Early marginal bone loss (MBL) is a non-infective remodeling process of variable entity occurring within the first year after implant placement. It has a multifactorial etiology, being influenced by both surgical and prosthetic factors. Their impact remains a matter of debate, and controversial information is available, particularly regarding implants placed subcrestally. The present multicenter prospective clinical study aimed to correlate marginal bone loss around platform-switched implants with conical connection inserted subcrestally to general and local factors. Fifty-five patients were enrolled according to strict inclusion/exclusion criteria by four clinical centers. Single or multiple implants (AnyRidge, MegaGen, South Korea) were inserted in the posterior mandible with a one-stage protocol. Impressions were taken after two months of healing (T1), screwed metal-ceramic restorations were delivered three months after implant insertion (T2), and patients were recalled after six months (T3) and twelve months (T4) of prosthetic loading. Periapical radiographs were acquired at each time point. Bone levels were measured at each time point on both mesial and distal aspects of implants. Linear mixed models were fitted to the data to identify predictors associated with MBL. Fifty patients (25 male, 25 female; mean age 58.0 ± 12.8) with a total of 83 implants were included in the final analysis. The mean subcrestal position of the implant shoulder at baseline was 1.24 ± 0.57 mm, while at T4, it was 0.46 ± 0.59 mm under the bone level. Early marginal bone remodeling was significantly influenced by implant insertion depth and factors related to biological width establishment (vertical mucosal thickness, healing, and prosthetic abutment height). Deep implant insertion, thin peri-implant mucosa, and short abutments were associated with greater marginal bone loss up to six months after prosthetic loading. Peri-implant bone levels tended to stabilize after this time, and no further marginal bone resorption was recorded at twelve months after implant loading.

Background: The purpose of this study was to compare clinical results of two different horizontal ridge augmentation techniques: guided bone regeneration with sticky bone (SB) and the bone-shell technique (BS). Methods: Records of patients who underwent horizontal ridge augmentation with SB (test) and BS (control) were screened for inclusion. Pre-operative and 6-month post-operative ridge widths were measured on cone beam computer tomography (CBCT) and compared. Post-operative complications and implant survival rate were recorded. Results: Eighty consecutive patients were included in the present study. Post-operative complications (flap dehiscence, and graft infection) occurred in ten patients, who dropped out from the study (12.5% complication rate). Stepwise multivariate logistic regression analysis showed a significant inverse correlation between the occurrence of post-operative complications and ridge width (p = 0.025). Seventy patients (35 test; 35 control) with a total of 127 implants were included in the final analysis. Mean ridge width gain was 3.7 ± 1.2 mm in the test and 3.7 ± 1.1 mm in the control group, with no significant difference between the two groups. No implant failure was recorded, with a mean follow-up of 42.7 ± 16.0 months after functional loading. Conclusions: SB and BS showed comparable clinical outcomes in horizontal ridge augmentation, resulting in sufficient crestal width increase to allow implant placement in an adequate bone envelope.

Objective: The aim of this study was to evaluate histomorphometric outcomes of lateral maxillary sinus augmentation in different areas of the same cavity and to correlate results to bucco‐palatal sinus width (SW) and residual bone height (RBH).Material and Methods: Patients needing maxillary sinus floor elevation (RBH <5 mm) to insert two nonadjacent implants were treated with lateral augmentation using a composite graft. Six months later, two bone‐core biopsies (mesial/distal) were retrieved in implant insertion sites. SW and RBH were measured on cone beam computed tomography, and correlations between histomorphometric and anatomical parameters were evaluated by multivariate linear regression analysis.Results: Twenty patients underwent sinus augmentation, and eighteen were included in the final analysis (two dropouts for membrane perforation). Mean newly formed mineralized tissue percentage (%NFMT) after 6 months in mesial and distal sites was 17.5 ± 4.7 and 11.6 ± 4.7, respectively (p = .0004). Multivariate linear regression showed a strong negative correlation between SW and %NFMT (β coefficient=−.774, p < .0001) and no correlation between RBH and %NFMT (β coefficient =−.038, p = .825).Conclusions: The present study confirms that %NFMT after lateral sinus augmentation occurs at different rates in different anatomical areas of the same maxillary sinus, showing a strong negative correlation with SW, whereas no influence of RBH was observed. Clinicians should regard SW as a guide for graft selection and to decide duration of the healing period. Researchers should consider SW as a predictor variable, when comparing regenerative outcomes of different biomaterials by using maxillary sinus as an experimental model.

