Color stability of compomer after immersion in various media

PURPOSE: The purpose of this study was to evaluate the effect of various media on the color stability of compomer and to compare these results to those of other materials that could be used in similar clinical circumstances. MATERIALS AND METHODS: In this test, six materials (shade A2) were used: four compomers (Dyract, Compoglass F, Xeno, F2000), one composite resin (Clearfil AP-X), and one resin-modified glass ionomer cement (Fuji II LC). There were four test solutions: one alcoholic (whiskey), two low pH soft drinks (Coca Cola, orange juice), and deionized water as a control. A plastic ring mold (9-mm diameter x 1-mm height) was used to prepare 120 disk specimens. For 60 days, the test specimens were immersed in the various media daily for 3 hours then transferred to the deionized water. Color was measured by CIE L* a* b* relative to CIE source against a white background, using a colorimeter. Color change (delta E*) was calculated as delta E* = [(delta L*)2 + (delta a*)2 + (delta b*)2]1/2. Color changes (delta E*) were recorded after 1, 7, 30, and 60 days. RESULTS: The results indicated that compomer and resin-modified glass ionomer were susceptible to discoloration in various solutions over an extended period of time. Composite resin showed minimal perceptible color change. Specimens immersed in whiskey showed a significantly high perceptible color change (p < .0001). Water caused no perceptible color changes.     

Color of restorative materials after staining and bleaching

This study determined the effect of a 10% carbamide peroxide bleaching agent on the removal of stain from restorative materials. Color changes (delta E*) of three restorative materials [compomer (Dyract); composite (TPH Spectrum); hybrid ionomer (Fuji II LC)] when exposed to juice/tea, chlorhexidine (CH), and water (control) for 120 hours were studied. Stained specimens were treated for two 2-hour periods with a bleaching agent (Platinum Tooth Whitening System) with and without the active ingredient. Color was measured at baseline, after staining, and after treatment using the CIE L*a*b* color system relative to CIE standard illuminant A (incandescent light) as measured by a reflection spectrophotometer. Means and standard deviations (n = 5) were calculated and data were analyzed by four-way ANOVA. All variables and interactions were statistically significant. Color changes caused by CH and water were not perceptible (delta E* < 3.3). After two 2-hour treatments, the following occurred with specimens stained with cranberry juice/tea: paste with and without active ingredient perceptibly changed color of stained composite. The stained hybrid ionomer perceptibly changed color after treatment with paste containing active ingredient but did not change after exposure to paste without active ingredient. The stained compomer was not perceptibly different with either treatment. Platinum successfully removed stains from the composite and hybrid ionomer tested.     

Correlations between Color Differences Based on Three Color-Difference Formulas Using Dental Shade Guide Tabs

Purpose: The purpose of this study was to determine the correlation among color-difference values based on three formulas between shade tab pairs from two shade guides [Vita Lumin (VITA) and Chromascop (CHRO)].
Materials and Methods: The color of shade tabs was measured relative to the standard illuminant D₆₅ under the 8° standard observer function, and distributions for CIE L *, a *, and b * values were compared. One hundred and twenty shade pairs from VITA and 190 shade pairs from CHRO were used to calculate color differences using CIELAB, DIN99, and CIEDE2000 formulas (Δ E*_ab , Δ E ₉₉, and Δ E ₀₀, respectively). A paired t- test was used to determine the difference between each pair of the three color-difference values (α= 0.01). Regression analysis was used to determine the correlations between the color differences (α= 0.01).
Results: For both shade guides, there were significant differences between Δ E*_ab and Δ E ₀₀, Δ E*_ab and Δ E ₉₉, and Δ E ₉₉ and Δ E ₀₀ ( p < 0.01). Δ E*_ab and Δ E ₀₀, and Δ E*_ab and Δ E ₉₉ were strongly correlated (r²= 0.90 to 0.94, p < 0.05). Although a simplified a * rescaling function of the CIE a * axis has been added in the CIEDE2000 formula, the influence of the opposite signs in the a * value were found to be irrelevant to the Δ E ₀₀ value.
Conclusion: Δ E*_ab, Δ E ₉₉, and Δ E ₀₀ can be used interchangeably for the evaluation of color difference of shade tabs.     

