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UBC Theses and Dissertations

Positive secular change in dental maturation over a 30-year period Yu, Cara


Objectives: Secular change refers the increased rate of growth and development to maturity that children are undergoing over successive generations. Secular change has been postulated to be the result of non-genetic changes in the environment that are associated with an improvement in the overall standard of living, such as improved quality of nutrition and lessening of infectious diseases. Evidence of secular change has been described across a multitude of populations, including Canada, and has included changes in height, craniofacial morphology, fetal growth and birth weight, and age of menarche. Though some secular changes in dental maturation and tooth emergence have been demonstrated, results have been mixed and limited and no studies on secular changes in dental maturation have been conducted in Canada. We sought to determine if a secular change in dental maturation has occurred in Vancouver children ages 6-12.99 over a 30-year period. Methods: Two cohorts of age and gender matched children age 6-12.99 were identified from a retrospective chart review of Orthodontic/Pediatric patients treated in the Vancouver, BC area. The historical group was born between 1960-1980 (n= 220) and the recent group between 2004-2010 (n=220). Stages of tooth mineralization were scored from panoramic radiographs according to the Demirjian method of assessing crown and root development (Demirjian et al., 1973, Hum. Biol. 45, 211-227). Seven mandibular teeth on the left were used were assigned a maturity score (A-H). To assess changes in the timing of dental maturation, the median age of attainment for each stage of maturation was calculated, using logistic regression. Differences in median age of attainment between the two time periods and between males and females will be obtained by logistic regression. Results: A significant positive secular change in dental maturation was observed. Advancement in median age-of-attainment in the recent sample relative to the historic sample ranged between 0.06 and 1.43 years (mean = 0.61years) in boys and between 0.05 and 1.43 years in girls (mean = 0.90 years). Conclusions: Positive secular changes have taken place in British Columbia during the last 30-years and that tooth maturation is a sensitive way in which to measure childhood development.

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