Staining susceptibility of resin composite materials.

PURPOSE: To evaluate the color stability of three resin-based materials continuously exposed to various staining agents. METHODS: 144 disc-shaped specimens were made of each of the three tested composites (Essentia, Brillant, Inspiro). Half of them were 1 mm thick, the other half 1.2 mm thick. The thicker group was then polished up to 4,000 grit and reduced to 1 mm thickness, also. All specimens, after 24-hour dry storage in an incubator, received an initial color measurement by means of a calibrated reflectance spectrophotometer (SpectroShade). Specimens were then divided into six groups (n=6) and immersed in five staining solutions or artificial saliva (control). All specimens were kept in an incubator at 37°C for 28 days. Staining solutions (red wine, curry mixed in water, curry mixed in oil, tea and coffee) were changed every 7th day to avoid bacteria or yeast contamination. After 28 days of storage, spectrophotometric measurements were repeated and L*a*b* scores once more recorded to determine the color (ΔE00) changes. RESULTS: All tested materials showed significant color changes after 28 days staining immersion. ΔE00 of polished samples varied from 1.1 (Essentia/distilled water measured over a white background as well as Essentia, Inspiro/distilled water measured over a black background) to 32.5 (Inspiro/wine measured over a white background). CLINICAL SIGNIFICANCE: Staining of restorative materials seems to be dependent on the composition of the product itself. Unpolished samples were more prone to staining than the polished ones.

Protection Against Discolouration by Two Over-the Counter Desensitising Products.

PURPOSE: To determine in vitro the protection potential against discolouration of two OTC (over-the-counter) desensitising products on enamel and dentin in comparison to a standard toothpaste and water by means of a spectrophotometer. MATERIALS AND METHODS: A total of 96 samples of bovine enamel-dentin complex and 48 of bovine dentin were alternatively immersed in red wine, tea, coffee or water after having been treated by a sodium monofluorophosphate- and calcium phosphate-based product (Curodont Protect), an amine fluoride-based toothpaste (Elmex Red), a stannous chloride-based toothpaste (Elmex Protection Erosion) or distilled water (negative control). Initial (T0) and final colour (T1, after 4 weeks of immersion in staining solutions) of each specimen were assessed by a spectrophotometer. Statistical analysis was done by means of repeated measures ANOVA followed by Fisher's LSD post-hoc test. Differences between T0 and T1 were considered stastistically significant at p ≤ 0.05. RESULTS: When enamel samples were measured over a black background, ΔE00 values (T0-T1) varied from 2.2 (SD 0.7) for amine fluoride-based product/water to 53.9 (SD 7.6) for amine fluoride-based-product/red wine. When dentin samples were measured over a black background, ΔE00 values (T0-T1) varied from 5.4 (SD 0.9) stannous chloride based product/water to 61.6 (SD 3.7) amine fluoride-based product/red wine. CONCLUSION: Specifically, the application of the sodium monofluorophosphate was able to statistically significantly (p ≤ 0.05) reduce discolouration induced by the staining solutions tested only on the enamel-dentin complex, while distilled water and the stannous fluoride-based product were able to statistically significantly (p ≤ 0.05) reduce discolouration induced by the staining solutions tested in pure dentin samples.

Color stability of different composite resins after polishing.

The goals of the present study were to evaluate, in vitro, the staining of different composite resins submitted to different common beverages, and to compare the staining effect of each of these solutions. A total of 288 specimens were randomly divided into six groups and immersed for 4 weeks in five staining solutions represented by red wine, orange juice, coke, tea and coffee or in artificial saliva as a control group. When analyzed over a black background, mean ΔE00 values varied from 0.8 for Venus Diamond, Saremco Microhybrid and ELS in saliva and Estelite Posterior in coke to 37.6 for Filtek Supreme in red wine. When analyzed over a white background, mean ΔE00 values varied from 0.5 for Saremco Microhybrid in saliva to 51.1 for Filtek Supreme in red wine. All materials showed significant changes in color after 4 weeks of immersion in staining solutions. Significant differences were found between the tested composite resins and also between the staining solutions.

Silorane, ormocer, methacrylate and compomer long-term staining susceptibility using ΔE and ΔE 00 colour-difference formulas.

