Synthetic plga block scaffolds versus autogenous dentin block grafts for alveolar ridge augmentation: a 6-month retrospective cbct cohort study

Alveolar ridge resorption following tooth loss impedes prosthetically driven dental implant placement. Although autogenous bone blocks remain the gold standard, donor-site morbidity limits their use. Autogenous dentin blocks (ADB) and synthetic poly(lactic-co-glycolic acid) combined with β-tricalcium phosphate (PLGA/β-TCP) scaffolds have been investigated in protocols avoiding separate autogenous block harvesting. This study evaluated 6-month radiographic augmented hard-tissue volume and horizontal ridge width changes achieved with PLGA/β-TCP scaffolds versus ADBs within standardized multi-material augmentation protocols. Sixty-five augmented sites in 41 patients were retrospectively evaluated (PLGA/β-TCP: 32 sites in 22 patients; ADB: 33 sites in 19 patients). Both protocols utilized screw fixation, a 1:1 mixture of autogenous bone scrapings and bovine xenograft, and titanium-prepared platelet-rich fibrin membranes. Preoperative and 6-month postoperative CBCT datasets were aligned using stable anatomical landmarks. Horizontal ridge widths (at 3, 5 and 7 mm depths) and 3D augmented hard-tissue volumes were evaluated using Romexis and ITK-SNAP software. Primary horizontal outcomes were analyzed using baseline-adjusted linear mixed-effects models (LMM), specifying random intercepts for patients and sites nested within patients. A patient-random-intercept model was used for volumetric analysis. Measurement repeatability was determined using the intraclass correlation coefficient (ICC). Intra-observer reliability was high (ICC:0.86–0.93). In primary LMM analyses, adjusted PLGA-minus-ADB differences in 6-month horizontal width were − 0.25 mm at 3 mm (95% CI: −0.71 to 0.22; p = 0.297), − 0.28 mm at 5 mm (95% CI: −0.74 to 0.18; p = 0.223), and − 0.35 mm at 7 mm (95% CI: −0.81 to 0.11; p = 0.135). The treatment-by-depth interaction was not statistically significant ( p = 0.875). For radiographic augmented hard-tissue volume, the adjusted difference was − 34.47 mm³ (95% CI: −288.10 to 219.15; p = 0.784). Seven patients experienced localized complications (5/22 PLGA vs. 2/19 ADB; Fisher’s exact test, p = 0.419), with zero graft loss. Both multimaterial protocols demonstrated descriptive increases in horizontal ridge dimensions and radiographic augmented hard-tissue volume at 6 months. In baseline-adjusted hierarchical models, no statistically significant between-group differences were detected. Both techniques successfully avoided harvesting a separate intraoral autogenous bone block; however, the confidence intervals do not demonstrate clinical equivalence or interchangeability, and long-term peri-implant stability warrants prospective investigation.