International Journal of Oral Implantology, 01/2021

Purpose: To update an existing systematic review assessing the clinical performance of full-arch implant-supported monolithic zirconia fixed dental prostheses. Materials and methods: The review was conducted according to the guidelines outlined in the Preferred Reporting Items of Systematic Reviews and Meta-analyses (PRISMA) statement. An electronic search was conducted using the PubMed, Science Direct and Cochrane Library databases to identify clinical studies on full-arch implant-supported monolithic and minimally layered zirconia fixed dental prostheses. Human studies with a mean follow-up of at least 1 year and published in an English-language peer-reviewed journal up to April 2020 were included. Two independent examiners conducted the search and the review process. Results: The search generated 2110 articles. Thirty-three qualifying studies were retrieved for full-text evaluation and a total of 17 studies were included on the basis of preestablished criteria. All 17 studies reported satisfactory clinical and aesthetic outcomes. The technical complication rate related to this type of prosthesis is still minimal and survival rates are high. Conclusions: Full-arch dental implant restoration with monolithic zirconia is associated with high short-term success. Long-term data from studies with a strong level of evidence are still lacking. Keywords: dental implant, digital dentistry, edentulism, monolithic zirconia, prosthetic complications Conflict-of-interest statement: The authors declare no conflicts of interest related to this study.

Purpose: Guided bone regeneration is a frequently used surgical procedure for hard tissue reconstruction when horizontal and or/vertical augmentation are needed. The treatment concept is based on the application of occlusive membranes like non-resorbable membranes or titanium mesh plus resorbable membranes. However, there are no studies comparing the microcomputed tomography results for bone obtained using these two procedures, and this was the purpose of the present study. Materials and methods: A total of 40 patients with vertical posterior bone mandibular atrophy were randomly assigned to group A (guided bone regeneration with titanium-reinforced polytetrafluoroethylene membrane and simultaneous implant placement) or group B (guided bone regeneration with titanium mesh and collagen membrane and simultaneous implant placement). Tissue biopsy specimens were obtained from augmented sites after 9 months for microcomputed tomography analysis of volume of interest. Bone volume (BV/TV), biomaterial volume (MatV/TV), soft tissue volume (StV/TV), trabecular thickness (TbTh), trabecular number (TbN) and trabecular separation (TbSp) were measured. The correlation between regenerated bone and native bone was also evaluated. STATA software (StataCorp, College Station, TX, USA) was utilised for statistical analysis (significance α = 0.05). Results: In group A, the values of BV/TV, MatV/TV and StV/TV in regenerated bone were 28.8%, 8.9% and 62.4%, respectively. In group B, the values of BV/TV, MatV/TV and StV/TV were 30.0%, 11.0% and 59.0%, respectively. No statistical differences were found between the two groups for any of the variables (P < 0.05). In both groups, considerable differences were noted between regenerated and native bone (P > 0.05), with a slight correlation between the microcomputed tomography parameters that suggests that native bone influences the quality of regenerated bone. Conclusions: Based on microcomputed tomography analysis, both surgical approaches facilitated the obtention of approximately 30% of newly formed bone with the same microarchitecture. Native bone influences the quality and microarchitecture of the obtained bone, irrespective of the technique used. Keywords: bone atrophy, bone augmentation, guided bone regeneration, microCT Conflict-of-interest statement: The authors declare there are no conflicts of interest relating to this study.

Purpose: To evaluate short-term clinical and radiographic outcomes of bone regeneration procedures using thin cortical porcine xenogeneic bone plates in combination with autogenous bone chips compared with thin autogenous cortical plates and autogenous bone chips. Materials and methods: A total of 19 patients (12 women and 7 men, mean age 58.24 ± 3.09 years) were randomly allocated to two different groups regarding surgical procedure: autogenous cortical plates (ACP group) and xenogeneic cortical plates (XCP group). Preoperative CBCT scans were performed for each patient. Surgical time and postoperative pain were recorded, as well as tissue healing and graft resorption after 4 months, then another surgical procedure was performed to place dental implants. Data were analysed using an analysis of covariance. Results: Twenty-one surgical procedures were performed on 19 patients (10 from the XCP group and 9 from the ACP group). The operative time was significantly lower in the XCP group (25.45 ± 3.88 minutes) than in the ACP group (44.10 ± 3.60 minutes). The XCP group also showed less pain, but not significantly less, than the ACP group. The graft resorption rate in the ACP and XCP groups was 2.03 ± 1.58% and 3.49 ± 2.38% respectively, showing no statistically significant difference. Conclusions: Despite the limited sample size and non-uniform distribution between the maxilla and mandible as surgical sites, the results suggest that XCP and ACP grafts are similar in terms of bone volume gain and graft resorption rate, with no significant differences in wound healing or complication rate. Nevertheless, the XCP group recorded lower pain levels and required significantly less operative time compared to the ACP group. Keywords: autogenous bone, bone regeneration, randomised clinical trial, xenogeneic bone Conflict-of-interest statement: The authors declare there are no conflicts of interest related to this study.

