Sexual dimorphism in permanent canine teeth and formulas for sex determination

Background and aims: Investigation of sexual dimorphism and sex determination has important implications in forensic sciences, anthropology and archaeology. As the strongest human teeth, canines are excellent for this purpose. This study investigated sexual dimorphism in maxillary and mandibular canines. In addition, cut-off points for sex determination were measured. Method: The sample comprised 220 dental casts, taken from dental students of Azad University in Tehran, aged from 18 to 22 years. The mesiodistal and buccolingual dimensions of all 4 canines were measured using callipers. Data were compared using independent samples and paired t-tests. A formula was drawn to identify gender based on canine measurements. Results: The mean values of mesiodistal dimensions of four canines and buccolingual dimension of maxillary left and right canines were statistically greater in males compared to females (P<0.05). The first equation can be written as follows: Logit p=-13.53+1.48 (MD of canine #13)+1.27 (MD of canine #43)-0.84 (BL of canine #33). The regression equation was computed as: Logit p=-12.67+2.08 (MD canine 13)-1.30 (BL canine 13)+0.9 (BL canine 23). For the mandible the equation was: Logit p=-5.52+1.68 (MD of right canine #43)-0.78 (BL of left #canine 33). In these equations if the value is greater than zero, the individual will be classified as male otherwise as female. Conclusion: Dimorphism of the canines could be used as a reliable device to identify gender in forensic sciences.