Suggested Interval of Chlorhexidine Varnish Application in Orthodontic Patients

Objectives: The effect of chlorhexidine (CHX) varnishes is reduced in patients with orthodontic appliances. To set an optimal application interval it is important to evaluate duration of MS supression in teeth with appliances after CHX therapy. The aim of the present study was to evaluate the recolonization pattern of MS on densely colonized teeth with fixed orthodontic appliances after treatment with a 40% chlorhexidine (CHX) varnish (EC 40, Explore Nijmegen). Materials and Methods: Healthy subjects, free of carious lesions with the need for fixed orthodontic appliances and high bacterial MS counts in saliva were recruited (n= 15). For baseline registration plaque from buccal sites was sampled and cultivated on Dentocult strips (Twetman et al. 1995). Following professional tooth cleaning, CHX varnish was applied on all teeth for 10 min. Afterwards orthodontic brackets were applied. The degree of recolonization with MS was assessed 1, 2, 4 and 6 weeks after varnish application on buccal sites. Results: The data were subjected to a repeated measures design. After 1 and 2 weeks the MS supression was existent. The MS values were statistically different to baseline values (p<0.05). This was not the case after 4 and 6 weeks. Conclusions: The results indicate that application of antimicrobial varnishes in orthodontic patients with high MS levels must be repeated after three to four weeks for optimal MS supression.