An overview was conducted of all randomized, controlled studies comparing NaF to SMFP dentifrices in the prevention of caries development. Data from these separate trials were subjected to a pooling procedure, or meta-analysis, in order to obtain a more stable estimate of comparative treatment efficacy and to aid in interpreting the generalizability of results. Based on a pool of studies involving over 7,000 subjects, NaF was associated with a significantly greater reduction in caries development compared to SMFP. The increment in D(M)FS was reduced an average of 0.28 (95% confidence limits 0.10 to 0.46) with the use of NaF as compared to SMFP over a 2- to 3-year follow-up period. This difference represents a 6.4% reduction in the rate of caries development observed with SMFP. The numerical advantage conferred by NaF over SMFP in caries risk reduction must be judged clinically as to its public health implications. Alternative analytic techniques and rules for including studies in the pooling process yielded consistent conclusions. A similar analysis of data from dual-active studies indicated that NaF in combination with SMFP provides greater lowering of the D(M)FS increment (approx. 0.16 over 2-3 years) compared to SMFP at the same total fluoride dose, whereas the dual-active product demonstrated no advantage over NaF alone.