Study On The Influence Of Saliva PH On The Microleakage Of The Edge Of Inlay

Objective:In this study,the effects of artificial saliva with three pH values on the marginal microleakage of three inlays made of different materials were compared,to provide some reference basis for the use of inlay to repair dental defects in clinic.Methods:Forty-five maxillary first premolars with intact and normal development were collected and randomly divided into 9 groups:Group A1 to Group A3 was Filtek^TMZ350XT nano resin inlay group:Filtek^TM Z350XT pH 5.5 group,Filtek^TM Z350XT pH 6.8 group,Filtek^TM Z350XT pH 8.2 group.Groups B1～B3 were E-max casting porcelain groups:E-max casting porcelain pH5.5 group,E-max casting porcelain pH6.8 group,and E-max casting porcelain pH8.2 group.The C1～C3 groups were the CAD/CAM cutting blue porcelain inlay groups:the CAD/CAM cutting blue porcelain pH5.5 group,the CAD/CAM cutting blue porcelain pH6.8 group,and the CAD/CAM cutting blue porcelain pH8.2 group.According to the principle of inlay tooth preparation,the MO surfaceⅡtype cavity was prepared for pretreatment and reserve.In strict accordance with the binder instructions to bond inlay,light curing,cultivation,polishing.They were immersed in artificial saliva of three different pH values respectively,and soaked at 37℃for 4 weeks.The artificial saliva was changed daily.Then they were respectively placed in 5g/L alkaline fuchsine aqueous solution and stored in an incubator at 37℃for 24h.Then they were taken out,washed with running water,wiped the sample surface with 95%alcohol to remove excess dye,and the hard tissue slicer was used to lengthways cut along the tooth near and far.Finally,the penetration depth of the dye along the inlay and the axial wall of the tooth and the gingival wall was measured by stereomicroscope and lateral micrometer.Results:1.Comparison of inlays in each group showed that the microleakage of the gingival wall was greater than that of the axial wall,P<0.05,the difference was statistically significant.2.The microleakage values of artificial saliva with different pH values of the same kind of materials after soaking were:A1>A2,A1>A3,P<0.05,the difference was statistically significant.A2>A3,P>0.05,the difference was not statistically significant.B1>B2,B1>B3,P<0.05,the difference was statistically significant.B2>B3,P>0.05,the difference was not statistically significant.C1>C2,C1>C3,P<0.05,the difference was statistically significant.C2>C3,P>0.05,the difference was not statistically significant.3.Comparison of inlays made with different pH values of the same saliva:B1>A1>C1,B2>A2>C2,B3>A3>C3,P<0.05,the difference was statistically significant.4.The results of stereoscopic microscope showed that the saliva would cause microleakage at the edge of the prosthesis.The greater the acidity of the saliva,the greater the microleakage.Conclusion:1.Under the experimental conditions,the microleakage between the gingival walls of each group was greater than the microleakage between the axial walls.2.The greater the acid value of saliva,the greater the microleakage value at the edge of the inlay.3.The edge of the CAD/CAM machinable blue porcelain inlay has the smallest leakage,followed by the edge of the Filtek^TM Z350XT nano-resin inlay,and the E-max cast porcelain inlay has the largest edge.