Effect of bovine bone and collagen membranes on healing of mandibular bone blocks: a prospective randomized controlled study

Aim: The aim of the present study was to evaluate if the use of deprotenized bovine bone mineral (DBBM) and collagen barrier membranes (CM) in combination with mandibular bone block grafts could reduce bone block graft resorption during healing. Methods: A prospective randomized controlled study has been designed. Twenty-two ridges presenting horizontal alveolar deficiency (crest width <4 mm) and at least two adjacent missing teeth were included in the study. In the control group, one or multiple mandibular blocks were used to gain horizontal augmentation of the ridge. In the test group, DBBM granules were added at the periphery and over the graft. The reconstructions were covered by two layers of CM. Implants were placed 4 months after grafting. Direct measurements of crest width were performed before and immediately after bone augmentation, and immediately before implant placement. Results: Statistical analysis showed no significant differences in crest width between test and control groups at baseline and immediately after grafting. Mean augmentation at first surgery in the test group was 4.18 vs. 4.57 mm in the control group. Final gain obtained at the time of implant placement was 3.93 mm in the test and 3.67 mm in the control groups. The difference in mean graft resorption between test and control sites was statistically significant (0.25 mm in the test group vs. 0.89 mm in the control group, P = 0.03). Complications seem to occur more often in the test group (complications recorded in three cases in the test group vs. one complication recorded in the control group). In all cases, implants could be placed in the planned sites and a total of 55 implants were placed (28 in the test group and 27 in the control group). All implants could be considered successfully integrated at the 24-month follow-up visit. Conclusion: The results from this study showed that the addition of bovine bone mineral and a CM around and over a mandibular bone block graft could minimize graft resorption during healing. On the other hand, the use of bone substitutes and barrier membranes in combination with block grafts increased the frequency of complications and the difficulty of their management.