol groups in the silica gels gradually decreased with increasing heat treatment temperature. The rate of silica dissolution from the gel into the simulated body fluid decreased remarkably by heat treatment above 900°C. This suggested that a special type of silanol group which is formed by soaking the gel treated below 800°C into the simulated body fluid is respon sible for apatite nucleation.
Article
Abstract In this study the microbiota associated with oral endosteal titanium hollow cylinder implants (ITI) was studied using microscopic, immunochemical and cultural methods. Samples from 5 edentulous patients with successfully incorporated implants serving as abutments for overdentures for more than one year were compared with samples from 7 patients with clinically failing implants. Unsuccessful sites were characterized by pocket probing depths of 6 mm or more, suppuration and visible loss of alveolar bone around the implant as visualized on radiographs. These sites harbored a complex microbiota with a large proportion of Gram-negative anaerobic rods. Black-pigmented Bacteroides and Fusobacterium spp. were regularly found. Spirochetes, fusiform bacteria as well as motile and curved rods were a common feature in the darkfield microscopic specimens of these sites. Control sites in the same patients harbored small amounts of bacteria. The predominant morphotype was coccoid cells. Spirochetes were not present, fusiform bacteria, motile and curved rods were found infrequently and in low numbers. The microbiota in control sites in unsuccessful patients and in site in successful patients were very similar. On the basis of these results, it is suggested that “periimplantitis” be regarded as a site specific infection which yields many features in common with chronic adult periodontitis.
Article
Zirconia ceramic material has been widely used in implant dentistry. In this in vitro study the physiochemical properties of titanium and zirconia materials were investigated and the affinity of different bacteria to different materials was compared. Disc samples with different surface states were used: polished partially stabilized zirconia (PZ), titanium blasted with zirconia (TBZ), titanium blasted with zirconia then acid etched (TBZA), and polished titanium (PT) as a control. Surface topography was examined using scanning electron microscopy and profilometry. Contact angle, surface free energy (SFE), surface microhardness and chemical composition were determined. Disc samples were separately incubated with Streptococcus mitis and Prevotella nigrescens, either with or without pre-coating with human saliva, for 6h and the surface area covered by bacteria was calculated from fluorescence microscope images. PZ and TBZ exhibited lower surface free energy and lesser surface wettability than PT. Also, PZ and TBZ surfaces showed lower percentage of bacterial adhesion compared with control PT surface. The zirconia material and titanium blasted with zirconia surface (TBZ surface) showed superior effect to titanium material in reducing the adhesion of the experimented bacteria especially after coating with saliva pellicle. Modifying titanium with zirconia lead to have the same surface properties of pure zirconia material in reducing bacterial adhesion. SFE appears to be the most important factors that determine initial bacterial adhesion to smooth surface.
Article
The purpose of this study was to evaluate the biomechanical bone tissue response to novel microstructured zirconia implants in comparison to sandblasted and acid-etched (SLA) titanium implants through the analysis of removal torque (RTQ) measurements. Ti-SLA implants with a sandblasted, large-grit and acid-etched surface were compared with zirconia implants with an acid-etched surface. All implants had the same shape, a diameter of 4.1 mm and a length of 10 mm. A total of 136 implants were placed in the maxillae of 17 miniature pigs. Six animals were sacrificed after both 4 and 8 weeks and five animals were sacrificed after 12 weeks, thus providing a total of 102 implants for RTQ testing (34 implants were reserved for future histological analysis). The RTQ analysis was successfully performed, using a mixed model regression with P-values calculated using the nonparametric Brunner-Langer method, on 100 of the 102 implants, two were excluded from the analysis. The adjusted mean RTQ values for Ti-SLA implants were 131 Ncm (95%CI: 107-155) at 4 weeks, 128 Ncm (108-148) Ncm at 8 weeks, and 180 Ncm (153-207 Ncm) at 12 weeks of healing, whereas RTQ values for the zirconia implants were 110 Ncm (86-134), 97 Ncm (76-118) and 147 Ncm (121-174) at the corresponding time intervals. A comparison of the implant materials resulted in P-values of P = 0.114 at 4 weeks, P = 0.034 at 8 weeks and P = 0.105 at 12 weeks (significance set at P < 0.05). Within the limits of the present study, it could be confirmed that the biomechanical bone-tissue response of the investigated zirconia implants is non-inferior to that of the well-documented, roughened titanium surface, at each time point, within the set tolerance. There were no statistically significant differences between the two materials after a healing period of 4 and 12 weeks. The RTQ values of both implant types increased significantly from the 8-week to the 12-week time point.
