BACKGROUND:Bone remodeling is the biological basis of orthodontic tooth movement.Type 2 diabetes mellitus leads to metabolic changes in the jaw and alveolar bone,so it is hypothesized that tooth mobility characteristics may be altered in a high-sugar environment.OBJECTIVE:To explore the impact of type 2 diabetes mellitus on orthodontic tooth movement in rats within one tooth movement cycle.METHODS:Seventy-two Sprague-Dawley rats were selected.Forty rats were randomly chosen and fed with a high-fat diet to construct a type 2 diabetes mellitus model.Thirty-two rats that were successfully modeled were randomly divided into a type 2 diabetes mellitus group(n=16)and a diabetic orthodontic group(n=16).The remaining 32 rats were randomly divided into a control group(n=16)and an orthodontic group(n=16).The rats in the orthodontic group and the diabetic orthodontic group were equipped with nickel-titanium coil spring orthodontic force application devices to move the unilateral maxillary first molars mesially with a force of 50 g.The rats were anesthetized and sacrificed on the 3rd,7th,14th,and 21st days after orthodontic treatment,and Micro-CT was used to measure the mesial displacement of the first molars and detect the changes in the bone microstructure parameters on the tension side.RESULTS AND CONCLUSION:There were significant differences in the tooth movement distances among the four groups of rats on the 3rd,7th,14th,and 21st days of orthodontic treatment(P＜0.05).There were significant differences in bone mineral density,bone volume fraction and trabecular bone separation on the tension side among the four groups on the 7th,14th,and 21st days of orthodontic treatment(P＜0.05).There were differences in the trabecular thickness among the four groups on the 3rd and 14th days of orthodontic treatment(P＜0.05).The diabetic orthodontic group had the smallest tension-side alveolar bone mineral density,bone volume fraction,and trabecular thickness,and the largest tooth movement distance and trabecular separation on the 21st day of orthodontic treatment.The above results indicate that type 2 diabetes mellitus adversely affects bone microstructural parameters on the tension side in orthodontic tooth movement in rats,suggesting the occurrence of an osteoporotic state.

BACKGROUND:Bone remodeling is the biological basis of orthodontic tooth movement.Type 2 diabetes mellitus leads to metabolic changes in the jaw and alveolar bone,so it is hypothesized that tooth mobility characteristics may be altered in a high-sugar environment.OBJECTIVE:To explore the impact of type 2 diabetes mellitus on orthodontic tooth movement in rats within one tooth movement cycle.METHODS:Seventy-two Sprague-Dawley rats were selected.Forty rats were randomly chosen and fed with a high-fat diet to construct a type 2 diabetes mellitus model.Thirty-two rats that were successfully modeled were randomly divided into a type 2 diabetes mellitus group(n=16)and a diabetic orthodontic group(n=16).The remaining 32 rats were randomly divided into a control group(n=16)and an orthodontic group(n=16).The rats in the orthodontic group and the diabetic orthodontic group were equipped with nickel-titanium coil spring orthodontic force application devices to move the unilateral maxillary first molars mesially with a force of 50 g.The rats were anesthetized and sacrificed on the 3rd,7th,14th,and 21st days after orthodontic treatment,and Micro-CT was used to measure the mesial displacement of the first molars and detect the changes in the bone microstructure parameters on the tension side.RESULTS AND CONCLUSION:There were significant differences in the tooth movement distances among the four groups of rats on the 3rd,7th,14th,and 21st days of orthodontic treatment(P＜0.05).There were significant differences in bone mineral density,bone volume fraction and trabecular bone separation on the tension side among the four groups on the 7th,14th,and 21st days of orthodontic treatment(P＜0.05).There were differences in the trabecular thickness among the four groups on the 3rd and 14th days of orthodontic treatment(P＜0.05).The diabetic orthodontic group had the smallest tension-side alveolar bone mineral density,bone volume fraction,and trabecular thickness,and the largest tooth movement distance and trabecular separation on the 21st day of orthodontic treatment.The above results indicate that type 2 diabetes mellitus adversely affects bone microstructural parameters on the tension side in orthodontic tooth movement in rats,suggesting the occurrence of an osteoporotic state.