The Impact of Birth Weight on the Enamel and Dentin Thickness of Mandibular First Molars

Background Early-life factors such as birth weight influence dental development. However, how birth weight affects enamel and dentin thickness in permanent mandibular first molars remains unknown. Aim Here, we quantitatively assess the impact of birth weight on enamel and dentin thickness in 7- to 8-year-old children. Methods Panoramic radiographs of 75 children were analyzed. The participants were stratified into very low (VLBW), low (LBW), and normal birth weight (NBW) groups. The enamel and dentin thicknesses were measured manually and via computer-assisted analysis. Statistical comparisons were performed via ANOVA and post hoc tests. Results Enamel thickness was not significantly different across the VLBW, LBW, and NBW groups (P > 0.05). In contrast, dentin thickness was significantly greater in the VLBW group in region D (VLBW vs LBW, P = 0.018; VLBW vs NBW, P = 0.047) and in region X (VLBW vs NBW, P = 0.001; LBW vs NBW, P = 0.006). Compared with that of NBW, the molar width of VLBW and LBW increased 1.1–1.2-fold (P = 0.005–0.047). Manual and computerized measurements were highly concordant (P > 0.05). Gender had minimal impact, except for slightly greater enamel thickness in Region C for boys (P = 0.020). Conclusions Birth weight does not affect enamel thickness but is associated with increased dentin thickness and molar width, likely reflecting compensatory growth. These findings challenge the prevailing view that low birth weight predisposes individuals to early tooth fragility and provide a framework for understanding dental development in pediatric populations.