|Year : 2014 | Volume
| Issue : 1 | Page : 20-26
Caries detector dyes: Do they stain only the caries?
Osman Tolga Harorli1, Çagatay Barutcigil1, Nilgün Akgül2, Yusuf Ziya Bayindir2
1 Department of Restorative Dentistry, Faculty of Dentistry, Akdeniz University, 07058 Antalya, Turkey
2 Department of Restorative Dentistry, Faculty of Dentistry, Ataturk University, 25240 Erzurum, Turkey
|Date of Web Publication||20-Mar-2014|
Osman Tolga Harorli
Department of Restorative Dentistry, Faculty of Dentistry, Akdeniz University, 07058 Antalya
Source of Support: None, Conflict of Interest: None
Objective: Caries detector (CD) dyes aid in caries diagnosis by staining the organic matrix of less mineralized infected dentine. However, detector dyes are not specific to bacteria and can discolor surrounding healthy tissues as dentino-enamel junction or the circumpulpal dentine. Possible discoloring effect of CD dye over restorative materials have not been evaluated until date. The aim of this study was to investigate the staining effects of four commercial CD dyes Caries Detector (CAD), Caries Marker (CAM),SEEK (SEE), Sable Seek (SES) on a variety of tooth colored restorative materials; Filtek Valux Plus (VLX), Filtek Z250 (Z25), Filtek Silorane (SIL) Fuji IX (FUJ). Materials and Methods: A total of 40 disc-shaped specimens were prepared from each restorative material. After 24 h distilled water storage, baseline color was measured according to the Commission International de l'Eclairage L* a* b* system by using a reflection spectrophotometer. Each CD dye was applied to 10 samples of each composite group for 10 s and applications were repeated for 2 times. Before the final color measurements, all samples was rinsed and dried. Color differences (ΔE) were measured and analyzed the data with two-way analysis of variance and Tukey honest significant difference post-hoc tests. Results: Independent of dyes, perceptible color changes were observed in glass ionomer restorative material (FUJ) (ΔE ab * > 3.3). CAD, CAM and SES caused staining on highly triethylene glycol dimethacrylate monomer containing composite resin (VLX). Silorane based restorative material (SIL) and micro hybrid resin composite (Z25) were more resistant to discoloration then VLX and FUJ (P < 0.05). Conclusion: CD dyes may cause discolorations in some restorative materials and should be used with maximum care.
Keywords: Caries detection, dental caries, discoloration, esthetic restorative materials
|How to cite this article:|
Harorli OT, Barutcigil Ç, Akgül N, Bayindir YZ. Caries detector dyes: Do they stain only the caries?. J Res Dent 2014;2:20-6
| Introduction|| |
The color alteration of esthetic restorative materials is one of the most common reasons for replacement of restorations.  Correct shade selection and proper clinical procedures may be invalidated as a result of discoloration. , Various extrinsic and intrinsic factors could influence the color stability.  Main intrinsic factors; composition of resin matrix, filler, loading and particle size distribution, type of photo-initiator or inhibitor and percentage of remaining C = C bonds are to be considered. On the other hand, intensity and duration of polymerization, exposure to environmental factors, including ambient and ultraviolet irradiation, heat, water and food colorants represent the main extrinsic factors. ,,,,,
In order to test the coloring effect of staining on resin composites, a variety of beverages, such as water, coffee, wine, tea and soft drinks have been used. , The specimens showed a range of discoloration depending on the resin composites themselves and test solutions. 
Carious dentin has been proved to consist of two main layers with different properties. The outer, highly demineralized layer of carious dentin is infected, unremineralizable and have no sensation. The inner layer (the second layer) of carious dentin is intermediately demineralized, remineralizable and sensitive. , In classical caries excavation, the operative tradition is to remove softened dentin in order to eliminate infected tissue and to left carious dentin that is "firm and leathery" where its removal might expose the pulp. However, the term "firm and leathery" is a subjective clinical assessment and may vary from operator to operator. 
