Effect of chlorhexidine treatment followed by stannous fluoride gel application on mutans streptococci in margins of restorations.

The effect of antimicrobial treatment on the numbers of mutans streptococci (MS) in plaque from margins of restorations and in saliva was studied. Nineteen persons with well-restored dentitions and > 0.5 x 10(6) MS per ml saliva were treated with 1% chlorhexidine (CHX) gel in individually designed applicators 5 min/day for 9 days. Ten of the subjects continued the treatment with 0.4% stannous fluoride (SnF2) gel and the remaining 9 with a placebo gel for another 14 days. Plaque samples from margins of selected restorations and stimulated saliva were collected at baseline, after the completion of each gel treatment and then again at regular intervals up to 24 weeks. The CHX gel treatment suppressed MS in the margins of restorations as well as in saliva. Additional treatment with the SnF2 gel prolonged this suppression compared with CHX treatment alone. In the CHX-SnF2 group, the number of MS in margins of amalgam and composite restorations was still significantly lower at the end of the study compared with the baseline. In the CHX placebo group, the margins of amalgam restorations, mainly placed in premolars and molars, were recolonized somewhat faster than the margins of composite restorations in the front teeth.