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Dental Implant Surgery: A Concise Review of the Literature
Abstract
Edentulism is a global challenge affecting patients’ psychosocial well-being, now well-treated by dental implants. Due to the advancement in the field of oral implantology, there is a plethora of surgical techniques and protocols at the disposal of clinicians, backed by an ever-divided body of research. Treatment with dental implants has become ever more sought after because of their high survival and success rates and increased affordability. In turn, this has put increased demand on clinicians who owe their patients the highest standard of care backed by sound scientific evidence. However, dentists are expressing concern over ambiguous dental implant guidelines and protocols. Implant survival, success and failure rates have been reported differently for various modalities and justified differently in various research. This lack of consensus appears to stem from erroneous or non-standardized study designs, yielding inconsistent results. Therefore, correctly designed and well-reported high-level studies are needed to aid clinicians in treatment decision-making.
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Objectives:
Mandibular retromolar (predominantly cortical) and maxillary tuberosity (predominantly cancellous) bone grafts are used in patients undergoing maxillary sinus floor elevation (MSFE) for dental implant placement. The aim of this retrospective cohort study was to investigate whether differences exist in bone formation and vascularization after grafting with either bone source in patients undergoing MSFE.
Methods:
Fifteen patients undergoing MSFE were treated with retromolar (n = 9) or tuberosity (n = 6) bone grafts. Biopsies were taken 4 months postoperatively prior to dental implant placement, and histomorphometrically analyzed to quantify bone and osteoid area, number of total, apoptotic, and receptor activator of nuclear factor-κB ligand (RANKL)-positive osteocytes, small and large-sized blood vessels, and osteoclasts. The grafted area was divided in three regions (caudal-cranial): RI, RII, and RIII.
Results:
Bone volume was 40% (RII, RIII) higher and osteoid volume 10% (RII) lower in retromolar compared to tuberosity-grafted areas. Total osteocyte number and number of RANKL-positive osteocytes were 23% (RII) and 90% (RI, RII) lower, but osteoclast number was higher (retromolar: 12, tuberosity: 0) in retromolar-grafted areas. The total number of blood vessels was 80% (RI) to 60% (RIII) lower, while the percentage of large-sized blood vessels was 86% (RI) to 25% (RIII) higher in retromolar-grafted areas. Number of osteocyte lacunae and apoptotic osteocytes were similar in both bone grafts used.
Conclusions:
Compared to the retromolar bone, tuberosity bone showed increased bone vitality and vascularization in patients undergoing MSFE, likely due to faster bone remodeling or earlier start of new bone formation. Therefore, tuberosity bone grafts might perform better in enhancing bone regeneration.
Background:
Studies have examined the benefit of having keratinized peri-implant mucosa width with mixed results.
Purpose:
This study examines whether the lack of a prespecified (2 mm) amount of keratinized mucosa width (KMW) is a risk factor for peri-implant diseases.
Methods:
A systematic electronic and manual search of randomized or nonrandomized controlled or noncontrolled clinical trials was conducted. Qualitative review, quantitative meta-analysis, and trial sequence analysis (TSA) of implants inserted at sites with <2 mm or ≥2 mm of KMW were analyzed to compare all the predetermined outcome variables. The level of evidence concerning the role of KMW in peri-implant health was evaluated via the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system guide.
Results:
Nine studies were included in the qualitative analysis and four in the meta-analysis and TSA. No significant inter-group difference (p > 0.05) and a low power of evidence were found for probing depth, soft-tissue recession, and marginal bone loss. A significant difference favoring ≥2 mm KMW had a lower mean plaque index (MD = 0.37, 95% CI: [0.16, 0.58], p = 0.002) (3 studies, 430 implants, low-quality evidence). GRADE system showed very low and low quality of evidence for all other outcome measures.
Conclusion:
Based on the available studies, the impact of amount of KMW (either <2 mm or ≥ 2 mm) as a risk factor for developing peri-implant disease remains low. Future control studies with proper sample size and longer follow-up are needed to further validate current findings.
Introduction:
The aim of this retrospective study was to analyze the radiographic peri-implant bone loss of bone level implants and tissue level implants with a convergent neck in screw-retained single crowns and in screw-retained fixed partial prostheses, after two years of functional loading.
Materials and methods:
The sample was divided into two groups according to their type: Group I: supracrestal implants with convergent transmucosal neck; Group II: crestal implants. In each group we distinguish two subgroups according to the type of prosthetic restoration: single crowns and a three-piece fixed partial prosthesis on two implants. To quantify bone loss, parallelized periapical radiographs were analyzed at the time of implant placement and after two years of functional load.
Results:
A total of 120 implants were placed in 53 patients. After statistical analysis it was observed that for each type of implant bone loss was 0.97 ± 0.91 mm for bone level and 0.31 ± 0.48 mm for tissue level. No significant differences were found regarding the type of prosthesis and the location (maxilla or mandible) of the implants.
Conclusions:
Tissue level implants with a convergent transepithelial neck exhibit less peri-implant bone loss than bone level implants regardless of the type of prosthesis.
Objectives: The aim of this retrospective study was to evaluate the effect of vertical soft tissue thickness (STT) on crestal bone loss (CBL) of early loaded implants after 1 and 5 years. Method and materials: Forty-four tapered implants with platform switching and conical connection were placed in the posterior mandible and maxilla to rehabilitate edentulous sites. STT at implant sites was divided into two groups: thin (n = 21, mean STT = 2.0 ± 0.3 mm) and thick (n = 23, mean STT = 3.0 ± 0.8 mm). The implants were loaded after 6 to 8 weeks. Survival and success rates and CBL were measured after 1 and 5 years.
Results: The survival and success rates at 1 and 5 years were 100% and 97.8%, respectively. At the 1-year follow-up, the CBL of the thin and thick gingival groups was 0.96 ± 0.49 and 0.55 ± 0.41 mm, respectively; the difference was statistically significant (P = .004). At 5 years, the CBL of the thin and thick gingiva groups increased to 1.12 ± 0.84 and 0.65 ± 0.69 mm, respectively; the difference was not statistically significant (P = .052).
