International Journal of Oral Implantology, 03/2020

Purpose: The evidence pertaining to the contribution of the sinus membrane to new bone formation following maxillary sinus augmentation procedures is equivocal. The purpose of this study was to analyse the evidence currently available on the osteogenic capacity of the sinus membrane following maxillary sinus augmentation procedures, and the effect of local delivery of recombinant human bone morphogenic proteins (rhBMPs) on the bone-forming potential of the sinus membrane. Materials and methods: An electronic search was conducted using six different databases to identify controlled trials, prospective and retrospective cohort studies, case series and case reports, as well as preclinical (animal) studies reporting on new bone formation in close proximity with the sinus membrane after maxillary sinus augmentation procedures, assessed through histological and/or histomorphometrical evaluation, on the basis of pre-established eligibility criteria. Results: No clinical studies were identified. Twenty-six preclinical studies were included in the review. Nine of them supported the osteogenic potential of the sinus membrane, while eight reported no evidence of osteogenicity from the sinus membrane. The nine remaining studies reported on the local effect of rhBMPs. The majority of these nine studies reported enhanced new bone formation in the sinus membrane region. Conclusions: The sinus membrane contains pluripotent mesenchymal cells with the capacity to differentiate and participate in the process of new bone formation. However, the findings from the studies selected in this systematic review do not consistently support that the sinus membrane significantly contributes to new bone formation following maxillary sinus augmentation procedures. Keywords: osteogenic, sinus elevation/graft, sinus membrane, systematic review Conflict-of-interest statement: The authors declare no conflicts of interest.

Purpose: Piezoelectric bone surgery was introduced into clinical practice almost 20 years ago as an alternative method for cutting bone in dental surgical procedures, in an attempt to reduce the disadvantages of using conventional rotary instruments. The aim of this Consensus Conference was to evaluate the current evidence concerning the use of piezoelectric surgery in oral surgery and implantology. Materials and methods: Three working groups conducted three meta-analyses with trial sequential analysis, focusing on the use of piezoelectric surgery in impacted mandibular third molar extraction, lateral sinus floor elevation and implant site preparation. The method of preparation of the systematic reviews, based on comprehensive search strategies and following preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines, was discussed and standardised. Results: Moderate/low evidence suggests that piezoelectric surgery is significantly associated with a more favourable postoperative course (less pain, less trismus) after impacted mandibular third molar extraction than conventional rotary instruments. Moderate evidence suggests that implants inserted with piezoelectric surgery showed improved secondary stability during the early phases of healing compared with those inserted using a drilling technique. Strong/moderate evidence suggests that piezoelectric surgery prolongs the duration of surgery in impacted mandibular third molar extraction, sinus floor elevation and implant site preparation, but it is unclear whether the slight differences in duration of surgery, even if statistically significant, represent a real clinical advantage for either operator or patient. Weak evidence or insufficient data are present to draw definitive conclusions on the other investigated outcomes. Conclusions: Further well-designed trials are needed to fully evaluate the effects of piezoelectric surgery, especially in implant site preparation and sinus floor elevation. Keywords: impacted mandibular third molar extraction, implant site preparation, piezoelectric surgery, sinus augmentation, systematic review

Purpose: Implant primary stability has long been considered a prerequisite for successful osseointegration. However, achieving stability may be difficult when placing implants in wide postextractive bone defects. The purpose of this study was to conduct a clinical and radiographic investigation of bone modifications at porous-structured implants inserted with or without primary stability. Materials and methods: Fifty porous-structured implants were inserted in the posterior sockets of 50 consecutive patients 2 months after tooth extraction, combined with allogeneic bone and a resorbable membrane. The implants were divided into two groups according to insertion torque: spinner (spinning at 35 Ncm, n = 23) and stable (stable at 35 Ncm, n = 27). Implant stability was assessed by resonance frequency analysis from baseline to 6-month function. Follow-up took place 3 years after implant placement. Results: At baseline, the implant stability quotient was undetectable in the spinner group and averaged 75.07 ± 5.84 in the stable group. At uncovering, the implant stability quotient increased to 71.33 ± 4.42 and 77.97 ± 3.30 in the spinner and stable group, respectively (P < 0.001). After 6 months of loading, no between-group difference in implant stability quotient was found (P = 0.13). Marginal bone level changes were similar between groups at all follow-ups, averaging −0.41 ± 0.77 mm and −0.15 ± 0.53 mm at 36-month follow-up in the spinner and stable group, respectively (P = 0.35). No implant failed throughout the observation period. Neither biological nor mechanical complications occurred. Conclusion: Implants with a moderately rough surface and a porous-structured body may osseointegrate even without primary stability. Keywords: alveolar bone resorption, bone regeneration, dental implants, implant primary stability, osseoincorporation, osseointegration, osseous defects Conflict-of-interest statement: Dr Bianconi, Prof Testori, Dr Fontanella and Prof Del Fabbro declare no conflicts of interest. Prof Wang received an honorarium to lecture at the Zimmer Biomet 3i NYU Symposium 2018.

