A Roentgenography Cephalometric Study On Lateral Craniofacial Structure Of The Han Nationality Adults With Normal Occlusion In Xinjiang Autonomous Region Of China

Objective: Through the cephalometric study by means of evaluation of the transverse and vertical structure of skull analysis to establish the norms and standard deviations of cephalometric roentgenograophy for local Han nationality adults with normal occlusion who have lived in Xinjiang region consectively for two generations at least. Method: Eighty-one subjects evaluated in the study were chosen from local universities and colleges including female 46 a mean age of 21.2 years old and male 35 a mean age of 24.6 years old both with balanced faces and normal occlusion who never accepted orthodontia treatment so far. Suitable software was developed to calculate linear and angular measurements. The X-ray images were processed to enhance their detail before the cephalometric analysis, thus making the calculation more accurate and allow getting the X-ray picture digitized and displayed on a black and white screen. By means of artificially recognizing 28 landmarks on digital image, 73 caphalometric parameters were analysed based on application of classic methods and the synthetical analyses arranged in four categories:skeletal angular relationships, skeletal linear relationships, dental angular ralationships and dental linear relationships. All of digital analyzer of images was stored on floppy or rigid disc. Using of PEMS 3.1 software package performed the statistic processing and correlationanalysis including descriptive and inferential statistics. Results: (1) Based on measured values of 73 items, established norms of cephalometric roentgenography of lateral skull structure for Xinjiang local Han ethnic adults and the range of observed values. (2) The comparison and correlation of differential structures features were made between local Han ethnic adults according to different genders. (3) Comparisons and correlation indicated the presence of statistically significant differences between the four subgroups examined, namely Han and Uygur; Han and Kazak; Xinjiang local Han's ethnic and Han's northerner and Southerner respectively. Conclusion: (1) On view of relevant statistical data, the normal tranverse and vertical skull structure had shown their own unique characteristics. On the whole, they are approaching similar to that of Han's northerners, except certain local peculiarities. (2) For Xinjiang local Han ethnic, the contour of their facial structure is straight and narrow in facial profile depth with a little bit forward protruding dentition and longer length of anterior and longer posterior and propriety in maxillofacial bottom as well. (3) For straight facial type group: their anterior craniofacial is shorter, while with a little bigger height of posterior one. For short facial and mediate type group: their upper jaws appear shrinked and showing some little deficiency in chins protrudness. (4) Structure growth pattern of male and female tends to be horizontal and mediate type respectively both with relatively protruding forehead appearance.