Objective:The aim of this study was to investigate the spatial and temporal mRNA expression changes of integrinB1during the healing process ofmandibularfractures.Methods:The in situ hybridizationwas performed using digoxigenin-labeled integrinB1 mRNA oligonucleotide probe. During the healing process of mandibular fractures, the staining pattern ofB1mRNAwas examined both spatially and time-dependently.Results:IntegrinB1was widely present in the cells of the fractured bone, especially in os- teoblasts. The positive stainingwas observed in the cytoplasm and nucleolus of osteoblasts. After7 days of fracture, the expression level of integrinB1increased. The peak appeared between the 14th and the 30th day, and almost recovered to normal between the 60th and 90th day.Conclusion:During the healing process ofmandibularfracture, the expression level of integrinB1in bone, es- pecially in osteoblasts rose. It is suggested that integrinB1may play an important role in the fracture healing process.