Effects of fluoride varnish on color of esthetic restorative material

PURPOSE: This study determined the color stability of a compomer, hybrid ionomer, and composite after staining with three fluoride varnishes. MATERIALS AND METHODS: Five disks (10 mm in diameter, 2 mm thick) of each material were prepared in a mold and incubated at 100% relative humidity at 37 degrees C for 24 hours. Duraphat, Duraflor, FluorProtector, and water (control) were applied to the disks, which were subsequently brushed with a soft toothbrush and dentifrice. Color was measured at baseline, after staining, and after brushing using CIE L*a*b* (source C) against white background on a reflection spectrophotometer, and color change (delta E*) was calculated. Means (n = 5) and standard deviations were calculated and compared using a repeated-measures analysis of variance (ANOVA). Tukey-Kramer intervals (p = .05) were calculated to compare means. RESULTS: Varnishes Duraflor and Duraphat caused perceptible color changes (delta E* > 3.3) in compomer, hybrid ionomer, and composite after application; however, FluorProtector did not affect the color of the materials. After brushing, none of the materials exhibited perceptible values of delta E*, except the composite with Duraflor (delta E* = 5.4).     

树脂粘结剂和树脂改良玻璃离子粘结托槽后对釉质颜色的影响

目的:比较在粘结托槽前后,树脂粘结剂和树脂改良玻璃离子粘结剂对牙面颜色的影响。方法:60颗新鲜离体前磨牙随机分为空白对照组、树脂粘结剂组和树脂改良玻璃离子组。在粘结托槽前、去托槽后和茶溶液着色后3个时间点,采用松风电脑比色仪测取牙面的L^*、a^*和b^*值,计算牙面粘结托槽前后和着色处理前后的△E*值以评估牙面颜色的变化。结果:托槽粘结前后的△E^*值,树脂粘结剂组(3.18±0.27)与玻璃离子组(3.17±0.64)显著高于对照组(1.89±0.16)(P<0.05);着色处理前后对比的△E^*值,树脂组和玻璃离子组发生临床可识别的颜色变化,△E^*分别为(4.25±0.51)和(4.60±0.52),显著大于对照组(2.43±0.24)(P<0.05);两种粘结剂之间在托槽粘结前后和着色处理前后均未见显著差异。结论:光固化复合树脂粘结系统与树脂加强型玻璃离子粘结系统均会影响牙面颜色,导致牙面易着色,但二者对牙面颜色影响无显著差异。     

Tooth-colored filling materials for the restoration of cervical lesions: a 24-month follow-up study

The recently developed resin-modified glass ionomer cements and the polyacid-modified composites are promising alternatives to conventional materials for restoring cervical defects. This clinical study evaluated the clinical condition of cervical fillings 24 months following placement. The study subjects were 197 cervical restorations placed on incisors, canines and premolars in 37 patients for restoration of erosion/non-carious lesions (69 cases), primary carious lesions (57 cases) and the replacement of deficient restorations (71 cases). The teeth were randomly divided into four groups for restoration with either Tetric (composite, Group A: n = 36), Dyract (compomer, Group B: n = 79), Fuji II LC (resin-modified glass ionomer cement, Group C: n = 51) or Photac-Fil (resin-modified glass ionomer cement, Group D: n = 31). The evaluation was done single-blind at baseline, 8 and 24 months after the placement of the fillings, according to a modified USPHS rating scale. The assessment criteria were color stability, anatomical form, surface texture, marginal integrity, marginal discoloration and loss of filling. Statistical analysis was completed using Pearson chi-square and Fisher's exact test at a significance level of 5% (p < 0.05). After the 24-month period, the composite restorations showed superior results. The compomer fillings demonstrated conditions that were only slightly worse. A substantial number of the resin-modified glass-ionomer fillings were evaluated with bravo or even charlie scores in respect to at least one of the criteria assessed.     

Color changes of restorative materials exposed in vitro to cola beverage

PURPOSE: The purpose of this in vitro study was to evaluate the color stability of restorative materials when exposed to a cola beverage. METHODS: Color changes in restorative materials caused by exposure to a cola beverage were studied using a split-plot experimental design. Three restorative materials (composite, resin-modified glass ionomer cement, and compomer) and 3 shades of each material under 2 surface conditions (polished and unpolished) were studied. Using a chromameter, color changes were determined as the difference between color dimensions before and after cola exposure. Scanning electron microscopy was used to characterize the surface morphology of all materials before and after polishing. RESULTS: 72-hour cola exposure resulted in significant changes in color, including gray level and chromaticity, both as a function of materials and their shades. Clinically, these changes compromised both color stability and esthetics in the resin-modified glass ionomer cement in all shades and in composites and compomers in the darkest shade. CONCLUSIONS: To avoid color degradation through cola, the lighter shades of composites and compomers should be favored over darker C shades to restore anterior and more visible lesions. Resin-modified glass ionomer cement is not recommended in esthetically critical areas due to its tendency to discolor due to cola exposure.     

