Prevalence of dental anomalies in various malocclusions

Introduction: The purpose of this study was to evaluate the prevalence of dental anomalies in different orthodontic malocclusions. Methods: Based on pretreatment diagnostic records, 900 orthodontic patients were classified as Class I (n = 358), Class II (n = 325), Class II Division 2 (n = 51), or Class III (n = 166). The occurrence rates of each dental anomaly were calculated as percentages of the total sample. Differences in incidence rates of each dental anomaly by sex and malocclusion were analyzed by using chi-square, Fisher exact, and z tests. The Mann-Whitney U test was used to determine whether there were significant differences in the occurrence of dental anomalies by age. Results: It was found that 40.3% of patients (n = 363) had at least 1 dental anomaly. Agenesis was the most common (21.6%), followed by dens evaginatus (6.2%), invaginatus (5.0%), pulp stones (4.2%), and impaction (2.9%). No statistically significant correlations were found between dental anomaly and type of malocclusion, with the exception of impaction and short or blunt roots (P < 0.01 and P < 0.05, respectively). The Mann-Whitney U test indicated no significant difference in dental anomalies by age. Conclusions: A remarkably high rate of dental anomalies was recorded in orthodontic patients; therefore, orthodontists should carefully examine pretreatment records for dental anomalies to include their management in the treatment planning. (Am J Orthod Dentofacial Orthop 2009;135:328-35)