Autogenous interpositional block graft vs onlay graft for horizontal ridge augmentation in the mandible

Background: Interpositional block graft revealed promising results in vertical ridge augmentation in the mandible, while scarce evidence is available regarding the use of interpositional block graft for horizontal ridge augmentation in the mandible.

Purpose: To compare the efficacy of autogenous block interpositional graft vs onlay graft in terms of horizontal ridge augmentation in the mandible.

Materials and methods: Twenty patients were randomly divided in two groups interpositional and onlay groups, using autogenous blocks harvested from the mandibular symphysis as the donor site. For the interpositional group, the mandibular ridge was split and the harvested block was inserted in the created space and fixated using titanium screws. For the onlay group, the defect site was decorticated and the harvested block was firmly fixated buccally using titanium screws. Immediate and 4 months postoperative cone beam computed tomography scans were taken for assessment.

Results: In the interpositional group, the mean preoperative bone width was 3.85 ± 0.6 mm, after 4 months, the mean bone width was 8.84 ± 0.54 mm. While in the onlay group, the mean preoperative bone width was 3.74 ± 0.83 mm while after 4 months the mean bone width was 7.37 ± 1.98 mm. this was statistically significant.

Conclusion: Within the limits of this study, interpositional block graft appears to be a viable treatment option for horizontal ridge augmentation in the mandible.