Sodium fluoride or sodium monofluorophosphate? A critical view of a meta-analysis on their relative effectiveness in dentifrices.

A detailed examination of nine publications used in a meta-analysis to compare the relative effectiveness of sodium fluoride and sodium monofluorophosphate in dentifrices showed important flaws in the process. Some studies were inappropriately chosen. Other selected comparisons between the two compounds favored sodium fluoride when more appropriate comparisons in the same studies, showing either an advantage for sodium monofluorophosphate or a lesser advantage to sodium fluoride, were ignored. Some simple errors also appear to have been made when taking data from the publications. When all these factors are taken into account it seems that three studies favor sodium monofluorophosphate, two favor sodium fluoride and the remaining five either could not or should not be included in a meta-analysis. The only two scientifically conceived and conducted studies failed to demonstrate an advantage of one compound over the other.