Background: Maxillary sinus floor augmentation (MSFA) is commonly used to increase posterior maxillary bone volume prior to implant placement. Although generally successful, late complications can impact long-term outcomes. The purpose of the study was to estimate the incidence and timing of atypical late complications following (MSFA) using bovine xenohybrid bone grafts. The study also aimed to evaluate whether preoperative bone volume is associated with the risk of complications. Methods: This retrospective cohort study was conducted at the Center of Oral and Maxillofacial Surgery, Danube Private University, Krems-Stein, Austria, and included patients who underwent MSFA with bovine xenohybrid bone grafts and either simultaneous or staged implant placement between January 2020 and December 2023. Preoperative bone volume of the posterior maxilla measured via cone beam computed tomography (CBCT) in the planned implant insertion position. The primary endpoint was the time (days) from MSFA to the occurrence of a graft-related complication (defined as atypical if occurring more than 6 months after MSFA and not related to peri-implantitis) The covariates included subjects’ age, sex, the quantity of graft used for MSFA, timing of dental implant insertion (simultaneous vs. staged) and implant dimensions. Kaplan–Meier analysis and Cox proportional hazards regression were used to evaluate time-to-event data. Only one graft site per patient was analyzed. Results: Atypical complications occurred in 9 out of 47 patients (19.1%), with an average time to onset of 645 days. In a multivariable analysis, a lower preoperative bone volume was found to be an independent predictor of an increased risk of complications (hazard ratio [HR]: 0.972; 95% confidence interval [CI]: 0.925–1.021; p = 0.252). However, the quantity of graft used for MSFA was not found to be a predictor (p = 0.46). Conclusions: Within the limitations of a retrospective study, reduced native bone volume appears to increase the risk of atypical late complications following MSFA with bovine xenohybrid grafts. This makes closer clinical and radiologic follow-up of patients over a longer period very necessary.

Background/Objectives: Maxillary sinus floor augmentation (MSFA) via the lateral approach is a well-established procedure for prosthetic rehabilitation of atrophic posterior maxillae. However, late complications are often nonspecific, with an incompletely understood aetiology. We evaluated patients with atypical late complications post-MSFA with bovine xenohybrid bone substitute NaturesQue SemOss B (BEGO GmbH, Bremen, Germany), describing their presentation, management, and outcomes. Methods: This retrospective, complication-selected clinical case series examined 47 patients who underwent lateral window MSFA with this graft from September 2020 to March 2023 in a single university department. Twelve complication cases were identified during the study period. Atypical late complications were defined as graft-associated clinical and/or radiological adverse outcomes, excluding peri-implantitis, that first manifested > 6 mo postoperatively. Baseline characteristics, perioperative findings, conservative and surgical management (including graft removal and reaugmentation), histology, and follow-up were assessed. Results: Twelve complication cases were identified among 47 patients treated during the study period. Seven experienced implant loss; seven, partial or complete lack of graft osseointegration; six, pain; and seven, signs of sinus infection. Histological analysis (6/12) revealed lymphocytes, plasma cells, and fibroblastic changes without detectable macrophages. No intraoperative complications were observed. Conclusions: Atypical late complications affected 25.5% of the patients. Despite comprehensive clinical, radiological, and histological assessments, the aetiology remained unclear, and the findings did not indicate a peri-implantitis-type infection; we hypothesised impaired early phase wound healing These patients were amenable to repeat augmentation post-non-osseointegrated graft removal, although larger studies are required.

Objective: This retrospective study investigated the relationship between the timing of single-tooth implant-supported restorations—including the interval from tooth extraction and socket preservation to implant placement and final prosthetic restoration—and the severity of periapical inflammation, as classified by the Dental Apical Inflammation Score (DAIS). Methods: A total of 87 patients were included (DAIS 1: 8; DAIS 2: 14; DAIS 3: 1; DAIS 4: 64). Procedural intervals (extraction, socket preservation, implant placement, and prosthetic restoration) were analyzed alongside histological assessment of periapical inflammation. Clinical parameters such as tooth location, endodontic treatment status, patient age, and sex were examined using ANOVA, chi-square tests, and Pearson’s correlation analysis. Results: An effective sample size of N = 86 (excluding the single DAIS 3 case) was included in the parametric analysis. No significant differences in procedural timing were found across DAIS groups for the intervals between extraction and implant placement (F(2, 83) = 0.338, p = 0.714) or restoration (F(2, 83) = 1.016, p = 0.367). Tukey’s HSD post hoc analysis showed no pairwise group differences. Histological diagnosis was not significantly associated with DAIS (χ²(6) = 7.00, p = 0.321), though small subgroup sizes warrant interpretive caution. A significant association was identified between DAIS score and tooth location (χ²(3) = 11.79, p = 0.008). Patient age showed a weak but significant positive correlation with DAIS (r = 0.222, p = 0.039). No significant associations were found for endodontic status (χ²(3) = 2.54, p = 0.468) or sex (χ²(3) = 2.63, p = 0.452). Histological assessment revealed that most specimens represented radicular cysts with varying proportions of acute and chronic inflammatory infiltrates, consistent with the DAIS classification. Conclusions: Procedural timing did not significantly differ between DAIS groups. However, the observed associations with tooth location and patient age may warrant further investigation into their potential relevance for treatment planning. These findings suggest that implant timing may not need to be substantially modified according to DAIS severity alone, but that anatomical site and patient age should be considered during clinical decision-making.

Introduction and importance: Internal tooth resorption is a rare, inflammation-mediated pathological process that is most often detected incidentally. Third molars appear to be disproportionately affected, possibly due to their anatomical and developmental characteristics. Reports comparing internal resorption of third molars in situ and after autologous transplantation remain scarce. Presentation of the case: This case series presents two uncommon clinical scenarios involving internal resorption of third molars. The first case describes simultaneous internal resorption affecting three third molars in situ without any identifiable triggering factors. The second case reports very late-onset internal resorption of a transplanted third molar, occurring nineteen years after successful autologous transplantation with long-term functional survival. Clinical discussion: The presented cases support the hypothesis of an intrinsic vulnerability in third molars to pulpal resorptive processes. Large pulp chambers, thin dentinal walls, delayed eruption, chronic low-grade inflammation, and cumulative biological stressors may contribute to odontoclastic activation. While autologous third molar transplantation can provide excellent long-term outcomes, late complications such as internal resorption may still arise after prolonged asymptomatic periods. Conclusion: Third molars may be particularly susceptible to internal resorption, both in situ and following transplantation. Although autologous transplantation is a reliable long-term treatment option, lifelong clinical and radiographic follow-up is essential to detect late-onset internal resorptive processes.