Immunohistochemical Analysis on Cortex-to-Cortex Healing After Mandibular Vertical Ramus Osteotomy: A Preliminary Study

Abstract

PURPOSE: The present study analyzed the expression of specific cytokines in the transforming growth factor (TGF)-beta superfamily postoperatively after mandibular vertical ramus osteotomy (VRO). MATERIALS AND METHODS: Four beagle dogs were enrolled and euthanized at 1, 2, 4, and 8 weeks postoperatively for immunohistochemical analysis using 6 specific antibodies (bone morphogenetic protein [BMP]-2/4, BMP-7, TGF-beta2, TGF-beta3, matrix metalloproteinase-3, and vascular endothelial growth factor [VEGF]). The results from the surgical site and control (adjacent area) were compared. RESULTS: Generalized upregulation of BMP-2/4 was observed in all healing periods, and the strongest expression of BMP-7 was observed at 1 week postoperatively. The strongest expression of TGF-beta2 was observed at 8 weeks with increasing pattern. The strong expression of TGF-beta3 was observed at 1 and 4 weeks, with the strongest expression of VEGF at 1 week, with a decreasing pattern. No notable uptake was detected with the 6 specific antibodies in the adjacent bone (control). CONCLUSIONS: The absence of internal fixation after VRO led to dynamic healing with a specific expression pattern of BMP-7 and TGF-beta2. The anatomic factors, including sufficient preexisting vascularity, led to the earlier expression pattern of VEGF.