RESUMEN
OBJECTIVE: The aim of this study was to investigate the clinical performance and to validate the Lesion Activity Assessment (LAA) in conjunction with the International Caries Detection and Assessment System (ICDAS) for occlusal caries diagnosis in permanent teeth. METHODS: Patients with erupted or partially erupted third molars were recruited from the surgery clinic of the School of Dentistry of the Universidade Federal de Minas Gerais, Brazil. A calibrated examiner evaluated 49 teeth using the ICDAS-LAA criteria. The histologic criterion proposed by Ekstrand and others was used to validate severity at the thresholds D1 (outer half of the enamel), D2 (inner half of the enamel and outer third of the dentin), and D3 (inner or middle third of the dentin). Lesion activity was validated using 0.1% methyl red solution. RESULTS: The method demonstrated good reliability (weighted kappa for severity=0.60; unweighted kappa for activity=0.61). The ICDAS presented a higher performance for lesion detection (area under the receiver operating characteristic curve [Az]=0.79) using the threshold D3. At the thresholds D1 and D2, the results for Az were 0.57 and 0.74, respectively. Regarding the ICDAS-LAA, Az = 0.59. CONCLUSIONS: Clinical protocols can use ICDAS for the severity diagnosis of occlusal caries, but the LAA performance was poor.