Journal of Investigative and Clinical Dentistry (2011), 2, 201–206
ORIGINAL ARTICLE Conservative Dentistry
Changes on the color parameters of air-abraded resin composite exposed to different colored beverages Livia Aguilera Gaglianone1, Joana Dourado Martins2, Thaı´s Re´gis Aranha Rossi2, Letı´cia Oliveira Saraiva2, Andrea No´brega Cavalcanti3 & Paula Mathias2 1 Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, Sa˜o Paulo, Brazil 2 Department of Clinical Dentistry, Federal University of Bahia, Salvador, Bahia, Brazil 3 Department of Oral Rehabilitation, School of Medicine and Public Health of Bahia, Salvador, Bahia, Brazil
Keywords air abrasion, beverage, composite resin, sodium bicarbonate, staining. Correspondence Dr Paula Mathias, School of Dentistry, Federal University of Bahia, Avenida Arau´jo Pinho, 62, Canela, CEP 40.110-060 Salvador/Bahia, Brazil. Tel: +55-71-3336-5776 Fax: +55-71-3336-5776 Email: [email protected] Received 17 May 2010; accepted 16 August 2010. doi: 10.1111/j.2041-1626.2011.00063.x
Abstract Aim: To evaluate the effect of prophylaxis using sodium bicarbonate and colored beverages on the color parameters of a resin composite. Methods: Eighty specimens (Z350–3M ESPE) were randomly allocated into eight groups (n = 10), according to the combination of staining solution (artificial saliva, cola, red wine, or coffee) and air-powder abrasion with sodium bicarbonate (either performed or not performed). Specimens were immersed in the staining solution for 48 h (two 24-h cycles). Color evaluation was based on the CIELab system. Two measurements were carried out using a spectrophotometer (Commission Internationale de L’Eclairage L* a* b* system) before and after the immersion period. Final measurement data were analyzed by two-way anova/Tukey’s test, and comparisons were made between initial and final measurements by anova/Dunnett’s test, with a 5% significance level. Results: Most comparisons between initial and final measurements were statistically significant. Red wine and coffee significantly affected the color parameters (L*, b*, and DE). However, only coffee significantly increased a* values. When compared with untreated surfaces, air-powder abrasion resulted in alterations of b* and a* parameters, but did not affect L* and DE. Conclusions: Both colored beverage solutions and air-powder abrasion can affect the color of composite resin restorations.
Introduction Professional cleaning or oral prophylaxis is commonly used in dentistry to provide adequate tooth cleaning and to remove dental biofilm and extrinsic stains. Agents for prophylaxis include pumice paste, abrasive dentifrices, air-powder abrasion with sodium bicarbonate, and air abrasion with aluminum oxide particles.1–3 Although a previous study2 showed that sodium bicarbonate particles are less abrasive than the other agents, some studies have demonstrated that air-powder procedures provide significant superficial alterations on composite restorations, like losing polishing because of resin matrix wear.1,3,4 Therefore, air-powder abrasion with ª 2011 Blackwell Publishing Asia Pty Ltd
sodium bicarbonate might act not only by removing stains, but also increasing the surface roughness of restorative materials. The increase in surface roughness of restorative materials has been associated with greater discoloration, mainly caused by the adsorption of dark pigments by rough surfaces.3,5–8 In resin composites, discoloration occurs after the absorption and adsorption of extrinsic pigments from a patient’s diet, such as those found in colored beverages, such as coffee, tea, red wine, cola, and some juices.5–14 Since air-powder abrasion with sodium bicarbonate might increase surface roughness in different restorative materials, it might potentially increase the stainability of esthetic resin composite restorations exposed to colored 201
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substances. Therefore, the aim of the present study was to evaluate the effect of colored beverages (cola, red wine, and coffee) and of air abrasion with sodium bicarbonate particles on the color parameters of composite resin specimens. The null hypothesis was that staining solutions allied to air abrasion do not increase pigmentation of the composite resin. Methods Eighty specimens were made from a nano-filled resin composite (Filtek Z350; 3M ESPE, St Paul, MN, USA; color A1). A Teflon mold with a central orifice, 6 mm in diameter, and with 2 mm thickness, was filled with a single increment of the composite. A Mylar strip was placed over the mold, and the specimens were light cured for 20 s with a LED unit (LED Ultrablue DMC; DMC Equipamentos LTDA, Sa˜o Paulo, Brazil) emitting 600 mW/cm2 light intensity. The tip of the light-curing unit was placed in contact with the Mylar strip during light activation. The specimens were polished with fine and ultra-fine aluminum oxide abrasive disks (Sof-Lex Pop-On; 3M ESPE, USA). Half of the composite resin specimens were air abraded using sodium bicarbonate particles (Profi II; Dabi Atlante, Sa˜o Paulo, Brazil), with 202.65-kPa pressure for 10 s at a 10 mm distance. Afterwards, all specimens were washed, stored in distilled water for 24 h, and allocated into eight groups (G1–G8) according to the surface treatment (control and air-abraded specimens) and staining solution (n = 10). In the first group (G1), the untreated surface was immersed in neutral artificial saliva (pH = 7); in the second group (G2), the untreated surface was immersed in cola (Coca Cola, Bahia, Brazil) (pH = 2.5); in the third group (G3), the untreated surface was immersed in red wine (Santa Helena, Vila Santa