Conclusion: At 1 year, the CBL was more pronounced at sites with a thin gingiva; at 5 years the difference between the groups was not statisically significantly different. Within the limitations of this study, early loading of implants with platform switched and conical connection was safe.
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It is not uncommon to encounter post-surgical complications after horizontal guided bone regeneration (GBR). The primary aim of this review was to evaluate the incidence and types of complications that occur after horizontal GBR and propose management strategies to deal with these clinical situations. A secondary aim was to conduct a histomorphometric review of the wound healing process at sites that experienced post-surgical complications after GBR. A keyword search of MEDLINE, EMBASE, and the Cochrane Central Register of Controlled Trials for studies published in English from January 2015 to January 2020 was conducted for the primary aim and 23 studies were selected. A second search addressing the secondary aim was conducted, and five studies were included. Site-level analysis showed that the weighted mean incidence proportion of minor wound dehiscence and minor infections occurring at the augmented site was 9.9% [95% CI 6.4, 13.9, P < 0.01] and 1.5% [95% CI 0.4, 3.1, P = 0.21) respectively. Patient-level analysis showed minor and major complications occurring at a weighted mean incidence proportion of 16.1% [95% CI 11.9, 20.8, P = 0.01] and 1.6% [95% CI 0.0, 4.7, P < 0.01] respectively, while neurosensory alterations at the donor site was 7.0% [95% CI 1.3, 15.5, P < 0.01]. Subgroup analysis also revealed that the use of block grafts increased the incidence proportion of minor post-surgical complications, whereas a staged GBR procedure increased the incidence proportion of both minor and major post-surgical complications. Although exposure of the barrier membrane is often associated with less bone regeneration and graft resorption, the type of membrane used (resorbable or non-resorbable) had no statistically significant influence on any post-surgical complication. Histologically, a layer of fibrous connective tissue instead of bone is commonly observed at the interface between the native bone at the recipient site and the regenerated bone in cases with membrane exposure after GBR procedure. Minor wound dehiscence was the highest incidence proportion of post-surgical complications. Methods ranging from daily application of antiseptics, use of systemic antimicrobials, regular reviews, and total removal of the non-integrated biomaterials are commonly prescribed to manage these post-surgical complications in attempt to minimise the loss of tissue at the surgical site.
Purpose of review: Oral rehabilitation with dental implants in head and neck cancer (HNC) patients is challenging. After tooth removal prior to radiotherapy, immediate placement of dental implants during panendoscopy or surgery is thought to reduce the oral rehabilitation time improving patients' quality of life.
Recent findings: There is lack of consensus on the timing of dental implant placement and loading protocols. The aim of this study was to perform a systematic review of the literature regarding the performance and survival rate of immediately inserted dental implants placed prior to radiotherapy. Of 1003 articles, 10 were finally included comparing immediate vs. delayed placement of implants and comparing the effect of radiotherapy on immediately placed implants. Meta-analysis demonstrated a slightly higher survival of immediately placed implants compared with postponed placed implants [risk ratio: 0.92, 95% confidence interval (95% CI): 0.48-1.78, P = 0.81, I = 0%]. The other meta-analysis comparing radiotherapy vs. nonradiotherapy showed a clearly better survival of immediately placed implants not having received radiotherapy (risk ratio: 5.02, 95% CI: 0.92-27.38, P = 0.10, I = 56%).
Summary: Guidelines are recommended for immediate dental implant placement in the edentulous mandible in HNC patients prior to radiotherapy to allow homogeneity regarding the treatment protocols and thus comparison of treatment outcomes.
Objective:
To analyze the outcomes of static computer‐aided implant placement (sCAIP) compared to partially guided (PGIP) and free‐handed (FHIP) implant placement.
Material and Methods:
This study was registered in PROSPERO (CRD42019131397). A comprehensive literature search was performed by two independent examiners. Only randomized controlled trials (RCTs) were selected. Treatment modalities included sCAIP, PGIP and FHIP. Data pertaining to the outcomes of interest were extracted. Random‐effects meta‐analyses were feasible for a subset of outcomes.
Results:
From an initial list of 2,870 records, fourteen articles for a total of ten RCTs were selected. Data from 7 of these studies allowed for the conduction of three meta‐analyses comparing accuracy of implant placement across modalities. Survival rate up to 12 months post‐loading was high (>98%) and comparable between treatments (low quality evidence). No tangible differences in terms of patient perception of intra‐ or postoperative discomfort were observed (low quality evidence). Quantitative analyses revealed significantly lower angular (MD = 4.41° , 95% CI 3.99 – 4.83, p < 0.00001), coronal (MD = 0.65 mm, 95% CI 0.50 – 0.79, p < 0.00001) and apical (MD = 1.13 mm, 95% CI 0.92 – 1.34, p < 0.00001) deviation values for sCAIP as compared to FHIP (8 studies, 383 patients, 878 implants, high quality evidence). A similar discrepancy, in favor of sCAIP, was observed for angular deviation only as compared to PGIP (MD = 2.11° , 95% CI 1.06 – 3.16, p < 0.00001).
Conclusions:
sCAIP is associated with superior accuracy compared to PGIP and FHIP.
Objectives
Conventional dental implants inserted in the molar region of the maxilla will reach into the sinus maxillaris when alveolar ridge height is limited. When surgery is performed without prior augmentation of the sinus floor, primary stability of the implant is important for successful osseointegration. This study aimed at identifying the impact of bone quality and quantity at the implantation site on primary implant stability of a simulated bicortical placement.Materials and methodsIn our in vitro measurements, bone mineral density, total bone thickness and overall cortical bone thickness were assessed by micro-computed tomography (μCT) of pig scapulae, which resembled well the bicortical situation found in human patients. Dental implants were inserted, and micromotion between bone and implant was measured while loading the implant with an axial torque.ResultsThe main findings were that primary implant stability did not depend on total bone thickness but tended to increase with either increasing bone mineral density or overall cortical bone thickness.Clinical relevanceLimited bone height in the maxilla is a major problem when planning dental implants. To overcome this problem, several approaches, e.g. external or internal sinus floor elevation, have been established. When planning the insertion of a dental implant an important aspect is the primary stability which can be expected. With other factors, the dimensions of the cortical bone might be relevant in this context. It would, therefore, be helpful to define the minimum thickness of cortical bone required to achieve sufficient primary stability, thus avoiding additional surgical intervention.
