A Cheiloscopy Study of Undergraduate Dental Students

Objective: To perform a cheiloscopy study by the analysis of lip characteristics as a method for human identification, observing the possible divergences among the phenotypical expression patterns of lip grooves, according to the gender. Method: The lip pattern of 104 undergraduate dental students was investigated. The lip thickness on the midline was measured, using the Hyzer-Krauss scale, which classifies the lips as thin, mean, thick or mixed. To analyze the lip commissure disposition, two photographs were taken of each participant, and classified as horizontal, downward and upward. For groove classification (Types: I - complete vertical lines; I' - incomplete vertical lines; II - branched lines; III - crossed lines; IV reticular lines and V - undefined patterns) individual lipsticks were used and impressions were made on white carton paper with a "roll" movement from left to right. Data were analyzed statistically by the Pearson's chi square and Fisher's exact tests (p=0.05). Results: The highest percentages were for horizontal commissures (58.7%) and mixed lips (64.4%) and the lower lips tended to be thicker. As for the grooves, Type II was the most frequent, followed by Types III (23.2%) and I (22.8%). For the gender variable, grooves types III and IV were more expressed among men, while types II and I prevailed among women (p<0.001). Conclusion: The study of lip characteristics revealed statistically significant differences relative to the analysis of lip grooves, according to the gender, and its analysis is relevant in cheiloscopy identification method. The lip commissures and lip thickness presented no divergent tendencies between men and women.