Helena SA, Molina, Chile) (pH = 3.7/13% ethanol); in the fourth group (G4), the untreated surface was immersed in coffee (Nescafe´ Classic, Nestle´ Brazil, Bahia, Brazil) (pH = 5.2) that was prepared according to the manufacturer’s recommendation (80 g coffee/1 L water); in the fifth group (G5), the air-abraded surface was immersed in neutral artificial saliva; in the sixth group (G6), the air-abraded surface was immersed in cola; in the seventh group (G7), the air-abraded surface was immersed in red wine; in the eighth group (G8), the air-abraded surface was immersed in coffee. The composition of the artificial saliva used in G1 and G5 was 2.2 g/L gastric mucin, 0.381 g/L sodium chloride, 0.231 g/L calcium chloride, 0.738 g/L potassium phosphate, 1.114 g/L potassium chloride, 1.5 g/L bicarbonate of sodium, and 0.3 g/L potassium sulphocyanide.15–17 Specimens from each group were individually stored in 5 mL of its respective solution for 48 h at 37C. After the first 24 h period, specimens were washed in distilled 202
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water for 10 s and then returned to the colored solution. Color measurements were performed before (baseline) and after immersion in the respective solutions. Color measurements were based on the Commission Internationale de l’Eclairage (CIE) L* a* b* system using a portable spectrophotometer (Easyshade Vita; VITA System 3DMaster, Brea, CA, USA). The spectrophotometer was calibrated before each color analysis session, in accordance with the manufacturer’s recommendation. To perform the color readings, each specimen was placed inside the central orifice of the white Teflon matrix. A mortise device was placed over the white, opaque Teflon, which was positioned over the specimens to standardize the contact of the tip from the spectrophotometer, with the surfaces of the specimens’ at an angle of 90. The distal end of the light guide from the hand-held spectrometer remained in contact with the specimen in a fixed position, controlling the influence of the external light and preventing the dissipation of the light. To perform the color analysis, the CIE L* a* b* color space system was used in this study. This international colorimetric system consists of three parameters: L*, a*, and b*, in which L* refers to lightness, and a* and b* represent a color variation between green–red and blue– yellow, respectively. Each color measurement was performed three times, and the mean values of L*, a*, and b* were calculated. The total color variation (DE) between the initial and final colors was calculated according to the following formula: DE = ([DL]2 + [Da]2 + [Db]2)½, where DL = L1 ) L0 (final reading ) initial reading), Da = a1 ) a0 (final reading ) initial reading), and Db = b1 ) b0 (final reading ) initial reading). The L*, b*, and a* values observed in the final measurement, and the DE values were analyzed with two-way anova, with the main factors being surface treatment (air abraded or not air abraded) and staining solution (artificial saliva, cola, red wine, and coffee). All possible interactions were included in the experimental model. Multiple pairwise comparisons were made with Tukey’s post hoc test. In order to meet the requirements of anova, b* values were transformed to inverse values, and a* values were converted to square root. anova/Dunnett’s test was used to compare the L*, b*, and a* values observed in the initial measurement with those found after immersion in the respective solutions, both in untreated and air-powdered surfaces. Analyses were performed using the sas 9.1 statistical package (SAS Institute, Cary, NC, USA), with a significance level of 0.05. Results Tables 1–4 present the mean values and standard deviations of the variables L*, b*, a*, and DE, respectively. For ª 2011 Blackwell Publishing Asia Pty Ltd
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Color changes of air-abraded composites
Table 1. L* values (standard deviation) of the surface type and staining solution
Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface Air-abraded surface Initial measurement
90.5 (2.1)* 89.9 (0.9)a 89.8 (1.1)
90.3 (1.0) 89.7 (1.1)a 89.6 (1.3)
70.0 (4.2)* 71.4 (2.0)*c 90.5 (0.8)
79.9 (2.7)*A 81.9 (3.0)*AB 90.1 (1.4)
Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions. *Means statistically different from the control (ANOVA/Dunnett’s test, P < 0.05).
Table 2. b* values (standard deviation) of the surface type and staining solution
Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface Air-abraded surface Initial measurement
28.6 (1.5)A 28.3 (0.9)A*d 29.9 (1.3)
30.8 (1.2)B* 31.1 (1.2)A*c 29.0 (1.3)
38.8 (4.1)A* 35.7 (3.8)B*a 29.3 (1.3)
34.6 (1.9)A* 33.0 (1.5)B*b 28.6 (1.6)
Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions. *Means statistically different from the control (ANOVA/Dunnett’s test, P < 0.05).
Table 3. a* values (standard deviation) of the surface type and staining solution.
Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface Air-abraded surface Initial measurement
0.4 (0.5)Ab 0.7 (0.4)Ab* 0.0 (0.6)
0.4 (0.3)Bb* 0.9 (0.3)Ab* )0.2 (0.4)
0.5 (1.0)Ab* )0.3 (0.7)Bb )0.2 (0.5)
5.1 (1.1)Aa* 4.8 (0.4)Aa* )0.2 (0.4)
Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions. *Means statistically different from the control (ANOVA/Dunnett’s test, P < 0.05).
Table 4. Total color variation (DE) values (standard deviation) of the surface type and staining solution Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface 2.0 (0.6) 2.1 (0.5) 21.9 (4.5) 12.8 (3.3)A Air-abraded surface 1.9 (0.7)c 2.6 (0.8)c 20.4 (2.9)a 10.9 (1.8)Ab Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions.
