Oral Hygiene Behaviours, Motivation and Perceived Competence in Adults Living With Mental Illness: A Cross‐Sectional Study

BACKGROUND: People living with mental illness experience poorer oral health than the general population, influenced by medication-related effects, behavioural risk factors, and structural barriers to dental care. Oral health behaviours and psychological determinants such as motivation and perceived competence are central to prevention and self-care, yet remain under-described in this population. METHODS: This cross-sectional study included sixty-three adults receiving mental health care in community settings and rehabilitation-focused inpatient programmes. Data were collected during a single session and included self-reported oral hygiene behaviours, oral health knowledge, motivation and perceived competence, alongside clinically assessed oral health status. Motivation and perceived competence were assessed using the Self-Regulation Questionnaire for Oral Health and the Perceived Competence Scale. A brief oral health education session was delivered as part of routine care and was not evaluated as an intervention. RESULTS: Participants reported inconsistent oral hygiene practices, including low rates of daily interdental cleaning (11.5%) and dental attendance within the previous year (34.4%), alongside variable oral health knowledge. Clinical assessments indicated widespread oral tissue changes and suboptimal oral hygiene. Motivation for oral hygiene was predominantly autonomous, and perceived competence scores were high. Higher oral health knowledge, autonomous motivation and perceived competence were associated with more favourable oral hygiene indicators. CONCLUSIONS: Adults living with mental illness demonstrated substantial unmet preventive oral health needs despite high motivation and perceived competence. These findings highlight a discrepancy between reported motivation and observed oral health behaviours and may inform future oral health promotion within mental health services and primary health care settings.