Histologic dyes are colored markers that have an affinity to the material to which it is being applied. When the staining substance is spilled out onto the surface of tissue or material, it will be trapped in the fibers, pores, indentations, or other structures. In general stains have very high affinity for this reason it could retain in materials or tissues even after rinsing. Dyes absorb some wavelengths of light more than others, therefore discolorations can be clearly distinguished. 
In 1972, a technique using a basic fuchsin red stain was suggested (and subsequently developed) to aid in the differentiation for the layers of the carious dentin , and today various commercially available caries detector (CAD) dyes with different chemistries are improved in order to aid the dentist in differentiation of softened dentin.
These are non-specific protein dyes that stain the organic matrix of less mineralized dentin, including normal circumpulpal dentin and sound dentin in the area of the amelo-dentinal junction. The use of caries-indicator dyes has also been suggested as an alternative diagnostic aid for occlusal caries.  These dyes are also used to identify caries in difficult to see places, for finding obliterated root-canals and even for finding micro-cracks in fillings and margins. Manufacturers recommend repeating the application until no dentine discoloration occurs. However, during the applications these fluent liquid dyes could spread surrounding or proximal restorations. Until date, there is no scientific data available about the staining effect of these materials over dental materials.
In assessing color differences Commission International de l'Eclairage (CIE) color system is generally used. According to the CIE L * a* b* color system, a particular shade in the color space is defined by three coordinates: L*, a* and b *. The color coordinates of the CIE system are L* (lightness, ranging from black to white), a* (redness, ranging from green to red) and b* (yellowness, ranging from blue to yellow). , This system is used by dental researchers to examine materials with regard to their color. The measure of the color difference between two objects can be described by ΔE ab *. With ΔE ab * values, color differences can be expressed in units that can be related to visual perception and clinical significance. ,
The aim of this study was to investigate the color change of three different composite and one glass ionomer material exposed to four different carious detector dyes. The null hypothesis was that; CADs would not cause color alterations in tested restorative materials.
| Materials and Methods|| |
Materials and manufacturers details, of tested materials are listed in [Table 1]. Four esthetic restorative materials, a hybrid resin composite (Filtek Valux Plus [VLX] [3M Espe, St. Paul, USA]), a microhybrid resin composite (Filtek Z250 [Z25] [3M Espe, St. Paul, USA]), a silorane-based composite (Filtek Silorane [SIL] [3M Espe, St. Paul, USA]) and conventional glass ionomer cement (Fuji IX [FUJ] [GC Corp., Tokyo Japan]) were studied in this study. An A2 shade was chosen in each restorative system.
|Table 1: Details of restorative materials and CAD dyes investigated in this study|
Click here to view
A total of 40 cylindrical specimens of each restorative material were packed into a polytetrafluoroethylene mold (6 mm in diameter and 2 mm in thickness) on a polyethylene terephthalate (Mylar) strip. After filling the mold, another Mylar strip was laid on top of the specimen surface. Then, resin samples were light cured for 20 s with a curing unit (Elipar FreeLight LED II, 3M ESPE Dental Products, St. Paul, MN, USA) as per the directions of the manufacturers. The output of the curing light (light intensity of this unit was 750-800 mW/cm 2 ) was checked with a radiometer (Hilux UltraPlus Curing Units, Benlioglu Dental, Istanbul, Turkey). After polymerization, the edges of all specimens were finished with polishing disks (Sof-Lex; 3M ESPE, St. Paul, MN, USA). Conventional glass ionomer cement was prepared with a capsule mixer (Rotomix, 3M ESPE Dental Products, St. Paul, MN, USA) in accordance with the manufacturer's recommendations in Teflon molds. Then, all specimens were stored in distilled water at 37°C for 24 h.
Four different CD; CAD (Kuraray Co., Ltd., Okayama, Japan), Caries Marker (CAM) (Voco GmbH. Cuxhaven, Germany), Sable Seek (SES) (Ultradent Products Inc., Utah, USA) and Seek (SEE) (Ultradent Products Inc., Utah, USA) were used. Materials and manufacturers details are represented in [Table 1]. Restorative materials samples were divided in four groups (n = 10) and in each group, every restorative material samples were numbered as 1-10.