Objectives:
The aim of this systematic review was to investigate the predictability of the sandwich osteotomy technique to provide sufficient alveolar bone height for dental implant therapy in vertically atrophic jaws.
Material and methods:
A MEDLINE (Pubmed), EMBASE and Cochrane Library electronic search and a manual search were performed until July 2018. Any clinical study published in English, reporting data on at least 10 patients rehabilitated with implant-supported dental prostheses after vertical ridge augmentation by means of the sandwich osteotomy technique and followed for at least 12 months after loading, was included. Data on study and patients' characteristics, interventions provided, implant and prostheses survival rates and complications were extracted from the included studies. Each study design was evaluated using the Cochrane Collaboration's tool for assessing risk of bias.
Results:
Initially, 415 records were identified, from which 10 full-text articles could be included in the final qualitative analysis. Implant survival rate after a mean follow-up of 3.7 years (median: 3 years; range: 1-7 years) was 94% (median: 93%; range: 91-100%). Peri-implant mean marginal bone resorption was 1.6 mm (median: 1.4 mm; range: 0.6-4.7 mm). The calculated mean alveolar bone height available at the time of implant placement was 11.3 mm (median: 11.5 mm; range: 7.8-16 mm). A temporary sensory disturbance of the inferior alveolar nerve was the most commonly reported complication following the sandwich osteotomy.
Conclusions:
The present systematic review documents that implant survival rate after mandibular vertical ridge augmentation using the sandwich osteotomy technique is high after up to 5 years of loading. The complication rate can be considered moderate and has predominantly a transient nature. Data on the long-term behavior of the augmented bone and inserted implants are missing.
Clinical relevance:
The present technique can be considered a reliable treatment option in cases of moderate vertical bone deficiency of the posterior mandible to provide suitable conditions for later implant placement. Intra- and post-operative complications do not seem to jeopardize the final outcome.
Functional and aesthetic treatments are challenging when ensuring maintain long-term successful prosthetic rehabilitation after alveolar ridge resorption of the anterior maxilla. The goal of this case series was to evaluate implant success rate, prosthetic stability and patient satisfaction in patients treated by onlay bone grafting in atrophic premaxilla. Nineteen patients treated for severe atrophic anterior maxilla by reconstruction using onlay bone grafting and implant restoration between 2002 and 2012 were examined. The surgical procedure was designed to allow the insertion of 49 endosseous implants in the grafted anterior maxillae. Bone resorption and implant success rate were retrospectively evaluated after a follow-up period of 5 years (from 5 to 15 years) subsequent to reconstruction. A questionnaire was the medium used to evaluate patient satisfaction and highlight functional and aesthetic outcomes. The bone grafting success rate was 74%. None of the grafted bones were reported to be infected. Four implants were removed. Implant survival rate was 91.8% after 8.9 years. The permanent reconstruction was fixed in 74% of the cases and removable in 26%. The level of patient satisfaction reported was 6.5/7. In conclusion, his study suggests that onlay bone grafting can be considered a predictable technique for rehabilitation in atrophic premaxilla. The procedure has a high implant survival rate, acceptable bone resorption over time, and promotes graft stability for longterm prosthetic fixation, thereby increasing patient satisfaction.
Purpose:
To compare planning and patient rehabilitation using 3D implant planning software and dedicated surgical templates with conventional freehand implant placement for the rehabilitation of partially or fully edentulous patients using flapless or mini-flap procedures and immediate loading.
Materials and methods:
Patients requiring at least two implants to be restored with a single prosthesis, having at least 7 mm of bone height and 4 mm in bone width were consecutively enrolled. Patients were randomised according to a parallel group study design into two groups: computerguided group or conventional freehand group. Implants were loaded immediately with a provisional prosthesis, replaced by a definitive prosthesis 4 months later. Outcome measures assessed by a blinded independent assessor were: implant and prosthesis failures, any complications, marginal bone levels, number of treatment sessions, duration of treatment, post-surgical pain and swelling, consumption of pain killers, surgical and prosthetic time, time required to solve complications, and patient satisfaction. Patients were followed up to 5 years after loading.
Results:
Ten patients (32 implants) were randomised to the computer-guided group and 10 patients (30 implants) were randomised to the freehand group. At the 5-year follow-up examination one patient of the computer-guided group and one of the freehand group dropped-out (both moved to another country). No prostheses failed during the entire follow-up. Two implants failed in the conventional group (6.6%) vs none in the computer-guided group (P = 0.158). Ten patients (five in each group) experienced 11 complications (six in the computer-guided group and five in the freehand group), that were successfully solved. Differences between groups for implant failures and complications were not statistically significant. Five years after loading, the mean marginal bone loss was 0.87 mm ± 0.40 (95% CI: 0.54 to 1.06 mm) in the computer-guided group and 1.29 mm ± 0.31 (95% CI: 1.09 to 1.51 mm) in the freehand group. The difference was statistically significant (difference 0.42 mm ± 0.54; 95% CI: 0.05 to 0.75; P = 0.024). Patient self-reported post-surgical pain (P = 0.037) and swelling (P = 0.007) were found to be statistically significant higher in patients in the freehand group. Number of sessions from patient's recruitment to delivery of the definitive prosthesis, number of days from the initial CBCT scan to implant placement, consumption of painkillers, averaged surgical, prosthetic, and complication times, were not statistically significant different between the groups. At the 5-year followup, all the patients were fully satisfied with the function and aesthetics of their definitive prostheses.