the variable L*, only the staining solutions presented statistically-significant differences (P < 0.0001). Irrespective of the surface treatment, the immersion in coffee and red wine resulted in significantly lower luminosity. Specimens immersed in saliva and cola presented similar values. Significant differences between the initial and final ª 2011 Blackwell Publishing Asia Pty Ltd
measurements of L* values were observed (P = 0.04), except for the cola groups and the group with airpowdered specimens immersed in saliva. Specimens with untreated surfaces immersed in saliva presented a higher L* value in comparison with the initial measurement. Groups immersed in red wine and coffee presented significantly lower L* values than the initial measurement (Figure 1; Table 1). The analysis of b* values demonstrated statistically-significant differences between surface treatments (P = 0.04) and staining solutions (P < 0.0001). Air-powdered surfaces demonstrated significantly lower b* values when compared with untreated surfaces, except for the cola group. Specimens immersed in red wine presented the highest b* mean, followed by coffee, cola, and saliva. With the exception of the group with untreated specimens immersed in saliva, all groups presented b* values that differed significantly from the initial measurement. 203
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Only air-powdered specimens immersed in saliva had b* values statistically lower than those of the initial measurement; the other groups had significantly higher values in comparison with the initial reading (Table 2). A statistically-significant interaction between the main factors, surface treatment and staining solution, was noted for a* values (P = 0.006), indicating that their effects could not be evaluated separately. Specimens immersed in coffee presented significantly higher means in both untreated and air-powdered surfaces. The other staining solutions resulted in similar values. Only specimens immersed in cola and red wine presented significant differences between untreated and air-powdered surfaces. with the exception of specimens with untreated surfaces immersed in saliva and specimens with air-powdered surfaces immersed in red wine, all groups presented significantly higher a* values when compared with those of the initial measurement (Table 3). 100 90 80
L* values
70 60 50 40 30 20 10 0
Saliva
Cola Red wine Staining solution
Coffee
Figure 1. L* values (mean and standard deviation) of the surface type (untreated and air abraded) and staining solution (saliva, cola, and red wine). , Untreated; , air-abraded; , initial measurement.
30 25
ΔE values
20 15 10 5 0
Saliva
Cola Red wine Staining solution
Coffee
Figure 2. Total color variation (DE) values (mean and standard deviation) of the surface type (untreated and air abraded) and staining solution (saliva, cola, and red wine). , Untreated; , air-abraded.
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The DE values only demonstrated statistically-significant differences between the staining solutions (P < 0.0001). Specimens immersed in red wine presented the highest mean, followed by coffee, cola, and saliva (Figure 2; Table 4). Discussion Color determination is very important in restorative dentistry, since esthetic restorations are a common procedure. Color analysis can be divided into two categories: visual and instrumental. The perception of color through visual analysis is subjective and psychological, thus it can broadly vary among different observers. For this reason, the use of specific instruments has been suggested to eliminate the subjectivity of visual color interpretation.8 Spectrophotometers and colorimeters are instruments to measure differences in the color of dental materials, and both have been shown to be very effective.8 In the present study, the CIELab system was chosen because it is capable of capturing tiny differences in color, as demonstrated by the results of previous studies.5,11,14 Some authors have stated that the extrinsic factors for the discoloration of tooth and restorative materials include the adsorption and absorption of pigments from exogenous sources, especially from diet.5–14 In the present study, the effect of highly-pigmented solutions (cola, red wine, and coffee) on the color parameters of resin composite specimens was investigated in two situations, using surfaces that were untreated after polishing procedures or air abraded with sodium bicarbonate particles. Each group also served as its own control, because color evaluations were performed before and after surface treatments and immersion in the solutions. Esthetic restorative materials, such as resin composite, should be able to maintain their luminosity and other color parameters when placed in the oral environment. According to the results of the present study, immersion in red wine and coffee significantly reduced luminosity and increased the DE and b* values (yellowish appearance) of the resin composite specimens, regardless of the surface treatment. In most experimental situations, the effect of red wine was highly pronounced in comparison with that of coffee. However, only coffee immersion was able to increase the a* parameter, indicating a trend to red pigmentation. Comparisons between the effects of red wine and coffee in color alterations vary considerably in the literature. Studies have stated that red wine causes higher DE in comparison with sports beverages, yogurt, coffee, cola, and fruit juices, which seems to be in agreement with most of the findings in the present study.6,7,18 Other authors reported that red wine and coffee produce similar DE values,19 and another study described a greater ª 2011 Blackwell Publishing Asia Pty Ltd
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Color changes of air-abraded composites
change in color variation caused by coffee compared to red wine.5 The staining capacity of red wine can be related to its greater alcohol content, capability of damaging the resin matrix,5,18,19 and also to its acidic pH that can increase the water sorption and solubility by the resin composite.5 The adsorption of some red wine components onto a pellicle-like protein layer formed was studied in vitro.20 Those authors observed that a highly-cohesive layer is formed after exposure to red wine, in contrast to other staining substances. This can be explained by the fact that red wine contains pigments referred to as anthocyanins, which originate from the outer few layers of grape skin. These pigments are complex polyphenolic materials that can be monomeric or polymeric in structure and form complexes with some oral proteins, causing tongue and tooth discoloration.20 The total DE values lower than 1 are not detected by the human eye. Values higher than 1 and lower than 3.3 can be detected by clinicians, but are clinically acceptable. Only values higher than 3.3 indicate color changes that can be visibly detected.6–8,11,12,19,21 In the present study, the composite resin specimens exposed to red wine presented values that significantly exceeded clinical perceptibility and acceptability (DE ‡ 20.4), which could be easily confirmed by the naked eyes. Also, specimens immersed in coffee showed a clinical significant DE, with DE means that ranged from 10.9 to 12.8. Irrespective of the surface treatment, groups immersed in artificial saliva and cola presented DE values that can be considered clinically acceptable (DE £ 2.6). These results are in agreement with the findings of some previous studies that demonstrated that coffee, red wine, and tea can promote significant color changes in composites, glass ionomer cements and provisional composite materials.5–7,14 Composite materials with rough or unpolished surfaces can be highly susceptible to staining, biofilm retention, gingival irritation and caries recurrence.19,21–23 During clinical prophylaxis procedures, the air-powder abrasion, using sodium bicarbonate, can remove the resin composite matrix, exposing filler particles.1 Moreover, air-powder abrasion with sodium bicarbonate particles was used as a surface treatment for the composite repair procedure.4 Scanning electron microscopy demonstrated increased roughness of air-powdered surfaces when compared with untreated surfaces, and also detected the presence of some
References 1 Johnson WW, Barnes CM, Covey DA, Walker MP, Ross JA. The effects of a commercial aluminum
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composite surfaces impregnated with powder remnants.4 In the present study, air-abraded surfaces presented significantly lower b* values, regardless of the staining solution. In addition, air-abraded specimens immersed in red wine resulted in lower a* values in comparison with untreated surfaces. To our knowledge, there is no similar finding in the literature, linking surface roughness of composite resins and staining with the isolated parameters of the CIE L* a* b* system. A possible explanation for the decrease in b* and a* values in some of the air-abraded groups might be the presence of powder remnants on composite surfaces. Although specimens were washed and stored in distilled water after the surface treatment, the presence of some sodium bicarbonate particles could have precluded pigment deposition. Another possible explanation is that the powder remaining on the resin surface can alter its color parameters. However, changes in isolated color parameters (b* and a*) noted in the air-abraded specimens did not affect the L* values and the final DE. This finding might be related to the lower abrasiveness of air powdering with sodium bicarbonate particles compared with other surface treatments, such as rough diamond burs and airborne aluminum oxide particle abrasion.3,4 The null hypothesis of this study was rejected, since the results strongly indicated that red wine and coffee can promote color changes on resin composite specimens, and air-powder abrasion resulted in alterations of b* and a* parameters, although it did not affect L* values and the total DE. Within the limitations of this laboratory study, it could be concluded that red wine and coffee can modify the color parameters of the resin composite tested. It was also demonstrated that composite surfaces air powdered with sodium bicarbonate might present some color changes. As both parameters evaluated affect the esthetic result of direct restorations, not only should patients be warned about the negative outcome of frequently ingesting colored beverages, but clinicians should also be aware of the possible effects of dental prophylaxis on restorative materials. Acknowledgments The authors thank 3M ESPE for material support used for this investigation.
