Inlay versus Onlay Iliac Bone Grafting in Atrophic Posterior Mandible: A Prospective Controlled Clinical Trial for the Comparison of Two Techniques

Abstract

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. 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. 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. 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.