Micrographic and spectroscopic analyses of the application of methyl methacrylate-p-styrene sulfonic acid copolymer-based desensitizing agents to bovine dentin

Purpose: This study compared the ability of three methyl methacrylate (MMA)-p-styrene sulfonic acid copolymer (MS polymer)-based desensitizers (Pain-Free Gel Dentin Desensitizer; PF-Gel, No-Mix Pain-Free Desensitizer; PF, No-Mix Pain-Free F Desensitizer; PF-F) to occlude dentinal tubules. Materials and Methods: Dentin disc specimens were prepared from bovine incisors and the desensitizers were applied. After dehydration for 24 h or immersion for 1 week in artificial saliva, the surfaces were observed by scanning electron microscope (SEM). PF-Gel specimens also underwent SEM/energy dispersive X-ray spectroscopy (EDS). Results: Application of the desensitizers produced complete occlusion of the dentinal tubules. Most dentinal tubules re-opened after immersion for 1 week in artificial saliva (PF and PF-F samples), but in PF-Gel samples, the dentinal tubules remained occluded. SEM/EDS analysis demonstrated that the granular crystals adhering to the dentin surface contained oxygen, carbon, and calcium, and the plugs occluding the dentinal tubules contained calcium and phosphorus. Conclusion: The findings in this study confirm the sustainable effect of PF-Gel on the occlusion of dentinal tubules. (Asian Pac J Dent 2019; 19: 51-57.)