Color stability of a resin-modified glass ionomer cement.

The color stability of a resin-modified glass ionomer cement (Fuji II LC) was investigated over six months using colorimetry. Five shades (A2, A3, A4, B3 and C4) were selected and 10 square specimens (7 mm wide and long, and 1.5 mm deep) were made for each shade using special grit molds. CIE L*, a*, b* color parameters of the specimens were taken at one day, one week, one month, three months and six months. Results were subjected to MANOVA and ANOVA/Scheffe's test at significance level 0.05. The effects of time on color parameters (L*, a*, b* values) were found to be shade dependent. All shades exhibited a decrease in L* values over time. With the exception of shade B3, significant differences in L* values were observed at six months. A general decrease in b* values was also observed but differences among the various time intervals were not significant except for shades A3 and C4. No apparent trends were observed for changes in a* values. For all shades, the largest color change (delta E) was observed between one day and one week. The color stability of the resin-modified glass ionomer investigated was shade dependent. A general decrease in lightness and yellow chroma was observed.     

Optical properties of four esthetic restorative materials after accelerated aging

PURPOSE: To determine the differences in CIE L*, a*, and b* values, translucency parameter (TP), opalescence parameter (deltaO*ab), and color difference caused by the fluorescence (deltaE*ab-FL) of resin composite, glass-ionomer, resin-modified glass-ionomer, and compomer of A2 shade before and after accelerated aging. METHODS: Color and spectral distribution of the materials were measured according to the CIELAB color scale relative to the standard illuminant D65 in the transmittance and reflectance modes. Aging was performed in an accelerated aging chamber with an energy exposure of 150 kJ/m2. The translucency parameter (TP) was calculated as the color difference (deltaE*ab) of the specimen over white and black backgrounds. Opalescence parameter (deltaO*ab) was calculated as the difference in blue-yellow coordinate (deltab*) and red-green coordinate (deltaa*) between the transmitted and reflected colors of a 1 mm-thick specimen. Color difference by the fluorescence (deltaE*ab-FL) in reflectance mode was calculated as an index of fluorescence. Differences and changes in optical properties were analyzed by the repeated-measures ANOVA. RESULTS: Type of material and the mode of measurement (transmittance and reflectance) influenced CIE L*, a* and b* values significantly (P< 0.05) before aging. Accelerated aging influenced CIE L*, a* and b* values. Aging and the type of material influenced TP, deltaO*ab and deltaE*ab-FL values significantly (P< 0.05).     

Dental color standards: shade tab arrangement

Purpose: The aim of this study was to analyze the shade tab arrangement of two popular dental shade guides, suggest possible improvements, and propose clinical guidelines. Materials and Methods: Data were recorded using a colorimeter set to standard illuminant source C and CIE L*a*b* system. The manufacturers' shade tab arrangement as well as the possible improvements in the arrangement of shade tabs of Vitapan Classical and Vitapan 3-D Master (Vita Zahnfabrik, Bad Säckingen, Germany) shade guides were examined by regression analysis. Results: Certain shortcomings in the manufacturers' arrangement of both color standards were observed. The Vitapan 3-D Master arrangement was more consistent, but with a decrease in lightness, tab saturation decreased as well in four of its five groups. When Vitapan Classical and Vitapan 3-D Master tabs were arranged according to ΔE* in relation to the lightest tab, r² was 0.98 and 0.96, respectively. After dividing the total ΔE* range into four equal segments for the newly established Vitapan Classical guide, r² was 0.91, 0.95, 0.68, and 0.94, respectively. Corresponding r² values for Vitapan 3-D Master were 0.96, 0.94, 0.90, 0.94, and 1.0.
CLINICAL SIGNIFICANCE
Total color difference in relation to the lightest tab, followed by the tab division into an adequate number of groups, is recommended as a possible and universally applicable mode of tab arrangement in dental color standards.     