Conclusions:
Both approaches achieved successful results over the 5-year follow-up period. Statistically higher post-operative pain and swelling were experienced at sites treated freehand with flap elevation. Less marginal bone loss (0.4 mm) was observed in the computer-guided group, at 5 years follow-up. Conflict-of-interest statement: This trial was completely self-funded and all the authors declare no conflicts of interest.
The aim of this study was to evaluate the evidence of a correlation between the stability of dental implants placed by piezosurgery, compared with implants placed by conventional drilling. An electronic search in MEDLINE, SCOPUS and the Cochrane Library was undertaken until August 2016 and was supplemented by manual searches and by unpublished studies at OpenGray. Only randomized controlled clinical trials that reported implant site preparation with piezosurgery and with conventional drilling were considered eligible for inclusion in this review. Meta-analyses were performed to evaluate the impact of piezosurgery on implant stability. Of 456 references electronically retrieved, 3 were included in the qualitative analysis and quantitative synthesis. The pooled estimates suggest that there is no significant difference between piezosurgery and conventional drilling at baseline (WMD: 2.20; 95% CI: -5.09, 9,49; p = 0.55). At 90 days, the pooled estimates revealed a statistically significant difference (WMD: 3.63; 95% CI: 0.58, 6.67, p = 0.02) favouring piezosurgery. Implant stability is slightly improved when osteotomy was performed by a piezoelectric device. More randomized controlled clinical trials are needed to verify these findings.
Aim:
The aim of this article is to systematically review the effect of subcrestal implant placement compared with equicrestal position on hard and soft tissues around dental implants with platform switch.
Material and methods:
A manual and electronic search (National Library of Medicine and Cochrane Central Register of Controlled Trials) was performed for animal and human studies published up to December 2016. Primary outcome variable was marginal bone level (MBL) and secondary outcomes were crestal bone level (CBL), soft tissue dimensions (barrier epithelium, connective tissue, and peri-implant mucosa), and changes in the position of soft tissue margin. For primary and secondary outcomes, data reporting mean values and standard deviations of each study were extracted and weighted mean differences (WMDs) and 95% confidence intervals (CIs) were calculated.
Results:
A total of 14 publications were included (7 human studies and 7 animal investigations). The results from the meta-analyses have shown that subcrestal implants, when compared with implants placed in an equicrestal position, exhibited less MBL changes (human studies: WMD = - 0.18 mm; 95% CI = - 1.31 to 0.95; P = 0.75; animal studies: WMD = - 0.45 mm; 95% CI = - 0.66 to - 0.24; P < 0.001). Furthermore, the CBL was located at a more coronal position in subcrestal implants with respect to the implant shoulder (WMD = - 1.09 mm; 95% CI = - 1.43 to - 0.75; P < 0.001). The dimensions of the peri-implant mucosa seem to be affected by the positioning of the microgap and were greater at implants placed in a subcrestal position than those inserted equicrestally (WMD = 0.60 mm; 95% CI = 0.26 to 0.95; P < 0.001). While the length of the barrier epithelium was significantly greater in implants placed in a subcrestal position (WMD = 0.39 mm; 95% CI = 0.19 to 0.58; P < 0.001), no statistical significant differences were observed between equicrestal and subcrestal implant positioning for the connective tissue length (WMD = 0.17 mm; 95% CI = - 0.03 to 0.36; P = 0.10).
Conclusion:
This systematic review suggests that PS implants placed in a subcrestal position have less MBL changes when compared with implants placed equicrestally. Furthermore, the location of the microgap seems to have an influence on the dimensions of peri-implant soft tissues. Clinical relevance When compared with PS placed in an equicrestal position, subcrestal implant positioning demonstrated less peri-implant bone remodeling.
Background:
Multiple variables have shown to affect early marginal bone loss (MBL). Among them, the location of the micro-gap with respect to the alveolar bone crest, occlusion and the utilization of a polished collar have traditionally been investigated as major contributory factors for this early remodeling. Recently, soft tissue thickness has also been investigated as a possible factor influencing this phenomenon. Hence, this study aimed at further evaluating the influence of soft tissue thickness upon early MBL around dental implants.
Material and methods:
An electronic and manual literature searches were performed by two independent reviewers (FSLA and AM) in several databases, including MEDLINE, EMBASE, and Cochrane Oral Health Group Trials Register databases for articles up to May 2015 reporting soft tissue thickness at time of implant placement and MBL with at least 12-month follow up. In addition, random effects meta-analyses of selected studies were applied to analyze the weighted mean difference (WMD) of MBL between groups of thick and thin peri-implant soft tissue. Meta-regression was also conducted to investigate any potential influences of confounding factors, i.e., platform switching design, cement/screw retained restoration, and flapped/flapless surgical techniques.
Results:
Eight articles were included in the systematic review and five were also included in the quantitative synthesis and meta-analyzed to examine the influence of tissue thickness upon early MBL. Meta-analysis for the comparison of MBL among selected studies showed a WMD of -0.80 mm, with a 95% CI= -1.18 mm to -0.42 mm (p< 0.0001), favoring the thick tissue group. However, meta-regression of the selected studies failed to demonstrate an association between MBL and confounding factors.
Conclusion:
The current study showed that implants placed with an initially thicker peri-implant soft tissue have less radiographic MBL in the short term.
Aim: To evaluate and compare the effect of flapless and “open flap” techniques of implant placement on crestal bone height (CBH) around implants.
Materials and Methods: This prospective study comprised of 32 implants placed in 16 subjects with a bilateral missing mandibular first molar. In each subject, one implant was placed with “flapless” and other using “open flap” technique. Radiographic assessment of CBH was carried out using standardized intraoral periapical radiograph of the site at baseline, 3 months, 9 months and 15 months after implant placement.
Statistical Analysis: Data were analyzed using STATA 11.0 statistical software. To determine the changes in CBH from baseline, at 3-, 9-, and 15-month, repeated measures analysis of variance followed by post-hoc Bonferroni was used for each of the two techniques for mesial and distal aspects separately. For both techniques, changes in CBH from baseline to 15 months were compared using an independent t-test with a confidence interval of 95%.
