Abstract: Aim The aim of the present cross-sectional study was to evaluate the relationship between childhood obesity and dental caries, in paediatric subjects, through the use of two methods of diagnosis of overweight-obesity: Body Mass Index (BMI), and Dual energy X-ray Absorptiometry (DXA).
Methods A total of 107 healthy patients, aged between 6 and 12 years (53.3% females, 46.7% males) were included in the study. Each patient underwent a nutritional examination and dental check-up. The nutritional examination was performed at the Department of Neuroscience, Human Nutrition Unit, University of Rome “Tor Vergata” and consisted of anthropometric measurements, BMI calculation, DXA exam, body fat mass (FM) assessment. Dental examinations were performed by a trained dentist of the Paediatric Dentistry Unit of PTV Hospital, University of Rome “Tor Vergata”. Dental caries was assessed using visual-tactile method and X-rays (bite-wing and panoramic radiography); the dmft/DMFT index was calculated. The subjects were classified as underweight, normal weight, pre-obese, obese, according to different criteria: a) age- and sex-specific BMI according to the Cacciari growth charts and cut-offs, b) body fat mass percentage (FM%) according to the WHO cut-offs, c) body fat mass percentage (FM%) according to the McCarthy growth charts and cut-offs. Statistics: The statistical analysis was performed with the SPSS software (version 11.01; SPSS Inc., Chicago, IL, USA). The dmft/DMFT index was checked for normality using the Kolmogorov-Smirnov test. Independence of the dmft/DMFT distribution from sex and age was checked by using the Mann Whitney and Kruskal Wallis tests. Differences in the dmft/DMFT values between groups, according to BMI and FM% classifications, were tested using the Mann Whitney test. The minimal level of significance of the differences was fixed at p-value≤0.05 for all procedures.
Results The comparison between BMI and DXA data shows statistically significant differences between BMI-%FM (WHO cut-offs) classifications (p≤0.001) and BMI-%FM (McCarthy cut-offs) classifications (p≤0.001). According to the BMI classification, there was no significant association between increase of dmft-DMFT and pre-obesity/obesity, but according to the FM% (WHO cut-offs) classification, the pre-obese/obese children had higher caries indexes than normal weight subjects, both in deciduous teeth (p=0.003) and permanent teeth (p=0.000). Furthermore, according to the FM% (McCarthy cut-offs) classification, obese children had higher caries indexes than normal weight and pre-obese subjects, both in deciduous teeth (p=0.030, p=0.02) and permanent teeth (p=0.019, p=0.011), respectively, but they had a dmft-DMFT value comparable with underweight children.
Conclusion The BMI misclassified adiposity status of the paediatric population compared to DXA, which provides a reliable screening and a more specific assessment of body composition. The misclassification of childhood obesity, determined by the BMI, could be used to explain the conflicting data in the literature on the association between obesity and dental caries. Our results highlighted for the first time the relationship between dental caries prevalence and body fat percentage measured by DXA.