Tianjin Medical Journal ›› 2024, Vol. 52 ›› Issue (4): 367-371.doi: 10.11958/20230630

• Experimental Research • Previous Articles     Next Articles

Effects of different masticatory pressures on alveolar bone remodeling in the pressure side during orthodontic tooth movement in rats

TIAN Jing1(), WANG Zilong2, XIAO Danna1,(), FAN Xiangfei1   

  1. 1 Department of Orthodontics, Tianjin Stomatological Hospital, Tianjin 300041, China
    2 School of Medicine, Nankai University
  • Received:2023-04-24 Revised:2023-06-12 Published:2024-04-15 Online:2024-04-19
  • Contact: E-mail:1259815407@qq.com

Abstract:

Objective To study the effect of different masticatory pressures on alveolar bone remodeling in rats with orthodontic moving teeth. Methods Forty-five male SD rats aged 8 weeks were randomly divided into 3 groups: the baseline group (n=5), the soft diet group (n=20) and the hard diet group (n=20). Rats in the baseline group were sacrificed at the beginning of the experiment. The experimental rat models of right upper first molar movement were established in the soft diet group and the hard diet group. Left side of the maxillary was used as the control group. Each group was fed with corresponding diet. Five rats were sacrificed in each group on the day 3, day 5, day 7 and day 14 after orthodontic treatment respectively. Micro CT was used to measure the mesial movement distance of molar, bone volume/tissue volume (BV/TV), trabecular separation (Tb.Sp) and trabecular thickness (Tb.Th) of the alveolar bone on the pressure side. The number of osteoclasts in alveolar bone was counted after TRAP staining. In situ hybridization was used to detect the expression of RANKL and OPG. Results The amount of tooth movement was smaller on day 14 in the soft diet group than that of the hard diet group (P<0.05). There were no significant differences in BV/TV, Tb.SP and Tb.Th between the soft diet group and the hard diet group. TRAP staining and in situ hybridization showed that the number of osteoclasts and the RANKL/OPG ratio on day 5 and day 7 were lower in the soft diet group than those of the hard diet group (P<0.05). Conclusion The osteoclast activity in the alveolar bone on the pressure side of the orthodontic tooth is decreased and the tooth movement is inhibited under lower masticatory pressure.

Key words: mastication, pressure, tooth movement techniques, orthodontics, osteoclasts, osteoprotegerin, RANKL

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