A prototype teledentistry service was established that incorporated a PC-based expert system designed to assist in orthodontic cases. It guided the general dental practitioner (GDP) through the assessment of a patient's malocclusion and helped ensure that all relevant clinical observations were made and details recorded. The resulting data file, containing radiographic images and clinical data, was then transferred via the Internet to a dental specialist. The specialist's recommendations were returned by the same route or, where appropriate, a realtime videoconference was conducted. During an eight-month trial, six GDPs referred 158 cases through the teledentistry system; another 24 cases were referred directly to a local consultant. The protocol used during the trial worked satisfactorily. The GDPs found that it was straightforward and covered all aspects of the cases they submitted.