airpolishing powder on dental restorative materials. J Prosthodont 2004; 13: 166–72. 2 Rosin C, Arana-Chavez VE, Netto NG, Luz MA. Effects of cleaning
agents on bond strength to dentin. Braz Oral Res 2005; 19: 127–33. 3 Salami D, Luz MA. Effect of prophylactic treatments on the superficial roughness of dental tissues and of two
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4
5
6
7
8
9
esthetic restorative materials. Pesqui Odontol Bras 2003; 17: 63–8. Cavalcanti AN, Lobo MM, Fontes CM, Liporoni P, Mathias P. Microleakage at the composite-repair interface: effect of different surface treatment methods. Oper Dent 2005; 30: 113–7. Bagheri R, Burrow MF, Tyas M. Influence of food-simulating solutions and surface finish on susceptibility to staining of aesthetic restorative materials. J Dent 2005; 33: 389–98. Guler AU, Kurt S, Kulunk T. Effects of various finishing procedures on the staining of provisional restorative materials. J Prosthet Dent 2005; 93: 453–8. Guler AU, Yilmaz F, Kulunk T, Guler E, Kurt S. Effects of different drinks on stainability of resin composite provisional restorative materials. J Prosthet Dent 2005; 94: 118–24. Yannikakis SA, Zissis AJ, Polyzois GL, Caroni C. Color stability of provisional resin restorative materials. J Prosthet Dent 1998; 80: 533–9. Chan KC, Fuller JL, Hormati AA. The ability of foods to stain two composite resins. J Prosthet Dent 1980; 43: 542–5.
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10 Douglas WH, Craig RG. Resistance to extrinsic strains by hydrophobic composite resin systems. J Dent Res 1982; 61: 41–3. 11 Kolbeck C, Rosentritt M, Lang R, Handel G. Discoloration of facing and restorative composites by UVirradiation and staining food. Dent Mater 2006; 22: 63–8. 12 Lee YK, Lu H, Oguri M, Powers JM. Changes in color and staining of dental composite resins after wear simulation. J Biomed Mater Res B Appl Biomater 2007; 82: 313–9. 13 Luce MS, Campbell CE. Stain potential of four microfilled composites. J Prosthet Dent 1988; 60: 151–4. 14 Yazici AR, Celik C, Dayangac B, Ozgunaltay G. The effect of curing units and staining solutions on the color stability of resin composites. Oper Dent 2007; 32: 616–22. 15 De March P, Berthod P, Haux E, Greset V. Corrosion of some selected ceramic alloys used in fixed partial dentures and their postsolder joints in a synthetic neutral saliva. Eur J Oral Sci 2009; 117: 76–85. 16 Lin MC, Lin SC, Lee TH, Huang HH. Surface analysis and corrosion resistance of different stainless steel orthodontic brackets in artificial saliva. Angle Orthod 2006; 76: 322–9.
17 Popa MV, Vasilescu E, Drob P, Vasilescu C, Demetrescu I, Ionita D. Long-term assessment of the implant titanium material – artificial saliva interface. J Mater Sci Mater Med 2008; 19: 1–9. 18 Omata Y, Uno S, Nakaoki Y et al. Staining of hybrid composites with coffee, oolong tea, or red wine. Dent Mater J 2006; 25: 125–31. 19 Villalta P, Lu H, Okte Z, GarciaGodoy F, Powers JM. Effects of staining and bleaching on color change of dental composite resins. J Prosthet Dent 2006; 95: 137–42. 20 Joiner A. Tooth colour: a review of the literature. J Dent 2004; 32(Suppl. 1): 3–12. 21 Turkun LS, Turkun M. Effect of bleaching and repolishing procedures on coffee and tea stain removal from three anterior composite veneering materials. J Esthet Restor Dent 2004; 16: 290–301. 22 Ozgunaltay G, Yazici AR, Gorucu J. Effect of finishing and polishing procedures on the surface roughness of new tooth-coloured restoratives. J Oral Rehabil 2003; 30: 218–24. 23 Sarac D, Sarac YS, Kulunk S, Ural C, Kulunk T. The effect of polishing techniques on the surface roughness and color change of composite resins. J Prosthet Dent 2006; 96: 33–40.
