In 2020, following the World Health Organization's declaration of COVID-19 as a pandemic, dental practices faced unprecedented disruptions globally. This retrospective cross-sectional study, conducted at a leading university dental hospital in the Lisbon Metropolitan Area, investigated the impact of these disruptions on dental caries. The study, spanning June 2019 to June 2021, included a full-mouth X-ray examination, along with sociodemographic, behavioral, and medical data. Our sample comprised 3,380 participants (2,007 females and 1,373 males), aged 18 to 99 years, divided into pre-lockdown and post-lockdown groups. We employed the Decayed, Missing, and Filled Teeth (DMFT) index to measure dental caries. Our findings revealed that nearly 90% of participants in both groups experienced dental caries, indicating a statistically significant difference between the pre-lockdown and post-lockdown periods. However, the impact of COVID-19 confinement varied among different demographic sectors, with age, educational background, and professional status emerging as the key determinants. This study highlights the need for a more nuanced understanding of the impact of the pandemic on oral health, emphasizing the role of sociodemographic factors in shaping dental health outcomes during such global health crises.