Abstract:

Objective To study the anatomical characteristics of Chinese alveolar bone to determine the safe zones of microscrews placement which are used for orthodontic anchorage. Methods Twenty-one normal Chinese jaws were scanned and reconstructed with helical CT technology. The mesiodistal and the buccolingual parameters were measured at the 3, 5, 7 and 9 mm from the alveolar crest. Results 1）In the anterior area of maxilla, the widest mesiodistal distance between roots was between the lateral incisor and the canine, the narrowest mesiodistal distance between roots was between the central incisor and the lateral incisor; in the posterior area of maxilla, the widest mesiodistal distance between roots was between the second premolar and the first molar, the narrowest mesiodistal distance between roots was between the first molar and the second molar. In the buccolingual dimension, the greatest bone thickness was between the first molar and the second molar, the least bone thickness was between the central incisor and the lateral incisor. 2）In the mandible, the widest mesiodistal distance between roots was between the first molar and the second molar, the narrowest mesiodistal distance between roots was between the central incisor and the lateral incisor. In the buccolingual dimension, the greatest bone thickness was between the first molar and the second molar, the least bone thickness was between the central incisors. Conclusion The reconstructed images of helical CT were high qualitative, which could fully identify the relationship of alveolar bone and the space between roots. Therefore, we provided the reference and indications for a safe application of the microscrews in the Chinese alvelar bone.

Key words: microscrews, applicational anatomy, safe zones, anchorage, helical CT