Color Stability and Surface Roughness of Composite submitted to Different Types and Periods of Finishing/Polishing: Physical Properties of Composites.

AIM: The aim of this study was to evaluate the influence of accelerated artificial aging (AAA) on color stability (AE) and surface roughness of composite submitted to different systems and periods of finishing/polishing. MATERIALS AND METHODS: A Teflon matrix was used to fabricate 60 specimens that were separated into four groups, according to the finishing/polishing system: G1: no polishing; G2: abrasive papers; G3: rubber polishing disks; and G4: G2 + G3. Polishing was performed at three different time intervals (n = 6): immediately (Im), 24 hours (24 hours) and 7 days (7 day) after specimen fabrication. Initial color and surface roughness readouts were taken. Afterwards, specimens were submitted to AAA (480 hours) and new readouts were taken. RESULTS: Results demonstrated that G2 (7 day) presented lower AE, statistically different from G1 and G4 (7 days) (two-way analysis of variance (ANOVA), Bonferroni, p < 0.05). CONCLUSION: Regarding roughness, there was no difference among groups and periods. Polishing performed with abrasive papers, 7 days after performing the restoration, promoted less color alteration. CLINICAL SIGNIFICANCE: Most of composite restorations are replaced within a period shorter than 5 years due to esthetic failure, and correct finishing and polishing procedures are fundamental to avoid these problems.

Influence of finishing/polishing on color stability and surface roughness of composites submitted to accelerated artificial aging.

AIM: To assess the influence of finishing/polishing procedure on color stability (ΔE ) and surface roughness (R(a)) of composites (Heliomolar and Tetric - color A2) submitted to accelerated artificial aging (AAA). MATERIALS AND METHODS: Sixty test specimens were made of each composite (12 mm × 2 mm) and separated into six groups (n = 10), according to the type of finishing/polishing to which they were submitted: C, control; F, tip 3195 F; FF, tip 3195 FF; FP, tip 3195 F + diamond paste; FFP, tip 3195 FF + diamond paste; SF, Sof-Lex discs. After polishing, controlled by an electromechanical system, initial color (spectrophotometer PCB 6807 BYK GARDNER) and R(a) (roughness meter Surfcorder SE 1700, cut-off 0.25 mm) readings were taken. Next, the test specimens were submitted to the AAA procedure (C-UV Comexim) for 384 hours, and at the end of this period, new color readings and R(a) were taken. RESULTS: Statistical analysis [2-way analysis of variance (ANOVA), Bonferroni, P < 0.05] showed that all composites demonstrated ΔE alteration above the clinically acceptable limits, with the exception of Heliomolar composite in FP. The greatest ΔE alteration occurred for Tetric composite in SF (13.38 ± 2.10) statistically different from F and FF (P < 0.05). For R(a), Group F showed rougher samples than FF with statistically significant difference (P < 0.05). CONCLUSION: In spite of the surface differences, the different finishing/polishing procedures were not capable of providing color stability within the clinically acceptable limits.

Effect of brushing and accelerated ageing on color stability and surface roughness of composites.

OBJECTIVES: The aim of this study was to evaluate the effect of brushing and artificial accelerated ageing (AAA) on color stability and surface roughness of aesthetic restorative materials. METHODS: One hundred and twenty specimens (12 mm diameter × 2 mm thick), 40 of each material (n=8) were obtained using nanosized composite Z350 (3M ESPE), nanohybrid composite Tetric N-Ceram (Ivoclar Vivadent) and ceramic IPS e.max Ceram (Ivoclar Vivadent), as control. Initial color (Spectrophotometer PCB 6807) and surface roughness (Surfcorder SE 1700) readouts were taken and the samples were separated into five groups (n=8) and treated as follows: Group 1: mechanical brushing with dentifrice RDA* 68 (Colgate), Group 2: mechanical brushing with dentifrice RDA* 180 (Colgate Total Plus Whitening), Group 3: AAA, Group 4: AAA followed by mechanical brushing with dentifrice RDA* 68 and Group 5: AAA followed by mechanical brushing with dentifrice RDA* 180. Mechanical brushing was performed for 205 min and AAA for 480 h; new color and surface roughness readouts were taken. Data were statistically analyzed (two-way ANOVA repeated measures, Bonferroni test, p<0.05). RESULTS: Dentifrice abrasiveness was not significant for color change and surface roughness. When submitted to AAA+brushing, the color stability of Tetric was statistically significant (p<0.05) with both dentifrices and with dentifrice RDA* 180 for Z350. The roughness was different (p<0.05) for Z350 when brushed with RDA* 68 after AAA. CONCLUSIONS: Dentifrice abrasiveness did not interfere in the ability to remove stains and roughness from aged samples. However, staining is material-dependent. CLINICAL SIGNIFICANCE: The abrasiveness of dentifrice does not change the color and surface roughness of the composites and does not help to remove surface stains from the aged samples.