Article
Dental implants are prone to bacterial colonization which may result in bone destruction and implant loss. Treatments of peri-implant disease aim to reduce bacterial adherence while leaving the implant surface intact for attachment of bone-regenerating host cells. The aims of this study were to investigate the antimicrobial efficacy of gaseous ozone on bacteria adhered to various titanium and zirconia surfaces and to evaluate adhesion of osteoblast-like MG-63 cells to ozone-treated surfaces. Saliva-coated titanium (SLA and polished) and zirconia (acid etched and polished) disks served as substrates for the adherence of Streptococcus sanguinis DSM20068 and Porphyromonas gingivalis ATCC33277. The test specimens were treated with gaseous ozone (140 ppm; 33 mL/s) for 6 and 24 s. Bacteria were resuspended using ultrasonication, serially diluted and cultured. MG-63 cell adhesion was analyzed with reference to cell attachment, morphology, spreading, and proliferation. Surface topography as well as cell morphology of the test specimens were inspected by SEM. The highest bacterial adherence was found on titanium SLA whereas the other surfaces revealed 50-75% less adherent bacteria. P. gingivalis was eliminated by ozone from all surfaces within 24 s to below the detection limit (≥99.94% reduction). S. sanguinis was more resistant and showed the highest reduction on zirconia substrates (>90% reduction). Ozone treatment did not affect the surface structures of the test specimens and did not influence osteoblastic cell adhesion and proliferation negatively. Titanium (polished) and zirconia (acid etched and polished) had a lower colonization potential and may be suitable material for implant abutments. Gaseous ozone showed selective efficacy to reduce adherent bacteria on titanium and zirconia without affecting adhesion and proliferation of osteoblastic cells. This in vitro study may provide a solid basis for clinical studies on gaseous ozone treatment of peri-implantitis and revealed an essential base for sufficient tissue regeneration.
Article
To compare the bone tissue response to surface-modified zirconia (ZrO2 ) and titanium implants. Cylindrical low-pressure injection moulded zirconia (ZrO2 ) implants were produced with an acid-etched surface. Titanium implants with identical shape, sandblasted and acid-etched surface (SLA) served as controls. Eighteen adult miniature pigs received both implant types in the maxilla 6 months after extraction of the canines and incisors. The animals were euthanized after 4, 8 and 12 weeks and 16 zirconia and 18 titanium implants with the surrounding tissue were retrieved, embedded in methylmethacrylate and stained with Giemsa-Eosin. The stained sections were digitized and histomorphometrically analysed with regard to peri-implant bone density (bone volume/total volume) and bone-implant contact (BIC) ratio. Statistical analysis was performed using Mann-Whitney' U-test. Histomorphometrical analysis showed direct osseous integration for both materials. ZrO2 implants revealed mean peri-implant bone density values of 60.4% (SD ± 9.9) at 4 weeks, 65.4% (SD ± 13.8) at 8 weeks, and 63.3% (SD ± 21.5) at 12 weeks after implantation, whereas Ti-SLA implants demonstrated mean values of 61.1% (SD ± 6.2), 63.6% (SD ± 6.8) and 68.2% (SD ± 5.8) at corresponding time intervals. Concerning the BIC ratio, the mean values for ZrO(2) ranged between 67.1% (SD ± 21.1) and 70% (SD ± 14.5) and for Ti-SLA between 64.7% (SD ± 9.4) and 83.7% (SD ± 10.3). For the two parameters investigated, no significant differences between both types of implants could be detected at any time point. The results indicate that there was no difference in osseointegration between ZrO2 implants and Ti-SLA controls regarding peri-implant bone density and BIC ratio.
