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

Atsushi Kameyama, DDS, PhD (1,2), Akiko Haruyama, DDS, PhD (2), Yuichi Nakazawa, DDS, PhD (2), Masahiro Furusawa, DDS, PhD (3), and Takashi Muramatsu, DDS, PhD (2)

(1) Department of Operative Dentistry, Endodontology, and Periodontology, School of Dentistry, Matsumoto Dental University, Shiojiri, (2) Department of Operative Dentistry, Cariology and Pulp Biology, and (3) Department of Endodontics, Tokyo Dental College, Tokyo, Japan

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.)
Key Words: dentin desensitizer, dentinal hypersensitivity, MS polymer, energy dispersive X-ray spectroscopy