Microhardness and Scanning Electron Microscopic Morphology of Permanent Dentin Following the Application of Iranian and Foreign-Made Desensitizing Toothpastes

Abstract

Background: This study aimed to assess the microhardness and morphology of permanent dentin following the application of Iranian and foreign-made desensitizing toothpastes. Methods: This in vitro, experimental study evaluated 48 dentin samples prepared of the extracted sound human permanent molars. Dentin samples were randomly divided into three groups (n=16) and subjected to the application of Pooneh Iranian desensitizing toothpaste, Colgate Sensitive Pro- Relief (Poland), and no intervention (negative control). Each dentin sample was then immersed in 5 mL of a demineralizing solution for 10 hours and underwent a demineralization/remineralization cycle (pH cycling) for 14 days. The mean microhardness of the samples was measured at baseline after demineralization and after 14 days. One sample of each toothpaste group was selected for the scanning electron microscopy (SEM) assessment of dentin morphology. Finally, repeated-measures ANOVA was used to analyze the effect of time and type of toothpaste on microhardness using SPSS, version 21. Results: The comparison of the mean microhardness of the control group with experimental groups revealed no significant difference at baseline or after demineralization (P > 0.05) although this difference was significant after 14 days (P < 0.001). The mean microhardness of the two toothpaste groups was not significantly different at different time points (P > 0.05). Finally, the SEM assessment revealed a greater tubular obstruction in Pooneh group after 14 days. Conclusions: Pooneh Iranian-made desensitizing toothpaste was comparable to Colgate Sensitive Pro-Relief foreign-made desensitizing toothpaste in terms of the microhardness of permanent dentin. It even demonstrated superior performance with regard to the obstruction of dentinal tubules.