Aim: The aim of this cross-sectional study was to evaluate the skeletal maturation assessed through cervical vertebral maturation (CVM) and dental age, in normal weight, pre-obese and obese patients, using the Body Mass Index (BMI) and the Dual energy X-ray Absorptiometry (DXA).
Materials and methods: A group of 107 healthy patients, aged between 6 and 12 years (mean age 8.77∓1.79), underwent anthropometric measurements, BMI calculation, and DXA exam at the Department of Neuroscience, Human Nutrition Unit, University of Rome "Tor Vergata" and the assessment of skeletal and dental age at the Paediatric Dentistry Unit of PTV Hospital, University of Rome "Tor Vergata". The subjects were classified as underweight, normal weight, pre-obese and obese according to FM% McCarthy cut-offs classification and BMI classification.
Statistics: The analyses were performed using the SPSS software (version 16; SPSS Inc., Chicago IL, USA). The assessment of differences through the means of continuous variables among the different groups were analysed using the One-Way-Anova test. The Student's t test was also applied for each group of children (using McCarthy and BMI classifications) between chronological and skeletal-dental age; the Fisher's exact test was performed between the gender categorical variable and McCarthy cut-offs classification, and between McCarthy and BMI classifications. Besides, to evaluate the association between skeletal and dental age, a Pearson correlation coefficient was calculated. In all the assessments a significant level of alpha = 0.05 was considered.
Results: The comparison between BMI and DXA data shows statistically significant differences between BMI- FM% (McCarthy cut-offs) classifications (p≤0.001). According to FM% (McCarthy cut-offs) classification, from the Anova analysis among the groups a statistically significant difference between skeletal age (p=0.03) and dental age (p=0.02) was observed, while the difference related to the chronological age (p=0.22) among the groups, was not significant. The correlation between dental and skeletal age is almost the highest (Pearson correlation coefficient=0.994) and statistically significant (p=0.01). According to FM% McCarthy classification, it is observed that with an increase in the FM% , that is passing from normal weight to obese children, the skeletal-dental age always increases with respect to the chronological age. The difference between chronological and skeletal-dental age is statistically significant for pre-obese (p=0.01) and obese (p<0.001) children, while it is not significant for underweight (p=0.46) and normal weight (p=0.33) children. According to the BMI classification, from the Anova analysis no statistically significant differences were observed among the groups as for chronological, dental and skeletal age. Applying the same inferential analyses and taking into account the BMI classification, in the obese subjects were observed not statistically significant differences as for chronological and skeletal-dental age (p=0.09).
Conclusion: The results highlighted a relation between skeletal-dental age acceleration and body fat percentage measured by DXA.