Effect of Potassium Iodide on the Tensile Bond Strength of Glass Ionomer Cement and Resin Modified Glass Ionomer Cement on Silver Diamine Fluoride treated Dentine: A Comparative in Vitro study

Abstract

AIM OF THE STUDY: Silver Diamine Fluoride (SDF) promotes remineralization, inhibits demineralization, increases dentin hardness and outperforms in bactericidal effect. A significant disadvantage of SDF is the unaesthetic permanent black staining of teeth caused by silver oxide. The black staining caused by SDF can be overcome by the use of Potassium iodide (KI). However, the influence of potassium iodide on the bond strength of SDF to restorative materials has no enough documentation. Hence this study was designed to estimate the effect of SDF/KI on the tensile bond strengths of restorative materials - glass ionomer cement (GIC) and resin- modified glass ionomer cement (RMGIC). METHODS: A total of 120 samples were used in the study. The occlusal surfaces were ground and polished using 600 grit silicon carbide abrasive paper under running water and embedded in self cure acrylic blocks. A hollow polyvinyl mould is placed on treated surface. Specimens were randomly divided into two groups (A, B) with 60 samples each. This in turn sub grouped to three subgroups each (A1, A2, A3 and B1, B2, B3) with twenty samples each. Subgroup A1 was conditioned with10% Polyacrylic acid (GC Dentin conditioner, GC Corp, Japan), rinsed, treated with 38% SDF (Fagamin) for ten seconds, rinsed, and then filled with GIC(GC IX, GC Corp, Tokyo, Japan). A 26 gauge ligature wire was twisted to form a loop at one end and placed inside the setting cement. Subgroup A2 was conditioned with10% Polyacrylic acid, rinsed, treated with 38% SDF for ten seconds, followed by potassium iodide (KI). On obtaining a creamy white precipitate it’s washed off and filled with GIC with the looped ligature wire. Subgroup A3 was conditioned with 10% Polyacrylic acid, rinsed and restored with GIC with the wire. Same procedure was followed for all subgroups in group B except that the restorative material here was RMGIC (GC II LC, GC Corp, Japan) and light cured at 400 nm/20 seconds. After complete setting the moulds were removed. All samples were tested for tensile bond strength by mounting onto the Universal Testing Machine running at a crosshead speed of 5mm/minute. RESULTS: The tensile bond strength of glass ionomer cement to dentin compared with the tensile bond strength of SDF followed by glass ionomer cement to dentin the P value was non significant (0.77). The comparison of tensile bond strength of resin- modified glass ionomer cement to dentin, to SDF followed by resin-modified glass ionomer cement to dentin was not statistically significant. (P-0.35). The P value for comparison of SDF treated glass ionomer cement was not significant to SDF/KI followed by GIC (P value - 0.23). Similarly the comparison of SDF treated resin modified glass ionomer cement was not significant to SDF/KI followed by RMGIC (P value - 0.46). On comparing the tensile bond strength of glass ionomer cement to dentin to tensile bond strength of resin-modified glass ionomer cement to dentin the mean difference was statistically significant (P < 0.001). CONCLUSION: Silver diamine fluoride does not affect the tensile bond strength of glass ionomer cement and resin-modified glass ionomer cement to dentin. Potassium iodide does not influence the tensile bond strength of glass ionomer cement and resin-modified glass ionomer cement on silver diamine fluoride treated dentin. Resin modified glass ionomer cement has higher tensile bond strength than glass ionomer cement and the choice of restorative material relies on the clinician’s choice based on individualized patient’s treatment needs