Laboratory evaluation of a compomer and a resin-modified glass ionomer cement for orthodontic bonding

The mean shear debonding force of stainless steel orthodontic brackets with microetched bases bonded with either a compomer or a resin-modified glass ionomer cement was assessed. In addition, the amount of cement remaining on the enamel surface following bracket removal was evaluated. Finally, survival time of orthodontic brackets bonded with these materials was assessed following simulated mechanical stress in a ball mill. Debonding force and survival time data were compared with those obtained for brackets bonded with a chemically cured resin adhesive, a light-cured resin adhesive, and a conventional glass ionomer cement. There were no significant differences in mean shear debonding force of brackets bonded with the compomer, resin-modified glass ionomer, chemically cured resin adhesive, or the light-cured resin adhesive. Brackets bonded with a conventional glass ionomer cement had a significantly lower mean shear debonding force than that recorded for the other materials. The Adhesive Remnant Index (ARI) mode score indicated that significantly less cement remained on the enamel following debonding of brackets cemented with resin-modified or conventional glass ionomers compared with other adhesives. The median survival time for brackets cemented with the compomer, resin-modified glass ionomer, chemically cured resin, or light-cured resin were significantly longer than for brackets cemented with conventional glass ionomer. The compomer and the resin-modified glass ionomer adhesive appear to offer viable alternatives to the more commonly used resin adhesives for bracket bonding.     

The color differences of direct esthetic restorative materials after setting and compared with a shade guide

BackgroundThe authors conducted a study to evaluate esthetic restorative materials’ color differences after setting and color matching between set materials and a shade guide.Materials and MethodsThe authors evaluated 13 resin-based composites, one silorane-based composite, two polyacid-modified resin composites and one conventional glass ionomer cement. They measured the color parameters of the samples, which were 8 millimeters in diameter and 1.5 mm in thickness, before and after they were set according to the Commission International de l’Eclairage (CIE) L*a*b* color scale relative to standard illumination against a white background by means of a dental colorimeter. They also compared the final colors of the restorative materials with a shade guide.ResultsColor difference values for each restorative material ranged from 3.25 to 14.04. With the exception of Fuji IX (GC, Tokyo), Filtek P60 (3M ESPE) and Te-Econom (Ivoclar Vivadent), the restorative materials exhibited a perceptible color change after setting. Color difference values between the set materials and the shade guide tabs ranged from 1.86 to 11.83. With the exception of Filtek Supreme XT (3M ESPE) and Fuji IX, the materials exhibited a perceptible difference.ConclusionMost of the materials tested exhibited a significant color change after polymerization and did not match the shade guide tab after undergoing light curing.     

Effect of alcoholic and low-pH soft drinks on fluoride release from compomer

PURPOSE: The purpose of this study was to evaluate the amount of fluoride released from compomer restorative materials after immersion in various media. MATERIALS AND METHODS: In this test, four materials were used: three compomers (Dyract, Dentsply, Konstanz, Germany; Compoglass, Vivadent, Schaan, Principality of Liechtenstein; and Xeno, Sankins, Tochigi, Japan) and one resin-modified glass ionomer cement (Fuji II LC, GC, Tokyo, Japan). There were four test solutions: one alcoholic (whiskey), two low-pH drinks (Coca-Cola, orange juice), and one deionized water. Over a period of 60 days, the tested specimens were immersed in the test solution for 3 hours every day, then kept in deionized water. The fluoride released was detected by using a fluoride ion selective electrode connected to a microprocessor ion analyzer. The fluoride ion concentration (ppm) of the test solutions and deionized water was recorded after 1, 2, 3, 4, 7, 30, and 60 days. Electron probe microanalysis was used for surface analysis of the fluoride released. RESULTS: When immersed in low-pH soft drinks, compomer showed a significantly higher fluoride release than when immersed in deionized water (p < .0001). For specimens immersed in Coca-Cola, the fluoride release levels (microgram/cm2, mean +/- SD) at 1, 7, and 60 days for Dyract (91.6 +/- 1.8, 39.3 +/- 3.1, 10.5 +/- 0.9), Compoglass (129.5 +/- 0.9, 66.5 +/- 2.7, 19.0 +/- 0.3), Fuji II LC (147.0 +/- 4.2, 50.8 +/- 3.1, 27.6 +/- 3.0), and Xeno (73.6 +/- 3.2, 27.3 +/- 2.1, 6.6 +/- 0.6) demonstrated the trend of significantly lower releases with time in water solution. Over a 60-day period, materials immersed in 100% orange juice released the highest amount of fluoride, which could be attributable to the erosive effect of the medium. Materials immersed in deionized water released the least amount of fluoride. Among the tested compomers, Compoglass released the most fluoride.     

