Correlations of Alkaline Phosphatase Expression with Osteoblast Number during Orthodontic Tooth Movement, in vivo

The alveolar bone has capacity adapting to tooth movement. Alveolar bone remodels whilst undergoing orthodontic tooth movement (OTM). There are two mechanisms happened after the administration of orthodontic force, the pressure side undergoes bone resorption, whilst the tension side undergoes bone apposition. Osteoblast activity can be determined from alkaline phosphatase (ALP). The purpose of this research was to investigate the correlations of alkaline phosphatase expression with osteoblast number during orthodontic tooth movement. The samples consisted of 30 Wistar rats which were selected at random and then split into 5 groups: group 0 (controlled group, no orthodontic tooth movement, day 0), group 1-4 (with orthodontic tooth movement, day 7,14, 21, and 28). The orthodontic tooth movement (OTM) was distal movement, produced using simple coil spring, installed between both upper central incisive with light force. Furthermore, the Alkaline phosphatase expression and osteoblast number was examined in the alveolar bone during OTM in vivo. Alkaline phosphatase expression was increased significantly 7 days after applying OTM and gradually increasing as the OTM progressed. Osteoblast count was also increased significantly 7 days after applying OTM. There are correlations of alkaline phosphatase expression with osteoblast number during orthodontic tooth movement. When the number of osteoblasts increases, the ALP expression also increases.