Introduction: The International Caries Detection and Assessment System (ICDAS) categorize dental caries/restorations and can be applied in Dental Medicine (DM) education, clinical practice, clinical and epidemiology research. Objective: This trial evaluated dental caries experience/severity and restorative interventions by ICDAS, in a population of university DM services. Material and Method: Observational, cross-sectional and descriptive study; random sampling: 284 individuals aged ≥ 18 years, attending the 1st dentistry appointment at the Faculty of Health Sciences, University Fernando Pessoa, over a period extending from September-2008 to July-2010. The intra-oral (visual/tactile) ICDAS record was validated by four examiners trained/calibrated (ICC=0.963) to identify the restorative and dental caries clinical (non-cavitated and cavitated carious lesion) conditions. Descriptive/inferential statistical analysis (alpha=0.05) was conducted. Results: In the sample (64.8% female) the average (±SD) age was 44.3 (±16.4) years, with no significant differences (t-student test, p=0.110) between genders. In average, 118.7 (±81.7) tooth surfaces/individual were observed; Decayed surfaces were: 9.1(±11.8) with primary caries, of which 5.63 (±8.48) were non-cavitated lesions (enamel); of those 0.15 (± 0.97) had fissure sealants and 3.6 (±4.3) were cavitated (dentin). Surfaces restored with definitive material: 9.2 (±13.2). There were secondary caries in 1.7 (±2.9) surfaces; Secondary caries in enamel and dentin occurred at 0.71 (±2.11) and 1.0 (±1.2) surfaces, respectively. The population dental surfaces' condition was: 56.3% healthy, 52.5% with caries (51.8% cavitated lesions (dentin) and 49.3% non-cavitated lesions (enamel)), 53.2% restored, but 42.6% had secondary caries (33.5% cavitated and 31% non-cavitated lesions). Discussion and Conclusions: The ICDAS clinical report revealed high experience/severity of dental caries and restorative interventions, but variable values when analyzing the individual and the population. Trials that include registration of caries activity are needed in order to define individual/population risk. The ICDAS assessment allows the definition of more accurate preventive/restorative decisions in clinical practice and clinical and epidemiological investigations. Keywords: dental caries, caries prevalence, caries severity, restoration, ICDAS, cross-sectional study