Edition V06N01 | Year 2012 | Editorial Artigo Selecionado | Pages 54 to 66
The objective of this research was to evaluate the regeneration of alveolar ridge width defects following surgical implantation of recombinant bone morphogenetic protein-2 (rhBMP-2) using two different carriers: a) Tricalcium Phosphate (TCP) / Hydroxyapatite (HA) / Absorbable collagen sponge (ACS) and b) α-BSM cement (CaPO4) in the baboon model. Standardized alveolar ridge defects (15 X 8 X 5 mm) were made in 4 edentulous areas, in 4 baboons. Sites were balanced as to treatments and maxilla/mandible. Two titanium pins were placed at the mid apical and coronal levels to provide landmarks for defect measurements (width) and comparisons pre and post – treatment reentry. Impressions of the pre and post treatment ridges were also taken and models made to determine changes in clinical defect volume. Five treatments were performed: rhBMP-2/TCP/HA/ACS, TCP/HA/ACS alone, rhBMP-2/α-BSM(CaPO4), α-BSM(CaPO4) alone and unimplanted Control. A dose of 0.4-mg/ml rhBMP-2 was used in rhBMP-2 treated sites. Qualitative radiographic observations were recorded at pre implantation and before reentry. Block sections (mid-defects) were harvested at 12 -16 weeks, processed for light microscopy and stained with Mason’s Trichrome. Three central histologic sections were evaluated for trabecular bone area, marrow space area and bone density using the Computerized Image Program. Statistical comparisons between treatments were made using ANOVA. Carriers by themselves demonstrated sufficient rigidity, resistance to compression and osteoconductive capacity to provide for modest ridge augmentation. Addition of rhBMP-2 resulted in almost double the increase in width and volume, and statistically significant more trabecular bone, less marrow space and higher density than the carriers alone. The rhBMP-2/α-BSM(CaPO4) construct demonstrated superior, but not statistically significant (p ≥ 0.05) results over the rhBMP-2/TCP/HA/ACS implant Both TCP/HA/ACS and α-BSM(CaPO4) appear to be suitable carriers for rhBMP-2. The enhancement of both carrier systems with rhBMP-2 provided a viable alternative to second site grafting for the augmentation of alveolar ridge defects prior to implant placement. In addition, these treatments were the only ones that provided enough clinical ridge width for implant placement.