This study showed that an increase in BMI is associated with a decrease in dental caries severity. Pupils with low BMI were at a higher risk of being in a higher caries severity than others. Sadeghi et al. in Isfahan, Iran, reported that caries prevalence in pupils with low BMI was higher than others (7). In a study by Mohammadi et al. in Kerman, Iran, pupils in primary schools underwent dental examination and BMI was evaluated (30). The au-thors reported that obese pupils had less caries severity than others. Also, the results of this study are consistent with those of some studies in other countries (3, 31-33). The nature of the hypothe-sized protective effect of weight on dental caries is still obscure. Low BMI may be associated with eating habits that have a negative impact on dental health; however, further longitudinal studies are necessary.