RESUMO
Objective:To study the morphologic standard values of craniofacial hard-tissue of the youths in Xi'an.Methods:CBCT scanned cephalometric data of 100 selected volunteers (50 males and 50 females)with individual normal occlusion were collected.31 landmarks and 31 measurements were compared between sexes and between 3D and 2D data with software InvivoDental 5.2,WinCeph 8.0.and SPSS 19.0.Results:1.In the 3D measurements,vertical growth of mandible in the females was more than that in the males. The values of torque of lower incisor,basis length,height of rumi mandibulae and length of corpora mandibulae in the males were bigger than those in the females.2.Compared with 2D measurements,there existed statistically significant differences in most parameters except U1-NA(mm).Conclusion:3D analysis with CBCT may provide more accurite morphologic data for craniofacial hard tissues.