Background and objective:
Pathologies of the oral cavity are great burden globally and one of the most expensive health treatments. In low and middle-income countries, such as São Tomé and Príncipe (STP), they have an even greater impact.

Objective:
To describe the prevalence of dental caries of caries, dental trauma, erosion and oral lesions and behaviors related to oral health in adults (≥18 years) in STP.

Methods:
Cross-sectional study. Convenience sample of 241 adults (≥18 years). Data collected through the clinical oral health assessment form based on the WHO Oral Health Surveys and extra and intraoral observations by a Dentist. The DMFT index was computed to determine the prevalence of dental caries. Descriptive statistical analysis of data.

Results:
Participants were frequently females (67.2%), 5.4% had no education and the mean age was 36.6 years. The prevalence of decayed, missing and filled teeth was respectively 84.6%, 78.0% and 9.1%. 0.4% of erosion lesions with pulp involvement and 0.8% of teeth lost by trauma. More than half of the individuals had no lesions of the oral mucosa (LOM) abnormal condition. The most frequent location of LOM was the gingiva and/or alveolar ridge (17.4%). Only 0.4% did not brush their teeth. 75.5% used fluoride toothpaste and more than half washed their teeth twice a day (90.0%). 66.0% had felt pain or discomfort in a tooth in the last year. However, 30.7% never received dental treatment.

Conclusions:
The prevalence of dental caries in the studied sample is high, with a low DMFT index, despite being higher compared to young age groups. The prevalence of dental trauma is below average for African countries. The prevalence of dental erosion was low. This study contributed to the description of oral health in adult age groups in STP, which had never been done before."