Results: For “flapless” technique, there was no statistically significant (P > 0.05) reduction of CBH in initial 9 months but was significant for the 9–15 months period while for “open flap” technique, statistically significant (P < 0.05) reduction was observed up to 15 months. Comparison of both techniques showed significantly lesser reduction with “flapless” than “open flap” technique. The overall average crestal bone loss was 0.046 ± 0.008 mm on mesial aspect, 0.043 ± 0.012 mm on distal aspect with “flapless” technique and 1.48 ± 0.085 mm on mesial aspect, 1.42 ± 0.077 on distal aspect “open flap” technique.
Conclusions: Both techniques showed a reduction in CBH with time but the flapless technique showed a lesser reduction. Therefore, the flapless technique can be considered as a better treatment approach for placement of implants, especially where adequate width and height of available bone are present.
Since the 1970s, modern Implantology is based on a concept of surgery with flap elevation. Gradually, several clinical trials demonstrated that a mid-crestal incision gives similar success rates compared to those obtained using the classical protocol.
However, over the past decade in medicine it has been established the concept of minimally invasive surgery, consisting in taking advantage of advancements experienced in diagnostic techniques and specific surgical instruments, to perform surgical procedures infringing as less damage as possible to the patient
The present work aims to produce a thorough review of the literature published on the field of Implantology with flapless surgery, to determine the current scientific evidence of the technique, along with illustrating the results with different clinical cases.
After presenting the clinical cases, and the review of literature, we can say that flapless surgeries should be restricted to well-selected cases in which a proper clinical and radiological planning has been made. Patients treated with anticoagulant drugs or medically compromised equally can get benefitted by this minimal invasion technique.
Key words:Flapless, minimally invasive surgery, dental implant.
D ental implants, compared to teeth, are less toler-able to traumatic occlusal forces due to the lack of periodontal ligaments. They are more vulnerable to nonaxial forces because of the higher moment, tor-sional, and shear forces exerted to the surrounding bone that damage the bone-to-implant contact sur-face. 1 As a result, implants should be placed in line to the direction of the loading. However, the proximity of anatomical structures, such as the maxillary sinus and the inferior alveolar nerve, often preclude standard implants from being placed axially. Solutions to inad-equate ridge height include the use of short implants, 2 vertical ridge augmentation procedures, 3 or cantilever prostheses. 4 Although having a comparable short-term survival rate, the long-term performance of short implants is less understood, especially in the posterior maxilla with lower bone density. 5,6 Vertical augmen-tation procedures increase patient morbidity and the outcome is unpredictable, especially when performed in the posterior mandible. 7 Cantilever prostheses might incur higher rates of prosthetic complications, such as abutment loosening and denture fracture. 8–10 Due to the unpredictable long-term prognosis associ-ated with the above-mentioned procedures, the use of tilted implants was proposed. 11,12 The use of tilted implants could provide several clinical advantages: (1) to allow for the placement of longer implants, which increases the bone-to-implant contact area as well as implant stability; (2) to create a wider distance between anterior and posterior im-plants, which results in better load distribution; (3) to reduce or eliminate the use of cantilevers; and (4) to avoid bone augmentation procedures. 13 One example of using tilted implants is the "All-on-Four" technique in
Most dental implants are positioned using a drilling surgery technique. However, dentistry recently experienced the implementation of piezoelectric surgery. This technique was introduced to overcome some of the limitations involving rotating instruments in bone surgery. This study used biomolecular and histologic analyses to compare the osseointegration of porous implants positioned using traditional drills versus the piezoelectric bone surgery technique.
Porous titanium implants were inserted into minipig tibias. Histomorphology and levels of bone morphogenetic protein (BMP)-4, transforming growth factor (TGF)-beta2, tumor necrosis factor-alpha, and interleukin-1beta and -10 were evaluated in the peri-implant osseous samples.
Histomorphological analyses demonstrated that more inflammatory cells were present in samples from drilled sites. Also, neo-osteogenesis was consistently more active in bone samples from the implant sites that were prepared using piezoelectric bone surgery. Moreover, bone around the implants treated with the piezoelectric bone surgery technique showed an earlier increase in BMP-4 and TGF-beta2 proteins as well as a reduction in proinflammatory cytokines.
Piezoelectric bone surgery appears to be more efficient in the first phases of bone healing; it induced an earlier increase in BMPs, controlled the inflammatory process better, and stimulated bone remodeling as early as 56 days post-treatment.
The purpose of this systematic review was to compare computer-guided (fully guided) and freehand implant placement surgery in terms of marginal bone loss, complications, and implant survival. This review followed the PRISMA guidelines and was registered in the PROSPERO database (CRD42019135893). Two independent investigators performed the search of the PubMed/MEDLINE, Scopus, and Cochrane Library databases for studies published up to April 2020 and identified 1508 references. After a detailed review, only four studies were considered eligible. These studies involved a total of 154 patients with 597 dental implants and a mean follow-up period of 2.25 years. There was no difference between computer-guided surgery and freehand surgery in terms of the marginal bone loss (mean difference -0.11mm, 95% confidence interval (CI) -0.27 to 0.04mm; P=0.16), mechanical complications (risk ratio (RR) 0.85, 95% CI 0.36-2.04; P=0.72), biological complications (RR 1.56, 95% CI 0.42-5.74; P=0.51), and implant survival rate (RR 0.53, 95% CI 0.11-2.43; P=0.41). This meta-analysis demonstrated that both computer-guided and freehand surgeries yielded similar results for marginal bone loss, mechanical and biological complications, and implant survival rate.
AIM:
The primary aim of this systematic review was to evaluate the effect of various techniques used for vertical ridge augmentation on clinical vertical bone gain.
