Risk factors for radiation-induced dental caries in patients with head and neck cancer

Purpose: One of the major causes of osteoradionecrosis of the jaw in patients with head and neck cancer is thought to be progressive dental caries after radiotherapy (RT). The purpose of this study was to investigate associations between various clinical factors and dental caries after RT in order to establish prevention methods for radiation-induced progressive caries. Materials and methods: Thirty-one patients with head and neck cancer who had undergone RT (RT group) and 25 patients who had undergone surgery alone (control group) were examined for dental caries at 1 or 2 years after RT. Various clinical factors were investigated with regard to their relationship with dental caries, via one-way analysis of variance followed by multiple regression analysis. Results: Dental caries were increased in both groups, and the increase was significantly higher in the RT group than in the control group. When the radiation field included salivary glands and teeth, the number of dental caries was significantly higher as determined via univariate analysis. In the multivariate analysis, only the number of teeth in the radiation field was significantly correlated with the increase in dental caries. Conclusion: The incidence of dental caries increases significantly after RT in patients with head and neck cancer. The major causes of progressive dental caries after RT seem to be direct damage to the tooth by the RT and reduced salivary flow due to the destructive effect of RT on the salivary gland. Correspondence to: Sakiko Soutome, Perioperative Oral Management Center, Nagasaki University Hospital, 1-7-1 Sakamoto, Nagasaki, 852-8588, Japan; Tel: 81-95-819-7698; Fax: 81-95-819-7700; [email protected]