Purpose: In recent years, dental malpractice claims have increased dramatically worldwide. The present study aimed to categorise and analyse claims related to implant dentistry that resulted in legal decisions in Israel, seeking to contribute to dental risk management and improve patient safety. Materials and methods: This study analysed legal claims registered by Medical Consultants International between 2005 and 2015. Only closed cases in which a decision was made were included. The parameters studied included patient age and sex, date of the complaint, treatment setting (private/public clinic), description of the adverse event and type of negligence claimed. Results: The cohort included 709 settled claims out of a total of 1066 that were litigated against dental practitioners in Israel during the study period. Of the patients included, 60.0% were women and 63.9% were aged 40 to 59 years. The most common treatment-related damage was neural injury in 133 patients (18.7% of the cohort). Unplanned changes in the treatment plan and violation of autonomy were the most frequent documentation-/information-related claims (66.3% and 32.7%, respectively). The legal responsibility of the dental practitioner was acknowledged in 89.0% of cases. Dental practitioners working in the private sector were more likely to be sued due to violation of autonomy than those working in public clinics. Conclusions: Although the main cause for lawsuits was actual bodily injury, the high percentage of documentation-/information-related malpractice claims calls for increased awareness of patients’ autonomy and rights. Practitioners should dedicate a significant part of the entire treatment time to preoperative diagnosis and planning. Keywords: implants, injury, lawsuit, malpractice Conflict-of-interest statement: The authors declare there are no conflicts of interest relating to this study.

Purpose: To compare immediate and delayed implant replacement at failed implant sites to evaluate the factors associated with early failure of second implants after replacement. Materials and methods: Data regarding early implant failure followed by replacement with another fixture in a private practice setting between 2003 and 2019 were analysed retrospectively. Early failure was defined as loss of the dental implant within 6 months of placement. The impact of patient-level (age, sex, diabetes, smoking history) and implant-level (timing of implant replacement, timing of prosthetic loading, bone grafting) variables on the early failure rate of second implants after replacement was evaluated. Due to the hierarchical structure of the data, a multivariate multilevel mixed-effects Poisson regression analysis was performed. Results: A total of 109 patients (63 men and 46 women) diagnosed with early implant failure at 124 implant sites were included in the present study. Fifty-eight implants were immediately replaced at the time of removal of the failed implant (test group), whereas 66 were replaced after a healing period of 2 to 4 months (delayed approach; control group). A total of 15 implants failed after replacement in 11 patients during the first 6 months of follow-up. Of these, nine failures (15.25%) occurred in seven patients (13.21%) after immediate replacement, and six (9.09%) occurred in four patients (7.02%) who underwent delayed replacement. No statistically significant differences were detected between the two groups (P = 0.431). Conclusions: No significant differences in implant survival at sites of previous failure were found according to the timing of implant replacement. Keywords: dental implant, implant failure, implant replacement, implantology, oral surgery Conflict-of-interest statement: The authors declare there are no conflicts of interest relating to this study.

Purpose: This study aimed to investigate the influence of the thickness of the sinus lateral wall on the incidence of sinus membrane perforation. Materials and methods: A retrospective study was conducted by reviewing dental records of patients who received lateral wall sinus elevation in two educational institutes. The wall thickness 4 mm and 6 mm coronal to the sinus floor was measured with CBCT. The occurrence of sinus membrane perforation was recorded and correlated to the wall thickness using a multilevel regression analysis. Results: A total of 209 CBCT scans and patient records (N = 251 sinuses, with 42 scans exhibiting bilateral sinuses) were included. The mean residual ridge height was 3.33 ± 1.41 mm. Sinus membrane perforation occurred in 67 sites. The overall mean lateral wall thickness was 1.59 ± 0.84 mm and 1.58 ± 0.83 mm at 4 mm and 6 mm coronal to the sinus floor, respectively. The mean wall thickness at 4 mm and 6 mm coronal to the sinus floor in the perforation group was 2.43 ± 0.56 mm and 2.41 ± 0.56 mm respectively, compared to 1.21 ± 0.40 mm and 1.23 ± 0.41 mm respectively in the non-perforation group (P < 0.01). The perforation rate was 56.4% if the lateral wall thickness at 4 mm coronal to the sinus floor was ≥ 2 mm and 12.1% if it was ≤ 1 mm. A similar difference in perforation rate was reported for the wall thickness measured at 6 mm coronal to the sinus floor (57.9% vs 13.4%). There was no statistically significant difference between smokers and non-smokers regarding perforation rate (P = 0.9604). The presence of sinus septa and sinus wall irregularities did not display a statistically significant difference (P = 0.7155 and P = 0.2971, respectively). Conclusion: The thickness of the lateral wall of the maxillary sinus was related to the occurrence of membrane perforation. Keywords: atrophied maxilla, lateral window, sinus elevation, sinus membrane Conflict-of-interest statement: The authors declare no conflicts of interest relating to this study.