Color stability of repaired composite submitted to accelerated artificial aging.

The aim of this study was to evaluate the color stability (ΔE) of nanoparticulate composite, with consideration for the type of surface treatment performed before repair. A Teflon matrix was used to fabricate 50 test specimens from composite. After initial color readout, the specimens were submitted to 100 hours of accelerated artificial aging (AAA). The samples were divided into five groups (n = 10), according to the surface treatment performed: sandblasting with aluminum oxide powder, phosphoric acid, and an adhesive system (Group 1); sandblasting with aluminum oxide powder, phosphoric acid, and a flowable composite (Group 2); abrasion with a diamond bur, phosphoric acid, and an adhesive system (Group 3); abrasion with a diamond bur, phosphoric acid, and a nanoparticulate composite (Group 4); and a control group (Group 5). After repair, a new color readout was taken, the test specimens were submitted to a new AAA cycle (300 hours), and the final color readout was taken. Comparison of the ΔE means (one-way ANOVA and Tukey tests, p < 0.05) demonstrated no statistically significant differences among the groups (p > 0.05) after 100 hours of AAA. After repair, Group 1 (4.61 ± 2.03) presented the highest color alteration with a statistically significant difference compared with the other groups (p < 0.05). After 300 hours, Group 4 specimens (13.84 ± 0.71) presented the lowest color alteration in comparison with the other groups, with a statistically significant difference (p < 0.05). It was concluded that the repair performed in Group 4 provided greater esthetic recovery, made possible by the regression in the ΔE values of the restorations after repair, and less color alteration of the restorations over the course of time.

Color stability of modern composites subjected to different periods of accelerated artificial aging

The aim of this study was to evaluate the color stability of composites subjected to different periods of accelerated artificial aging (AAA). A polytetrafluorethylene matrix (10 x 2 mm) was used to fabricate 24 test specimens of three different composites (n=8): Tetric Ceram (Ivoclar/Vivadent); Filtek P90 and Z250 (3M ESPE), shade A3. After light activation for 20 s (FlashLite 1401), polishing and initial color readout (Spectrophotometer PCB 687; BYK Gardner), the test specimens were subjected to AAA (C-UV; Comexim), in 8-h cycles: 4 h exposure to UV-B rays at 50°C and 4 h condensation at 50°C. At the end of each cycle, color readouts were taken and the test ended when the mean value of ΔE attained a level ≥3.30. Tetric Ceram presented alteration in ΔE equal to 3.33 in the first aging cycle. For Filtek P90 and Z250, two (ΔE=3.60) and four (ΔE=3.42) AAA cycles were necessary. After each cycle, there was a reduction of luminosity in all the samples (ΔL). It was concluded that a short period of AAA was sufficient to promote clinically unacceptable color alteration in composites, and that this alteration was material-dependent.

O objetivo deste estudo foi avaliar estabilidade de cor de compósitos submetidos a diferentes períodos de envelhecimento artificial acelerado (EAA). Foram confeccionados, em matriz de teflon (10x2 mm), 24 corpos-de-prova de três compósitos (n=8): Tetric Ceram (Ivoclar/Vivadent); Filtek P90 e Z250 (3M ESPE), cor A3. Após fotoativação por 20 s (FlashLite 1401), polimento e leitura inicial de cor (espectrofotômetro PCB 687; BYK Gardner), os corpos-de-prova foram submetidos ao EAA (C-UV, Comexim), com ciclos de 8 h: 4 h de exposições a raios UV-B a 50°C e 4 h de condensação a 50°C. Ao final de cada ciclo, leituras de cor eram realizadas e quando o valor médio de ΔE atingisse índice ≥3,30, o ensaio era encerrado. Observou-se que Tetric Ceram apresentou alteração de ΔE igual a 3,33 já no primeiro ciclo de envelhecimento. Com Filtek P90 foram necessários dois ciclos de EAA (ΔE=3,60) e para Z250 quatro (ΔE=3,42). Observou-se que a cada ciclo ocorria diminuição na luminosidade de todas as amostras (ΔL). Concluiu-se que um curto período de EAA já é suficiente para que compósitos apresentem alteração de cor inaceitável clinicamente e que esta alteração é material dependente.

