Background: Tooth size is an important factor that affects alignment of the teeth in the dental arch and occlusion development during dentition transition.
Objectives: This study was carried out to measure mesiodistal dimensions of primary teeth to provide standard for the tooth size. Knowledge of such a standard of tooth size is significant for a better analysis of the space and more appropriate planning of orthodontic treatments.
Patients and Methods: The current study was conducted on 32 children, aged 5.5 - 6.5 years, in late primary dentition. The dental casts were prepared and the tooth size was measured by a digital caliper. The obtained data were analyzed by ANOVA and t-test.
Results: The mesiodistal width of primary central incisor in the upper left quadrant was larger than those of the rest of quadrants. Also, the mesiodistal widths of primary lateral incisors in the upper left quadrant, primary canines in the upper left quadrant, primary fist molars in the lower right quadrant and primary second molars in the lower left quadrant were larger than those of the other quadrants. Moreover, it was concluded that the mesiodistal diameter of permanent central incisors could be obtained according to the primary central incisors using the formula: 1.12 × (Deciduous central incisor width) + 1.27 = (Permanent central incisor width).
Conclusions: The findings of this study can be used as a base and standard for the measurement of primary dentition in Iranian children. Also, measurement of mesiodistal width of deciduous central incisors can be used to predict the mesiodistal width of permanent central incisors.