MATERIAL AND METHODS:
A protocol was developed to answer the following focused question: "In patients with vertical alveolar ridge deficiencies, how effective are different augmentation procedures for clinical alveolar ridge gain?" Randomized and controlled clinical trials and prospective and retrospective case series were included, and meta-analyses were performed to evaluate vertical bone gain based on the type of procedure and to compare bone gains in controlled studies.
RESULTS:
Thirty-six publications were included. Results demonstrated a significant vertical bone gain for all treatment approaches [n=33; weighted mean effect = 4.16 mm; 95% CI 3.72-4.61; p<0.001]. Clinical vertical bone gain and complications rate varied among the different procedures, with a weighted mean gain of 8.04 mm and complications rate of 47.3% for distraction osteogenesis, 4.18 mm and 12.1% for guided bone regeneration (GBR) and 3.46 mm and 23.9% for bone blocks. In comparative studies, GBR achieved a significant greater bone gain when compared to bone blocks [n=3; weighted mean difference=1.34 mm; 95% CI 0.76-1.91; p<0.001].
CONCLUSIONS:
Vertical ridge augmentation is a feasible and effective therapy for the reconstruction of deficient alveolar ridges, although complications are common.
Introduction
The aim of this systematic review is to analyze current evidence regarding differences in early and late implant failure as well as in marginal bone level (MBL) changes between submerged and non‐submerged healed dental implants.
Methods
PUBMED, SCOPUS, EMBASE and Web of Science databases were searched for prospective randomized and non‐randomized controlled studies addressing direct comparison between submerged and non‐submerged implant healing, without performing immediate loading. Early and late implant failure (before or after 6 months from implant placement, respectively), together with MBL were the investigated outcomes. Risk of bias assessment was performed using the Cochrane Collaboration Tool for Randomized clinical trials. Meta‐analysis was performed and the power of the meta‐analytic findings determined by trial sequential analysis (TSA).
Results
11 studies met the inclusion criteria and were included in the review. Results of this systematic review revealed a small higher rate (2%) of early implant failure when a non‐submerged healing approach is performed. Late implant failure appears not to be different in submerged or non‐submerged healing, but the power of evidence, as determined by TSA, is not high. If we consider MBL changes at 1 year from implant load, it seems that non‐submerged healing may better preserve marginal bone, although with a small effect size (0.13 mm).
Conclusions
Implants placed with a non‐submerged technique have a higher risk (2%) of early failure. The power of the evidence about the effects on MBL is low, but present results seem to favor submerged healing, although with a very small effect size.
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This systematic review aimed to determine: (1) the expected bone volume gain with the split crest technique, and (2) how the use of surgical instruments affects the performance of this technique. An electronic search was performed in the Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, Embase, PubMed/MEDLINE, Scopus, and Web of Science databases. Twenty-seven articles met the selection criteria and were subjected to meta-analysis of bone gain and survival rate; 17 reported the use of conventional surgical instruments and nine the use of surgical ultrasound. A total of 4115 implants were installed in 1732 patients (average patient age 52 years). The overall implant survival rate was 97%. The average bone gain in studies that used conventional surgical instruments was 3.61 mm, while this was 3.69 mm in those that used ultrasound. Only two studies presented a low risk of bias. The greatest problems identified during the qualitative analysis were related to random selection of the population and the absence of statistical analysis. The split crest technique appears to be a promising and effective technique to gain bone width, regardless of the surgical instruments used. Considering the diversity of the studies and implant types, no definitive recommendations can be made, especially with regard to the best instruments and implant design to be used.
Objectives:
This randomized clinical trial analyzed crestal bone changes and soft tissue dimensions surrounding implants with an internal tapered connection placed in the mandible anterior region at different depths (equicrestal and subcrestal).
Materials and methods:
Eleven edentulous patients (five implants per patient) were randomly divided in a split-mouth design: G1, 28 equicrestal implants; and G2, 27 subcrestal implants. All implants were immediately loaded. Correlation between keratinized tissue width (KTW) and vertical mucosa thickness (MT) with soft tissue recession was analyzed. Intraoral radiographs were used to evaluate crestal bone changes. Patients were assessed immediately, 4-, and 8-months after implant placement. Rank-based ANOVA-type statistical test was used for comparison between groups (α = 0.05).
Results:
Fifty-five implants (G1 = 28 and G2 = 27) were assessed in 11 patients. Implant survival rate was 100% for both groups. Both tested implant placement depths presented similar crestal bone loss (P > 0.05). Significant crestal bone loss for each group was found in the different measurement times (T4 and T8) (P < 0.05). Implant placement depths, KTW, and vertical MT had no effect on soft tissue recession (P > 0.05).
Conclusions:
Different implant placement depths do not influence crestal bone changes. Soft tissue behavior is not influenced by different implant placement depths or by the amount of keratinized tissue.
To evaluate the effect of piezoelectric surgery (PS) implant osteotomy on biochemical and radiological parameters of crestal bone (CB) loss.
In this randomized, controlled, clinical study, 38 osteotomies were prepared with PS and drilling in the posterior maxilla in a split-mouth design. Implants were placed and left for non-submerged healing. Osteotomy time, insertion torque, pain perception, probing depth, and modified gingival and plaque indices were recorded. Peri-implant sulcular fluid (PISF) was collected from four sites of each implant at 2, 4, 8, 12, and 24 weeks. PISF samples were analyzed by ELISA for receptor activator of nuclear factor kappa-B-ligand (RANKL) and osteoprotegerin. CB loss was assessed on periapical radiographs at the 12th and on cone beam computed tomography (CBCT) at the 24th weeks. The influence of time and osteotomy method on biochemical and radiological parameters of CB loss employed statistical method of Brunner-Langer.
Osteotomy time for PS group was significantly longer than the drill group (P < 0.05). Pain perception that was lower in the PS than in the drill group depended on osteotomy method (P < 0.05). PS group had lower RANKL total amount than the drill group (P < 0.05). Mean CB loss on periapical radiographs at the 12th week for PS and drill groups were 0.11 and 0.18 mm, respectively (P > 0.05). At the 24th week, PS and drill groups showed 0.11 and 0.12 mm CB losses on CBCT, respectively (P > 0.05). However, CB loss values did not depend on osteotomy modality (P > 0.05).