Color stability, surface roughness and microhardness of composites submitted to mouthrinsing action.

OBJECTIVE: The purpose of this study was to evaluate the effect of mouth rinse solutions on color stability, surface roughness and microhardness of two composite resins. MATERIAL AND METHODS: Fifty test specimens of each composite (Filtek Z250 and Z350; 3M ESPE) were made using a teflon matrix (12x2 mm). Color, surface roughness and Knoop microhardness baseline measurements of each specimen were made and specimens (n=10) were immersed in 5 mouth rinse solutions: G1: distilled water (control), G2: Plax Classic, G3: Plax alcohol-free; G4: Periogard, and G5: Listerine. Final measurements of color, roughness and microhardness were performed and the results submitted to statistical analysis (2-way ANOVA, Bonferroni's test; p<0.05). RESULTS: The most significant color change was observed for Z250 when immersed in Listerine (p<0.05). Z350 showed greater color change when immersed in Plax alcohol-free (p<0.05), but with no significant difference for Listerine (p>0.05). With regard to roughness, both composites showed significant changes when immersed in Listerine in comparison with Plax alcohol-free (p<0.05). Microhardness of Z350 was shown to be significantly changed when the composite was immersed in Plax alcohol-free (p<0.05). CONCLUSION: Composite changes depended on the material itself rather than the mouth rinse solution used.

Color stability, surface roughness and microhardness of composites submitted to mouthrinsing action

OBJECTIVE:The purpose of this study was to evaluate the effect of mouth rinse solutions on color stability, surface roughness and microhardness of two composite resins. MATERIAL AND METHODS: Fifty test specimens of each composite (Filtek Z250 and Z350; 3M ESPE) were made using a teflon matrix (12x2 mm). Color, surface roughness and Knoop microhardness baseline measurements of each specimen were made and specimens (n=10) were immersed in 5 mouth rinse solutions: G1: distilled water (control), G2: Plax Classic, G3: Plax alcohol-free; G4: Periogard, and G5: Listerine. Final measurements of color, roughness and microhardness were performed and the results submitted to statistical analysis (2-way ANOVA, Bonferroni ’s test; p<0.05). RESULTS: The most significant color change was observed for Z250 when immersed in Listerine (p<0.05). Z350 showed greater color change when immersed in Plax alcohol-free (p<0.05), but with no significant difference for Listerine (p>0.05). With regard to roughness, both composites showed significant changes when immersed in Listerine in comparison with Plax alcohol-free (p<0.05). Microhardness of Z350 was shown to be significantly changed when the composite was immersed in Plax alcohol-free (p<0.05). CONCLUSION: Composite changes depended on the material itself rather than the mouth rinse solution used.

Color and opacity of composites protected with surface sealants and submitted to artificial accelerated aging.

OBJECTIVES: To evaluate the color similarity, stability and opacity of composites (TPH, Charisma, and Concept, shade A2) protected with surface sealants (Fortify Plus and Biscover) and cyanoacrylate (Super Bonder). METHODS: Forty specimens of each composite were made and separated into 4 groups (n=10) according to the surface protection: GI - without sealant; GII - cyanoacrylate; GIII - Fortify Plus; GIV - Biscover. Color and opacity readings were taken before and after Artificial Acelerated Aging (AAA) and the values obtained for color stability were submitted to statistical analysis by 2-way ANOVA and Bonferroni's test (P<.05). The values acquired for color similarity were submitted to 1-way ANOVA and Tukey's test (P<.05). The specimen sufaces were compared before and after AAA using Scanning Electronic Microscopy (SEM). RESULTS: Studied composites did not present the same values for the coordinates L*, a* and b * before AAA, indicating that there was no color similarity among them. All composites presented color alteration after AAA with clinically unacceptable values. Protected groups presented lower opacity variation after AAA, in comparison with the control goup. SEM evaluation demonstrated that AAA increased the surface irregularities in all of the studied groups. CONCLUSION: Surface sealants were not effective in maintaining composite color, but were able to maintain opacity.

