Aspects of Dental Development and Skeletal Maturation in New Zealand Polynesian Children and Adolescents

Dentistry Biology research New Zealand

Objectives: This cross-sectional, retrospective study investigates dental development and skeletal maturation in a sample of New Zealand children and adolescents of Polynesian descent. The aim was to determine the dental age and skeletal maturation in New Zealand Polynesian children and adolescents (NZPCA), and determine if they are developmentally advanced, dentally and skeletally, compared to New Zealand children and adolescents. Method: A convenience sample of 300 New Zealand Polynesian children and adolescents were selected from private and university orthodontic clinics in New Zealand. The age range was between six to fourteen years. Ethnicity was determined on patients' self-reported information in patient records or obvious Polynesian surnames (Samoan). For statistical reasons, ten females and ten males were included in each age group (six to fourteen years). Dental development was assessed using the Demirjian et al. (1973) method and as an extension, included the lower left wisdom tooth in a separate dataset. In total, 180 Orthopantomagramic radiographs were collected. Skeletal maturation was assessed using the cervical vertebral maturation index (CVMI) method of Hassel and Farman (1995). In total, 120 Lateral Cephalometric radiographs of ten females and ten males per age group were selected. Results: One examiner (JP) assessed all radiographs and observed acceptable intra-examiner repeatability. The Demirjian et al. (1973) method overestimated the chronological age of NZPCA by 2.4 years. No statistical difference was found between females and males. Similarly, analysis of age using the wisdom teeth showed no sexual dimorphism. The mean age in Stage A was 9.70 years (standard deviation 1.65 years). A prediction equation of chronological age (six to fourteen) was formulated using regression analysis. Box and whisker plots revealed the distribution of skeletal maturation. Females were significantly more mature compared to males of the same age. The discussion section draws comparisons between the New Zealand Polynesian population, and two datasets conducted within the University of Otago; a general New Zealand sample as well as a New Zealand Maori sample. It is clear in New Zealand, Polynesian children and adolescents are dentally advanced compared to Maori children and adolescents, who in turn are advanced compared to New Zealand children and adolescents. The same pattern is observed in Polynesian children and adolescents when their skeletal maturity is compared to data on New Zealand children and adolescents. Conclusions: Polynesian children and adolescents showed advanced dental development and skeletal maturation when compared to other population groups in New Zealand. While no sexual dimorphism existed for dental development, skeletal maturity as determined by CVMI showed that females matured statistically earlier than males.

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