RESUMO
OBJECTIVES: To appraise the feasibility of the caries assessment spectrum and treatment (CAST) severity score according to the formula (F) recommended in the CAST manual. METHODS: Data from an epidemiological survey of 680 schoolchildren (mean age ± standard deviation: 7.45 ± 0.91 years), living in a low-income area in Brasília, were used. The CAST instrument was used for assessing enamel carious lesions (CAST code = 3), dentine carious lesions (CAST codes = 4-7) and tooth loss from caries (CAST code = 8). RESULTS: The prevalence of carious lesions including enamel and dentine in both deciduous and permanent dentitions was 49.41% and 69.12%, respectively. Calculating the CAST severity score per child using F was unsatisfactory because of the undiscriminating weight given for each CAST code. Modification of weights according to the accepted levels of disease severity for individual CAST codes resulted in a new formula (F1), in which the weight given to cavitated dentine lesions was quadrupled in relation to that given to enamel carious lesions; this was different from F, in which the weight given to such lesions was twofold. F1 was able to categorise satisfactorily the study children into one of three levels of dental caries severity: mild (34.1%); moderate (29.5%); or severe (36.4%). CONCLUSION: According to the outcomes of the present appraisal, it was concluded that the numerical score provided by the CAST severity scores allows an overview of the severity of caries disease and the classification of individuals into mild, moderate or severe levels of dental caries when the new formula (F1) is used.