Color stability of modern composites subjected to different periods of accelerated artificial aging.

The aim of this study was to evaluate the color stability of composites subjected to different periods of accelerated artificial aging (AAA). A polytetrafluorethylene matrix (10 x 2 mm) was used to fabricate 24 test specimens of three different composites (n=8): Tetric Ceram (Ivoclar/Vivadent); Filtek P90 and Z250 (3M ESPE), shade A3. After light activation for 20 s (FlashLite 1401), polishing and initial color readout (Spectrophotometer PCB 687; BYK Gardner), the test specimens were subjected to AAA (C-UV; Comexim), in 8-h cycles: 4 h exposure to UV-B rays at 50°C and 4 h condensation at 50°C. At the end of each cycle, color readouts were taken and the test ended when the mean value of ΔE attained a level ≥3.30. Tetric Ceram presented alteration in ΔE equal to 3.33 in the first aging cycle. For Filtek P90 and Z250, two (ΔE=3.60) and four (ΔE=3.42) AAA cycles were necessary. After each cycle, there was a reduction of luminosity in all the samples (ΔL). It was concluded that a short period of AAA was sufficient to promote clinically unacceptable color alteration in composites, and that this alteration was material-dependent.

Color stability, opacity and degree of conversion of pre-heated composites.

OBJECTIVES: To assess color stability and opacity associated with the degree of conversion of a pre-heated nanohybrid composite (Tetric N-Ceram, Ivoclar/Vivadent, Schaan, Liechtenstein). METHODS: Twenty-seven specimens were prepared (n=9) using a Teflon matrix following storage of compules containing the composite at temperatures of 8°C, 25°C or 60°C. After photoactivation and polishing, baseline readings of six specimens were taken regarding their color and opacity (Spectrophotometer PCB 6807, Byk Gardner, Geretsried, Germany). Then, the specimens were submitted to artificial ageing for 384 h (C-UV, Adexim Comexim, São Paulo, SP, Brazil), after which the final readings were taken. Three specimens for each temperature were submitted to analysis of degree of conversion (Nicolet 380, Thermo Scientific, Waltham, MA, USA). The results were analysed by 1-way ANOVA/Tukey (p<0.05). RESULTS: There was no significant difference in color stability and opacity variation amongst the temperatures evaluated. The composite pre-heated at 60°C had a higher degree of conversion (65.13%), with statistically significant difference compared to the other temperatures (p<0.05). CONCLUSIONS: Composite pre-heating does not promote changes in the optical properties, despite the increase in the degree of conversion.

Composites associated with pulp-protection material: color-stability analysis after accelerated artificial aging.

OBJECTIVES: This study assessed the color stability of two composites associated with two pulp protectors submitted to accelerated artificial aging (AAA). METHODS: 60 test specimens were made with 0.5 mm of protection material (calcium hydroxide - CH or glass ionomer cement - GIC) and 2.5 mm of restoration material (Concept or QuixFil) and divided into 3 groups (n=10) according to the type of protection material/composite, and the control group (no protection). After polishing, color readings were obtained with a spectrophotometer (PCB 6807 Byk Gardner) before and after AAA for 384 hours, and L*, a*, and b* coordinates and total color variation (DeltaE) were analyzed (2-way ANOVA, Bonferroni, alpha=05). RESULTS: Composites placed on CH presented lower L* levels than those on GIC, which presented higher L* values than the control group and lower b* values than those of the CH group. The Concept composite presented higher DeltaE levels for all groups, differing statistically from QuixFil, except when placed on GIC. CONCLUSIONS: It was concluded that the protection material could affect the color stability and AAA is a factor that enhances this effect, depending on the type of composite used.

Color stability of dental ceramics submitted to artificial accelerated aging after repeated firings.

