Effects of combined application of antimicrobial and fluoride varnishes in orthodontic patients.

A randomized prospective clinical study, with 220 patients scheduled for fixed orthodontic therapy, was conducted to test the hypothesis that application of an antimicrobial varnish in combination with a fluoride varnish (group 1) is significantly more efficient in reducing white spot lesions on the labial surfaces than application of the fluoride varnish alone (group 2). The effects of the antimicrobial varnish on the occurrence of gingivitis and plaque formation were also studied. A third aim was to investigate whether white spot lesion development could be predicted early during treatment. The antimicrobial varnish significantly reduced the number of mutans streptococci in plaque during the first 48 weeks of treatment. This effect did not result in significantly less development of white spot lesions on the labial surfaces compared with the group receiving only the fluoride varnish application. There was however a clear trend that the combination of the antimicrobial and fluoride varnishes more effectively reduced the increments of new lesions on the maxillary incisors. It was speculated that this could be due partly to an inhibiting effect of the antimicrobial varnish in an area with low oral clearance (with low pH and loss of fluoride) and partly to an inhibiting effect of the varnish on mutans streptococci. No significant differences between the groups with respect to gingivitis and plaque were found. Lesion development was difficult to predict early after bonding, despite a number of caries-relevant parameters of orthodontic importance. The best predictors for white spot lesions at debonding were visible plaque and mutans streptococci (eg, the level of oral hygiene and thus the cariogenic challenge) around the appliance shortly after bonding.