Cheiloscopic Study among Monozygotic Twins, Non-Twin Brothers and Non-Relative Individuals

Abstract This study aimed to investigate cheiloscopic patterns among monozygotic twins (MT), non-twin siblings (NTS) and unrelated individuals (UI). The sample consisted of 20 pairs of monozygotic twins (G1), 20 pairs of non-twin siblings (G2) and 20 pairs of unrelated individuals (G3). Lip thickness, commissures and grooves were evaluated and the latter were classified as: I - clear-cut vertical grooves; I’ - incomplete vertical grooves; II - branched grooves; III - intersecting; IV - reticular grooves and V - undetermined, in 8 labial regions (sub-quadrants). The data were analyzed using descriptive and inferential statistics, with a 5% significance level. Concordance Correlation Coefficient (CCC) and Kappa coefficient, with a 95% confidence interval, were employed to check for agreement rates between G1, G2 and G3 pairs. There was a weak correlation for lip thickness (