[Establishment of animal model for research of first molar mesial movement in rat].

PURPOSE: To establish an animal model for research of first molar mesial movement in rat. METHODS: Forty 7-weeks-old SPF female Wistar rats were chosen in this experiment, which were divided into two groups. In each group, the two central incisors were used as anchorage to move the maxillary first molars mesially. In one group, traditional orthodontic appliances was used to move the first molars, while in another group modified device was used for moving the first molars. The distance of first molar mesial movement, the drop-off rate of orthodontic appliances and the periodontal status of first molars were evaluated. The data were analyzed with SPSS 11.0 software package. RESULTS: The drop-off rate in the group of individual orthodontic appliances was 5%. The drop-off rate in the group of traditional orthodontic appliance was 35%. There was significant difference in drop-off rate of orthodontic appliances and periodontal status of first molars between the two groups. But there was no significant difference on the molar moving distance. CONCLUSIONS: Individual orthodontic appliances are more suitable for tooth movement research than traditional ones. This animal model using individual orthodontic appliances can be used in future tooth movement research.