Objective To explore the change of bone density of children′s mandible measured by quantitative computed tomography（QCT）. Methods 71 children aged between 10- 16 years were measured by QCT in left mandible angle, middle of mandible and right mandible angle. The differences were analyzed according to the age and sex respectively. Results The density of mandible of left mandible angle, middle of mandible, right mandible angle were 44.29, 89.70, 54.31 mg/dL in the 10 - 12 ages group, and 63.85, 122.47, 70.23 mg/dL in the 13 - 16 ages group. Conclusion Male youngster′s mandible density was increased with the age between 10- 12 and 13- 16 ages. There were significant differences between left mandible angle, middle of mandible and right mandible angle. There were significant differences of mandible density between male and female.