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ORIGINAL ARTICLE Conservative Dentistry
Changes on the color parameters of air-abraded resin composite exposed to different colored beverages Livia Aguilera Gaglianone1, Joana Dourado Martins2, Thaı´s Re´gis Aranha Rossi2, Letı´cia Oliveira Saraiva2, Andrea No´brega Cavalcanti3 & Paula Mathias2 1 Department of Restorative Dentistry, Piracicaba Dental School, University of Campinas, Piracicaba, Sa˜o Paulo, Brazil 2 Department of Clinical Dentistry, Federal University of Bahia, Salvador, Bahia, Brazil 3 Department of Oral Rehabilitation, School of Medicine and Public Health of Bahia, Salvador, Bahia, Brazil
Keywords air abrasion, beverage, composite resin, sodium bicarbonate, staining. Correspondence Dr Paula Mathias, School of Dentistry, Federal University of Bahia, Avenida Arau´jo Pinho, 62, Canela, CEP 40.110-060 Salvador/Bahia, Brazil. Tel: +55-71-3336-5776 Fax: +55-71-3336-5776 Email: [email protected] Received 17 May 2010; accepted 16 August 2010. doi: 10.1111/j.2041-1626.2011.00063.x
Abstract Aim: To evaluate the effect of prophylaxis using sodium bicarbonate and colored beverages on the color parameters of a resin composite. Methods: Eighty specimens (Z350–3M ESPE) were randomly allocated into eight groups (n = 10), according to the combination of staining solution (artificial saliva, cola, red wine, or coffee) and air-powder abrasion with sodium bicarbonate (either performed or not performed). Specimens were immersed in the staining solution for 48 h (two 24-h cycles). Color evaluation was based on the CIELab system. Two measurements were carried out using a spectrophotometer (Commission Internationale de L’Eclairage L* a* b* system) before and after the immersion period. Final measurement data were analyzed by two-way anova/Tukey’s test, and comparisons were made between initial and final measurements by anova/Dunnett’s test, with a 5% significance level. Results: Most comparisons between initial and final measurements were statistically significant. Red wine and coffee significantly affected the color parameters (L*, b*, and DE). However, only coffee significantly increased a* values. When compared with untreated surfaces, air-powder abrasion resulted in alterations of b* and a* parameters, but did not affect L* and DE. Conclusions: Both colored beverage solutions and air-powder abrasion can affect the color of composite resin restorations.
Introduction Professional cleaning or oral prophylaxis is commonly used in dentistry to provide adequate tooth cleaning and to remove dental biofilm and extrinsic stains. Agents for prophylaxis include pumice paste, abrasive dentifrices, air-powder abrasion with sodium bicarbonate, and air abrasion with aluminum oxide particles.1–3 Although a previous study2 showed that sodium bicarbonate particles are less abrasive than the other agents, some studies have demonstrated that air-powder procedures provide significant superficial alterations on composite restorations, like losing polishing because of resin matrix wear.1,3,4 Therefore, air-powder abrasion with ª 2011 Blackwell Publishing Asia Pty Ltd
sodium bicarbonate might act not only by removing stains, but also increasing the surface roughness of restorative materials. The increase in surface roughness of restorative materials has been associated with greater discoloration, mainly caused by the adsorption of dark pigments by rough surfaces.3,5–8 In resin composites, discoloration occurs after the absorption and adsorption of extrinsic pigments from a patient’s diet, such as those found in colored beverages, such as coffee, tea, red wine, cola, and some juices.5–14 Since air-powder abrasion with sodium bicarbonate might increase surface roughness in different restorative materials, it might potentially increase the stainability of esthetic resin composite restorations exposed to colored 201
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substances. Therefore, the aim of the present study was to evaluate the effect of colored beverages (cola, red wine, and coffee) and of air abrasion with sodium bicarbonate particles on the color parameters of composite resin specimens. The null hypothesis was that staining solutions allied to air abrasion do not increase pigmentation of the composite resin. Methods Eighty specimens were made from a nano-filled resin composite (Filtek Z350; 3M ESPE, St Paul, MN, USA; color A1). A Teflon mold with a central orifice, 6 mm in diameter, and with 2 mm thickness, was filled with a single increment of the composite. A Mylar strip was placed over the mold, and the specimens were light cured for 20 s with a LED unit (LED Ultrablue DMC; DMC Equipamentos LTDA, Sa˜o Paulo, Brazil) emitting 600 mW/cm2 light intensity. The tip of the light-curing unit was placed in contact with the Mylar strip during light activation. The specimens were polished with fine and ultra-fine aluminum oxide abrasive disks (Sof-Lex Pop-On; 3M ESPE, USA). Half of the composite resin specimens were air abraded using sodium bicarbonate particles (Profi II; Dabi Atlante, Sa˜o Paulo, Brazil), with 202.65-kPa pressure for 10 s at a 10 mm distance. Afterwards, all specimens were washed, stored in distilled water for 24 h, and allocated into eight groups (G1–G8) according to the surface treatment (control and air-abraded specimens) and staining solution (n = 10). In the first group (G1), the untreated surface was immersed in neutral artificial saliva (pH = 7); in the second group (G2), the untreated surface was immersed in cola (Coca Cola, Bahia, Brazil) (pH = 2.5); in the third group (G3), the untreated surface was immersed in red wine (Santa Helena, Vila Santa Helena SA, Molina, Chile) (pH = 3.7/13% ethanol); in