The aim of this study was to evaluate the staining susceptibility of a silorane (Filtek Silorane), an ormocer (Ceram X Duo), a methacrylate (Tetric EvoCeram) and a compomer (Dyract) exposed on the long term to various staining agents by using ΔE and ΔE 00 colour-difference formulas. Thirty-six disc-shaped specimens were made of each of the four chemically different materials, randomly divided in six groups (n = 6) and immersed in five staining solutions (red wine, juice, coke, tea and coffee) or stored dry (control) in an incubator at 37 °C for 99 days. Spectrophotometric measurements by means of a spectrophotometer (Spectroshade Handy Dental, MHT) were repeated over a white (L* = 92.6, a* = -1.2, b* = 2.9) and black (L* = 1.6, a* = 1.2, b* = -1.0) background made of plasticized paper, in order to determine the colour changes according to ΔE, ΔE 00 and translucency formulas. Statistical analysis was performed by means of factorial Anova, Fisher's LSD test (post hoc) and a Spearman rank correlation between ΔE and ΔE 00. When analysed over a white background, mean ΔE 00 values were highly significantly different and varied from 0.8 (Ceram X Duo/air) to 20.9 (Ceram X Duo/red wine). When analysed over a black background, mean ΔE 00 values were highly significantly different and varied from 1.0 (Ceram X Duo and Tetric/air) to 25.2 (Ceram X Duo/red wine). Differences in translucency varied from 0.3 (Ceram X Duo/air) to 21.1 (Ceram X Duo/juice). The correlation between ΔE and ΔE 00 over a white background was 0.9928, while over a black background, it was 0.9886.

Evaluation of the Effect of Different Surface Treatments on Luting CAD/CAM Composite Resin Overlay Workpieces.

PURPOSE: To evaluate the effect of different surface treatments on luting CAD/CAM composite resin workpieces. MATERIALS AND METHODS: One-hundred eight (108) composite CAD/CAM block sections (Lava Ultimate) 3 mm in thickness were polished up to 4000 grit and then randomly assigned to 6 experimental groups according to the applied surface treatment (no treatment, sodium bicarbonate [NaHCO3], glycine, alumina [Al2O3], CoJet, and SilJet). After standardized sandblasting procedures, 2 block sections from each group were randomly chosen for the qualitative SEM evaluation of the sandblasted surfaces. The remaining 96 CAD/CAM block sections were luted in pairs using a bonding agent (Single Bond) and a restorative composite resin (Filtek Ultimate). Specimens were aged for 2 weeks in 37°C water with 3000 thermal cycles (5°C/55°C), the microtensile test was performed (n = 30), and the values were statistically analyzed with ANOVA and Tukey's HSD post-hoc test (p = 0.05). RESULTS: The qualitative SEM evaluation of the sandblasted surfaces showed that sodium bicarbonate and glycine had almost no conditioning effect on the CAD/CAM composite resin. In contrast, aluminum oxide, CoJet, and SilJet had a profound conditioning effect on the CAD/CAM composite resin. No treatment, sodium bicarbonate, and glycine specimens were debonded after thermal stressing (0 MPa), while aluminum oxide, CoJet, and SilJet showed high microtensile values (Al2O3: 104.45 ± 18.76 MPa; CoJet: 105.55 ± 11.88 MPa; SilJet: 105.02 ± 20.84 MPa), which were not statistically significantly different from each other. CONCLUSION: Aluminum oxide-based sandblasting powders are the best choice for the surface treatment of CAD/ CAM workpieces.

Colour stainability of indirect CAD-CAM processed composites vs. conventionally laboratory processed composites after immersion in staining solutions.

