Palatal Rugae Coding: Evaluating its Usefulness in Differentiating Sex and Establishing Identity

Abstract

Background: Under certain circumstances, the most common techniques used for establishing identity may not be applicable; hence, fast and reliable alternative methods would scientifically be welcomed. Aim and Objectives: This study investigates the practical usability of palatal rugae in establishing sex and identity in a premortem state and evaluating its usefulness for post-mortem identification. Materials and Methods: A total of 359 subjects, 165 males and 194 females between ages 20-60 years were selected from among volunteer subjects in Port Harcourt, Nigeria. Maxillary dental cast were formed by alginate impressions, the palatal rugae were traced using a high precision graphite HB pencil and then analyzed for their various patterns (using Thomas and Kotze, and Kapali’s classifications). The observed rugae were assigned the following codes; from anterior to posterior -Wavy (W), Curved (Cr), Straight (S), Circular (Ci), Converge (Cv), Diverging (Dv) for both sides of the palate. Results: Statistical analysis using the Z-test for proportionality difference (males vs females) showed no significant difference in the distribution of the rugae shapes (P=0.877), Chi-square analysis of association showed insignificant distributive relationship with respect to sides (P>0.05); while sex and the distribution of all rugae types (by length) was significant (P<0.05). From the coding, the most common configuration was “WWWW” without duplicity of the pattern in any two individual; while in combination with other patterns, the straight was most frequent. Conclusion: This research emphasizes the importance of the rugae configuration; as it is very difficult for sex differentiation but reliable for establishing the identity of an individual in both post- and pre-mortem state.