Brushing Teeth and Acute Respiratory Infections in Day Care Facilities: An Ecological Study in Selected Regions of Lower Saxony, Germany (2013-2018)

Abstract

Dental group prophylaxis in day-care centers with teeth brushing as one of its components is intended to reduce caries incidence and promote dental health. However, various barriers can hinder implementation of this preventive measure. One concern relates to an increased risk of transmission of acute respiratory infections (ARI) in day-care centers. The ZINFEKT study aimed at determining whether and to what extent there are differences in the occurrence of ARI between day-care centers that implement vs. those that do not implement teeth brushing. In an ecological study, 2013-2018 data from the ARI surveillance of the Public Health Agency of Lower Saxony were merged with information from the Dental Services on teeth brushing for n=33 day-care facilities from the urban municipality of Braunschweig, the region of Hannover, and the administrative district of Osnabrück (all Lower Saxony, Germany). Following the concept of patient days from hospital infection surveillance, "ill child weeks" were specified as observational units, defined as weeks for which an ARI had been reported for a registered child. Besides cross-tabulations, relative risks for ill child weeks by teeth brushing and Breslow-Day Tests for interactions with area, size of day-care center, ARI season and time slot with ARI seasons were computed. Overall, the ARI-rate, defined at the proportion of ill child weeks, was 4.6% higher in day-care centers in which teeth brushing took place, vs. centers in which this measure was not implemented (17.9 vs. 13.3%, p<0.0001). In analyses stratified by the geographic and temporal co-variables, the direction of this difference did not change (with one exception: day-care centers with 50 or less registered children) . The assumption that regular teeth brushing is associated with higher ARI rates in day-care centers does seem to have an empirical basis. However, despite the study's limitations (primarily its ecological design and possibly limited representativeness of the day-care centers), the identified difference - due both to its magnitude and possibly improvable hygiene compliance - to our assessment does not speak against brushing teeth as a component of dental group prophylaxis in day-care centers.