3D-driven alveolar ridge augmentation based on reverse planning: a retrospective case series study

Reconstruction of advanced vertical and combined alveolar ridge defects still remains a challenge in implant dentistry. Digital technologies and virtual planning may potentially improve the predictability of guided bone regeneration (GBR). This study aimed to evaluate a fully digital, reverse-planning workflow for vertical ridge augmentation using membrane-cutting guides.

This retrospective case series included 15 surgical sites presenting with vertical or combined alveolar ridge defects. A digital workflow integrating cone-beam computed tomography (CBCT), intraoral scanning, and virtual prosthetic planning was used to simulate ideal implant positions and corresponding hard tissue augmentation. Membrane-cutting guides were designed and fabricated using additive manufacturing to shape dense polytetrafluoroethylene membranes. Vertical GBR was performed using a split-thickness flap design and a tent-pole approach. Linear and volumetric hard tissue changes were assessed by comparing baseline and 9-month postoperative CBCT scans.

Significant vertical bone gain was observed at all measurement points (p = 0.007), with mean increases from 15.70 mm ± 4.34 mm to 19.96 mm ± 3.83 mm at the central site. The mean volumetric hard tissue gain was 755.33 mm³ ± 411.22 mm³, closely matching the planned volume (757.50 mm³ ± 417.78 mm³), with no significant difference (p = 0.649). Using Spearman's correlation, a strong positive correlation was found between planned and achieved volumes (Spearman's ρ = 0.825, p = 0.0004). The mean augmentation efficacy was 20.13 ± 15.21 mm³/mm.

The proposed 3D-driven reverse-planning workflow enabled predictable vertical ridge augmentation with high agreement between planned and achieved outcomes. This approach represents a feasible and accessible alternative to fully customized systems; however, further prospective controlled studies are required to validate these findings.