Interrelations of Oral Microorganisms, Immunoglobulins, and Dental Caries Following Radiotherapy

Abstract

Of 42 head and neck cancer patients with radiotherapy-induced xerostomia, 36 survived to permit a postirradiation caries evaluation. Twenty-three developed an average of 17.6 caries lesions and 13 had no new lesions within 30 months postirradiation. All caries-inactive patients had been initially assigned to daily self-application of a 1% sodium fluoride gel. The preirradiation caries experience and the oral microbial profile were comparable in both groups. After tumoricidal irradiation, the mean plaque increase of Streptococcus mutans was 25 times greater in the caries-active than in the caries-inactive group. Postirradiation caries was also associated with increased plaque Lactobacillus sp, Candida sp, and Streptococcus sp, and serum IgD and IgG concentrations. Conversely, plaque Staphylococcus sp, Streptococcus salivarius, and Veillonella sp and saliva IgA concentrations were significantly higher in the caries-inactive than in the caries-active group. Both groups demonstrated decreases in plaque Streptococcus sanguis, Neisseria sp, Fusobacterium sp, and Bacteroides sp.