Effects of fluoride and chlorhexidine on the microflora of dental root surfaces and progression of root-surface caries.

The effects of fluoride and chlorhexidine varnishes on the microflora of dental root surfaces and on the progression of root-surface caries were studied. Forty-four patients, surgically treated for advanced periodontal disease, were distributed at random among three groups. All patients received a standardized preventive treatment. Furthermore, the dentition of the patients in the two experimental groups was treated, at three-month intervals, with chlorhexidine and fluoride varnish, respectively. Patients in the control group received no additional treatment. In the experimental groups, plaque samples were collected from selected sound and carious root surfaces at baseline and at three, six, and nine months after the onset of the study. The presence of root-surface caries was scored at baseline and after one year. In addition, the texture, depth, and color of the root-surface lesions were monitored. Mutans streptococci on root surfaces were suppressed significantly (p less than 0.05) during the whole experimental period in the chlorhexidine varnish group, but not in the fluoride varnish group. A non-significant increase in the number of Actinomyces viscosus/naeslundii was noted after treatment with chlorhexidine and fluoride varnish. The increase in the number of decayed and filled root surfaces after one year was significantly lower in the experimental groups than in the control group. After treatment with chlorhexidine varnish, significantly more initial root-surface lesions had hardened than in the other groups.