Abstract: PURPOSE: Based on the process of patients with anterior maxillary jaws were scanned by cone beam CT, analyze the changes of contrast micro implant bone density in different positions of implantation of the posterior region of jaw, micro implant anchorage implants for clinical reference. METHODS: 20 cases of maxillary protrusion patients using cone beam CT scanning and three-dimensional reconstruction of the oral and maxillofacial region in the first molar and the second molar second posterior maxillary premolar and the first molar area, distance 3, alveolar crest 5, 7 and 9mm, the first to select the near far posterior root area between the ridge center layer to select coronal posterior region of the outer cortical distance of 2, 4 and 6mm for the measurement of bone mineral density in lip and palate, the difference of bone mineral density in different areas. RESULTS: There were statistical differences in bone mineral density at the same depth, at different depths, at different depths and at the same height (P < 0.001). At the same depth as the bone cortex, the bone density was higher than that of the other groups at the height of 7mm from the crest of the alveolar ridge. At the same height, the bone density decreased with the increase of the depth.CONCLUSIONS: The peripheral bone density of the maxillary posterior region was measured by CBCT at different heights and depths, and the bone density was higher than the other locations at the distance from the crest of alveolar ridge to 7mm. It can provide reference for Micro Implant.

Key words: maxillary protrusion, micro implant, CBCT