Correlation of Angle SNA to Angle NSAR in Normal Occlusion, Class II Division I and Class III Malocclusion in Vidarbha Region - A Cephalometric Study

Abstract

BACKGROUND Facial prognathism may be because of prognathic maxilla, prognathic mandible or aggregate of both. Numerous studies performed to diagnose a single morphological feature commonly producing protrusive relationship, revealed that ‘a single morphological feature does not ordinarily produce a protrusive relationship. Existence of structural imbalance in one area also affects the nature of balance in other areas. A number of separate but inter-related cause and effect factors tend to augment each other in a cumulative and composite manner. Effect of marked discrepancy of an individual’s facial part could be cancelled or nullified by deviation of another part in opposite direction, ultimately resulting in good facial harmony. In this study by means of cephalometric roentgenography, the relation between Angle SNA and Angle NSAr was assessed in Vidharbhites, having normal occlusion, Class II division I and class III malocclusion. METHODS 40 individuals of normal occlusion, Class II division I and Class III Malocclusion, each between 16 and 25 years were analysed. These subjects were selected from patients reporting the outpatient department of Government Dental College, Nagpur. Statistically correlation between angles SNA and NSAr at level of significance 5 % was assessed. RESULTS After data collection a thorough observation & analysis was done and co-relation coefficient between SNA angle & NSAr (F--1.054 M--0.7981), also standard deviation of angular cephalometric measurement between males & females was found out in the population, leading to discussion on topic ‘Facial prognathism is due to maxillary prognathism, mandibular prognathism or combination of both’. In Females SNA was found to be 81 - 800 1.91310 and in males SNA was 82.1660 4. 380 respectively. CONCLUSIONS The results inferred that “Marked part of variation in Angle SNA can be explained by variation in Angle NSAr. KEY WORDS Angle SNA, Angle NSAr, Correlation