Efficacy of Chlorhexidine Varnish

Root caries has become a significant problem for the dentate senior population.1,2 Exposed root surfaces are vulnerable to demineralization at a higher critical pH than enamel because cementum and dentin contain less percentage of minerals.1 In addition, restorative management of root caries lesions is difficult due to access and may require extensive removal of dentin.1 As such, dental hygienists need to be able to identify patients at high risk and employ appropriate preventive interventions and/or noninvasive treatment for active lesions. Risk factors for root caries include age, decreased salivary flow, dietary habits, presence of microbial plaque, lack of fluoride exposure, past and current dental caries, and chronic medical conditions. Whenever possible, preventive measures should be used. Fluoride toothpaste, fluoridated water, and dietary improvements are the cornerstones of caries prevention.3 However, patients with elevated caries risk may benefit from additional fluoride sources, as well as adjunctive therapies, such as fluoride varnish and chlorhexidine varnish, in the treatment of root caries lesions. The evidence is mixed regarding chlorhexidine. A recent systematic review1 evaluated the results of studies regarding several chemical agents to decrease initiation or inactivate root caries lesions. The quarterly application of chlorhexidine varnish had a moderate effect in reducing progression and initiation of root caries lesions. Another review4 studied the effect of chlorhexidine varnish and did not find additional benefits for patients who received a regular dental prophylaxis. Papas et al5 conducted a clinical trial that failed to show that chlorhexidine varnish was superior to a placebo for the prevention of new caries, but the author stated that chlorhexidine varnish may help prevent root caries in very high-risk populations. In 2011, the American Dental Association (ADA) published evidence-based clinical recommendations regarding nonfluoride caries preventive agents.3 The panel concluded with moderate certainty that a 1:1 mixture of chlorhexidine-thymol varnish applied every 3 months can reduce the incidence of root caries.3 Fluoride varnish plays a significant role in the prevention of caries and dentinal hypersensitivity. However, evidence regarding its specific use in the prevention of root caries lesions is weak (eg, case studies, qualitative studies) to moderate (eg, case-control or cohort studies). The ADA published updated recommendations regarding topical fluorides in 2013.6 For patients at an elevated risk, fluoride varnish administered every 3 months to 6 months is recommended for the prevention of adult root caries. However, this is based on expert opinion because current evidence is lacking.6 Another systematic review2 compared seven leading agents for their efficacy in the primary prevention (initiation) and secondary prevention (arrest) of root caries lesions: fluoride, chlorhexidine, xylitol, amorphous calcium phosphate, sealants, saliva stimulators, and silver diamine fluoride. Both fluoride varnish and chlorhexidine varnish reduced the initiation of new root caries lesions for the general adult population. Fluoride varnish applied every 1 month to 3 months was found to be the overall best choice for the arrest of root caries lesions. Fluoride varnish was also the overall best choice for the secondary prevention of root caries lesions in the vulnerable senior population. While there is evidence to support both chlorhexidine varnish and fluoride varnish in the prevention of root caries lesions, I would recommend using fluoride varnish for those at elevated risk. Fluoride varnish can be applied to all teeth, including root surfaces, and is approved by the United States Food and Drug Administration for the treatment of dentinal hypersensitivity. I would reserve chlorhexidine varnish as an adjunct for those patients at very high risk for root caries lesions. REFERENCES

1. 1.  Wierichs RJ, Meyer-Luekel HM. Systematic review on non-invasive treatment of root caries lesions. J Dent Res. 2015;94:261–271.
   2. Gluzman, RI, Katz RV, Frey BJ, McGowan R. Prevention of root caries: a literature review of primary and secondary preventive agents. Spec Care Dentist. 2013;33:133–140.
   3. Rethman M, Beltrán-Aguilar ED, Billings RJ, et al. Non-fluoride caries-preventive agents: executive summary. J Am Dent Assoc. 2011;142:1065–1071.
   4. Slot E, Vaandrager NC, Van Loveren C, Van Palenstein Helderman WC, Van der Weijden GA. The effect of chlorhexidine varnish on root caries: a systematic review. Caries Res. 2011;45:162–173.
   5. Papas AS, Vollmer WM, Gullion CM, et al. Efficacy of chlorhexidine varnish for the prevention of adult caries: a randomized trial. J Dent Res. 2012;91:150–155.
   6. Chi DL, Berg JH, Kim AS, Scott J. Correlates of root caries experience in middle-aged and older adults within northwest precedent. J Am Dent Assoc. 2013;144:507–516.