Onlay grafting with bovine bone mineral block for horizontal reconstruction of severely atrophic alveolar ridges in anterior maxillae: A 6-year prospective study.

PURPOSE: The aim of this prospective study was to evaluate the efficacy and long-term outcomes of onlay grafting with bovine bone mineral block for reconstruction of horizontal alveolar ridge defects in anterior maxillae. MATERIALS AND METHODS: Fourteen patients requiring rehabilitation of edentulous anterior maxillae were enrolled to receive onlay grafting in two layers. A cortical block harvested from the lateral aspect of the mandibular ramus was split to acquire approximately 1-mm-thick bone laminae. The cortical bone plate and block graft were compressed and fixed to the recipient sites. After 6 months, the width of the augmentation was recorded, and implants were inserted. Provisional and definitive prostheses were delivered 3 and a further 6 months later. Implant success and associated complications were assessed. RESULTS: The horizontal bone gain was 8.73 +/- 0.82, with a resorption rate of 7.03%. Severe bone resorption was noticed 6 months and 2 years after loading. Fistula occurred with the nonintegrated bovine block on the labial sides of the augmented sites 6 years after loading. CONCLUSION: Onlay grafting with bovine bone mineral block in the anterior maxilla may yield optimal horizontal gain with low resorption rates, under the condition of at least 6 months' healing time, mixation with autogenous particulate bone, and application of a membrane to cover the graft site.