Manage Sensitivity With Fluoride
As older adults are able to retain more teeth due to better prevention and intervention, the prevalence of dentinal hypersensitivity (DH) is expected to increase due to the high rate of gingival recession among older populations.
As older adults are able to retain more teeth due to better prevention and intervention, the prevalence of dentinal hypersensitivity (DH) is expected to increase due to the high rate of gingival recession among older populations. DH is characterized by a short, sharp pain that arises from exposed dentin in response to thermal, tactile, or chemical stimuli. This pain ranges from slight to severe, and may significantly impact patients’ quality of life. The current prevalence of DH ranges from 3% to 98% depending on the diagnostic method used and the population studied. In older patients with periodontitis, the prevalence of DH can reach as high as 60% to 98%.
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Causes Behind the Pain
Gingival recession—as a result of clinical attachment loss—is the most widespread risk factor contributing to DH. Gingival recession and periodontitis are common among older adults. However, dentin can also become exposed through enamel loss, which may be caused by erosion, abrasion, attrition, or abfraction. When the exposed dentin comes into contact with thermal, tactile, or chemical stimuli, painful symptoms may occur. DH can also be caused by untreated caries lesions on the root surfaces. As a result of gingival recession, the root surfaces are exposed to plaque accumulation and this eventually leads to root surface caries lesions. The prevalence of root surface caries—a major oral health problem in later life—ranges from 22% to 77%.
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Sodium fluoride varnishes were approved by the US Food and Drug Administration (FDA) in the 1990s for the treatment of DH. Research shows that 5% sodium fluoride (NaF) varnish can be effective in treating DH. When NaF varnish is applied to hypersensitive dentin surfaces, the formation of calcium fluoride crystals block the open dentinal tubules, controlling the permeability of the exposed dentin. This, in turn, reduces the painful symptoms associated with DH. Although NaF varnishes have been approved for the treatment of DH, they are typically used off-label for caries prevention.
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Silver Diamine Fluoride
In 2014, the FDA approved silver diamine fluoride (SDF) as a desensitizing agent in adults older than age 21. The 38% solution contains 25% silver, 5% fluoride, and 8% ammonia. The fluoride promotes remineralization of enamel and dentin surfaces, the silver salts provide an antimicrobial action, and the ammonia helps the solution remain concentrated. SDF is a colorless alkaline liquid, however newer formulas now offer a tinted option, which aids in clinical application. SDF at a 38% concentration contains 44,800 ppm fluoride, the highest among all fluoride agents available for use. Evidence shows that SDF is an inexpensive and safe treatment option for caries prevention and DH. Although studies show that SDF significantly reduces symptoms of DH, it is most often used off-label for caries arrest. Known contraindications to SDF are silver allergy, presence of stomatitis or ulcerative gingival conditions, and teeth that require pulpal therapy. A major disadvantage of SDF is the possibility of staining. The silver particles in SDF darken active caries lesions, however, SDF does not stain sound enamel.
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The cost effectiveness of in-office fluoride varnishes varies among populations with different risk levels. Schwendicke et al found that fluoride varnish costs twice as much and was shown to be slightly more effective than not using fluoride varnish among low-risk populations. For populations at low-risk, fluoride varnish did not significantly reduce caries. However, for individuals at high-risk, fluoride varnish was able to reduce caries and the cost-effectiveness was much greater. A study evaluating elderly patients in Germany compared the cost-effectiveness of SDF and other preventive agents. Results showed that SDF was most cost-effective when compared to fluoride mouthrinses and chlorhexidine among high-risk populations.
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Although SDF was approved by the FDA as a desensitizing agent, minimal evidence exists to support its use as such. Further, no research has been done comparing the efficacy of SDF to NaF varnish in the management of DH. Castillo et al found that SDF was effective and safe in treating DH with reductions in sensitivity persisting 7 days after application. Research has shown that NaF varnish is also effective in treating DH, but its effects are short-lived. For arresting caries lesions, 38% SDF is more effective in hardening or arresting caries lesions than 5% NaF varnish. Both SDF and NaF are cost-effective; however, research shows that SDF was more cost-effective in the management of root caries when compared to other preventive agents such as fluoride mouthrinses.