关键词: 牙槽骨厚度, 拔牙, 切牙, 头影测量

Abstract:

Objective To investigate the changes of alveolar bone thickness after retraction of lower incisor. Methods 47 patients of slight crowding and four first premolars extracted for orthodontics purpose, were collected as study samples. Their pre- and post treatment cephalometric films were analyzed by blind method for hard and soft tissue changes and remodeling of anterior alveolar after treatment. Paired t test was used to evaluate the hard and soft tissue changes with SPSS 13.0 software package. Results The cephalometric values demonstrated that: Lower incisor alveolar thickness showed a significant decrease after incisor retraction. From sagittal view, the lingual cortical plate thickness reduced more than the labial one; from vertical view, alveolar bone thickness at the apical level decreased more than that at the coronal level. Conclusion The absorption of alveolar bone exceed the apposition during lower incisor retraction, so that the alveolar thickness decreased significantly. The labial and lingual cortial plates at the level of incisor apex may represent the anatomic limits of tooth movements which help doctors to make treatment decisions.

Key words: alveolar thickness, extraction, incisor, cephalometry