Inlay versus onlay iliac bone grafting in atrophic posterior mandible: a prospective controlled clinical trial for the comparison of two techniques

Abstract

Purpose: To compare the efficacy of inlay and onlay bone grafting techniques in terms of vertical bone formation and implant outcomes for correcting atrophic posterior mandibles.

Materials and methods: Twenty surgical sites were assigned to two treatment groups, inlay and onlay, with iliac crest as donor site. After 3 to 4 months, 43 implants were placed and loaded 4 months later. The median follow up after loading was 18 months.

Results: For the inlay versus onlay group, median bone gain was 4.9 versus 6.5 mm (p = .019), median bone resorption was 0.5 versus 2.75 mm (p < .001), and median final vertical augmentation was 4.1 versus 4 mm (p = .190). The implant survival rate was 100% in both groups, while the implant success rate was 90% versus 86.9% (p = .190, not significant). A minor and major complication rate of 20% and 10%, respectively, for both groups was encountered.

Conclusions: Inlay results in less bone resorption and more predictable outcomes, but requires an experienced surgeon. In contrast, onlay results in greater bone resorption and requires a bone block graft oversized in height, but involves a shorter learning curve. Once implant placement has been carried out, the outcomes are similar for both procedures.