Investigation on the mode of action of three desensitizing agents using scanning electron microscopy and spectroscopy: An in-vitro study

Aim: This in-vitro study aimed to ascertain the mode of action of three desensitizing agents namely, Arginine-containing, Propolis-containing and Potassium Nitrate-containing dentifrices using scanning electron microscopy and energy-dispersive X-ray spectroscopy. Materials and methods: Ninety dentin slices from non carious human premolar teeth were used for the study. The teeth were randomly divided into three groups (n=30), according to the type of dentifrice applied:- Group I: Arginine-containing paste, Group II: Propolis-containing paste and Group III: Potassium nitrate-containing paste. Each group was divided into two subgroups (n=15) for the assessment by two different techniques: Subgroup A: Scanning electron microscopy examination and Subgroup B: Energy-dispersive X-ray spectroscopy examination. SEM was used to assess the tubule occlusion and the change in the diameter of the dentinal tubules. EDXS was used to characterize the elemental composition of the occlusive material. Analysis of agents, both prior to and after application on dentine discs was performed for comparative purposes. Statistical analysis was done using one-way analysis of variance (ANOVA) and the Bonferroni post hoc test for multiple comparison. Results: The dentin discs treated with arginine-containing paste (93.220% by SEM) showed statistically (p?001) highest mean percentage of occluded tubules followed by Potassium Nitrate-containing paste (34.777% by SEM) and Propolis-containing paste (13.58 % by SEM). There was a strong evidence (p?001) that group I (68%) was most effective in reducing the mean tubule diameter, while group II (47%) and III (44%) did not produce a significant reduction. The EDXS studies show that the dentin surface deposit and occluded tubule plugs contain high levels of calcium, phosphorus, fluorine, silica in group I and III treated specimens.