Effects of Different Patient and Prosthetic Variables on Marginal Bone Behavior in Dental Implants: A Clinical Retrospective Study.

Background and Objectives: This study aimed to evaluate marginal bone level (MBL) changes in implant-supported rehabilitation based on patient demographics, implant location, transmucosal abutment height, and crown emergence profile. Materials and Methods: A total of 50 patients (28 females and 22 males), with 111 implant-abutment (IA) sets, were analyzed. The mean age was 65.2 ± 10.9 years (range: 33-81). Implants were placed in the maxilla (68.5%) and mandible (31.5%), with an average evaluation period of 12.7 ± 4.1 months. MBL changes at mesial (MBLm) and distal (MBLd) sites were recorded and analyzed based on sex, age, implant location, abutment transmucosal height, and crown emergence profile. Statistical comparisons were performed using Bonferroni's multiple comparison test and one-way ANOVA with Tukey's post hoc test. Results: MBL changes did not show significant differences based on sex (p > 0.05) or age group (p > 0.05). However, maxillary implants exhibited greater bone loss than mandibular implants, though this difference was not statistically significant. Transmucosal abutment height (TMh) significantly influenced MBL, with taller abutments (TMh3: -1.07 ± 0.93 mm) showing less bone loss than shorter abutments (TMh1: -2.11 ± 1.82 mm) (p < 0.05). Crown emergence profile also affected MBL, particularly in the distal emergence profile, where design 1 exhibited the least bone loss compared to designs 2 and 3 (p = 0.0176). Conclusions: The study findings suggest that transmucosal abutment height and crown emergence profile significantly influence peri-implant bone stability. Transmucosal abutment height (> 2.5 mm) was associated with reduced bone loss. Further research is recommended to evaluate the long-term effects on peri-implant bone maintenance.