Introduction: This study analyzes early marginal bone modifications occurring around platform‐switched implants with conical connection placed 1 or 2 mm subcrestally.Methods: This crossover randomized controlled trial enrolled partially edentulous patients needing two implants in either the posterior maxilla or mandible. Each patient received two platform‐switched implants with conical connection inserted 2 mm (Test) and 1 mm (Control) subcrestally. Definitive abutments were immediately connected and, after 4 months of unsubmerged healing, screwed metal‐ceramic crowns were delivered. Radiographs were taken at implant placement (T0), prosthesis delivery (T1), and after 1 year of prosthetic loading (T2).Results: Fifty‐one patients (25 males and 26 females; mean age 61.2 ± 12.1 years) totaling 102 implants were included in the final analysis. Mean peri‐implant bone level (PBL) reduction from T0 to T2 was not significantly different around Test (0.49 ± 0.32 mm) and Control implants (0.46 ± 0.35 mm;p = 0.66). Multivariate linear regression models highlighted a significant positive correlation between history of periodontitis and PBL reduction. At T2, no Test group implant and 6 Control group implants exhibited PBL below the implant platform (11.8% of Control group implants).Conclusion: No significant differences in peri‐implant marginal bone changes were demonstrated after 1 year of prosthetic loading between platform‐switched implants with conical connection inserted either 1 or 2 mm subcrestally. However, 2 mm subcrestal placement resulted in deeper implant positioning at T2, with no exposure of treated implant surface and potential preventive effect against subsequent peri‐implant pathology.

Background: Numerous clinical variables may influence early marginal bone loss (EMBL), including surgical, prosthetic and host-related factors. Among them, bone crest width plays a crucial role: an adequate peri-implant bone envelope has a protective effect against the influence of the aforementioned factors on marginal bone stability. The aim of the present study was to investigate the influence of buccal and palatal bone thickness at the time of implant placement on EMBL during the submerged healing period. Methods: Patients presenting a single edentulism in the upper premolar area and requiring implant-supported rehabilitation were enrolled following inclusion and exclusion criteria. Internal connection implants (Twinfit, Dentaurum, Ispringen, Germany) were inserted after piezoelectric implant site preparation. Mid-facial and mid-palatal thickness and height of the peri-implant bone were measured immediately after implant placement (T0) with a periodontal probe and recorded to the nearest 0.5 mm. After 3 months of submerged healing (T1), implants were uncovered and measurements were repeated with the same protocol. Kruskal-Wallis test for independent samples was used to compare bone changes from T0 to T1. Multivariate linear regression models were built to assess the influence of different variables on buccal and palatal EMBL. Results: Ninety patients (50 females, 40 males, mean age 42.9 ± 15.1 years), treated with the insertion of 90 implants in maxillary premolar area, were included in the final analysis. Mean buccal and palatal bone thickness at T0 were 2.42 ± 0.64 mm and 1.31 ± 0.38 mm, respectively. Mean buccal and palatal bone thickness at T1 were 1.92 ± 0.71 mm and 0.87 ± 0.49 mm, respectively. Changes in both buccal and palatal thickness from T0 to T1 resulted statistically significant (p = 0.000). Changes in vertical bone levels from T0 to T1 resulted not significant both on buccal (mean vertical resorption 0.04 ± 0.14 mm; p = 0.479) and palatal side (mean vertical resorption 0.03 ± 0.11 mm; p = 0.737). Multivariate linear regression analysis showed a significant negative correlation between vertical bone resorption and bone thickness at T0 on both buccal and palatal side. Conclusion: The present findings suggest that a bone envelope > 2 mm on the buccal side and > 1 mm on the palatal side may effectively prevent peri-implant vertical bone resorption following surgical trauma. Trial Registration: The present study was retrospectively recorded in a public register of clinical trials (www.clinicaltrials.gov - NCT05632172) on 30/11/2022.