A correlation of three-dimensional stereophotogrammetry and cephalometric measurements in hypodontia

Background: Conventional cephalometric radiographs do not reflect the real three-dimensional (3D) facial structures as they projected on a two-dimensional plane. Measuring parameters using non-invasive 3D imaging techniques may be helpful for regular diagnosis and treatment planning in hypodontia patients. Objectives: To compare cephalometric and 3D measurements in children with hypodontia. Methods: Twenty-seven hypodontia male and female aged 8-17 years attending the Hypodontia clinic at Newcastle Dental Hospital, UK participated in the study. 3D stereophotogrammetric facial images were obtained using a 3dMD imager(3dMD & 3Q company, Atlanta, USA). Cephalometric radiographs were recorded conventionally. 3D analyses were undertaken using MorphAnalyser software developed by the Universities of Newcastle and St Andrews. Radiographs were analysed using GELA software developed in the University of Newcastle. 54 linear and 51 angular measurements were analysed for each 3D image and then compared with equivalent 2D data. Results: There was generally a good agreement between identical 2D and 3D Linear and angular soft-tissue measurements (Paired t test). Pearson correlation analysis indicated significant correlations between some 2D and equivalent 3D variables where the Pearson correlation coefficient > 0.6 (p<0.01). Conclusion: There were significant correlations between the cephalometric and 3D measurements in hypodontia children. This suggests that 3D imaging could replace conventional cephalometric radiographs.