After, in order of each sample's color was measured and CD was applied. CDs were applied according to the manufacturer's instructions for 10 s with a scrubbing motion, using a brush. After applying CD, sample was rinsed with distilled water during 15 s. For each sample, application of CD was repeated for 2 times. Before the final color measurements, all samples were rinsed and dried.
Color was measured according to the CIE L* a* b* color scale relative to standard illumination D65 against a standard white background (L* = 96.3, a* = −0.9, b* = 3.9) with a reflectance spectrophotometer (ShadePilot, Degudent® , Hanau, Germany) connected to a personal computer using a Degudant Shadepilot™ dijital shade matching software. Illuminating and viewing configurations were CIE d/0 O .
Color change (ΔE ab *) was calculated by the following equation;
ΔE ab *= ([ΔL*] 2 + [Δa*] 2 + [Δb*] 2 )½
The value of ΔE ab * of 3.3 was considered clinically acceptable in the study.
The ΔE ab * values were analyzed for each restorative material. To compare the differences among all the groups, analysis of variance (two-way ANOVA) and Tukey honest significant difference (HSD) post-hoc tests were performed with a specific software (SPSS version 16; SPSS Inc., Chicago IL, USA) (P < 0.05).
| Results|| |
The mean ΔE ab * values of restorative materials after CD applications are presented in [Figure 1]. Furthermore, [Figure 2] shows the color differences of the materials exposed to staining agents. The differences among the restorative materials and the CAD dyes, as determined by the two-way ANOVA and Tukey HSD post-hoc tests, are also given in [Table 2]. Changes in color after staining were ranging from ΔE ab * = 0.62 ± 0.11 (VLX + SEE) to ΔE ab * = 10.40 ± 2.70 (FUJ + SEE). The distribution of L*, a* and b* values are shown in [Figure 3], [Figure 4] and [Figure 5].
|Figure 1: Mean ΔEab* values after dye applications. Error bars represent standard deviations. Plot line points perceptible threshold level (ΔEab* = 3.3)|
Click here to view
|Figure 2: Color changes of tooth color restorative materials after dye application|
Click here to view
|Figure 3: Mean L* values at the beginning and after dye applications. Error bars represent standard deviations|
Click here to view
|Figure 4: Mean a* values at the beginning and after dye applications. Error bars represent standard deviations|
Click here to view
|Figure 5: Mean b* values at the beginning and after dye applications. Error bars represent standard deviations|
Click here to view
The most intense discolorations occurred in glass ionomer based restorative material (FUJ) (P < 0.05) and all ΔE ab * values were over clinically acceptable threshold (ΔE ab * > 3.3). Silorane based restorative material (SIL) and microhybrid resin composite (Z25) did not demonstrate significant color changes in all CD dyes. (P > 0.05) and the ΔE ab * values were under clinically acceptable threshold (ΔE ab * ≤ 3.3). Water soluble propylene based CD dye (SEE) produced the minimal discoloration in all restoratives (P > 0. 05) with the exception of glass ionomer (FUJ).
| Discussion|| |
The null hypothesis was partially rejected; tested CD dyes caused significant color changes in glass ionomer restorative material FUJ. Furthermore after CAM, CAD and SES applications, unacceptable discolorations were detected in hybrid composite VLX (P < 0.05) (ΔE ab * ≤ 3.3). The minimum color differences detected by the human eye range from a ΔEab* value of 0.3 to 0.5. Small differences in color variations are almost imperceptible to the human eye or still be clinically acceptable. However, color differences of this magnitude (ΔE ab * ≤ 3.3) have been characterized as unacceptable in literature. ,,,
Numerous studies have investigated the discolorations caused by beverages ,,, but up to now, there has been no documentary evidence regarding the staining effect of CD dyes. These dyes could spread over restorative materials during their clinical applications. While diagnosing occlusal caries restorative materials in neighborhood might be stained or during the use of a carious detection dye in a composite repair existing restoration could be effected. Furthermore in a proximal cavity, indicator dye could disperse to surrounding restorations.
