Title:  Prevalence of cross-bite in a sample of Italian preschoolers

Abstract:  Aim To clinically evaluate the prevalence of cross-bite in a sample of 1960 children in our Local Health Unit n°15 Alta Padovana (Veneto region, Northeast Italy). Methods Study design: A cross-sectional study was carried out in the area of Health District n. 15, Veneto region, including 7,364 children from 3 to 5 years, attending a total of 88 nursery schools A convenience sample of 27 nursery schools (30% of total) was randomly selected, for a total of 2,603 eligible children; of these, 1960 children formed our study base (76%). The day of examination 566 children were absent and 77 did not meet the inclusion criteria by age (less than 3 or more than 5 years old). Anterior cross-bite was considered when one or more primary or permanent mandibular incisors occluded labially to their antagonists. Posterior cross-bite (uni- or bilateral) was considered when the buccal cusps of one or more maxillary teeth was lingual to the buccal cusps of the mandibular teeth of the primary dentition. In this definition, edge to edge occlusion is not regarded as cross-bite. The examination was carried out by two calibrated dentists with children sitting on a dental chair with good operative lighting. The data were recorded in a special clinical chart. Results The prevalence of cross-bite was 3.7% We observed a slight prevalence of cross-bite in females, but with no overall statistical significance. Conclusion The prevalence of cross-bite in this area was low compared with European and American data.