Oral Health and Dietary Habits Before and After COVID-19 Restrictions in a Portuguese Adult Population: An Observational Study

<b>Background:</b> The declaration of COVID-19 as a pandemic by the World Health Organization in 2020 led to the widespread suspension of clinical practices, including dentistry. This study aims to evaluate the impact of these restrictions on oral health and dietary habits. <b>Methods:</b> A retrospective cross-sectional study was conducted at Egas Moniz University Clinic (Lisbon Metropolitan Area), covering from June 2019 to June 2021. A total of 3380 participants were included and categorized into two cohorts: pre- and post-COVID-19 restrictions. Data were collected through a structured questionnaire assessing oral health behaviors and dietary habits. <b>Results:</b> Of 3469 incoming patients, 3380 met the inclusion criteria. Statistically significant post-lockdown changes were observed, including increased smoking prevalence, higher coffee with sugar consumption, reduced use of dental floss and mouthwash, and redistribution in tooth brushing frequency, with fewer individuals brushing 2-3 times daily. <b>Conclusions:</b> COVID-19-related restrictions had a heterogeneous impact on oral health and dietary behaviors. While some individuals reported improved hygiene routines, others showed negative changes, such as increased tobacco use or decreased use of oral hygiene products. These contrasting effects call for targeted public health strategies to reduce inequalities and support vulnerable groups during crises.