The purpose of this study was to compare results of 4 different methods of diagnosing dental caries in 12-year-old children by evaluating their influence on the DMFS index and analyzing the correlation of the radiographic exam with the clinical exam. The tools used were: 1) dental mirror; 2) dental mirror and dental explorer, both performed in an outdoor setting under natural light; 3) dental mirror; 4) dental mirror and dental explorer, both performed in a traditional dental setting under artificial light. The radiographic exam was carried out after the clinical exam. The dental explorer may be omitted from the clinical exam in epidemiological surveys and in clinical exams performed in dental offices. Methods 3) and 4) performed better in diagnosing dental caries than methods 1) and 2), which underestimated decay. In the traditional dental setting, the process of dental cleaning and drying as well as artificial light, improved the diagnosis of dental caries. The radiographic exam used for epidemiological surveys, in relation to method 2), improved the clinical exam by 4%.70115-9