The Correlation between Lower Crowding and the Size of Lower Incisors

This study was conducted to evaluate a relation between mesiodistal and buccolingual size of lower incisors and crowding. Methods & Materials: We divided the study in two parts. First we measured mesiodistal and buccolingual incisor dimentions and lower incisor crowding on dental casts of two groups. Group 1 consisted of 65 adult persons (36 M, 29 F) with lower incisor crowding more than 3 mm and group 2 consisted of 60 cases with well-aligned teeth. (36 M, 24 F). Then the MD and BL dimensions and their ratios were compared in two groups by statistical analysis. In part II we evaluated the crowding changes of 57 persons (24 M, 33 F) during 3 years from 12-13 to 15-16 year old. Increasing in crowding was seen only in 27 persons, and other 30 cases showed no increase in crowding. The MD and BL dimensions of lower ant teeth were compared in these two groups. Cases with lower incisor crowding had larger dimensions (with exception of buccolingual of 2) (P<0.05). And there was no correlation between the changes of crowing and the size of lower incisors, either mesiodistal or buccolingual (P>0.05). The MD dimention of lower incisors are larger in persons with crowding than persons with aligned teeth, but we cant use MD dimension to predict later lower incisor crowding.