ĐẶC ĐIỂM XƯƠNG SỌ-MẶT THEO PHÂN TÍCH RICKETTS Ở TRẺ TỪ 10-12 TUỔI HẠNG II DO LÙI XƯƠNG HÀM DƯỚI TẠI THÀNH PHỐ HÀ NỘI

Abstract

Objective: To describe several craniofacial structural indices in 10-12-year-old Class II children with mandibular retrognathia using Ricketts analysis in Hanoi City. Subject and methods: A cross-sectional descriptive study was conducted on 78 Class II subjects with mandibular retrognathia (43 males and 35 females) using Ricketts lateral cephalometric analysis on the VNCEPH tracing software. Results: The anterior cranial base length (Cc-N) was 53,36±2,29mm; and the posterior cranial base length (Po-PtV) was 37,29±2,14mm. The cranial base inclination (BaN/FH) was 24,17±2,79°; the total facial height (BaN/XiPm) was 58,05±2,76mm and the lower facial height (ANS-Xi-Pm) was 46,92±2,43mm. The mandibular plane angle (GoMe/FH) was 32,26±2,57°; the mandibular body length (Xi-Pm) was 54,10±3,29mm and the mandibular arch angle (DcXi/XiPm) was 37,00±2,84°. The maxillary depth (N-A/FH) was 90,01±2,49° and the position of point A (Ba-N-A) was 62,59±2,31°. There were no significant differences between genders for these indices. However, facial convexity (A→NPog) (5,85±1,13mm), facial axis angle (CcGn/BaN) (82,69±2,43°) and facial depth (NPog/FH) (77,23±2,32°) were significantly higher in females than in males. Conclusions: The mandible tends to grow in a backward and downward rotation, exacerbating mandibular retrusion and limiting its forward growth.