Assessment of Oral Health-Related Quality of Life in Preschool-Aged Children in Alto Alentejo

This observational, analytical, and cross-sectional study aims to deepen understanding of the factors associated with Oral Health-Related Quality of Life (OHRQoL) among preschool children in the Portalegre District. For participant selection, a probabilistic, multi-stage sampling process, stratified by type of preschool (public or private) and by municipality, was used. The final sample comprises 33 preschools, including 22 public and 11 private. Data collection comprises two complementary components: a questionnaire completed by parents or caregivers and an intraoral examination for each participating child. The questionnaire comprises seven sections with multiple-choice and open-ended items. It collects information on the child's general health, access to oral healthcare, child and caregiver behaviors, OHRQoL, parental beliefs and attitudes regarding oral health, and sociodemographic characteristics. Distribution is carried out by educators and assistants from the institutions, ensuring delivery to parents or caregivers. The intraoral examination collected data on oral hygiene, gingival health, the presence of dental caries, malocclusion, and traumatic dental lesions. All records were documented on a standardised form developed for the study. Examinations were carried out in a schoolroom with good natural and artificial lighting, using existing furniture. All infection control and cross-contamination prevention measures were implemented, including the use of disposable gloves and masks, as well as sterilized instruments. The instruments used included a LED headlight, a flat intraoral mirror, a millimetre ruler, and a CPI (Community Periodontal Index) periodontal probe, in accordance with World Health Organization specifications, with a 0.5 mm ball tip. The examination followed a standardized sequence: assessment of oral hygiene status, recording of gingival health, toothbrushing with a disposable toothbrush, drying the teeth with gauze, and subsequent evaluation of dental caries, malocclusion, and traumatic dental injuries.