Divergence in prevalence of mesiocclusion caused by different diagnostic criteria.

Introduction: The divergence in prevalence of a specific malocclusion is often striking. In addition to differences in ethnic background, sex, and age, inconsistency in diagnostic criteria might be important. Our aim was to investigate the prevalence of mesiocclusion in the same group by modifying the diagnostic criteria.

Methods: We examined clinically 3358 young white men. The prevalence of mesiocclusion was determined by applying diagnostic criteria based on the sagittal relationship of the anterior teeth. Correlations to the molar sagittal relationship were calculated.

Results: When the diagnosis was based on anterior crossbite, the prevalences were 9.0% for 1 incisor, 4.7% for 2 incisors, and 1.3% for 4 incisors involved. The prevalence decreased when teeth in edge-to-edge positions were excluded (5.2%, 1.9%, and 0.5%, respectively). When canine relationship was used, the prevalences varied from 5.2% to 0.2%, with mesiocclusion increasing from a quarter to 1 cusp width on average. When incisors and canines were combined, prevalences ranged from 0.2% to 3.0 %. The sagittal relationship of the anterior teeth was moderately correlated to the molars.

Conclusions: Subtle differences in diagnostic criteria lead to varying prevalence values for mesiocclusion. The diagnostic criteria of at least 2 incisors in crossbite or edge-to-edge and a mean canine mesiocclusion of at least a half cusp width are recommended for future epidemiologic studies as the anterior tooth relationship that correlates relatively highly to the sagittal molar relationship.