When people develop teeth may have more to do with whether they are overweight or obese than their genetic origins, according to a study published on March 13 in Orthodontics and Craniofacial Research.
Obesity accelerated tooth growth; however, ancestry appeared to make no difference in the timing of dental development. The study has implications for the timing of orthodontics and forensic age estimation, the authors wrote.
"BMI (body mass index) appears to have a greater impact on relative timing of dental development than ancestry in this population," wrote the authors, led by Christina Nicholas, PhD, of the department of orthodontics at the University of Illinois at Chicago.
One of the most accurate features for age estimation in children is teeth. However, some studies have shown that when children develop teeth varies across populations. More recent research suggests that environmental factors like obesity may affect dental development. Since population differences in average body mass exist, it is plausible that it may be a confounding factor that was not considered in past research.
To compare the correlation between body mass index and ancestry and the timing of dental development, the researchers conducted a retrospective cross-sectional chart review using panoramic x-rays of 281 children between the ages of 6 and 12 who visited the University of Illinois Chicago College of Dentistry. Of the children, 47 were African American or Black, 29 were white, non-Hispanic; 191 were white, Hispanic; and 14 were Asian. Of the patients, 153 were boys and 128 were girls. The charts also contained the children's age, height, weight, and ancestry, the authors wrote.
Tooth development was assessed using the Demirjian method, which is a standard tool for dental age estimation. Chronological age was subtracted from estimated dental age to determine the relative timing of dental development. The height and weight, which were recorded within six months of the x-ray, were used to calculate body mass index, according to the study.
Overweight and obese children had statistically significantly advanced tooth development (p < 0.001). Compared to normal-weight subjects, on average, the dental development of overweight children was overestimated by 5.76 months, and it was 5.97 months for obese children, the authors wrote. Neither accelerated nor delayed timing of development was found among African American, Euro-American, Hispanic, and Asian patients (p = 0.15), they noted.
The study had several limitations, including that race and ethnicity were not always self-reported by the patients. Some patients had their initial intake forms, which included questions about race and ethnicity, filled in by front office staff at a pediatric dentistry department, they wrote.
Nevertheless, additional research is needed to confirm the lack of association between the timing of tooth development and ancestry when controlling for body mass index in bigger samples with stronger demographic data, they wrote.
"The result that BMI, but not ancestry, appears to influence timing of dental development (or is associated with it, potentially through a shared variable such as socioeconomic status) has implications for timing of orthodontic treatment and forensic age estimation," Nicholas and colleagues concluded.