EFFECT OF DIFFERENT CHLORHEXIDINE VARNISH REGIMENS ON MUTANS STREPTOCOCCI LEVELS IN INTERDENTAL PLAQUE AND SALIVA

The aim of the present study was to evaluate and compare the effects o f an intensive and a monthly mode of antibacterial varnish application on the levels of mutans streptococci (MS) in interdental plaque and w hole saliva. Eighty-eight healthy schoolchildren (11-13 years) with hi gh scores of salivary MS were selected by a screening procedure and ra ndomised into two groups. MS were enumerated at all mesial interdental sites of the first permanent molars with the aid of a modified chair- side technique, disclosing a total of 161 sites with moderate or high colonisation levels. The subjects were treated with a 1% chlorhexidine -thymol-containing varnish (Cervitec(R)) either in an intensive mode ( IM) with 3 applications within a 2-week period or in a monthly mode (M M) during a 3-month period. The varnish was applied with a miniball bu rnisher after the teeth had been cleaned interdentally with dental flo ss and dried with air. Follow-up samples of saliva and plaque from the interdental areas were collected after 1, 3 and 6 months. Both groups exhibited a statistically significant (p < 0.05) reduction of interde ntal MS after 1 month when compared with baseline. An eliminated MS gr owth appeared more frequently following the IM compared with the MM. A fter 3 months, a significant reduction compared with baseline was stil l found in the IM group but not in the MM group. No reduction was foun d in either group after 6 months. MS levels in saliva were mainly unaf fected at the follow-up samplings, with the exception of a slight redu ction in the IM group after 1 month. In conclusion, the results sugges t that an intensive mode of chlorhexidine-thymol varnish application i s more effective against interdental MS than the monthly mode of appli cation. Bacterial growth should be monitored in a site-specific way, s ince interdental reductions were not adequately reflected in whole sal iva samples.