The Increase of Maxillary Lateral Expansion Limit by Local Application of Fluvastatin

Statins are known not only for HMG-CoA reductase inhibitors, but also as drugs with bone formation ability. The objective of this study was to investigate the possibility of increasing the lateral expansion limit in orthodontic treatment by induce bone formation in the buccal alveolar bone through local application of fluvastatin（statins）. The effectiveness of statins was evaluated by using MC3T3-E1 cells to cell proliferation ability, osteoblast differentiation ability, and mRNA levels of mineralization maker genes. Further, we mounted a lateral enlargement device to the maxillary molar region of a 10-week-old male C57BL/6J mouse. After 14 days, we used specimens of the first molar alveolar bone to carry out width diameter measurement, measurement of the amount of root exposure, and histological evaluation of specimen sections. For the statin group, we injected optimal concentration statins into the gingiva. As a result, mRNA levels of mineralization maker genes expressions in the MC3T3-E1 cells increased in the administered 10 nM statins compared to the control. Further, the calcification ability of the 10 nM statins increased compared to the control. In vivo, there was no significant difference in the amount of lateral enlargement, but the amount of root exposure was significantly less, and the amount of bone added to the buccal alveolar bone was higher in the statin group than in the control group. In conclusion, local application of statins to the alveolar process during lateral enlargement of maxillary dentition prevents exposure of root surfaces through buccal alveolar bone resorption, suggesting the possibility of increasing the lateral expansion limit. applications in chronic periodontitis, alveolar bone loss from tooth extraction or chronic periodontitis, osseointe-gration of implants, pulp cells, orthodontics, and tooth movement（20）.