Micro-computed tomography for evaluating alveolar bone resorption induced by hyperocclusion

Occlusal trauma, resulting in the destruction of alveolar bone, is a form of periodontal disease caused by excessive mechanical stress (MS) during hyperocclusion. Previously, we showed that CC chemokine ligand (CCL) 2/CCR2 receptor axis plays a crucial role in MS-dependent osteoclastogenesis. However, in the previous work, we were unable to precisely measure changes in alveolar bone profiles. In the present study, we sought to establish a precise method for evaluating alveolar bone resorption induced by hyperocclusion using micro-computed tomography. Under anesthesia, a stainless steel wire was attached to the molars of 5-week-old C57/BL6 wild-type (WT) mice, CCL2−/− mice, and CCR2−/−mice to induce occlusal force overload. At days 0 and 7, hard tissue samples were harvested and analyzed by micro-computed tomography. In the WT mice, bone mineral density of the alveolar bone was significantly decreased at day 7 as compared with day 0, with marked alveolar bone resorption observed. Similarly, significant alveolar bone resorption was observed in the CCL2−/− and CCR2−/− mice at day 7 as compared with day 0. Micro-computed tomographic images can be used to measure changes in bone mineral density in a mouse model of hyperocclusion. This method may be useful for further investigating bone changes in other periodontal disease research fields.