Comparative Study of Tweed Triangle in Angle Class II Division 1 Malocclusion between Nepalese and Chinese Students
Introductions: The establishment of specific cephalometric norms for specificÂ race or ethnic group has been documented in literatures. The aim of theÂ present study was to compare the Tweed triangle for Nepalese and ChineseÂ subjects with Angle Class II division 1 malocclusion.
Methods: The cephalometric radiographs of 52 Nepalese and 52 Chinese
students age between 14 to 18 years, Class II division 1 malocclusion with PointÂ A-Nasion-Point B angle larger than 4 degrees were analyzed for 9 parameters.
Results: Mean age of Nepalese participants was 14.28 years and that of
Chinese 14.09. The comparative variables of Nepalese and Chinese populationÂ were: Y axis (61.39 and 67.52), Sella Nasion Point A angle (83.69 and 81.14),Â Sella Nasion Point B angle (76.87 and 74.62), Occlusal plane angle (19.0 andÂ 23.12), Frankfort Mandibular plane angle (28.13 and 32.87) and Lower IncisiorÂ to Frankfort Horizontal plane Angle (54.77 and 48.23).
Conclusions: The Class II skeletal pattern, well positioned maxillas and
retrusive mandibles were present in both samples. The Chinese showed moreÂ protruded maxilla, more buccal inclination of lower incisors and longer faceÂ than Nepalese.
Keywords: angle class II division 1, cephalometry, tweed triangle