11h10 3D bone graft design for preprosthetic reconstruction of the jaw: presentation of 3D Work-Flow and Preliminary Results

Keywords: bone grafting; segmentation; 3D; preprosthetic surgery.

Objectives: autologous bone grafting is considered the gold standard for reconstructing the atrophic jaw. With advancements in technology, patient-specific 3D design has gained significant traction in the field of preprosthetic reconstruction. However, comparative studies examining the differences in success rates between conventional and 3D-planned preprosthetic procedures for local monoblock reconstructions are lacking. The primary objective of this study is to evaluate the potential benefits of 3D-planned local jaw augmentation using an autologous bone graft from the retromolar area for patients with a local defect in the alveolar ridge. The focus includes predictive reconstruction, time efficiency, and postoperative outcomes.

Material and Methods: a prospective study was conducted with the study population randomized into three groups: 1) 3D Planned (3P) group: Jaw augmentation was virtually planned; 2) 3D Planned and Guided (3PG) group: Jaw augmentation was virtually planned, and a 3D-printed cutting guide was utilized for harvesting the bone graft; 3) Control (C) group: Conventional jaw augmentation was performed without any 3D preparation. 3D segmentation and guide designs were created using 3D Slicer (https://www.slicer.org) and Meshmixer (Autodesk Inc.). The guides were fabricated through a commercial laboratory. Patients were followed for four months post-procedure. Statistical analysis was performed using IBM SPSS Statistics for Windows, version 21.0 (IBM Corporation, NY, USA). A significance threshold of P < 0.05 was applied to determine statistical relevance.

Results: this presentation focuses on outlining a 3D workflow and showcasing intermediate key findings supported by appropriate data visualizations from this ongoing study. Sample size calculations were informed by similar previous trials, determining that 10 patients per group are required to detect a 60% difference between groups with a significance level of 0.05 and a power of 80% (two-sided z-test with pooled variance for comparing proportions).

Conclusion: current experience with the 3D workflow for small monoblock autologous bone graft procedures demonstrates a feasible and practical protocol for planning local preprosthetic reconstructions. Preliminary findings indicate significant benefits in improving the predictiveness of these reconstructions. Specifically, visualization of the intended dimensions of the required bone graft provides advantages in reducing harvesting time and overall operating time. Additionally, 3D preparations minimize the need for intraoperative adjustments to the bone graft for optimal reconstruction. When compared to solely using 3D preparation, the inclusion of a cutting guide during surgery further enhances these benefits. However, final conclusions will only be possible after the completion of patient recruitment and comprehensive statistical analysis.