Prevalence of developmental maxillary midline diastema in Taiwanese children

Background/purpose: Midline diastema in mixed dentition is a concern for both parents and children; therefore, determining the timing of closure of developmental diastema is essential for clinical practice. Data on midline diastema in Taiwanese children are scant. The purpose of this study was to investigate the prevalence of maxillary midline diastema in different age groups of children in Taiwan and to determine the time of closure of the developmental diastema. Materials and methods: The sample population comprised elementary school children in Taichung City, Taiwan, whose ages were between 6 and 12 years. We screened a total of 1136 children and selected 917 for this study. Inclusion criteria were the presence of both permanent maxillary central incisors and absence of obvious dental or dentofacial abnormalities. Children who had a history of orthodontic treatment or crown restoration of anterior teeth were excluded. Diastema widths were measured clinically with a Boley gauge. Results: The prevalence of diastema was 64.6% among 6-year-old children but only 14.3% among the 12-year-olds. The prevalence of diastema was higher in boys than girls after the age of 9. There were statistically significant differences between boys and girls in the prevalence of diastema at ages 9 and 12. The mean size of diastema was 1.9 mm for 6-year-olds and 1.21 mm for 12-year-old children, indicating a significant reduction of diastema size with age. Before the eruption of lateral incisors, the prevalence of midline diastema was 60.4% among all children, and it declined to 14.5% after the eruption of canines. Conclusion: The prevalence of midline diastema decreased with age. It also declined with lateral incisor and canine eruption; it was 14.5% after canine eruption. Therefore the orthodontic intervention of diastema should be delayed until canine eruption. Copyright (c) 2012, Association for Dental Sciences of the Republic of China. Published by Elsevier Taiwan LLC. All rights reserved.