The aim of this paper was to re-assess the available literature examining the value of the bitewing radiograph in the diagnosis of approximal caries and to compare the relative values of radiographic and clinical examinations. To this end, results from 29 research studies have been re-presented and tabulated. These results show that the use of the bitewing radiograph is essential if much approximal caries is not to be missed. It is particularly important in the detection of the small lesion which may be managed preventively rather than operatively. Although there is a proper need to ensure that radiographic exposures are minimised, the evidence suggests that both clinicians and epidemiologists must balance this need with the ethical issues associated with failing to employ an established diagnostic aid.