the fourth group (G4), the untreated surface was immersed in coffee (Nescafe´ Classic, Nestle´ Brazil, Bahia, Brazil) (pH = 5.2) that was prepared according to the manufacturer’s recommendation (80 g coffee/1 L water); in the fifth group (G5), the air-abraded surface was immersed in neutral artificial saliva; in the sixth group (G6), the air-abraded surface was immersed in cola; in the seventh group (G7), the air-abraded surface was immersed in red wine; in the eighth group (G8), the air-abraded surface was immersed in coffee. The composition of the artificial saliva used in G1 and G5 was 2.2 g/L gastric mucin, 0.381 g/L sodium chloride, 0.231 g/L calcium chloride, 0.738 g/L potassium phosphate, 1.114 g/L potassium chloride, 1.5 g/L bicarbonate of sodium, and 0.3 g/L potassium sulphocyanide.15–17 Specimens from each group were individually stored in 5 mL of its respective solution for 48 h at 37C. After the first 24 h period, specimens were washed in distilled 202
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water for 10 s and then returned to the colored solution. Color measurements were performed before (baseline) and after immersion in the respective solutions. Color measurements were based on the Commission Internationale de l’Eclairage (CIE) L* a* b* system using a portable spectrophotometer (Easyshade Vita; VITA System 3DMaster, Brea, CA, USA). The spectrophotometer was calibrated before each color analysis session, in accordance with the manufacturer’s recommendation. To perform the color readings, each specimen was placed inside the central orifice of the white Teflon matrix. A mortise device was placed over the white, opaque Teflon, which was positioned over the specimens to standardize the contact of the tip from the spectrophotometer, with the surfaces of the specimens’ at an angle of 90. The distal end of the light guide from the hand-held spectrometer remained in contact with the specimen in a fixed position, controlling the influence of the external light and preventing the dissipation of the light. To perform the color analysis, the CIE L* a* b* color space system was used in this study. This international colorimetric system consists of three parameters: L*, a*, and b*, in which L* refers to lightness, and a* and b* represent a color variation between green–red and blue– yellow, respectively. Each color measurement was performed three times, and the mean values of L*, a*, and b* were calculated. The total color variation (DE) between the initial and final colors was calculated according to the following formula: DE = ([DL]2 + [Da]2 + [Db]2)½, where DL = L1 ) L0 (final reading ) initial reading), Da = a1 ) a0 (final reading ) initial reading), and Db = b1 ) b0 (final reading ) initial reading). The L*, b*, and a* values observed in the final measurement, and the DE values were analyzed with two-way anova, with the main factors being surface treatment (air abraded or not air abraded) and staining solution (artificial saliva, cola, red wine, and coffee). All possible interactions were included in the experimental model. Multiple pairwise comparisons were made with Tukey’s post hoc test. In order to meet the requirements of anova, b* values were transformed to inverse values, and a* values were converted to square root. anova/Dunnett’s test was used to compare the L*, b*, and a* values observed in the initial measurement with those found after immersion in the respective solutions, both in untreated and air-powdered surfaces. Analyses were performed using the sas 9.1 statistical package (SAS Institute, Cary, NC, USA), with a significance level of 0.05. Results Tables 1–4 present the mean values and standard deviations of the variables L*, b*, a*, and DE, respectively. For ª 2011 Blackwell Publishing Asia Pty Ltd
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Table 1. L* values (standard deviation) of the surface type and staining solution
Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface Air-abraded surface Initial measurement
90.5 (2.1)* 89.9 (0.9)a 89.8 (1.1)
90.3 (1.0) 89.7 (1.1)a 89.6 (1.3)
70.0 (4.2)* 71.4 (2.0)*c 90.5 (0.8)
79.9 (2.7)*A 81.9 (3.0)*AB 90.1 (1.4)
Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions. *Means statistically different from the control (ANOVA/Dunnett’s test, P < 0.05).
Table 2. b* values (standard deviation) of the surface type and staining solution
Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface Air-abraded surface Initial measurement
28.6 (1.5)A 28.3 (0.9)A*d 29.9 (1.3)
30.8 (1.2)B* 31.1 (1.2)A*c 29.0 (1.3)
38.8 (4.1)A* 35.7 (3.8)B*a 29.3 (1.3)
34.6 (1.9)A* 33.0 (1.5)B*b 28.6 (1.6)
Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions. *Means statistically different from the control (ANOVA/Dunnett’s test, P < 0.05).
Table 3. a* values (standard deviation) of the surface type and staining solution.
Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface Air-abraded surface Initial measurement
0.4 (0.5)Ab 0.7 (0.4)Ab* 0.0 (0.6)
0.4 (0.3)Bb* 0.9 (0.3)Ab* )0.2 (0.4)
0.5 (1.0)Ab* )0.3 (0.7)Bb )0.2 (0.5)
5.1 (1.1)Aa* 4.8 (0.4)Aa* )0.2 (0.4)
Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions. *Means statistically different from the control (ANOVA/Dunnett’s test, P < 0.05).
Table 4. Total color variation (DE) values (standard deviation) of the surface type and staining solution Staining solution Surface
Saliva
Cola
Red wine
Coffee
Untreated surface 2.0 (0.6) 2.1 (0.5) 21.9 (4.5) 12.8 (3.3)A Air-abraded surface 1.9 (0.7)c 2.6 (0.8)c 20.4 (2.9)a 10.9 (1.8)Ab Different letters indicate statistically-significant differences (two-way ANOVA/Tukey’s test, P < 0.05). Upper case letters compare surface treatments, whereas lower case letters compare staining solutions.
