| Objective: To research the color stability of different dental restorative materials in tea,coffee,red wine,and human saliva for the choice of materials for reference in the clinical.Methods:1 Specimens preparation: Ceramic specimens were made in a self-made pistons mold to control the thickness of the porcelain. Dentin porcelain of A2 color shade of Vintage ( SHOFU , Japan ) was selected for forming porcelain-blasts, and fired following the manufactures'instructions. Resin specimens were made in a silastic mold with 3.2mm in depth and 10 mm in diameter, A2 color shade of Charisma was filled and using 40s exposure to the both surfaces. Polymer-ceramic specimens were made in the same mold with resin. The materials were A2 color shade of Ceramage and cured in the Solidilite Light-curing with 3 minutes in every face. All specimens were polished on both sides with 380,600, 800, 1000, 1200and1500 -grit silicone carbide paper under water flow to a final thickness of 3.0±0.02mm. The ceramic specimens glazing themselves, resin specimens were polished with toothpaste by rubber wheel, polymer-ceramic specimens were polished with buffing paste by Soft wheel. Finally, every group formed 12 specimens and 10 mm in diameter. According to the experiments of restorative materials, specimens were divided into resin group, polymer–ceramic group and ceramic group.2 Measurement of surface roughness: A surface roughness tester was used to measure the value of surface roughness (Ra) of every specimen. Three points were respectively selected on the upper and inferior surfaces, and the mean of the roughness value of the three points were considered to be the surface roughness value of the specimen. 3 Solution preparation: Using the ISO/TR10271 standard recipes for the saliva of PH 6.8, and saved in the 4℃refrigerator. 3g tea was poured into 500 ml of boiling distilled water, soaking 5 minutes and mixed with glass rod.1.5g coffee was poured into 300ml of boiling distilled water,mixed 5 minutes with glass rod .4 In vitro study of stain: All specimens were preserved 24h in 37±1℃thermostatic water tank after ultrasonically cleaning 5 minutes, took out and dried。The each 5ml of red wine, tea, coffee, and saliva of PH 6.8 was put into tube. Every group of specimens were randomly divided into four groups in the tubes that have different solution, and the tubes were put into the 60±1℃thermostatic water bath avoid light saving. The color values of the specimens were determined by a spectrophotometer (CR-10 Minolta) on CIE L﹡a﹡b﹡color stem before and after immersion at 1,2.3,4 weeks, color difference (△E) was calculated as△E=〔(△L﹡)2+(△a﹡)2+(△b﹡)2〕1/2. Measuring characteristics of the colorimeter were standard illuminant D65 and illuminant/viewing geometry d/8°,CIE10°standard observation. The testing apparatus had a measuring head aperture of 8 mm diameter and measured the diffuse reflection of the specimen. Three readings were made for each specimen, and take the mean value as the result of each specimen. All values each specimen of color were statistical analyzed by SPSS 13.0.Results:1 Surface roughness of value of each group: the mean value of surface roughness of the ceramic group was 0.1722±0.017μm; the mean value of surface of the resin group was 0.1817±0.014μm; the mean value of surface the polymer -ceramic group was 0.1746±0.010μm. There were no different among groups by Kruskal-Wallis H analysis (X2= 5.870,P>0.05).2 Statistical analysis results of the color differences among groups2.1 Results of the repeated-measures ANOVA indicated that all factors (time, material, and solution), and all possible interactions among them , were statistically significant (P<0.05).2.2 The multiple comparison results among the different times of the same material and in the same solution : the color differences have change of the ceramic group in 4 solutions as the time increases. the visible color changes were happened in the red wine,△E was 1.04-1.45, mainly displays in L﹡decrease and a﹡increase.△E was less than 1 in other solutions; The△E of resin group all increase gradually in tea, coffee, red wine and saliva solution, and respectively in 3.72-8.45, 6.12-16.25, 6.92-14.64 and 1.86-4.63, in the tea and coffee solution mainly displays in L﹡ decrease and b﹡ increased obviously, in the red wine solution mainly displays in L﹡decrease ,a﹡and b﹡all increased obviously, in the saliva solution mainly displays in b﹡increased obviously; The△E of polymer–ceramic group all increase gradually in tea, coffee, red wine and saliva solution, and respectively in 2.74-4.07, 3.35-8.53, 2.95-10.06 and 1.09-1.79, in the tea mainly displays in L﹡decrease and b﹡decrease obviously, in the coffee solution mainly displays in L﹡decrease and b﹡increased obviously, in the red wine solution mainly displays in L﹡decrease ,a﹡and b﹡all increased obviously, in the saliva solution mainly displays in L﹡decrease and a﹡increased obviously.2.3 The multiple comparison results among the different solution of the same material times and in the same times: For the ceramic group, in every week, the biggest△E was caused by red wine, the minimal△E was caused by the saliva, the△E was caused by coffee and tea between the two former; For the resin and polymer–ceramic group, in every week, the△E was approaching in the coffee and red wine solution, significantly higher than in tea and saliva, saliva causes minimal△E.2.4 The multiple comparison results among the different materials of the same solution times and in the same times: There was difference between each other in the three groups of the resin group, the polymer–ceramic group and the ceramic group, in the same solution there was the biggest△E in the resin group, the minimum△E in the ceramic group, the△E of polymer–ceramic group between the two former. Respectively in the 1, 2, 3 and 4 weeks, the△E was approaching of the ceramic group and the polymer–ceramic group in the saliva solution, the△E of the resin group and the polymer–ceramic group significantly higher than the ceramic group in other solutions .Conclusion:1 There is color difference of the there kinds of materials in the four kinds of solutions in this experiment, the△E of the resin group and the polymer–ceramic group has increased as the time increases besides the ceramic group, the initial increases the maximum, and with time increasing the△E tends to gently2 There is difference among the different materials of the same solution and in the same times, the minimum△E in the ceramic group, color is the most stable, the△E of the resin group is bigger than the polymer–ceramic group, both the biggest the△E beyond the scope of clinical acceptable.3 There is difference among the different solutions of the same material and in the same times, both red wine and coffee solution can cause the resin group and the polymer-ceramic group serious dyeing, tea and saliva dyeing lighter.4 The△E of the resin group was caused by tea and coffee solution mainly displays in L﹡decrease and b﹡increase5 The△E of the polymer–ceramic group was caused by coffee solution mainly displays in L﹡decrease and b﹡increase.6 The△E of the resin group and the polymer-ceramic group was caused by red wine solution mainly displays in L﹡decrease and a﹡increase.
|
PDF Full Text Request