The study of twins is a well-known and a unique method that is used to investigate the genetic contributions to physical features and diseases in human.
To estimate the relative contributions of genetic and environmental influence to observed variations in different dental features or traits.
Thirty twins in the age group of 15–30 years were selected for the study, and the dental caries experience scores, dental anomalies, and morphometric analysis of monozygotic (MZ) and dizygotic (DZ) twins were compared.
MZ twins unlike DZ twins showed within-pair resemblance in decayed, decayed missing and filled teeth (DMFT), and molar relation. No morphometric analysis parameters and dental anomalies had significant mean difference between the groups. Decay, filling, DMFT, spacing, mandibular irregularity, open bite, and mesiodistal width of the right and left canine showed a higher positive correlation in MZ than DZ twins. Heritability estimate was low for morphometric analysis parameters. There is genetic dominance in decay, DMFT, spacing, molar relation, and diastema. Pearson's correlation revealed a positive and statistically significant correlation among all morphometric analysis parameters for MZ twins, but not DZ twins. Dental caries has a higher concordance rate (87.5%), correlation (71.6%), and heritability (87.8%).
Most of the dental parameters are significantly heritable with up to 85% of the variance attributable to genetic factors. Environmental factors play a major role in developing malocclusion and causing dental caries. Morphology of canines can be used as a supplementary tool to determine zygosity.