Three-dimensional cephalometric norms of Chinese adults in Hong Kong with balanced facial profile.

OBJECTIVE: The objectives of this study were (1) to develop a 3D cephalometric analysis scheme applicable to assessing dentofacial deformities; and (2) to create a normative database of 3D cephalometric measurements for adult Chinese in Hong Kong. STUDY DESIGN: A cross-sectional study was conducted on 50 male and 50 female adults with normal balanced facial profile and occlusion. Cone-beam computed tomography and stereo photogrammetry imaging were performed on all subjects. Three-dimensional virtual models were generated from imaging data, and cephalometric analysis was performed using specialized software. A new 3D cephalometric analysis scheme appropriate for orthognathic surgery as well as a new reference plane (supraorbital margin plane) for midfacial assessment was used in this study. RESULTS: The cephalometric norms generated in this study were comparable with those reported in the literature for conventional 2D cephalometric analysis and the unique features of Chinese faces. The results also showed significant differences between males and females in most of the facial height measurements (P < .01). CONCLUSIONS: This is the first database of 3D cephalometric norms based on CBCT and 3D photogrammetry of the Chinese population in Hong Kong. This can be a useful reference for characterizing facial deformities in 3 dimensions. Moreover, 3D cephalometric analysis has the potential of incorporating new measurement methods that are difficult if not impossible in 2D cephalometric analysis.

Orofacial and dental trauma of young children in Dunedin, New Zealand.

AIM: The aims were to identify the predominant causes and types of orofacial injury in young children attending clinics at a University Dental School in Dunedin, New Zealand. MATERIAL AND METHODS: A retrospective analysis of data from the records of all children aged 0-10years who had been seen for orofacial trauma in 1999 and 2000 was undertaken. RESULTS AND CONCLUSIONS: Three hundred traumatic incidents in 288 children were analysed; 86.6% had causes noted. In very young children, most injuries were because of falls, while collisions, falling and sports were responsible for more injuries in school-aged children. Playground equipment and ride-on vehicles played a role particularly in the older children. There were no incidents of trauma as a result of road traffic accidents. Ten injuries were caused by animals, mainly dogs. Location was recorded for two-thirds of accidents: the predominant place was at home, followed by school. No seasonal variation was apparent. There were 228 non-dental injuries, of which the majority were to the lips. The predominant dental injuries in both dentitions were concussions and subluxations with a significantly higher occurrence of both in the primary dentition (P<0.001). Upper central incisors were most often involved. The age distribution for boys and girls was similar. In conclusion, the causes and types of orofacial trauma in this group of young New Zealand school children attending a university dental school were similar to other studies, except for the high proportion of concussions recorded in both dentitions. While the injuries were well described, not all records noted the cause or location. This has resulted in changes to the standard recording form to provide consistency in data capture. Information from this study will also be used to support child injury prevention strategies in New Zealand.