Dentine hypersensitivity is characterized by short, sharp pain arising from exposed dentine in response to stimuli typically thermal, evaporative, tactile, osmotic or chemical and which cannot be ascribed to any other form of dental defect or pathology (Orehardson & Collins 1987a, Addy 1992).¹ It typically affect individuals aged from 20–49 years, with a peak incidence between 30–39 years. The buccal cervical regions of the permanent teeth are the most commonly affected surfaces, with canine, premolar and incisor teeth being more frequently affected than molars. ^2,3

The hydrodynamic theory proposed by Brännström M in 1963 is still the most accepted theory used to explain the mechanism of dentin hypersensitivity. According to this theory, open tubules of exposed dentine allow the movement of dentinal fluid within the dentinal tubules, indirectly stimulating the pulp nerves.⁴

The severity of symptoms does not depend on the breadth and depth of lesions, but on the number of non-occluded tubules exposed to the oral cavity, consequently, the sealing of exposed and patent tubules should reduce or eliminate the pain and discomfort of the patient.⁵

There are two principal treatment options. These are plugging the dentinal tubules, preventing fluid flow and desensitizing the nerve, making it less responsive to stimulation.⁶ Occlusion of the dentin tubules is the most common therapeutic approach. Many of the agents in this category result in precipitative intratubular occlusion or in the formation of a smear layer over dentin that blocks entry to the tubules.^7,8

 As a non-invasive treatment for dentin hypersensitivity, 38% SDF was first introduced into the United States (US) market in 2015. The silver particles on the surface and within the tubules decrease tubule diameter markedly and thus reduce tubular fluid movement, an established mechanism to relieve dentin hypersensitivity.⁹Nanoseal® (Nippon Shika Yakuhin, Shimonoseki, Japan) a tooth surface coating product to clinically reduce dentin hypersensitivity, is composed of two liquids: an aqueous dispersion of nanoparticulate calcium-fluoroaluminosilicate glass and phosphoric acid solution). After mixing the two liquids, calciumfluoroaluminosilicate glass particles begin to aggregate by the acid-base reaction. The aggregates occlude the dentinal tubules like a type of silicate cement filling. ¹⁰

Gluma (Heraeus Kulzer, Armonk, NY, USA) a non-fluoride product, is one of the systems marketed solely for the treatment of dentin hypersensitivity. Gluma consists of glutaraldehyde-hydroxyethyl-methacrylate and prevents hypersensitivity by reducing dentinal permeability and clotting the proteins and amino acids in the peripheral dentinal tubules. This inhibits the flow of fluid through the tubules, which is the cause of the sensitivity.¹¹

The patient’s experience has become increasingly important in evaluations of the effectiveness of dental treatments as it complements the dentist evaluations and other measures completed in a more traditional manner.¹² However, there are limited well-designed clinical trials that investigate the effectiveness of SDF in reducing dentine hypersensitivity. Hence, the present clinical study will be intended to assess the efficacy of four different desensitizing agents in providing relief from dentin hypersensitivity and to help the clinician choose the most effective treatment solution for dentin hypersensitivity.