Seventy three head and neck cancer patients were radiated between 1987 and 1993 at the Faculty of Medicine, Ramathibodi Hospital, Mahidol University. The incidence of dental extraction was much decreased after fluoride treatment regardless of the method of treatment with 54.8 per cent of the patients followed-up for more than 36 months. There was no significant difference of the dental status between application of fluoride gel, fluoride solution month rinse and combination of gel and solution. The incidence of dental extraction decreased to 6.9-22.7 per cent but dental filling increased to 54.5-68.2 per cent. We would like to conclude that continuing dental care with daily home fluoride month rinse and 3-6 months follow-up by the dentists will be the proper way to prevent radiation dental caries.