Resistance of restorative materials to discolorations depends on their structure.  Since glass ionomer cements and composites have different compositions they will not be equally susceptible to staining. The esthetics expectation for glass ionomers is usually low. Glass ionomers can be used in a variety of clinical scenarios especially in pediatric dentistry. They maintain adhesion for long periods and are the material of choice to be placed in the cervical area of the permanent teeth. , According to Bagheri et al. beverages such as coffee, red wine and tea could cause intense discolorations in glass ionomers.  In our study, significant color changes were observed in FUJ after CD dyes application (P < 0.05).
Discoloration of composites may be caused by intrinsic and extrinsic factors. Intrinsic factors involve the discoloration of the resin material itself, such as the alteration of the resin matrix and the interface of matrix and fillers.  Extrinsic discolorations are closely related to adsorption or absorption of stains. The nature of the resin may influence the staining potential.  Due to polar nature of dimethacrylates, all dimethacrylate based composites absorb water and chemicals, such as those found in saliva or food (acids, bases, salts, alcohols, etc.) from oral environment. , In bisphenol A-glycidyl methacrylate/triethylene glycol dimethacrylate (TEGDMA) resin systems partial substitution of TEGDMA with urethane dimethacrylate (UDMA) co-monomer has been shown to reduce water uptake and stain susceptibility. For this reason resin materials incorporating UDMA seemed to be more stain resistant than were resin materials using dimethacrylate as a matrix.  In our study, ΔE ab * values of highly TEGDMA containing (5-10% by wt.) hybrid composite VLX were over perceptible threshold after CAD and CAM applications (ΔE ab * > 3.3). There were no statistical difference between ΔE ab * values of micro-hybrid composite Z25 and silorane based composite SIL. A recent in vitro study reported that silorane based composite SIL is more resistant to wine and coffee staining because of its distinctive monomer content. 
First CD dyes presented in 1970s were based on basic fuchsin - propylene glycol solution. , Due to concern about the potential carcinogenicity of basic fuchsin it was subsequently replaced with a safe and effective alternative; acid red solution. ,, The usual formulation was 1% acid red solution in propylene glycol. 
The efficiency of CD dyes are under discussion because they do not stain only the bacteria and are not specific for infected dentin.  These dyes could stain the organic matrix of less mineralized dentine. In sound teeth, circumpulpal dentine and the enamel - dentine junction could be stained. Alternative dyes such as carbolan green, coomassie blue and lissamine blue were also not successful to specifically stain the infected dentin.
In our study, it is not possible to interpret the results in the view of dyes since the producer firms did not mention the exact formulations. Nevertheless, for the tested composites, CAD SEE, which includes glycol based D and C dyes, did not caused a perceptible color change (ΔE ab * ≤3.3) and was significantly caused less staining when compared with other dyes (P < 0. 05). On the other hand, it caused an intense discoloration in glass ionomer FUJ.
The results of this study demonstrates that inattentive use of CD dyes could cause perceptible color changes in tooth colored restorative materials. However, several factors may influence the in vivo results. Establishing an exact correlation between in vitro and in vivo tests could be misleading, since the oral environment cannot be reproduced in the laboratory. 
| Conclusion|| |
Inattentive use of carious detector dyes could cause perceptible discolorations on some restorative materials. Hence, clinicians should be aware of the staining potential of CD dyes over restorative materials and should give supreme attention to the application process.