Short-term fluoride release from various aesthetic restorative materials

The short-term fluoride release of a giomer (Reactmer), a compomer (Dyract AP), a conventional glass ionomer cement (Fuji II Cap) and a resin-modified glass ionomer cement (Fuji II LC) was evaluated and compared. Specimen discs (6 +/-0.2 mm diameter and 1 +/- 0.2 mm thick) were prepared for each material using custom molds. Each disc was placed in 1 ml of deionized for 24 hours at 37 degrees C. After one day, the water was extracted and analyzed. The specimen discs were then re-immersed into another 1 ml of fresh deionized water. The procedure of removing and refilling the water was repeated for 28 days. Sample solutions taken during the first seven days and at days 14, 21 and 28 were introduced into a capillary electrophoresis system using field amplified sample injection (FASI) to determine fluoride release. Data was analyzed using factorial ANOVA/Scheffe's post-hoc test at significance level 0.05. An initial fluoride "burst" effect was observed with glass ionomers. Both compomer and giomer did not show an initial fluoride "burst" effect. With the exception of the compomer, fluoride release at day one was generally significantly greater than at the other time intervals. The glass ionomers released significantly more fluoride than the compomer and giomer at day one. Although fluoride release of the giomer was significantly greater than the other materials at day seven, it became significantly lower at day 28.     

Color stability of resin cements after accelerated aging

PURPOSE: To study the color stability of different resin cements after accelerated aging. METHODS: The color stability of a self-adhesive resin cement (Unicem), one resin-based composite cement (Variolink II), one compomer cement (Principle) and one hybrid ionomer cement (FujiCEM) was studied. Two curing modes of Unicem (self-cured and dual-cured) and Variolink II (light-cured and dual-cured) were also tested. Specimen disks (n = 5) were prepared with a polytetrafluoroethylene split mold and subjected to accelerated aging for 150, 300 and 450 kJ/m2. Color (CIELAB system) was measured before and after each of the three aging cycles on a reflection spectrophotometer. deltaE*, deltaL*, deltaC* and deltaH* were calculated and analyzed by ANOVA. RESULTS: The largest color change occurred during the first 150 kJ/m2 aging cycle, where deltaE* values ranged from 5.6 to 20.5 with Principle showing the least color change and FujiCEM the most. The color changes of all the tested materials were perceptible. The greatest changes were recorded for deltaL* and/or deltaC*. All specimens became significantly rougher and showed evidence of cracking and degradation after aging except Variolink II.     

Color difference of four esthetic restorative materials by the illuminant

PURPOSE: To determine the difference in lightness, chroma, hue angle and color of four kinds of esthetic restorative materials of the same shade designation by the change of standard illuminants of D65 (daylight), A (incandescent lamp) and F2 (fluorescent lamp). METHODS: Spectral reflectance and color of four resin composites, a glass ionomer, a resin-modified glass ionomer and a compomer of shade A2 were measured according to the CIELAB color scale relative to the illuminants D65, A and F2. Spectral reflectance curves were compared, and changes in lightness (deltaL*), chroma (deltaC*ab), hue angle (deltah degrees) and color (deltaE*ab) by the changes of illuminants from D65 to A or F2 were compared as "value relative to the illuminant A or F2 - value relative to the illuminant D65". RESULTS: In curves of spectral reflectance, the curves were in the similar range of reflectance (%) except glass ionomer. Changes in lightness were low (0.42-1.27), and changes in chroma were 0.26-2.23 for both conditions. These values were different by the kind of materials. The magnitude of the changes in hue angle was the most prominent in both conditions and was significantly different by the illuminants of A and F2 (P< 0.05). The range of color difference was 1.13-3.02 in both conditions.     

Cytotoxicity of resin-based restorative materials on human pulp cell cultures

OBJECTIVE: The objective of this study was to determine the cytocompatibility of 5 different extracts of resin-based restorative materials (2 resin-modified glass ionomer cements, 1 compomer, and 2 composite resins) on human pulp cells. STUDY DESIGN: Set specimens from 2 resin-modified glass-ionomer cements (Fuji II LC and Fuji IX), 1 compomer (Dyract), and 2 composite resins (Tetric and Superfil) were eluted with culture medium for 2 and 5 days. The effects of resin-based restorative materials on human pulp cells were evaluated with cytotoxicity and mitochondrial activity assays. RESULTS: The results showed that the eluates from resin-modified glass-ionomer, compomer, and composite resins were cytotoxic to primary human pulp cells. In addition, Superfil, Fuji IX, and Tetric demonstrated an inhibitory effect on mitochondrial activity of human pulp cells. It was found that composite resin Superfil was the most toxic restorative material among the chemicals tested. CONCLUSION: The influence of the cytotoxicity depended on the materials tested. Compomer or light-curing resin-modified glass ionomer may initially react more favorably to pulp cells.     