Article
The purpose of this study was to compare zirconium oxide and titanium alloys with respect to their tendency to adhesion and colonization of two periodontal pathogens on both hard surfaces and on soft tissues in vivo. The present study was designed as a prospective stratified randomized controlled clinical trial. Patients were scheduled to receive two implants with different types of abutments in the posterior mandible. Three months after implant placement, titanium and zirconium abutments were connected. Five weeks after abutment connections, the abutments were removed, probing depth measurements were recorded, and gingival biopsy samples were obtained. Abutments and biopsy specimens were analyzed by reverse-transcriptase polymerase chain reaction to compare the DNA copy numbers of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis, and total bacteria. The surface free energy of the abutments was calculated by sesile water drop before replacement. No statistically significant differences were found between probing depths or DNA copy numbers of A actinomycetemcomitans, P gingivalis, and total bacteria both for both titanium alloys and zirconium oxide surfaces and the biops specimens obtained from their buccal gingival. With respect to the surface free energy of zirconium and titanium abutments, zirconium abutments showed lower surface free energy than titanium abutments. The results of this study showed that zirconium oxide surfaces have comparable properties to titanium alloy surfaces in their tendency to adhesion and colonization of two periodontal pathogens on both hard surfaces and in soft tissues.
Article
Peri-implant diseases present in two forms - peri-implant mucositis and peri-implantitis. The literature was systematically searched and critically reviewed. Four manuscripts were produced in specific topics identified as key areas to understand the microbial aetiology and the pathogenesis of peri-implant diseases and how the implant surface structure may affect pathogenesis. While peri-implant mucositis represents the host response of the peri-implant tissues to the bacterial challenge that is not fundamentally different from gingivitis representing the host response to the bacterial challenge in the gingiva, peri-implantitis may differ from periodontitis both in the extent and the composition of cells in the lesion as well as the progression rate. A self-limiting process with a "protective" connective tissue capsule developing appears to dominate the periodontitis lesion while such a process may occasionally be lacking in peri-implantitis lesions. Bacterial biofilm formation on implant surfaces does not differ from that on tooth surfaces, but may be influenced by surface roughness. Nevertheless there is no evidence that such differences may influence the development of peri-implantitis. It was agreed that clinical and radiographic data should routinely be obtained after prosthesis installation on implants in order to establish a baseline for the diagnosis of peri-implantitis during maintenance of implant patients.
Article
To describe the microbiota associated with peri-implant disease, with a specific emphasis on the differential diagnosis of the condition. The potentially relevant literature was preliminarily assessed via scoping searches to find the most appropriate search terms and the most efficient Boolean search algorithm. We identified 29 reports on subjects with osseointegrated implants, with a pathological condition compatible with the definition of "peri-implant disease", and reporting microbiological data from samples taken in affected sites. In most studies bacterial samples were obtained by methods that destroy the three-dimensional structure of the biofilm. The samples therefore describe mixtures of bacteria from unspecified districts of biofilm associated with peri-implant diseases. Analyses of such samples with various methods indicate that peri-implant disease maybe viewed as a mixed anaerobic infection. In most cases the composition of the flora is similar to the subgingival flora of chronic periodontitis that is dominated by Gram-negative bacteria. Peri-implant infections may occasionally be linked to a different microbiota, including high numbers of peptostreptococci or staphylococci. Beneficial effects of mechanical and chemical interventions to disrupt the peri-implant biofilm demonstrate that microorganisms are involved in the disease process, even if they may not always be the origin of the condition.
Article
Peri-implantitis is common in patients with dental implants. We performed a single-blinded longitudinal randomized study to assess the effects of mechanical debridement on the peri-implant microbiota in peri-implantitis lesions. An expanded checkerboard DNA-DNA hybridization assay encompassing 79 different microorganisms was used to study bacterial counts before and during 6 months following mechanical treatment of peri-implantitis in 17 cases treated with curettes and 14 cases treated with an ultrasonic device. Statistics included non-parametric tests and GLM multivariate analysis with p<0001 indicating significance an