the variable L*, only the staining solutions presented statistically-significant differences (P < 0.0001). Irrespective of the surface treatment, the immersion in coffee and red wine resulted in significantly lower luminosity. Specimens immersed in saliva and cola presented similar values. Significant differences between the initial and final ª 2011 Blackwell Publishing Asia Pty Ltd
measurements of L* values were observed (P = 0.04), except for the cola groups and the group with airpowdered specimens immersed in saliva. Specimens with untreated surfaces immersed in saliva presented a higher L* value in comparison with the initial measurement. Groups immersed in red wine and coffee presented significantly lower L* values than the initial measurement (Figure 1; Table 1). The analysis of b* values demonstrated statistically-significant differences between surface treatments (P = 0.04) and staining solutions (P < 0.0001). Air-powdered surfaces demonstrated significantly lower b* values when compared with untreated surfaces, except for the cola group. Specimens immersed in red wine presented the highest b* mean, followed by coffee, cola, and saliva. With the exception of the group with untreated specimens immersed in saliva, all groups presented b* values that differed significantly from the initial measurement. 203
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Only air-powdered specimens immersed in saliva had b* values statistically lower than those of the initial measurement; the other groups had significantly higher values in comparison with the initial reading (Table 2). A statistically-significant interaction between the main factors, surface treatment and staining solution, was noted for a* values (P = 0.006), indicating that their effects could not be evaluated separately. Specimens immersed in coffee presented significantly higher means in both untreated and air-powdered surfaces. The other staining solutions resulted in similar values. Only specimens immersed in cola and red wine presented significant differences between untreated and air-powdered surfaces. with the exception of specimens with untreated surfaces immersed in saliva and specimens with air-powdered surfaces immersed in red wine, all groups presented significantly higher a* values when compared with those of the initial measurement (Table 3). 100 90 80
L* values
70 60 50 40 30 20 10 0
Saliva
Cola Red wine Staining solution
Coffee
Figure 1. L* values (mean and standard deviation) of the surface type (untreated and air abraded) and staining solution (saliva, cola, and red wine). , Untreated; , air-abraded; , initial measurement.
30 25
ΔE values
20 15 10 5 0
Saliva
Cola Red wine Staining solution
Coffee
Figure 2. Total color variation (DE) values (mean and standard deviation) of the surface type (untreated and air abraded) and staining solution (saliva, cola, and red wine). , Untreated; , air-abraded.
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The DE values only demonstrated statistically-significant differences between the staining solutions (P < 0.0001). Specimens immersed in red wine presented the highest mean, followed by coffee, cola, and saliva (Figure 2; Table 4). Discussion Color determination is very important in restorative dentistry, since esthetic restorations are a common procedure. Color analysis can be divided into two categories: visual and instrumental. The perception of color through visual analysis is subjective and psychological, thus it can broadly vary among different observers. For this reason, the use of specific instruments has been suggested to eliminate the subjectivity of visual color interpretation.8 Spectrophotometers and colorimeters are instruments to measure differences in the color of dental materials, and both have been shown to be very effective.8 In the present study, the CIELab system was chosen because it is capable of capturing tiny differences in color, as demonstrated by the results of previous studies.5,11,14 Some authors have stated that the extrinsic factors for the discoloration of tooth and restorative materials include the adsorption and absorption of pigments from exogenous sources, especially from diet.5–14 In the present study, the effect of highly-pigmented solutions (cola, red wine, and coffee) on the color parameters of resin composite specimens was investigated in two situations, using surfaces that were untreated after polishing procedures or air abraded with sodium bicarbonate particles. Each group also served as its own control, because color evaluations were performed before and after surface treatments and immersion in the solutions. Esthetic restorative materials, such as resin composite, should be able to maintain their luminosity and other color parameters when placed in the oral environment. According to the results of the present study, immersion in red wine and coffee significantly reduced luminosity and increased the DE and b* values (yellowish appearance) of the resin composite specimens, regardless of the surface treatment. In most experimental situations, the effect of red wine was highly pronounced in comparison with that of coffee. However, only coffee immersion was able to increase the a* parameter, indicating a trend to red pigmentation. Comparisons between the effects of red wine and coffee in color alterations vary considerably in the literature. Studies have stated that red wine causes higher DE in comparison with sports beverages, yogurt, coffee, cola, and fruit juices, which seems to be in agreement with most of the findings in the present study.6,7,18 Other authors reported that red wine and coffee produce similar DE values,19 and another study described a greater ª 2011 Blackwell Publishing Asia Pty Ltd
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Color changes of air-abraded composites
change in color variation caused by coffee compared to red wine.5 The staining capacity of red wine can be related to its greater alcohol content, capability of damaging the resin matrix,5,18,19 and also to its acidic pH that can increase the water sorption and solubility by the resin composite.5 The adsorption of some red wine components onto a pellicle-like protein layer formed was studied in vitro.20 Those authors observed that a highly-cohesive layer is formed after exposure to red wine, in contrast to other staining substances. This can be explained by the fact that red wine contains pigments referred to as anthocyanins, which originate from the outer few layers of grape skin. These pigments are complex polyphenolic materials that can be monomeric or polymeric in structure and form complexes with some oral proteins, causing tongue and tooth discoloration.20 The total DE values lower than 1 are not detected by the human eye. Values higher than 1 and lower than 3.3 can be detected by clinicians, but are clinically acceptable. Only values higher than 3.3 indicate color changes that can be visibly detected.6–8,11,12,19,21 In the present study, the composite resin specimens exposed to red wine presented values that significantly exceeded clinical perceptibility and acceptability (DE ‡ 20.4), which could be easily confirmed by the naked eyes. Also, specimens immersed in coffee showed a clinical significant DE, with DE means that ranged from 10.9 to 12.8. Irrespective of the surface treatment, groups immersed in artificial saliva and cola presented DE values that can be considered clinically acceptable (DE £ 2.6). These results are in agreement with the findings of some previous studies that demonstrated that coffee, red wine, and tea can promote significant color changes in composites, glass ionomer cements and provisional composite materials.5–7,14 Composite materials with rough or unpolished surfaces can be highly susceptible to staining, biofilm retention, gingival irritation and caries recurrence.19,21–23 During clinical prophylaxis procedures, the air-powder abrasion, using sodium bicarbonate, can remove the resin composite matrix, exposing filler particles.1 Moreover, air-powder abrasion with sodium bicarbonate particles was used as a surface treatment for the composite repair procedure.4 Scanning electron microscopy demonstrated increased roughness of air-powdered surfaces when compared with untreated surfaces, and also detected the presence of some
References 1 Johnson WW, Barnes CM, Covey DA, Walker MP, Ross JA. The effects of a commercial aluminum
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composite surfaces impregnated with powder remnants.4 In the present study, air-abraded surfaces presented significantly lower b* values, regardless of the staining solution. In addition, air-abraded specimens immersed in red wine resulted in lower a* values in comparison with untreated surfaces. To our knowledge, there is no similar finding in the literature, linking surface roughness of composite resins and staining with the isolated parameters of the CIE L* a* b* system. A possible explanation for the decrease in b* and a* values in some of the air-abraded groups might be the presence of powder remnants on composite surfaces. Although specimens were washed and stored in distilled water after the surface treatment, the presence of some sodium bicarbonate particles could have precluded pigment deposition. Another possible explanation is that the powder remaining on the resin surface can alter its color parameters. However, changes in isolated color parameters (b* and a*) noted in the air-abraded specimens did not affect the L* values and the final DE. This finding might be related to the lower abrasiveness of air powdering with sodium bicarbonate particles compared with other surface treatments, such as rough diamond burs and airborne aluminum oxide particle abrasion.3,4 The null hypothesis of this study was rejected, since the results strongly indicated that red wine and coffee can promote color changes on resin composite specimens, and air-powder abrasion resulted in alterations of b* and a* parameters, although it did not affect L* values and the total DE. Within the limitations of this laboratory study, it could be concluded that red wine and coffee can modify the color parameters of the resin composite tested. It was also demonstrated that composite surfaces air powdered with sodium bicarbonate might present some color changes. As both parameters evaluated affect the esthetic result of direct restorations, not only should patients be warned about the negative outcome of frequently ingesting colored beverages, but clinicians should also be aware of the possible effects of dental prophylaxis on restorative materials. Acknowledgments The authors thank 3M ESPE for material support used for this investigation.