Purpose: The present study aimed to identify the systemic risk indicators associated with peri-implant mucositis and peri-implantitis in individuals with implant-supported fixed prostheses. Materials and methods: In this cross-sectional study, clinical evaluations of periodontal and peri-implant conditions were performed by a single examiner in a sample of 71 volunteers with 360 implants. Peri-implant mucositis was defined as the occurrence of bleeding on probing in association with redness and swelling or suppuration, without bone loss. Peri-implantitis was defined based on a radiograph of bone loss ≥ 3 mm and/or a probing depth ≥ 6 mm with bleeding and/or suppuration on probing. The systemic factors evaluated were obesity, hormone replacement therapy, osteopaenia and osteoporosis, high blood pressure and hypercholesterolaemia. Logistic models were applied to assess the associations between peri-implant diseases and systemic factors. Results: Mucositis and peri-implantitis were found in 83.1% and 16.9% of the individuals, respectively. The regression analysis showed that obesity (prevalence ratio = 5.23; 95% confidence interval, 1.91 to 96.83; P = 0.01) and high systolic blood pressure (prevalence ratio = 4.23; 95% confidence interval, 1.66 to 12.87; P = 0.03) were associated with peri-implantitis at the individual and implant levels, respectively. No systemic factor was associated with peri-implant mucositis (P ≥ 0.06). Conclusion: Obesity and high systolic blood pressure were associated with peri-implantitis, whereas no systemic factor was associated with peri-implant mucositis. Future prospective studies are required to confirm these as true risk factors. Patients with obesity and/or high systolic blood pressure could be informed of the likely association with peri-implantitis, preferably before implant placement. Keywords: cross-sectional study, obesity, peri-implantitis, risk factors Conflict-of-interest statement: The authors have no commercial relationships to declare.

Purpose: To compare the short-term clinical and radiographic outcomes of angulated screw-retained and cemented implant crowns following flapless immediate implant placement. Materials and methods: The study was designed as a prospective cohort study with 1-year follow-up. Eligible patients were divided into two groups according to restoration type: the angulated screw group (AG) and the cemented group (CG). Implant survival, marginal bone loss, mechanical complications, probing depth, bleeding on probing% and pink aesthetic score were evaluated. Results: After 1 year of loading, the implant survival rate was 100% in both groups (AG, n = 23; CG, n = 20). A significantly lower bleeding on probing% was found in the AG than in the CG (11.6 ± 19.1% vs. 33.3 ± 33.8%, P = 0.04). No significant differences in marginal bone loss, probing depth and mechanical complication rates were found between the two groups (P = 0.53, 0.48, 0.41, respectively). The overall pink aesthetic score value was 8.96 ± 0.88 in the AG and 8.98 ± 0.62 in the CG at 1-year examination (P = 0.96). The percentage of excellent pink aesthetic scores (≥ 9) value increased from 48% at baseline to 83% at 1 year in the AG, and from 45% at baseline to 85% at 1 year in the CG. Conclusion: Based on the 1-year results, both treatment options provide high implant survival, a stable marginal bone level and excellent aesthetic outcomes in the short term. Angulated screw-retained crowns might benefit the long-term peri-implant conditions. Keywords: angulated screw-retained crown, cemented implant crown, flapless, immediate implant placement Conflict-of-interest statement: The authors declare no conflicts of interest.

Purpose: To investigate the influence of vertical mucosal thickness on marginal bone loss around implants with short and long prosthetic abutments and the marginal bone loss progression rate up to 18 months after prosthetic loading. Materials and methods: Internal hex platform-switched implants were placed equicrestally using a two-stage protocol in the posterior mandible of two groups of patients with different vertical mucosal thickness, thin (≤ 2.0 mm) and thick (> 2.0 mm). Elevated prosthetic abutments of different heights (1 mm or 3 mm) were randomly assigned for single screw-retained crowns in both groups. Mesial and distal marginal bone loss were measured at implant placement (T0) and crown delivery (after 4 months [T1]), and after 6 (T2), 12 (T3) and 18 months (T4) of functional loading. Results: Eighty implants were placed in eighty patients. Three patients dropped out at T2. At T4, 74 out of 77 implants were functioning, resulting in a 96% survival rate. Marginal bone loss (mean ± SE) at T2 was significantly greater in the 1-mm abutment groups (0.61 ± 0.09 mm with thin mucosa; 0.64 ± 0.07 mm with thick mucosa) than in the 3-mm abutment groups (0.32 ± 0.07 mm with thin mucosa; 0.26 ± 0.04 mm with thick mucosa). The marginal bone loss pattern over 18 months of loading showed that the greatest amount of marginal bone loss occurred during the first 6 months of function. Conclusions: Internal hex platform-switched implants placed equicrestally and restored with 1-mm abutments presented greater marginal bone loss than identical implants with 3-mm abutments, with vertical mucosal thickness having no significant influence. Keywords: abutment height, marginal bone loss, platform switching, vertical mucosal thickness Conflict-of-interest statement: The authors have no direct or indirect financial interest in the products listed or information presented in this article.

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. Conclusions: The use of extended-length subcrestal angulated implants provides surgical and prosthetic advantages for immediate fixed rehabilitation of the severely atrophic maxilla. It is potentially an alternative to the placement of zygomatic implants. Keywords: atrophic maxilla, case report/series, complete edentulous, immediate loading, sinus elevation/graft, subcrestal angulated implants