Study On Er, Cr: YSGG Laser Assisted Dentin Remineralization

Objective In the biomimetic mineralization system constructed in vitro,the demineralized collagen matrix can be remineralized.The structure formed by mineralization is similar to that of natural dentin and has good function.However,this technology mostly stays in the laboratory stage.The natural mineralization process takes several days to weeks.Some experimenters use other laboratory methods that are difficult to be applied in the mouth to accelerate the mineralization process.On the basis of natural mineralization,er,Cr: YSGG laser was introduced.Er,Cr: YSGG laser was used to accelerate the whole mineralization process,so that the demineralized exposed dentin collagen fibers deposited more minerals at the same time,so as to realize the remineralization of demineralized collagen fibers and reduce the diameter of dentin tubules.On the basis of natural mineralization,er,Cr: YSGG laser is introduced in this experiment.Er,Cr: YSGG laser is used to accelerate the whole mineralization process,so that the demineralized exposed dentin collagen fibers can deposit more minerals at the same time,realize the remineralization of demineralized collagen fibers and reduce the diameter of dentin tubules,It is used to treat dentin hypersensitivity and prevent secondary caries caused by exposure of some collagen fibers after bonding repair.Methods In this experiment,human healthy eighth molars were selected.Under the condition of water cooling,the enamel on the occlusal surface was removed and the dentin was exposed to prepare 1.0 cm × 1.0cm × 1mm dentin slices were evenly divided into 0.5cm × 1.0cm × 1mm two parts are marked respectively for the control experiment to reduce the experimental error caused by individual differences.Then,ethylenediamine tetraacetic acid was used to demineralize and remove the inorganic mineral crystals on the dentin surface,so that the dentin collagen fibers were exposed,and the demineralized dentin model was constructed.Then,the mineralized solution was constructed with anhydrous calcium chloride,anhydrous disodium hydrogen phosphate and polyaspartic acid reagent as the main components,and the demineralized dentin was mineralized in the mineralized solution.The experimental group was treated with Er,Cr: YSGG laser and the control group was not treated with Er,Cr: YSGG laser.10 specimens in each group were observed.Then the specimens were dehydrated by alcohol gradient,dried and sprayed with gold.The surface morphology and longitudinal section morphology of dentin specimens were observed by scanning electron microscope;The distribution of elements on the surface of dentin specimens was analyzed by X-ray energy spectrum;The surface hardness of dentin specimens was measured by Vickers hardness tester.Result Scanning electron microscopy showed that after demineralization with EDTA,the type I collagen fibers on the dentin surface were exposed.There was no significant difference in the surface morphology of the specimens treated only with mineralizing solution and not irradiated with Er,Cr: YSGG laser;After treatment with mineralized solution and ER,Cr: YSGG laser irradiation,there was obvious mineral deposition in the dentin tubules,the exposed dentin collagen matrix was covered,and the diameter of the dentin tubules decreased compared with that before laser treatment.X-ray energy spectrum analysis showed that the distribution of calcium and phosphorus on the surface of mineralized specimens without Er,Cr: YSGG laser treatment was not significantly different from that before mineralization;Compared with that before laser treatment,calcium and phosphorus on the surface of specimens treated with Er,Cr:YSGG laser increased significantly.Vickers hardness test showed that there was no significant difference in Vickers hardness of dentin samples before and after the experiment only in the mineralized solution treatment group;After Er,Cr: YSGG Laser and mineralizing solution,the hardness of dentin specimens increased significantly,indicating that demineralized dentin produced remineralization and improved its hardness.Conclusion In this experiment,er,Cr: YSGG laser combined with mineralizing solution was used to treat demineralized dentin samples,and new mineral deposits were generated on demineralized dentin collagen matrix.Compared with natural mineralization,this method can produce more mineral deposits at the same time.