PS may modify and reduce bone-destructive inflammatory response during implant osseointegration. Therefore, on the molecular level, it might be a less traumatic osteotomy modality than drilling although this was not reflected by CB loss values in the present study.
© 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.
We used resonance frequency analysis to evaluate the implant stability quotient (ISQ) of dental implants that were installed in sites prepared by either conventional drilling or piezoelectric tips. We studied 30 patients with bilateral edentulous areas in the maxillary premolar region who were randomised to have the implant inserted with conventional drilling, or with piezoelectric surgery. The stability of each implant was measured by resonance frequency analysis immediately after placement to assess the immediate stability (time 1) and again at 90 days (time 2) and 150 days (time 3). In the conventional group the mean (SD) ISQ for time 1 was 69.1 (6.1) (95% CI 52.4-77.3); for time 2, 70.7 (5.7) (95% CI 60.4-82.8); and for time 3, 71.7 (4.5) (95% CI 64.2-79.2). In the piezosurgery group the corresponding values were: 77.5 (4.6) (95% CI 71.1-84.3) for time 1, 77.0 (4.2) (95% CI, 69.7-85.2) for time 2, and 79.1 (3.1) (95% CI 74.5-87.3) for time 3. The results showed significant increases in the ISQ values for the piezosurgery group at each time point (p=0.04). The stability of implants placed using the piezoelectric method was greater than that of implants placed using the conventional technique.
Immediate placement refers to the placement of an implant into a tooth socket at the time of extraction; early placement refers to the placement of an implant after substantial gingival healing, but before any clinically significant bone fill occurs within the socket. This study evaluated the success and survival rates of implants following immediate and early placement. 50 implants were placed in 36 patients. 26 immediate (group I) and 24 early placements (group II) were performed. Pain or tenderness with function, mobility, radiographic bone loss from initial surgery and exudate history were evaluated. Mean vertical bone loss in the immediate placement group was 0.55mm and 0.80mm in the early placement group. The survival rate for the immediate placement group was 96.16% with 51.6 months follow-up and in the early placement group was 100% with 61.9 months follow-up. The results of this study suggest that although the success and survival rates of early placed implants were a little higher and the follow up period was longer than immediately placed implants, the difference was not remarkable. In conclusion, both implant insertion techniques are safe and reliable procedures with considerably high survival rates.
Following tooth loss, the maxillary alveolar ridge is affected by extensive resorption and its cancellous bone substance undergoes intense remodeling processes. This is particularly important for endosseous implant surgery as the primary stability and thus the prognosis of endosseous implants depends on the cancellous bone density and structure of the alveolar ridge. To analyze the structure of alveolar trabecular bone, 156 sections were obtained from 52 edentulous maxillae (29 female, 23 male; mean age: 72.5 years) from the lateral incisor, first premolar, and first molar regions. The structural histomorphometric analysis was performed on cancellous bone of the section surfaces using semiautomatic image analysis. The following parameters were measured: trabecular bone volume, trabecular number, trabecular thickness, trabecular plate separation and trabecular interconnection. All examined parameters showed an extreme range of variation. A difference of more than 45% between the highest (=51.93%) and the lowest (=6.73%) trabecular bone volumes was found. Furthermore, the measurements showed that trabecular bone volume, thickness and number were distinctly lower in the molar region than in the incisal and premolar regions. Significant sex-specific differences were found in all investigated regions, female maxillae showing a smaller amount and a lower connectivity of cancellous bone than male maxillae.
The aim of this systematic review was to evaluate the best timing for placing implants after tooth extraction, by comparing early vs. delayed implant placement and evaluating the hard and/or soft tissue ridge dimensional changes and the outcomes related with implant survival and prosthesis success.
An online search of the main databases including The National Library of Medicine (MEDLINE via Pubmed), Embase and The Cochrane Central Register of Controlled Trials was conducted up to February 2011. Randomized controlled clinical trials (RCTs), prospective cohort studies and case-control retrospective studies, with a follow-up of at least 1 month after loading of dental implants, comparing: (i) early vs. delayed implant placement, (ii) augmentation vs. no augmentation at implant placement in early placed implants and/or (iii) the comparison of various augmentation procedures at early implant placement, were conducted. A hand search of relevant journals was also performed. Screening of eligible studies, assessment of their methodological quality and data extraction were conducted in duplicate by two independent reviewers. Authors of studies were contacted for clarification or missing information.
Eight studies were included, although meta-analysis could only be performed with the data from two studies comparing early vs. delayed implant. The percentage of bone height and bone width reduction favoured the early placement, with pooled mean difference between groups of 13.11% (95% CI: from 3.83 to 22.4; P = 0.057) and 19.85% (95% CI: from 13.85 to 25.81) respectively. Implant survival demonstrated a non-significant higher implant survival rate for the early group (RR = 1.02, 95% CI: 0.96-1.1).With regard to patient satisfaction, statistically significant differences between the groups in favour of the early group for overall satisfaction and appearance with the restoration were demonstrated at 2 years, although these differences were lost at 5 years.
Placement of dental implants at an early timing after tooth extraction may offer advantages in terms of soft and hard tissue preservation, when compared with a delayed protocol. Nevertheless, well-designed, high quality, randomized clinical trials, are needed, because the available evidence is today limited in terms of available studies and quality.
Osseointegrated dental implantation is traditionally performed by a flap approach that involves soft tissue flap reflection, but this technique is associated with several drawbacks. Conversely, the flapless method requires only minimal removal of soft tissue but is not suitable for all patients. The objective of this study was to compare the flapless (FL) method of implant placement with the traditional flap (TR) method with regard to achievement of success, change in bone level, and overall safety.
In this single-center, open, retrospective, investigator-driven, nonrandomized, comparative study, patients were pre- or intraoperatively assigned to the FL or TR treatment. The primary success criteria were the absence of mobility, radiolucency, pain, and infection.