STATEMENT OF PROBLEM: Color stability is an important factor to ensure the long-term clinical success of ceramic restorations. There is a lack of information on how color is affected by fabrication procedures, such as the number of firings. PURPOSE: The purpose of this study was to evaluate the effects that the number of firings and type of substrate have on the color stability of dental ceramic submitted to artificial accelerated aging. MATERIAL AND METHODS: Sixty specimens were fabricated: 30 metal ceramic (Verabond II + IPS d.SIGN) and 30 all-ceramic (IPS d.SIGN). Specimens were divided into 3 groups (n=10), and submitted to 2, 3, or 4 firings (+/-900 degrees C), respectively, according to the manufacturer's instructions. Color readings were obtained with a spectrophotometer before and after artificial accelerated aging, and L*, a*, and b* coordinates and total color variation (Delta E) were analyzed (2-way ANOVA, Bonferroni, alpha=05). RESULTS: For metal ceramic specimens, differences for the L* coordinates were significant (P<.05) only for the group submitted to 3 firings. With respect to the all-ceramic specimens, smaller L* coordinates were obtained for greater a* and b* coordinates, indicating that the greater the number of firings, the darker and more reddish/yellowish the specimen. All Delta E values, for all groups, were below 1.0. All-ceramic specimens submitted to 3 and 4 firings presented Delta E means differing statistically (P<.05) from those of the metal ceramic group. CONCLUSIONS: The type of substrate and number of firings affected the color stability of the ceramic material tested. Artificial accelerated aging did not produce perceptible color stability changes (Delta E<1.0).

Resistência flexural e rugosidade superficial de resinas acrílicas utilizadas para confecção de placas oclusais / Flexural strength and superficial roughness of acrylic resins used for confection of occlusal splints

O objetivo deste trabalho foi avaliar in vitro o efeito da adição de fibras de vidro na resistência flexural por três pontos e rugosidade superficial de resinas utilizadas para a confecção de placas oclusais. Para este estudo, foram utilizadas as seguintes resinas com diferentes tipos de polimerização: resina acrílica autopolimerizável Vipi Flash® (RA), resina acrílica termopolimerizável por banho de água Vipi Cril® (RT) e resina acrílica termopolimerizável por calor de microondas Vipi Wave® (RM),com e sem adição de fibras de vidr (FV). Hipóteses em estudo: a adição de fibras de vidro aumenta a resistência flexural por três pontos e a rugosidade superficial dos corpos-de-prova. Foram confeccionadas doze amostras (n = 12) para cada grupo, a partir de uma matriz metálica com 67 mm de comprimento x 12,60 mm de largura x 3,00 mm de espessura. Os corpos-de-prova foramsubmetidos ao teste de resistência flexural em máquina de ensaio universal (EMIC DL 2000®), a uma velocidadede 5 mm/min, e ao teste de rugosidade superficial em rugosímetro (Mitutoyo®). Os dados foram submetidos à análise de variância e ao teste complementar de Tukey (p < 0,01). De acordo com os resultados, em relação à resistência flexural (MPa) houve diferença estatisticamente significativa somente para o fator tipo de polimerização das resinas (RA = 81,54 ± 4,94, RT = 92,86± 16,85, RM = 86,24 ± 8,89). Em relação à rugosidade superficial (RA-μm), houve diferença para os dois fatores fatores avaliados: tipo de polimerização (RA = 0,10 ± 0,02, RT = 0,13 ± 0,03, RM = 0,11 ± 0,13) e adição de fibras de vidro (CF = 0,13 ± 0,02, SF = 0,10 ± 0,11). Pode-se concluir que a adição de fibras de vidro aos grupos experimentais não alterou os valores de resistência flexural, no entanto aumentou os valores de rugosidade superficial das amostras testadas

Nova metodologia para análise comparativa da liberação de flúor de cimentos de ionômero de vidro restauradores e compômeros / New methodology for comparative analysis of the fluoride release of glass-ionomer cement and compomers

Esse trabalho apresentou nova metodologia para avaliar a liberação dinâmica de flúor de três materiais, um cimento de ionômero de vidro restaurador (Vidrion R), um ionômero de vidro modificado por resina (Vitremer) e um compômero (Dyract AP). Após manipulação dos materiais segundo recomendações dos fabricantes e da obtenção dos corpos-de-prova, os mesmos foram armazenados em saliva artificial sem flúor por 30 dias. A concentração de fluoreto nas soluções estoque foram determinadas com um potenciômetro, utilizando um eletrodo íon seletivo para fluoreto (Orion n°9609BN) conectado a um registrador (HANNA Instruments HI n°9321). Os resultados indicaram um melhor comportamento do ionômero de vidro convencional, seguido do ionômero modificado e posteriormente do compômero.