Effect of recombinant human bone morphogenetic protein-2 on bisphosphonate-treated osteoblasts

OBJECTIVES: Bisphosphonate-related osteonecrosis of the jaw (BRONJ) is a side effect of bisphophonate therapy that has been reported in recent years. Osteoclastic inactivity by bisphosphonate is the known cause of BRONJ. Bone morphogenetic protein-2 (BMP-2) plays an important role in the development of bone. Recombinant human BMP-2 (rhBMP-2) is potentially useful as an activation factor for bone repair. We hypothesized that rhBMP-2 would enhance the osteoclast-osteoblast interaction related to bone remodeling. MATERIALS AND METHODS: Human fetal osteoblast cells (hFOB 1.19) were treated with 100 microM alendronate, and 100 ng/mL rhBMP-2 was added. Cells were incubated for a further 48 hours, and cell viability was measured using an MTT assay. Expression of the three cytokines from osteoblasts, receptor activator of nuclear factor-kappaB ligand (RANKL), osteoprotegerin (OPG), and macrophage colony-stimulating factor (M-CSF), were analyzed by real-time polymerase chain reaction and enzyme-linked immunosorbent assay. RESULTS: Cell viability was decreased to 82.75%+/-1.00% by alendronate and then increased to 110.43%+/-1.35% after treatment with rhBMP-2 (P<0.05, respectively). OPG, RANKL, and M-CSF expression were all decreased by alendronate treatment. RANKL and M-CSF expression were increased, but OPG was not significantly affected by rhBMP-2. CONCLUSION: rhBMP2 does not affect OPG gene expression in hFOB, but it may increase RANKL and M-CSF gene expression.

An Evaluation of Initial Stability after Maxillary Posterior Impaction

Stability after surgical correction of mandibular prognathism using bilateral saggital split ramus osteotomy and fixation with Poly-L/DL-Lactide copolymer screws (biosorbTMFX)

Fibrosis that ocurred after conservative therapy of large odontogenic keratocyst

Odontogenic keratocysts are developmental odontogenic cysts which derived from rests of dental laminas and often found in posterior area of mandible. Because this lesion has tendency of frequent recurrence, treatment of choice is often radical removal of the lesion. Sometimes in case of large cysts, however, conservative therapy like marsupialization is often selected in treatment plan. A 39-years old woman referred to our department for evaluation of large radiolucent lesion that occupies the areas from mandible angle to upper part of ramus and condyle. In cytology, the lesion was identified as odontogenic keratocyst. Marsupialization was our treatment of choice, and the result was so favorable. 2 years later, there was small radiolucent lesion on upper part of mandibular ramus on panoramic view. It was suspected as recurred lesion, and excisional biopsy was done. On biopsy result, it was not a cystic lesion but fibrosis.