Orthopantomography and use of Mandibular Indices for the Evaluation of Gender Distribution in Navi Mumbai Population - A Retrospective, Single Blind Study

Introduction: The study of forensic sciences often leaves the forensic expert to draw conclusions from any and every material available in determining the identity of the deceased. The initial step in identifying a person is to determine their gender based on their adult skeleton. The human skeleton displays sexual dimorphism, of which the skull is most dimorphic providing an accurateness of 92%. However, in certain situations where the skull may not be found intact, the mandible plays a vital role. The mandible's thick covering of compact bone helps keep it from exploding during a mass tragedy. Dimorphism in the mandible is gender specific and is mainly reflected in its shape and size. The mandible is also easily radiographed and specific linear measurements of the mandibular rami as seen on an OPG are useful indices for gender determination.

Aims: To examine the efficacy of mandibular rami measures such as maximum ramus breadth, maximum ramus height, minimum ramus breadth, condylar height, coronoid height, mandibular body length and gonial angles on the right and left side of an OPG in determining gender.

Materials and methods: 110 digital OPG’s (55 males, 55 females) of a Navi Mumbai population were obtained retrospectively from a reputed dental college and hospital. The OPG’s were taken using Xtropan 2000 OPG machine, 10x12 PSP plates, exposure parameters of 75 Kvp, 8 mas, 13 sec, and KODAK CR 7400 digitizer. Master View 3.0 software was used on the desktop computer to measure the mandibular ramus's width and thickness. Maximum ramus breadth, Maximum Ramus height and lowest ramus breadth of the mandibular rami, as well as the height of the condyle and the coronoid bone, and the length of the mandibular body and gonial angles on the right and left sides of the mouth, were all measured. Using a statistical formula, the measurements were substituted and gender was estimated.

Result: We used the IBM SPSS v 21.0 statistical software for social sciences to do our statistical study. p0.05 was deemed statistically significant, with a 5% margin of error and a 20% margin of error, giving the study an 80 percent power. In the study group, 51 of the 55 men were expected to be males, while 49 of the 55 females were anticipated to be females, while 6 of the 55 females were predicted to be males.

Conclusion: This research shows that the mandibular ramus is a useful tool for determining gender, and digital panoramic imaging yielded the best accurate linear measures. There was considerable sexual dimorphism in the mandibular ramus in the chosen Navi – Mumbai subpopulation, and the combination of 8 factors demonstrated an accuracy of 91.81 percent and was helpful for gender determination.