Effect Of Ethanol On Color And Transluence Stability Of Light-cured Composite Resins

Objective:The color and susceptibility to staining of three kinds of light-cured composite resins(Filtek Z250,Filtek Z250 XT and Filtek Z350XT)treated with different concentrations of ethanol were compared by ethanol soaking and dyeing experiments,and the effect of ethanol as a single factor on color stability and stain susceptibility of different resins was discussed.It provides a reference for the aesthetic repair of clinical composite resin and the development and improvement of the material.Methods:In this experiment,three composite resins(Filtek Z250,Filtek Z250 XT and Filtek Z350XT)were selected and were made into circular samples(8mm diameter and2 mm height).50 specimens of each composite resin were prepared and was randomly divided into five groups(5%,13%,43%,75%ethanol and distilled water)(n=10).All the processes were carried out under the environment of relative humidity of 60±3%and temperature of 37±1℃.On the baseline,7th,14 th,21th and 28 th days,the color and transluence of each sample were measured by spectrophotometer,and L*a*b* values were recorded.The color difference value ΔE and the transluence parameter TP were calculated.Then,the composite resins soaked for 28 days were placed in Nestle coffee solution for 14 days.All samples were stored in a 37°C constant temperature water bathand.The solution was stirred 3 times a day to prevent settlement.The color and transluence values were measured and recorded,and the L*a*b* values were recorded to calculate the color difference ΔE and the transluence parameter TP.The data were analyzed by spss27.0statistical software.The effects of resin type,time,and ethanol concentration on ΔE andΔTP were analyzed using a multivariate design variance analysis with repeated measurements.The effects of resin type and ethanol concentration on ΔE and ΔTP in the28-day immersion and dyeing experiments were evaluated by two-factor analysis of variance.The effects of resin type and soaking media on ΔE and ΔTP after staining were evaluated by two-factor analysis of variance(ANOVA).Tukey’s posthoc adjustment and simple effect analysis were used for multiple comparisons of all ANOVA analyses.Pearson correlation analysis was used to investigate the correlation between changes in ΔE andΔTP.Results:1.The effects of resin type,soaking medium,time and their interactions on ΔE and TP were statistically significant(P<0.01),and the changes of Δ E increased with the increase of ethanol concentration and time.At 28 day,the ΔE performance of all three resins was :Filtek Z250> Filtek Z250XT> Filtek Z350 XT,the color change of Filtek Z250 in75% ethanol group was clinically unacceptable(ΔE>3.3),and the remaining discoloration was clinically acceptable.2.When soaked in different media for 28 days,the TP value of Filtek Z250 decreased,ΔTP increased with the increase of ethanol concentration,and the TP of the other two resins increased;The TP change of Filtek Z250 was greater than the others,and the difference was statistically significant(P<0.05),but there was no statistically significant difference between Filtek Z250 XT and Filtek Z350XT(P>0.05).There was a correlation between ΔE and ΔTP among the three resins(P<0.05),a negative correlation between Filtek Z250 and a positive correlation between Filtek Z250 XT and Z350 XT.3.The color of the three resins changed significantly after dyeing experiment,Filtek Z250 has the strongest stain susceptibility and Filtek Z350 XT has the weakest stain susceptibility.ΔE increased with the increase of ethanol concentration.Compared with the control group,the difference in Δ E among different ethanol concentrations was statistically significant(P<0.05);The TP of the three resins became smaller after staining,and the changes of TP of different concentrations of ethanol were statistically significant(P<0.05).Conclusions:1.Ethanol can change the color of composite resins,and increase the color change with the increase of the time.Ethanol has an effect on the transluencey of composite resin,and the resin discoloration is related to the change of transluence.2.After ethanol treatment,the color stability of the three photocured composite resins was as follows: Filtek Z350XT>Filtek Z250XT>Filtek Z250,among which,Filtek Z250 treated in 75% ethanol for 28 days,the discoloration was the most serious and clinically unacceptable,while the remaining discoloration was clinically acceptable.3.Ethanol can increase the stain susceptibility of composite resins and reduce the transluence after staining,and the higher the concentration of ethanol,the stronger the stain susceptibility,the more change of transluencey,Filtek Z250 has the strongest stain susceptibility and Filtek Z350 XT has the weakest stain susceptibility.