A Scaning Electron Microscopic Investigation Of Occluding Effects Of Several Methods For Dentine Hypersensitivity On Human Dentinal Tubules

Objective: To investigate the occluding effects of several methods for dentine hypersensitivity (NaF ,GLUMA, Nd:YAG laser , NaF combined with Nd:YAG laser) on human dentinal tubules. To provide experimental foundation for the effectiveness of dentine hypersensitivity treatment. Methods : (1) Specimen collection: Thirty-five intact bicuspids extracted for orthodontic treatment were randomly divided into seven groups as DH simulation group(control group)(A), NaF treatment group(B), GLUMA treatment group(C), Nd:YAG laser(50mj 10Hz) treatment group(D),Nd:YAG laser(50mj 15Hz ) treatment group(E), Nd:YAG laser (100mj 10Hz) treatment group(F), NaF followed by Nd:YAG laser(50mj 15Hz) treatment group(G).(2)Treatment procedure: dentin discs for DH simulation were made after cutting coronal enamel and etching with 37% phosphoric acid for 10s. then six treatments treat the dentin disc individually.(3) Scaning electron microscopic examination was conducted to observe the occluding effects of these treatments on dentin tubules.Results: Group A, DH simulation group(control group): the dentinal tubules lined up in order and regularity. The surface of dentin disc was open and clean. Group B, NaF treatment group: Some of dentinal tubule orifices were covered with white NaF pellet ,but most of them occluded only half , even quarter orifice. Some of dentinal tubule orifices were exposed. Group C, GLUMA treatment group: Some of dentinal tubule orifices were occluded by GLUMA ,most of them occluded half,three quarters orifice.Group D, Nd:YAG laser(50mj 10Hz) treatment group: The surface of dentin were not fused. Some of dentinal tubule orifices were covered with white fused layer . but Some of dentinal tubule orifices were partly sealed. Group E, Nd:YAG laser (50mj 15Hz) treatment group: The surface of dentin was fused partly , more of dentinal tubule orifices were covered with white fused layer . Some of dentinal tubule orifices were mostly sealed. Group F, Nd:YAG laser (100mj 10Hz) treatment group: The surface of dentin was fused entirely , all of dentinal tubule orifices were covered with white fused layer . All of dentinal tubule orifices were sealed. GroupG, NaF followed by Nd:YAG laser (50mj 15Hz) treatment group: The surface of dentin was covered with white fused layer and white NaF pellet. Most of dentinal tubule orifices were covered with whitefused layer, most of dentinal tubule orifices were sealed.Conclusion: (1)After cut coronal enamel and etched with 37% phosphoric acid,the dentin disc simulated the DH patient dentinal tubule shape well .(2) NaF treatment occluded the dentinal tubule not well.(3) GLUMA treatment did much better than NaF treatment.(4) Nd:YAG laser can fuse the dentin surface and seal the tubule orifice, the stronger the laser power , the better occluding effects.(5)The NaF followed by Nd:YAG laser (50mj 15Hz) treatment can occlude dentin tubules more effectively than NaF or laser alone.