Dental resin composites containing ceramic whiskers and precured glass ionomer particles.

OBJECTIVES: Glass ionomer, resin-modified glass ionomer, and compomer materials are susceptible to brittle fracture and are inadequate for use in large stress-bearing posterior restorations. The aim of this study was to use ceramic single crystal whiskers to reinforce composites formulated with precured glass ionomer, and to examine the effects of whisker-to-precured glass ionomer mass ratio on mechanical properties, fluoride release, and polishability of the composites. METHODS: Silica particles were fused onto silicon nitride whiskers to facilitate silanization and to improve whisker retention in the matrix. Hardened glass ionomer was ground into a fine powder, mixed with whiskers, and used as fillers for a dental resin. Four control materials were also tested: a glass ionomer, a resin-modified glass ionomer, a compomer, and a hybrid composite. A three-point flexural test was used to measure flexural strength, modulus, and work-of-fracture. A fluoride ion-selective electrode was used to measure fluoride release. Composite surfaces polished simulating clinical procedures were examined by SEM and profilometry. RESULTS: At whisker/(whisker + precured glass ionomer) mass fractions of 1.0 and 0.91, the whisker composite had a flexural strength in MPa (mean (SD); n = 6) of (196 (10)) and (150 (16)), respectively, compared to (15 (7)) for glass ionomer, (39 (8)) for resin-modified glass ionomer, (89 (18)) for compomer, and (120 (16)) for hybrid composite. The whisker composite had a cumulative fluoride release of nearly 20% of that of the glass ionomer after 90 days. The whisker composites had surface roughness comparable to the hybrid resin composite. SIGNIFICANCE: Composites filled with precured glass ionomer particles and whiskers exhibit moderate fluoride release with improved mechanical properties; the whisker-to-glass ionomer ratio is a key microstructural parameter that controls fluoride release and mechanical properties.     

Colorimetric Assessment of Laser and Home Bleaching Techniques

Abstract: Purpose: This study recorded in vitro color change of three tooth bleaching techniques that included laser-activated hydrogen peroxide and two concentrations of carbamide peroxide.
Materials and Methods: Forty extracted human central incisors were exposed to argon laser-activated 35% H₂O₂, 10% carbamide peroxide, or 20% carbamide peroxide. A fourth group (control) did not receive any bleach treatment (n = 10/group). Commission International de ľEclariage (CIE) L*a*b* coordinates were recorded prior to bleaching (baseline), at 1 week, and at 2 weeks. The color difference (ΔE*ab) between baseline and subsequent measurents was calculated.
Results: The control group did not demonstrate significant color difference over time ( p > .05). The laser group was not statistically different from the control group ( p > .01). The color difference of the 10% and 20% carbamide peroxide groups was statistically different from the control group ( p < .01).     

Color stability of provisional restorative materials after accelerated aging

PURPOSE: Color of 11 provisional restorative materials (4 acrylic resins and 7 resin composites) was evaluated by reflection spectrophotometry immediately after fabrication, after aging for 15 kJ/m(2), and after aging for 60 kJ/m(2) to determine relative color stability under experimental aging conditions. MATERIALS AND METHODS: Specimens of provisional restorative materials were polymerized according to manufacturers' instructions and aged in an artificial aging chamber with exposure to a total ultraviolet irradiation of 60 kJ/m(2) in increments of 15 kJ/m(2). Color was measured by CIE L*a*b* on a reflection spectrophotometer before and after aging. Color change (Delta E*) was calculated and analyzed statistically by analysis of variance with repeated measures after 15 and 60 kJ/m(2) intervals of aging. RESULTS: Statistically significant changes in color were observed after accelerated aging at both the initial and final aging intervals. Five of the 11 provisional materials tested showed perceptible color change (Delta E* from 3.6 to 9.3) after accelerated aging of 15 kJ/m(2). Seven of the 11 provisional materials tested showed perceptible color change (Delta E* from 3.4 to 9.4) after accelerated aging of 60 kJ/m(2). CONCLUSIONS: Clinically perceptible color changes (Delta E* Delta 3.3) can be expected in some acrylic resin and composite resin provisional materials after accelerated aging.