OBJECTIVES: The aim of this study was to determine, by using a spectrophotometer device, the colour stainability of two indirect CAD/CAM processed composites in comparison with two conventionally laboratory-processed composites after being immersed 4 weeks in staining solutions such as coffee, black tea and red wine, using distilled water as control group. METHODS: Two indirect CAD/CAM composites (Lava Ultimate and Paradigm MZ100) and two conventionally laboratory-processed composites (SR Adoro and Premise Indirect) of shade A2 were selected (160 disc samples). Colour stainability was measured after 4 weeks of immersion in three staining solutions (black tea, coffee, red wine) and distilled water. Specimen's colour was measured each week by means of a spectrophotometer (CIE L*a*b* system). Statistical analysis was carried out performing repeated ANOVA measurements and Tukey's HSD test to evaluate differences in ΔE00 measurements between groups; the interactions among composites, staining solutions and time duration were also evaluated. RESULTS: All materials showed significant discoloration (p<0.01) when compared to control group. The highest ΔE00 observed was with red wine, whereas black tea showed the lowest one. Indirect laboratory-processed resin composites showed the highest colour stability compared with CAD/CAM resin blocks. CONCLUSIONS: CAD/CAM processed composites immersed in staining solutions showed lower colour stability when compared to conventionally laboratory-processed resin composites. CLINICAL SIGNIFICANCE: The demand for CAD/CAM restorations has been increasing; however, colour stainability for such material has been insufficiently studied. Moreover, this has not been performed comparing CAD/CAM processed composites versus laboratory-processed indirect composites by immersing in staining solutions for long immersion periods.

The effect of toothbrushing on surface gloss of resin composites.

PURPOSE: To determine the changes in surface gloss of different composite materials after laboratory toothbrushing simulation. METHODS: 36 specimens were fabricated for each material and polished with 120-, 220-, 500-, 1200-, 2400- and 4000-grit SiC abrasive paper, respectively. Gloss measurements were made with a glossmeter (Novocurve) prior to testing procedures and then subjected to simulated toothbrushing for 5, 15, 30 and 60 minutes by means of an electric toothbrush with a pressure of 2N while being immersed in a 50 RDA toothpaste slurry. Four supplementary samples per group were analyzed under SEM immediately after polishing procedures and four samples after 60 minutes simulated toothbrushing in order to evaluate the causes of the gloss decrease. The tested resin composite materials were Filtek Supreme XTE, Durafill, HRi Enamel Plus, Miris 2, Empress Direct, Venus Diamond, Gradia Direct, Clearfil Photo Posterior and G-aenial. Natural enamel represented the control group. Statistical analysis was performed using Kruskal Wallis and Tukey post-hoc test, with a level of significance set at 0.05. RESULTS: Resin composite initial gloss values ranged from 68.9 to 100.5 at baseline to 10.6 to 62.6 after 1 hour of brushing. Highest gloss values were obtained by Filtek Supreme XTE, followed by Empress Direct and Durafill. Lowest values were obtained by Clearfil Photoposterior, Miris 2, Enamel HRi and Venus Diamond. Natural enamel was the only substrate to maintain its gloss throughout the brushing procedure (110.4 after 60 minutes). SEM analysis revealed different patterns of surface degradation depending on the composite material.

Pilot in vivo image spectro-photometric evaluation of optical properties of pure enamel and enamel-dentin complex.

OBJECTIVES: The aim of this in vivo study is to investigate the L*a*b*and the opacity (CR) of front teeth by means of an image spectrophotometer and to evaluate the eventual influence of the background color on the results. The second aim is to investigate if there is a relationship between tea, coffee, red wine drinking habits or smoking habits of the test subjects and tooth color. METHODS: A novel image based spectro-photometric approach was developed and applied on a Swiss Army recruits group quantifying L*a*b* of pure enamel as well as of enamel-dentin complex against black and white background together with CR. RESULTS: When 2mm thick pure enamel was considered, the values obtained were (mean (SD)) L*(76.3 (3.4)), a*(3.4 (1.2)) and b*(17.2 (2.45)) against white background and L*(63.5 (4.2)), a*(0.8 (1.3)) and b*(10.7 (2.7)) against black background. The opacity (CR) of 2mm thick pure enamel was (64.4 (0.1)). When 3mm thick enamel-dentin complex was considered, the values obtained were L*(79.0 (2.6)), a*(3.9 (1.3)) and b*(20.4 (3.0)) against a white background and L*(74.9 (3.0)), a*(1.8 (1.2)) and b*(16.7 (3.1)) against a black background. The opacity (CR) of 3mm thick enamel-dentin complex was (87.4 (0.1)). SIGNIFICANCE: The application of this method on a larger group of subjects of different ages may serve as a database for a more exact characterization of optical properties of natural enamel and dentin.