Research On The Influence Of Potassium Mixing Nano-hydroxyapatiteon Dentinal Tubules And Its Surface Hardness And Roughness

ObjectiveThe destine hypersensitivity is caused by cutting down clinically a large numberof tooth organization because dental prosthesis needs enough space when cliniciansrepair the fixed partial denture. There are three kinds of hypothesis about thepathogenesis of dentin hypersensitivity,of which,the fluid dynamic theory is widelyheld. The theory is that the external stimulation to teeth causes the inward or outwardabnormal flow of dentinal tubules content, which is passed on to the dental pulp,producing the pain of teeth. At present, the clinical tooth desensitizer is producedbasically based on this theory. Nano hydroxyapatite and the complex in the field oforal treatment and health care get more and more attention from the domestic andforeign scholars. The research shows that nano hydroxyapatite(nHA) can seal dentinaltubules. This experiment puts the desensitization element potassium ion into nanohydroxyapatite, Observes the new material effect in vitro dentinal tubules with thescanning electron microscopy,and measures whether the desensitization elementpotassium ion affects the dentin surface hardness and roughness. It’s aim to provide atheoretical basis to the development of new dental desensitization materials.Experimental methodsCollect the first premolar of maxillary,which is pulled out orthodontic ally andcompletely without caries. Make models of dentin hypersensitivity. Treat the dentinsurface of each group respectively with nano-hydroxyapatite, potassium mixingnano-hydroxyapatite (K-nHA) and Gluma desensitizer (Gluma). Observe thecharacteristic of the dentinal surface and the section with the scanning electronmicroscope(SEM)Measure the changes of the hardness and roughness with micro hardness testerand roughness measuring instrument. Then analysis the result using SPSS13.0software. Experimental result1、The reagents of each group formed a closed layer on the dentin surface. SEMobservation showed that the reagents deepened into the dentinal tubules in group nHAand group K-nHA, K-nHA can deep into the dentinal tubules internal about16μ m,nHA can deep into the dentinal tubules internal about12μ m.2、The average of dentin surface hardness treated with K-nHA is about58.2733HV, which is higher than that of the dentin wafer without any treatment.3、The average of dentin surface roughness treated with K-nHA is about3.7851μm, which is higher than that of the dentin wafer without any treatment.SEMobservation shows almost all of the dentinal tubule were closed. The dentin surface isnot smooth. there are patch protuberance on the surface.Conclusion1、The K-nHA can seal dentinal tubules effectively, and deep into the dentinaltubules internal about16μ m.2、The K-nHA can improve the hardness of the dentin surface.3、The K-nHA make the roughness Ra of dentin surface increase.