This paper questions the effectiveness of current oral health promoting activities in reducing social inequalities in oral health. An attempt is made to address the needs of dental professionals and nutritionists in communicating an understanding of biological aspects of the aetiology of caries and erosion. With a clear understanding of the disease process oral health promoters can possibly reduce social inequalities in oral health. A clear common message which satisfies both dental and nutritional professionals is presented. The issues of commonality and ambiguity are fundamental to effective behavioural/teaching practice. Currently the evidence base suggests that dietary messages are inconsistent and ambiguous. Therefore, a clear common and unambiguous dietary message, based on science, could go some way to improving oral health inequalities.