Master of Science (M.S.) in Dentistry
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College of Dental Medicine
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Adam G. Danze. 2019. Correlation of Body Mass Index Percentile and Craniofacial Morphology: A Retrospective, cross-sectional study. Master's thesis. Nova Southeastern University. Retrieved from NSUWorks, College of Dental Medicine. (122)
Introduction: Obesity rates are rising exponentially in many countries around the world, particularly in the United States. This epidemic is affecting people of all ages, and little to no progress has been made it slow it down. Lack of physical activity and increased consumption of energy rich foods and caloric intake have been recognized as contributing factors for the concerning increase in the prevalence of obesity in child and adult populations. The high prevalence of obesity is believed to be a complex interplay of genetic, environmental, socioeconomic, cultural, and psychological factors. Childhood obesity is occurring at progressively younger ages, leading to increased risk for chronic health issues that include Diabetes Mellitus type II, cardiovascular disease, decreased bone density and obstructive sleep apnea. Childhood obesity can have a significant impact on the psychological development, self-esteem and well-being of a child or adolescent. Weight status in children is typically classified by body mass index (BMI), which is a numerical index that is used to classify a person’s weight status in relation to “normal”. Obesity has been reported to have an effect on the timing of development of the permanent dentition. A significant relationship between increased BMI percentile and advanced skeletal maturation has also been reported in several previous investigations. Several studies have found obesity be associated with greater craniofacial measurements that include bimaxillary prognathism and longer lower facial height. The effects of obesity on the developing craniofacial complex and its implications on orthodontic treatment are still fairly misunderstood.
Methods: Potential subjects for this study consisted of patients treated in the post-graduate orthodontic clinic at the University of North Carolina at Chapel Hill. Following IRB approval, initial records for deidentified potential subjects were reviewed retrospectively. Initial records used for the study included lateral cephalometric and panoramic radiographs, height, and weight. Four hundred subjects were chosen for the study and all were greater than 8.0 years and less than 15.0 years of age. The normal weight BMI group consisted of subjects with a BMI percentile less than 85.0 (N=200). The overweight/obese BMI group consisted of subjects with a BMI percentile of 85.0 or greater (N=200). BMI is calculated as weight (kg) divided by height(m)2. BMI percentile is determined by using growth charts published by the CDC in 2000. Data included: craniofacial linear and angular measurements, Demirjian index values, dental age, and Cervical Vertebrae Maturation Stage (CVMS).
Results: There was an equal number of subjects in each BMI group (n=200) and the mean chronological age (measured in years and months) for each BMI group was also the same (M=12.6 years). For craniofacial morphology, the cephalometric linear measurements that were found to be statistically significant were: Ar-Gn (mm), Co-ANS (mm), and ANS-Me (mm) (p<.05), in which the overweight/obese group had a greater mean value for all three of these variables. Angular cephalometric measurements that were found to be statistically significant between the two BMI groups when not grouped by age were: SNA (deg), SNB (deg), and SNPg (deg) (p<.05), in which the overwight/obese BMI group had greater mean values. The mean dental age for the normal weight group when not grouped for age was 11.8 + 1.5 years, while it was 13.2 + 1.4 years for the overweight/obese group (p<.001). This means that the overweight group was dentally advanced with a mean difference of 1.4 years. The mean CVMS for normal weight subjects not grouped for age was 2.09 + 1.06, while for all overweight/obese subjects it was 2.49 + 1.19. The mean difference between the two BMI groups was 0.4, resulting in a significant p-value of less than .001.
Conclusions: Growing children with a BMI percentile categorized as “overweight” or “obese” are more likely to have proportionally larger growth in the antero-posterior and vertical dimensions in comparison to growing children with a BMI percentile in the normal weight range. Overweight and obese children are also more likely to experience advanced dental maturation in comparison to normal weight growing children. Overweight and obese subjects showed a statistically significant higher value for cervical vertebrae maturation score (CVMS) in comparison to normal weight subjects. This finding suggests that overweight and obese growing children are more likely to experience their pubertal growth spurt and peak growth potential at ayounger age than normal weight growing children, which can have an effect on the timing of treatment with growth-dependent modalities such as headgear and functional appliances.
Body Mass Index, Cervical Vertebrae Maturation, Craniofacial, Dental Maturation, Obesity, Orthodontics
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