OBJECTIVE To examine the quality of oral health promotion research evidence and to assess the effectiveness of health promotion, aimed at improving oral health using a systematic and scientifically defensible methodology. METHODS Systematic review of oral health promotion research evidence using electronic searching, iterative hand-searching, critical appraisal and data synthesis. METHODS The settings of the primary research reviewed were clinical, community, schools or other institutions. The participants were children, the elderly, adults and people with handicaps and disabilities. METHODS Only studies which reported an evaluative component were included. Theoretical and purely descriptive papers were excluded. METHODS The review examined the evidence of effectiveness of oral health promotion on caries, oral hygiene, oral health related knowledge, attitudes and behaviours. RESULTS Very few definitive conclusions about the effectiveness of oral health promotion can be drawn from the currently available evidence. Caries and periodontal disease can be controlled by regular toothbrushing with a fluoride toothpaste but a cost-effective method for reliably promoting such behaviour has not yet been established. Knowledge levels can almost always be improved by oral health promotion initiatives but whether these shifts in knowledge and attitudes can be causally related to changes in behaviour or clinical indices of disease has also not been established. CONCLUSIONS Oral health promotion which brings about the use of fluoride is effective for reducing caries. Chairside oral health promotion has been shown to be effective more consistently than other methods of health promotion. Mass media programmes have not been shown to be effective. The quality of oral health promotion evaluation research needs to be improved.