airpolishing powder on dental restorative materials. J Prosthodont 2004; 13: 166–72. 2 Rosin C, Arana-Chavez VE, Netto NG, Luz MA. Effects of cleaning
agents on bond strength to dentin. Braz Oral Res 2005; 19: 127–33. 3 Salami D, Luz MA. Effect of prophylactic treatments on the superficial roughness of dental tissues and of two
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4
5
6
7
8
9
esthetic restorative materials. Pesqui Odontol Bras 2003; 17: 63–8. Cavalcanti AN, Lobo MM, Fontes CM, Liporoni P, Mathias P. Microleakage at the composite-repair interface: effect of different surface treatment methods. Oper Dent 2005; 30: 113–7. Bagheri R, Burrow MF, Tyas M. Influence of food-simulating solutions and surface finish on susceptibility to staining of aesthetic restorative materials. J Dent 2005; 33: 389–98. Guler AU, Kurt S, Kulunk T. Effects of various finishing procedures on the staining of provisional restorative materials. J Prosthet Dent 2005; 93: 453–8. Guler AU, Yilmaz F, Kulunk T, Guler E, Kurt S. Effects of different drinks on stainability of resin composite provisional restorative materials. J Prosthet Dent 2005; 94: 118–24. Yannikakis SA, Zissis AJ, Polyzois GL, Caroni C. Color stability of provisional resin restorative materials. J Prosthet Dent 1998; 80: 533–9. Chan KC, Fuller JL, Hormati AA. The ability of foods to stain two composite resins. J Prosthet Dent 1980; 43: 542–5.
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10 Douglas WH, Craig RG. Resistance to extrinsic strains by hydrophobic composite resin systems. J Dent Res 1982; 61: 41–3. 11 Kolbeck C, Rosentritt M, Lang R, Handel G. Discoloration of facing and restorative composites by UVirradiation and staining food. Dent Mater 2006; 22: 63–8. 12 Lee YK, Lu H, Oguri M, Powers JM. Changes in color and staining of dental composite resins after wear simulation. J Biomed Mater Res B Appl Biomater 2007; 82: 313–9. 13 Luce MS, Campbell CE. Stain potential of four microfilled composites. J Prosthet Dent 1988; 60: 151–4. 14 Yazici AR, Celik C, Dayangac B, Ozgunaltay G. The effect of curing units and staining solutions on the color stability of resin composites. Oper Dent 2007; 32: 616–22. 15 De March P, Berthod P, Haux E, Greset V. Corrosion of some selected ceramic alloys used in fixed partial dentures and their postsolder joints in a synthetic neutral saliva. Eur J Oral Sci 2009; 117: 76–85. 16 Lin MC, Lin SC, Lee TH, Huang HH. Surface analysis and corrosion resistance of different stainless steel orthodontic brackets in artificial saliva. Angle Orthod 2006; 76: 322–9.
17 Popa MV, Vasilescu E, Drob P, Vasilescu C, Demetrescu I, Ionita D. Long-term assessment of the implant titanium material – artificial saliva interface. J Mater Sci Mater Med 2008; 19: 1–9. 18 Omata Y, Uno S, Nakaoki Y et al. Staining of hybrid composites with coffee, oolong tea, or red wine. Dent Mater J 2006; 25: 125–31. 19 Villalta P, Lu H, Okte Z, GarciaGodoy F, Powers JM. Effects of staining and bleaching on color change of dental composite resins. J Prosthet Dent 2006; 95: 137–42. 20 Joiner A. Tooth colour: a review of the literature. J Dent 2004; 32(Suppl. 1): 3–12. 21 Turkun LS, Turkun M. Effect of bleaching and repolishing procedures on coffee and tea stain removal from three anterior composite veneering materials. J Esthet Restor Dent 2004; 16: 290–301. 22 Ozgunaltay G, Yazici AR, Gorucu J. Effect of finishing and polishing procedures on the surface roughness of new tooth-coloured restoratives. J Oral Rehabil 2003; 30: 218–24. 23 Sarac D, Sarac YS, Kulunk S, Ural C, Kulunk T. The effect of polishing techniques on the surface roughness and color change of composite resins. J Prosthet Dent 2006; 96: 33–40.
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