First Primary Tooth Eruption and its Relationship with Birth Weight

Background and purpose: In this study we aimed to identify the association between birth weight and first primary tooth eruption. Materials and methods: This retrospective cohort study was done in infants attending for 12 and 18 months vaccination in Qaemshahr health centers. Multi-stage cluster sampling was performed. Information, including birth weight, height, and head circumference were extracted from vaccination cards. Other information including feeding type, gestational age, type of delivery, and the time of first primary tooth eruption was also obtained. Pearson statistical test and linear regression model were applied to identify the relationship between first tooth eruption and other variables. Results: Data of 704 children were analyzed. The mean values for body weight, height and head circumference at birth were 3222 ± 554 g, 50.01± 2.75 cm, and 35.20 ± 2.23 cm, respectively. Pearson test showed a significant reverse relationship between the time of first teeth eruption and birth weight (r= -0.091, P= 0.01), height (r= -0.122, P= 0.006), and head circumference (r = -0.147, P= 0.002). Linear regression analysis showed a significant revers relationship between head circumference and time of first teeth eruption (B= -0.11, P= 0.02). Conclusion: In current study, after adjustment of confounding variables, head circumference remaind reveresly associated with time of first teeth eruption. It seems that some variables such as gentic factors along with environmental factors affect ttime of first teeth eruption.