Bone remodeling during orthodontic tooth movement in rats with type 2 diabetes

• We investigated bone remodeling during orthodontic tooth movement in rats with type 2 diabetes.
• Goto-Kakizaki rats were used as the diabetes animal model; Wistar rats were the controls.
• Diminished bone formation was present after force application in rats with type 2 diabetes.
• A slight increase in bone resorption was found during tooth movement in the rats with diabetes.
• An increased rate of orthodontic tooth movement in patients with diabetes should not be expected.

IntroductionType 2 diabetes is known to affect bone metabolism. In this study, we aimed to determine the effects of type 2 diabetes on bone remodeling during orthodontic tooth movement.MethodsThe 48 rats were divided into 4 groups: Wistar control group (n = 8), Goto-Kakizaki (GK) control group (n = 8), Wistar appliance group (n = 16), and GK appliance group (n = 16). The distances between the teeth were measured weekly. On day 42, maxillary alveolar bone specimens were obtained for histologic evaluation and determination of the gene expression levels of the receptor activator of nuclear factor ҡB (RANK), RANK ligand (RANKL), and osteoprotegerin (OPG).ResultsNo significant difference was observed in the levels of tooth movement between the 2 appliance groups. After orthodontic force application, the alveolar bone volume and osteoblast surface in the GK rats were diminished compared with those in the Wistar rats. The increase in the osteoclast surface relative to the control groups was 2.4-fold greater in the GK rats than in the Wistar rats. Significant upregulations of the RANK and OPG gene expression levels in the Wistar appliance group were observed. The RANKL/OPG ratio was increased in the GK appliance group compared with the Wistar appliance group.ConclusionsDiminished bone formation and slightly increased bone resorption were observed during orthodontic tooth movement in the rats with type 2 diabetes.