Association between peri-implant bone morphology and marginal bone loss: A retrospective study on implant-supported mandibular overdentures

Purpose: The present study aimed to explore the association between marginal bone loss and type of peri-implant bony defect determined using a new peri-implant bony defect classification system. Materials and Methods: A total of 110 patients with implant-supported mandibular overdentures were involved. Clinical information was collected, including gender, age, smoking habit, and the overdenture attachment system used. Peri-implant bony defect types and marginal distances (ie, distance between the marginal bone level and the top of the implant shoulder) of all sites were identified on panoramic radiographs by a single experienced observer. The associations between marginal distance and peri-implant bony defect type, gender, age, smoking habit, attachment system, and time after implantation were investigated using marginal generalized linear models and regression analysis. Results: A total of 83 participants were included in the final sample with a total of 224 implants involving 3,124 implant sites. The mean observation time was 10.7 years. All peri-implant bony defect types except Type 5 (slit-like) were significantly related to marginal distance in all models (P <.01). Smoking and time after implantation were significantly related to marginal distance while gender, age, and the overdenture attachment system used were not. Conclusions: The periimplant bony defect type, determined using the new classification system, is associated with the extent of marginal bone loss.