1Health Sciences Library and Informatics Center, University of New Mexico, 2Department of Anthropology, University of New Mexico
Saturday All day, Clinch Concourse
Dental crowding is extremely common, with 70 to 80% prevalence in contemporary populations. Crowding was less frequent in the past although some population specific studies have shown high rates. Researchers have variously associated the increase in dental crowding and malocclusions with diet, mutation, and selection. Using small sample sizes, relationships between crowding and cephalometric (head x-ray) measurements have been studied. Results range from no relationship to significant correlations for multiple length and angle variables.
We analyzed data from a sample of 1,975 patients (968 with and 1,007 without crowding) from the Economides Orthodontic Collection of the Maxwell Museum of Anthropology, University of New Mexico. The material spans 1972-1999 in Albuquerque, NM, and represents African, Asian, European, Hispanic, and Native Americans. Each subject had cephalometric measurements and a diagnosis of crowding made by a single treating orthodontist. There was no difference in crowding frequency between the sexes (p=0.306) but multiple measurements were significantly different (p<0.05). Significant differences between individuals with and without crowding were detected for four measurements in males and 11 measurements in females, with only one measure seen in both. A logistic regression was performed; for both sexes only one variable was significant in predicting crowding. Anterior cranial length (as defined by Ricketts) was significant (p<0.0001) for males, and the angle describing Sella-Nasion-Pogonion (p<0.0001) for females. Discriminant logistic analysis determined that these single measurements correctly predicted individuals having crowded teeth 62-69%. The significant variables suggest that crowding is related to maxillary length in males and mandibular length in females.