Cephalometric norms for orthognathic surgery for North India (Eastern Uttar Pradesh)

The present study was aimed at development of the cephalometric norms for orthognathic surgery for the population of eastern Uttar Pradesh in North India. This study was conducted at a dental college. The study sample consisted of 50 males and 50 females. Each lateral cephalogram was taken in occlusion and subsequently traced. All reference points, landmarks, and measurements were made according to cephalometrics for orthognathic surgery (COGS) system. The statistical analysis involved calculation of mean and standard deviation for each of the 23 parameters assessed for each subject. The data was subsequently compared with COGS study by using Normal (Z) test. The norms were derived for the purvanchal population of North India and these were found to be quite distinct compared to those obtained from COGS study with respect to specific parameters. Male subjects indicated greater prominence of chin relative to the face, decreased posterior divergence, infraeruption of upper and lower molar as well as lower incisors, decreased total effective length of the maxilla, tendency towards Class III occlusion, and procumbent lower incisors. Female subjects, however, indicated increased anterior cranial base length, greater prominence of chin relative to the face, prognathic maxilla and mandible, increased middle third facial height, infraerupted lower incisors, increased mandibular body length, and procumbent lower incisors.