Disclosed are dental varnishes comprising reaction products of rosins with polyalcohols dissolved in mixtures of C.sub.2-C.sub.4 alcohols with C.sub.5-C.sub.7 hydrocarbons or C.sub.5-C.sub.7 hydrocarbons alone which have been found effective in preventing tooth decay and alleviating tooth sensitivity. Such varnishes may, optionally, incorporate therapeutic, antimicrobial and sensory enhancing ingredients.