Purpose: To compare radiographic predictors of medication-related osteonecrosis of the jaw in dental extraction sites. Materials and methods: Forty-one oncological patients undergoing intravenous or subcutaneous antiresorptive treatment, with a history of dental extraction visualised by panoramic imaging, were included in this retrospective study. Age-, sex- and extracted tooth–matched healthy patients who had previously undergone panoramic imaging were selected as controls (n = 57). A total of 288 extraction sites were independently evaluated by two oral and maxillofacial radiologists, who assessed eight distinct radiographic features. The radiographic features of extraction sites were noted to allow comparison between and within subjects regarding healing and osteonecrosis development. The association between radiographic findings, underlying dental disease and medication-related osteonecrosis of the jaw was also tested. The level of significance was set at 5%. Results: Patients under antiresorptive treatment presented with widening of the periodontal ligament space, thickening of the lamina dura, sclerotic bone pattern, horizontal bone loss and periapical radiolucency with bone reaction (P ≤ 0.05). Development of medication-related osteonecrosis of the jaw was associated with altered bone pattern, angular bone loss, furcation involvement and unsatisfactory endodontic treatment (P ≤ 0.05). An association between medication-related osteonecrosis of the jaw and previous dental disease was also found, particularly for periapical lesions and endodontic-periodontal disease (P ≤ 0.05). Conclusions: Radiographic predictors of further development of medication-related osteonecrosis of the jaw in extraction sites include heterogeneous bone pattern, angular bone loss and furcation involvement. Extraction sites with underlying bony changes related to endodontic and endodontic-periodontal disease are more prone to development of medication-related osteonecrosis of the jaw. Keywords: bisphosphonates, denosumab, extraction socket, maxillofacial surgery, neoplasms, osteonecrosis, radiology, risk factors, systemic health, tooth extraction Conflict-of-interest statement: The authors declare no conflicts of interest relating to this study.

Purpose: To compare 100% deproteinised bovine bone matrix grafts (DBBM, test group) and 100% autogenous bone grafts (AB, control group) for lateral maxillary sinus floor elevation in a blinded, parallel-group, randomised clinical trial. Materials and methods: Patients with 1 to 3 mm of residual bone height were randomised for sinus floor elevation with DBBM or AB grafts and simultaneous implant placement. The outcome variables were implant failure, complications, subjective satisfaction and radiographic peri-implant bone level 7 years after loading. Results: A total of 20 patients (27 implants) were randomised to the test group and 20 (32 implants) to the control group. Ten patients from the test group and seven from the control group dropped out. Two implant failures occurred in the test group, whereas none were observed in the control group (P = 0.178). One complication occurred in the test group and two were recorded in the control group (P = 1.000). The radiographic peri-implant crestal bone level was 2.5 ± 1.3 mm in the test group and 0.9 ± 0.9 mm in the control group. The difference was 1.6 mm, favouring the control group (95% confidence interval 0.7–2.6; P = 0.002). The difference in vertical bone height was −0.4 mm, favouring the control group (95% confidence interval −1.9–1.1; P = 0.590). The difference in satisfaction measured using a visual analogue scale 7 years after loading was 0.0 mm (95% confidence interval −1.0–0.0; P = 0.639). Conclusions: Differences between treatments were found for crestal bone level, favouring the control group. No differences were observed for the other variables evaluated. Keywords: bone substitutes, dental implants, maxillary sinus, randomised controlled trial, sinus floor augmentation Conflict-of-interest statement: The authors declare that this study was self-funded and that none of the authors have any conflict of interest.