| Objective:To evaluate the color stability of different dental restorativematerials by saliva and ultraviolet(UV) aging for the choice of materials forreference in the clinical.Methods：1Specimens preparation:Different resin specimens preparation.Resin specimens were made in acustom mold with3.2mm in thickness and10.0mm in diameter, A2colorshade of Surefil,BEATIFIL Ⅱ and Filtek was filled and using40sexposure to the both surfaces. Ten round porcelain specimens that were10.0mm in diameter and3.2mm in thickness were fabricated with Camaragepolymer-ceramic of A2shade by custom mold and Solidilite Light-curingunit.The testing surfaces of all the specimens are burnished in turn by watersand paper of400#,600#,800#,1000#,1200#and1,500#.All thickness ofspecimens are controlled in3.0±0.01mm.2The measurement of surface roughness：The measuring apparatus of surface roughness measures theroughness(Ra) of the testing surfaces.3Saliva preparation:Using the ISO/TR10271standard recipes for the saliva.The compositionof saliva is as follows:NaCl0.4g, KCl0.4g,Na2HPO4·2H2O0.78g,Na2S·2H2O0.005g, Urea1.0g, CaCl2·2H2O0.795g,Distilled water1000ml.Adjust the saliva of PH6.8by using NaOH and Hcl,and save thesaliva in the4℃.4Experimental methods4.1Saliva-aging experiment:All specimens were preserved24h in37±1℃thermostatic water tank after ultrasonically cleaning5minutes, took out and dried.Every group ofspecimens were randomly divided into four groups in the tubes wich filled5ml saliva,and the tubes were put into the60±1℃thermostatic water bathavoid light saving.The color values of the specimens were determined by aspectrophotometer (Vita Easyshade) on CIE L﹡a﹡b﹡color stem before andafter immersion at1,2.3,4weeks, color difference (△E)was calculated as△E=〔(△L﹡)2+(△a﹡)2+(△b﹡)2〕.4.2UV-aging experiment:All specimens were preserved24h in a dark,dry conditions.The colorvalues of the specimens were determined by a spectrophotometer (VitaEasyshade) on CIE L﹡a﹡b﹡color stem before and after UV aging for8,16and24hour, color difference (△E)was calculated as△E=〔(△L﹡)2+(△a﹡)2+(△b﹡)2〕.The specimens were put with the distance of ultravioletlight sources by10cm.5The statistics analysis of data measurement:By the use of SPSS13.0of statistical analysis software,we take thestatistical analysis of roughness and color value of the surfaces of eachspecimen, and analyze single factor of variance. The SNK inspection betweengroups comparison concludes that the inspection standards is that alpha equals0.05.Results:1The mean roughness of Surefil surface were0.184±0.003.The meanroughness of BEAUTIFIL Ⅱ surface were0.200±0.007.The meanroughness of Ceramage surface were.The mean roughness of Filtek surfacewere0.207±0.009.By single factor analysis of variance(One-Way ANOVA),the roughness value results of specimens surface(Table1), P>0.05, shows thatby each specimen there is no statistical significance between the surfaceroughness.2The analysis result of the measurement which four materials' colorvalues in artificial saliva environment at different point of time：SureFillexperimental group's△E reach the maximum during week1,and the visible color changes were happened.△E was3.56-5.07.The color difference (△E)was increases as the time increases,mainly displays in L﹡decrease and a﹡increase.BEAUTIFIL Ⅱexperimental group's△E was increases as the timeincreases,it reach the maximum during week4,and the visible color changeswere happened.△E was3.37-4.36,mainly displays in L﹡decrease and a﹡increase.Ceramic experimental group's△E was increases as the timeincreases.△E of week4was2.52-3.10,mainly displays in L﹡decrease and a﹡increase.Although the visible color changes were happened,the△E underthe scope of clinical are still acceptable.Filtek experimental group's△E wasincreases as the time increases.△E of week4was4.89-5.50,mainly displaysin L﹡decrease and a﹡increase.3The analysis result of the measurement which four materials' colorvalues after UV-aging at different point of time.Surefil experimental group's△E was increases as the time increases.The△E reach the maximum afterUV-aging for24h.△E was6.61-8.04,mainly displays in L﹡decrease and a﹡increase.BEAUTIFIL Ⅱexperimental group's△E was increases as the timeincreases.The△E reach the maximum after UV-aging for24h.△E was3.29-4.45,mainly displays in L﹡decrease and a﹡increase.Ceramicexperimental group's△E was increases as the time increases.The△E reachthe maximum after UV-aging for24h.△E was6.61-8.19,mainly displays in L﹡decrease and a﹡increase.Filtek experimental group's△E was increases asthe time increases.The△E reach the maximum after UV-aging for24h.△Ewas4.17-5.78,mainly displays in L﹡decrease and a﹡increase.4Filtek experimental group's△E is the biggest of the fourexperimental groups after4weeks in saliva solution.△E was4.89-5.50,andthe visible color changes were happened.BEAUTIFIL Ⅱexperimental group's△E was3.37-4.36,the△E beyond the scope of clinical acceptable.△E ofSurefil experimental group and Ceramic experimental group was2.09-3.29and2.52-3.10.Although the visible color changes were happened,the△Eunder the scope of clinical are still acceptable.5Ceramic experimental group's△E is the biggest of the four experimental groups after UV-aging for24h,△E was6.61-8.19.BEAUTIFILⅡ experimental group's△E was3.29-4.45.Surefil experimental group's△E was6.61-8.04.Filtek experimental group's△E was4.17-5.78. The visiblecolor changes of four groups were happened,anf the△E beyond the scope ofclinical acceptable.Conclusion：1The color of different dental restorative materials specimens waschanged in the saliva solution.The△E of Surefil and Ceramic experimentalgroup was increases as the time increases compared with Filtek andBEAUTIFIL Ⅱ.The initial△E increases the maximum,and with timeincreasing the△E tends to gently.The△E of Filtek and BEAUTIFILⅡwas increases as the time increases.The△E reach the maximum during week4.2All four materials have changed color after the ultraviolet light8h,16h,and24h. Polymer ceramic specimens have the most different color in16h timemark. The color has huge different change at8h and16h. The rest of threematerials color change follow by the time are kind of flatten.3Using the same time, the Filtek resin has the most color change in theartificial saliva immersion aging test, and the color change is visible.4Using the same time, three materials color changes exceed theclinically acceptable range besides BEAUTIFIL Ⅱ resin which effect byultraviolet radiation. |
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