In-Situ vs. Ex-Situ Bone Onlay Grafting for Horizontal Ridge Augmentation of Anterior Teeth: A Retrospective Study

This study aimed to systematically compare the efficacy and resorption of in-situ and ex-situ bone onlay grafting in reconstructing horizontal alveolar ridge defects of anterior teeth.

One-hundred and twenty five patients receiving autogenous bone onlay grafts in the anterior tooth region were included in this study, which comprised 55 patients with 66 implants receiving in-situ bone grafts (in-situ group) and 70 patients with 77 implants receiving ex-situ bone grafts (ex-situ group). All patients were examined by CBCT scanning before bone augmentation (T0), immediately after bone augmentation (T1), at 5-8 months after bone augmentation (T2), immediately after implant placement (T3), and 5-8 months after implant placement (T4). Horizontal bone width (HBW) and bone volume (BV) were measured at different postoperative time points after automated image registration of consecutive CBCT imaging.

The resorption rate of HBW from T1 to T2 in the in-situ group (23.84% ± 17.07%) was significantly lower than that in the ex-situ group (38.77% ± 19.94%) (p < 0.0001). However, from T3 to T4, no significant difference was observed between the two groups. Additionally, from T1 to T2, there were significant differences in the resorption rate of BV between the in-situ group (20.03% ± 16.14%) and the ex-situ group (28.20% ± 17.58%) (p < 0.05). In contrast, no significant differences between the two groups from T3 to T4 were noted.

Both in-situ and ex-situ onlay graftings showed a satisfactory outcome in bone augmentation, yet in-situ bone graft had more bone augmentation and better stability than ex-situ bone graft.