[An experimental study of tooth mesial migration].

OBJECTIVE

To study the mechanism of tooth mesial migration with animal experiment.

METHODS

The upper and lower first molars of Wuzhishan miniature pigs were used as experimental teeth. The mesial migration of experimental teeth was calculated and analysed by measuring the models. Fluorescent mark was used and analysed by injecting tetracycline and xvlenol orange, and histological changes were analyzed.

RESULTS

The lower teeth migrate mesially 0.14 mm and 1.21 mm during 16 weeks, and the upper teeth migrate mesially 1.36 mm and 2.08 mm during 24 weeks. The distal alveolar bones of experimental teeth had fluorescent bands; alveolar bones of teeth without antagonist teeth reconstructed in vertical direction; the distance between fluorescent bands of lower experimental teeth without antagonist teeth was wider than that of teeth with antagonist teeth. The fluorescent bands formed in both mesial and distal cementum.

CONCLUSION

The results don't support the point that transseptal fibre or force of molar eruption makes teeth migrate mesially; the mesial migration of teeth is related with the reconstruction of alveolar bones and the stress distribution in the bones.