In Vitro Study of Dentin Hypersensitivity Treated by ۹۸۰-nm Diode Laser

Abstract Introduction: To investigate the ultrastructural changes of dentin irradiated with ۹۸۰-nm diode laser under different parameters and to observe the morphological alterations of odontoblasts and pulp tissue to determine the safety parameters of ۹۸۰-nm diode laser in the treatment of dentin hypersensitivity (DH).Methods: Twenty extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into four areas and was irradiated by ۹۸۰-nm diode laser under different parameters: Group A: control group, ۰ J/cm²; Group B: ۲ W/CW (continuous mode), ۱۶۶ J/cm²; Group C: ۳W/CW, ۲۵۰ J/cm²; and Group D: ۴W/CW, ۳۳۳ J/cm². Ten additional extracted human third molars were selected to prepare dentin discs. Each dentin disc was divided into two areas and was irradiated by ۹۸۰-nm diode laser: Group E: control group, ۰ J/cm²; and Group F: ۲.۰ W/CW, ۱۶۶ J/cm². The morphological alterations of the dentin surfaces and odontoblasts were examined with scanning electron microscopy (SEM), and the morphological alterations of the dental pulp tissue irradiated by laser were observed with an upright microscope.Results: The study demonstrated that dentinal tubules can be entirely blocked after irradiation by ۹۸۰-nm diode laser, regardless of the parameter setting. Diode laser with settings of ۲.۰ W and ۹۸۰-nm sealed exposed dentin tubules effectively, and no significant morphological alterations of the pulp and odontoblasts were observed after irradiation.Conclusions: Irradiation with ۹۸۰-nm diode laser could be effective for routine clinical treatment of DH, and ۲.۰W/CW (۱۶۶ J/cm²) was a suitable energy parameter due to its rapid sealing of the exposed dentin tubules and its safety to the odontoblasts and pulp tissue. Keywords: dentin sensitivity lasers scanning electron microscopy