Objective       To measure the surrounding bone density when simulation of micro implants were inserted in the maxillary posterior region with different heights and angels by cone beam CT (CBCT).       Methods       Thirty adults’ CBCT image data were collected as the research objects to reconstruct the maxillary. From the distal of the maxillary first premolar backward

each area was set between the roots (not including tuber maxillae) to alveolar ridge crest with 2

4

6

8

and 10 mm in distance as a simulation embedded point

a similar image to micro implant with 1.5 mm in diameter and  6 mm in length was inserted into the alveolar bone surface in an angle of 30°

45°

60°

and 90° respectively. The bone density around 1 mm of the implant was measured.       Results       In different heights with the same angle

and the same height with different angels

there were statistical differences in the bone density (P0.05

P0.01). At the same height

the bone density of 30° angle was greater than the other angels. While at the same angle

the higher the inserted position was

the greater the density was.       Conclusion       The surrounding bone density after the simulation of micro implant inserted in the maxillary posterior region with different heights and angles is tested by the CBCT.