(23) Retrospective analysis of factors related to the clinical outcome of alveolar ridge augmentation using guided bone regeneration

Introduction: Following tooth loss, bone remodeling is characterized by constant alveolar resorption, which may lead to horizontal, vertical, or combined ridge deficiencies. Various procedures were developed to increase bone volume, including alveolar distraction osteogenesis, ridge expansion, inlay/onlay block grafting procedure, and guided bone regeneration (GBR).

Significant effort has been made to develop novel GBR techniques and materials to improve clinical outcomes. Bone grafts in modern implant dentistry may be autogenous, allogenic, xenogenic, and alloplastic in nature, all of which vary in their osteogenic, osteoinductive, and osteoconductive capabilities.

Similarly, various barrier membranes have been considered to optimize bone regeneration by stabilizing bone graft material, maintaining space, and preventing epithelial cellular ingrowth.

Due to such a diverse library of materials, clinicians must have an evidence-based approach to material selection to optimize alveolar ridge augmentation, clinical outcomes and minimize complications. The aim of this study is to retrospectively analyze factors related to the difficulties of alveolar ridge augmentation using guided bone regeneration in a university setting.

Methods: This retrospective case-control study retrospectively reviewed medical records of 137 patients at Penn Dental Medicine who received guided bone regeneration between 2019 and 2021. Eligible candidates were determined by automated search using the procedure code in the electronic health record system. Descriptive statistics were used to evaluate correlations between surgical complications and other covariance using the Chi-Square test.

Patient demographics, surgical techniques and materials (gender, smoking status, ASA classification, pre-and post-operative medication, bone graft material, barrier membrane material, graft stabilization technique, use of biologics, and suture material) and risk factors with complications related to GBR were evaluated (infection, membrane exposure, osteonecrosis and the need for prospective additional grafting).

Results: Resorbable barrier membranes were associated with a significant decrease in complications (30.5%) (p < 0.05) when compared to non-resorbable membranes (77.8%).

Health status (including ASA classification, diabetes) failed to show significant influences on the incidence of complications (p>0.05). While females had greater complications (37.8%) than males (26.6%), the differences observed were not significant.

Bone graft materials showed a similar incidence of complications. The absence of graft stabilization (40.7%) was associated with a greater incidence of complications compared to the use of tacks (35.8%) and suture stabilization (23.2%). Although differences were observed among stabilization techniques, these differences were not significant (p>0.05).

Conclusions: Within the limitations of this study, non-resorbable barrier membranes seem to increase the number of complications during the healing time, however further evaluation is needed to check clinical outcomes both during and after implant placement.

Patient factors and surgical techniques did not significantly influence the incidence of complications associated with GBR. However, due to the limitation of the sample size, further investigations are needed to expand the power for logistic regression.

Lead Author’s Contributions to the Research Project: The lead author was responsible for and involved in complete data collection, partial statistical analysis, literature review and composition of the abstract.