Abstract
Aims: To determine the possible effect of genetic factor on Bolton tooth size discrepancy between sib-lings in families living in Mosul City (Iraq). Material and methods: The study sample included 126 subjects distributed between 45 families in Mosul City (Iraq), (56 females and 70 males) whose ages ranged between (20– 35) years. The sibling pairs were divided into three groups according to gender: male –male (24 pairs), female–female (18pairs), male–female (21 pairs). Electronic digital vernire with fine tips was used to measure the maximum mesio–distal widths of the teeth, and Bolton anterior and over all ratios was calculated. The effect of Heritability on Bolton ratios was studied by means of Har-vey’s mixed model least–squares and maximum likelihood computer program (LSMLMW) model type II. Results: Statistical analysis showed that Heritability was effective on Bolton tooth–size discrepancy in all groups, with the higher means for the anterior and over all ratios are for the male– male group. While the female–male group showed the lowest mean for the anterior ratio and the female –female group showed the lowest mean for the overall ratio. Conclusions: Siblings showed similar malocclu-sions, and examination of older sibling can provide clues to the need for interception and early treat-ment of malocclusion.