The FL method was applied to 174 implants (46%) in 121 patients and the TR method to 203 implants (54%) in 98 patients. At visit 1, implantation was rated successful in 171/174 (98.3%) implants with the FL method and in 200/203 (98.5%) with the TR method. Success rate remained constant until visit 2. The difference between the 2 groups in the rate of success was not significant. Similarly, no significant difference was observed for mean time to last follow-up for success.
Based on pre- or intraoperative decision-making, patients eligible for FL surgery can benefit from a less straining procedure without affecting the high success rate of dental implant surgery. The FL approach is a predictable procedure when patient selection and surgical technique are appropriate.
Alveolar distraction is a constantly evolving technique. A review of the literature within the past 14 years reveals that there are clear indications for its use, with outcomes similar to and sometimes even more predictable than traditional bone grafting techniques in preparation for implant placement. Although complications exist with alveolar distraction, it seems that most are minor and easy to manage. Appropriate patient selection and a better understanding of the technique are paramount to successful bone regeneration with alveolar distraction osteogenesis. This article discusses newer research and provides clinical advice on the practice of alveolar distraction osteogenesis for dental implant preparation.
Although it has been shown that the exclusion of the mucoperiosteal flap can prevent postoperative bone resorption associated with flap elevation, there have been only a few studies on the peri-implant mucosa following flapless implant surgery. The purpose of this study was to compare the morphogenesis of the peri-implant mucosa between flap and flapless implant surgeries by using a canine mandible model.
In six mongrel dogs, bilateral edentulated flat alveolar ridges were created in the mandible. After 3 months of healing, 2 implants were placed in each side by either the flap or the flapless procedure. Three months after implant insertion, the peri-implant mucosa was evaluated by using clinical, radiologic, and histometric parameters, which included the gingival index, bleeding on probing, probing pocket depth, marginal bone loss, and the vertical dimension of the peri-implant tissues.
The height of the mucosa, length of the junctional epithelium, gingival index, bleeding on probing, probing depth, and marginal bone loss were all significantly greater in the dogs that had the flap procedure than in those that had the flapless procedure (P < .05).
These results indicate that gingival inflammation, the height of junctional epithelium, and bone loss around nonsubmerged implants can be reduced when implants are placed without flap elevation.
The aim of this study was to indicate the necessity of overcorrection regarding the occurrence of bone height relapse at the end of consolidation period in distracted alveolar bone.
Eleven patients with a total of 17 distractions performed and 43 implants placed were included in this study. Bone height was evaluated on computed tomography before the procedure and on orthopantomographic radiographs following distraction and consolidation. Measurement was performed on the aproximal surfaces of implants and on identical points before and after distraction.
The mean of distraction performed was 6.08 +/- 1.82 mm at mesial points and 6.18 +/- 1.90 mm at distal points of measurement. The mean of bone relapse following consolidation period was 1.57 +/- 1.82 mm at the mesial and 1.79 +/- 1.68 mm at the distal aspects of implants. Statistical evaluation revealed that alveolar bone distraction should include 20% of overcorrection for both mesial and distal points of measurements plus 0.34 mm for mesial and 0.52 mm for distal points of measurement.
Occurrence of relapse found in this study indicates that overcorrection should be included when performing alveolar distraction osteogenesis.
Vertical distraction of the alveolar process is an efficient method for augmentation prior to inserting dental implants. In this study, complications of this procedure and relapse of the transport segment were evaluated in partially dentulous patients. Twenty patients underwent distraction by means of extraosseous distractors. The location of the defects was the anterior mandible (4), posterior mandible (4), anterior maxilla (10) and posterior maxilla (2). Bone height was measured on panoramic radiographs preoperatively, after distraction and after implant placement at the mesial and distal point of the implant(s). Mean alveolar distraction was 6.5mm at the mesial point (P<0.001) and 6.1mm at the distal point (P<0.001). The mean relapse at the mesial point was 20% and at the distal point 17% (P<0.05). The intraoperative and postoperative problems encountered were fracture (1) and lingual (4) and palatal (6) displacement of the transport segment. Overall complication rate was 55%. Of all implants placed (n=63) one was lost. Implant success rate was 98%. Distraction seems to be a suitable treatment for vertically deficient alveolar bone, but a relatively high although manageable complication rate must be confronted, including considerable relapse.
To investigate the association between keratinized mucosa (KM) width and mucosal thickness (MTh) with clinical and immunological parameters around dental implants.
Sixty-three functioning dental implants (3I osseotite) were examined. Clinical examinations included plaque index (PI), probing depth (PD), bleeding on probing (BOP), KM width, MTh and buccal mucosal recession (MR). Peri-implant crevicular fluid (PICF) samples were collected for PgE2 assay.
KM width ranged from 0 to 7 mm (mean 2.5+/-2), MTh ranged from 0.38 to 2.46 mm (mean 1.11+/-0.4) and the mean MR was 0.62 mm, ranging from 0 to 3 mm. A negative correlation was found between MTh and MR (r=-0.32, P=0.01); Likewise, KM width showed a negative correlation with MR, periodontal attachment level (PAL) and PgE2 levels (r=-0.41, P<0.001; r=-0.26, P=0.04; r=-0.26, P=0.04, respectively). In contrast, a positive correlation was found between KM width and PD (r=0.27, P=0.03). When data were dichotomized by KM width, a wider mucosal band (>1 mm) was associated with less MR compared with narrow (<or=1 mm) band (0.27 and 0.9 mm, respectively, P=0.001). A wider KM band was also associated with a greater PD (3.13 mm) compared with a narrow band (2.66 mm, P=0.04). Similarly, a thick mucosa (>or=1 mm) was associated with lesser recession compared with a thin (<1 mm) mucosa (0.45 and 0.9 mm, respectively, P=0.04).
The KM around dental implants affects both the clinical and the immunological parameters at these sites. These findings are of special importance in the esthetic zone, where thin and narrow KM may lead to a greater MR.
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