International journal of oral implantology (Berlin, Germany)最新文献

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.

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.

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.

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.

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.

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.

Aims: Immediate fixed full-arch implant-supported prosthetic rehabilitation of the severely atrophic maxilla is a challenging treatment modality with favourable patient interest. The delivery of the treatment is challenging due to the difficulty in providing adequate posterior implant positioning with high primary stability in the absence of alveolar bone distal to the maxillary lateral incisors. Current trends in posterior implant placement and immediate loading include the placement of zygomatic implants or distally tilted implants placed anterior to the sinus cavity. The development of an extended-length subcrestal angulated implant gives an additional option to provide posterior occlusal support for reconstruction of the severely atrophic maxilla with an immediate full-arch fixed prosthesis.

Materials and methods: This article describes a trans-sinus nasal protocol for fixed full-arch rehabilitation in the severely atrophic maxilla when the residual alveolar bone does not extend distally from the permanent maxillary lateral incisors. The extended-length distally tilted implant transverses a simultaneously augmented sinus cavity and engages the anterior maxilla and bone of the lateral nasal wall.

Results: The placement of an extended-length distal tilted implant placed the implant head at the crest of the alveolar ridge in the first permanent molar position, promoting favourable prosthetic biomechanics for a full-arch fixed prosthesis. Passivity of fit of the fixed prosthesis was achieved due to the 24-degree subcrestal angulation feature of the implant and use of multi-unit abutments.

Purpose: To evaluate whether the use of piezoelectric bone surgery (PBS) for implant site preparation reduces surgical time, improves implant stability, preserves marginal bone level and improves the survival rate of oral implants compared with conventional drilling techniques.

Materials and methods: This meta-analysis followed the PRISMA (preferred reporting items for systematic review and meta-analysis) guidelines and was registered in the PROSPERO (international prospective register of systematic reviews) database (CRD42019142749). The PubMed, Embase, Scopus and Open Grey databases were screened for articles published from 1 January 1990 to 31 December 2018. The selection criteria included randomised controlled trials (RCTs) and case-control studies (CCTs) comparing the PBS with conventional rotary instruments for implant site preparation, and reporting any of the selected clinical outcomes (surgical time, implant stability, marginal bone variations and implant failure rate) for both groups. The risk of bias assessment was performed using the Cochrane Collaboration tool for RCTs and the Newcastle-Ottawa scale (NOS) for CCTs. A meta-analysis was performed, and the power of the meta-analytic findings was assessed by trial sequential analysis (TSA).

Results: Eight RCTs and one CCT met the inclusion criteria and were included in the review. The meta-analysis and the TSA showed moderate evidence suggesting that the PBS prolongs surgery duration and improves secondary stability 12 weeks after implant placement compared with conventional drilling techniques. Insufficient data are available in literature to assess if the PBS reduces marginal bone loss and/or improves the implant survival rate compared with conventional drilling techniques.

Conclusions: Adequately powered randomised clinical trials are needed to confirm the PBS positive effect on the secondary stability and to draw conclusions about the influence of PBS on marginal bone stability and implant survival.

Purpose: To assess the technical and biological complications of screw- and cement-retained implant-supported full-arch dental prostheses.

Materials and methods: An electronic search was conducted on Medline/PubMed and Cochrane databases in February 2019; irrespective of any time restrictions using MeSH terms. All studies were first reviewed by abstract and subsequently by full-text reading. Further hand search was performed to identify other related references. Articles only related to cement-retained and/or screw-retained reconstructions in full-arch fixed dental prostheses (FDP) were included.

Results: The initial literature search resulted in 3670 papers. 3478 articles remained after removing duplicate articles, and 3439 articles were further excluded by the reviewers after the abstract screening, which resulted in a selection of 39 studies. 12 studies were further excluded due to not fulfilling the inclusion criteria. Hand searching resulted in two additional papers being included, and finally, 29 articles were included in this review. Screw-retained full-arch fixed dental prostheses have fewer complications than cemented reconstructions. Biological complications such as marginal bone loss > 2 mm occurred more frequently in cemented reconstructions, and technical complications such as screw-loosening and screw fracture occurred more in screw-retained reconstructions.

Conclusion: Cemented reconstructions exhibited more biological complications (implant loss, bone loss > 2 mm) and screw-retained prostheses exhibited more technical problems. Clinical outcomes were influenced by both fixations in different ways. The screw-retained restorations were more easily retrievable than cemented ones, therefore, technical and eventually biological complications could be treated more easily. For this reason, and for their higher biological compatibility, these reconstructions are preferable.

Purpose: To describe implant survival at least 1 year after the surgical treatment of early apical peri-implantitis (EAP) and explore potential risk factors of failure of such treatment.

Materials and methods: An ambispective cohort study was conducted, involving all patients in whom EAP was detected and surgically treated between 1996 and 2016. Reporting followed the STROBE guidelines. The time from implant placement (IP) to EAP surgery (EAPS), the diagnostic stage and intraoperative variables (location, apical lesion in the tooth being replaced, mesial and distal tooth-implant distance measured at the apex, periapical surgery of the adjacent tooth, guided bone regeneration, implant resection, explantation) were recorded to determine their impact upon treatment outcome.

Results: The initial sample consisted of 58 implants in 46 patients. The mean time from IP to EAPS was 21.7 ± 10.1 days. At the time of surgery, eight implants presented mobility and were explanted. The final sample consisted of 50 implants in 39 patients evaluated for implant survival after surgical treatment. A cumulative survival rate of 78.3% was recorded. The mean survival time of the EAP treated implants was 85.4 months (standard deviation [SD] 5.94). The diagnostic stage (P < 0.001) and the existence of a previous periapical lesion in the tooth being replaced (P = 0.022) had a significant influence upon implant survival.

Conclusions: The cumulative survival rate was 78.3%, with a mean survival time of 85.4 months. The diagnostic stage of EAP and the presence of a lesion in the tooth being replaced significantly influenced the survival of implants with EAP subjected to surgical treatment.