An abbreviated caries clinical trial design validated over 24 months

Abstract

Conventional caries trials last from 24 to 36 months. This study evaluated whether the previously established difference in efficacy between 1000- and 2500-ppm-fluoride dentifrices could be detected after 12 months. Caries was assessed by clinical visual assessment (CVA-simplified version of Dundee Selectable Threshold Method - DSTM), bitewing radiography, and Fiber Optic Transillumination (FOTI). Changes in status for individual surfaces were classified by means of pre-prepared matrices as 0 (unchanged), +1 (initiation or progression), or -1 (regression) and summed for each subject to yield an event score. Mean group event scores were calculated for each product. DSTM at the D(1) [enamel and dentin] threshold showed significant inter-group differences in mean event scores (p < 0.003) and D(1)MFS increment (< 0.007) at 12 months; these were confirmed at 24 months by traditional increment analysis (CVA & FOTI at the D(3) (dentin only) threshold + radiography, p < 0.03). This study confirms the validity of an abbreviated trial protocol.