A transition scoring system of caries increment with adjustment of reversals in longitudinal study: evaluation using primary tooth surface data.

OBJECTIVES The aim of this paper is to evaluate a new comprehensive scoring system for longitudinal studies using the International Caries Detection and Assessment System (ICDAS). METHODS A sample of 638 children were examined in 2002-2003 and again in 2007. Caries was assessed using the ICDAS criteria which assess six clinical stages of dental caries. Based on a transition matrix matching the baseline and follow-up ICDAS scores, we developed transition weights to best describe the progression, regression, or no progression nor regression of dental caries. Differential weights were assigned to transitions involved with noncavitated, cavitated, filled, crowned, or missing lesions. This method [transitional scoring system (TSS)] differentiated biologically plausible reversals from those because of examiner's misclassification. We computed and compared mean dmfs (decayed, missing, and filled tooth surfaces) increment scores including (d(t) mfs) or excluding the noncavitated stage (d(c) mfs) from TSS and another adjustment method proposed by Beck (modified Beck's method). The coefficients of variation (CV) of the two methods were also compared. RESULTS Mean d(t) mfs from TSS was slightly higher than that from modified Beck's method. There was no difference in mean d(c) mfs between two methods. The ratios of CV indicated that the CV of TSS was significantly smaller than those from modified Beck's method. CONCLUSIONS There were differences in caries increment scores between the two methods when we accounted for the transition of noncavitated lesions. The evaluation of CV concluded that TSS was more efficient because it requires less sample size compared with the modified Beck's method to detect a treatment effect. Both methods can be used to compute caries increments for populations with similar distribution of the dmfs scores to the sample used in this study.