Further studies are needed to be develop a specific CD dye, which stains only the carious dentin and would not cause discoloration in restorative materials and sound tooth structures.
| References|| |
|1.||Catelan A, Briso AL, Sundfeld RH, Goiato MC, dos Santos PH. Color stability of sealed composite resin restorative materials after ultraviolet artificial aging and immersion in staining solutions. J Prosthet Dent 2011;105:236-41. |
|2.||Ardu S, Gutemberg D, Krejci I, Feilzer AJ, Di Bella E, Dietschi D. Influence of water sorption on resin composite color and color variation amongst various composite brands with identical shade code: An in vitro evaluation. J Dent 2011;39 Suppl 1:e37-44. |
|3.||Vichi A, Ferrari M, Davidson CL. Color and opacity variations in three different resin-based composite products after water aging. Dent Mater 2004;20:530-4. |
|4.||Aguiar FH, Georgetto MH, Soares GP, Catelan A, Dos Santos PH, Ambrosano GM, et al. Effect of different light-curing modes on degree of conversion, staining susceptibility and stain's retention using different beverages in a nanofilled composite resin. J Esthet Restor Dent 2011;23:106-14. |
|5.||Calheiros FC, Daronch M, Rueggeberg FA, Braga RR. Influence of irradiant energy on degree of conversion, polymerization rate and shrinkage stress in an experimental resin composite system. Dent Mater 2008;24:1164-8. |
|6.||Dietschi D, Campanile G, Holz J, Meyer JM. Comparison of the color stability of ten new-generation composites: An in vitro study. Dent Mater 1994;10:353-62. |
|7.||Hosoya Y. Five-year color changes of light-cured resin composites: Influence of light-curing times. Dent Mater 1999;15:268-74. |
|8.||Ertaº E, Güler AU, Yücel AC, Köprülü H, Güler E. Color stability of resin composites after immersion in different drinks. Dent Mater J 2006;25:371-6. |
|9.||Kolbeck C, Rosentritt M, Lang R, Handel G. Discoloration of facing and restorative composites by UV-irradiation and staining food. Dent Mater 2006;22:63-8. |
|10.||Türkün LS, Türkün 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. |
|11.||Park JK, Kim TH, Ko CC, García-Godoy F, Kim HI, Kwon YH. Effect of staining solutions on discoloration of resin nanocomposites. Am J Dent 2010;23:39-42. |
|12.||Kidd EA. How 'clean' must a cavity be before restoration? Caries Res 2004;38:305-13. |
|13.||Kuboki Y, Liu CF, Fusayama T. Mechanism of differential staining in carious dentin. J Dent Res 1983;62:713-4. |
|14.||Horobin RW. How histological stains work. In: Suvarna SK, Layton C, Bancroft JD, editors. Bancroft's Theory and Practice of Histological Techniques. 7 th ed. London: Churchill Livingstone; 2013. p. 156-71. |
|15.||McComb D. Caries-detector dyes - How accurate and useful are they? J Can Dent Assoc 2000;66:195-8. |
|16.||Westland S. Review of the CIE system of colorimetry and its use in dentistry. J Esthet Restor Dent 2003;15 Suppl 1:S5-12. |
|17.||Barutcigil C, Harorli OT, Yildiz M, Ozcan E, Arslan H, Bayindir F. The color differences of direct esthetic restorative materials after setting and compared with a shade guide. J Am Dent Assoc 2011;142:658-65. |
|18.||Lee YK, Lim BS, Kim CW. Difference in polymerization color changes of dental resin composites by the measuring aperture size. J Biomed Mater Res B Appl Biomater 2003;66:373-8. |
|19.||Francisconi LF, Scaffa PM, de Barros VR, Coutinho M, Francisconi PA. Glass ionomer cements and their role in the restoration of non-carious cervical lesions. J Appl Oral Sci 2009;17:364-9. |
|20.||Heintze SD, Ruffieux C, Rousson V. Clinical performance of cervical restorations - A meta-analysis. Dent Mater 2010;26:993-1000. |
|21.||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. |
|22.||Villalta P, Lu H, Okte Z, Garcia-Godoy F, Powers JM. Effects of staining and bleaching on color change of dental composite resins. J Prosthet Dent 2006;95:137-42. |
|23.||Peutzfeldt A. Resin composites in dentistry: The monomer systems. Eur J Oral Sci 1997;105:97-116. |
|24.||Sideridou ID, Karabela MM. Sorption of water, ethanol or ethanol/water solutions by light-cured dental dimethacrylate resins. Dent Mater 2011;27:1003-10. |
|25.||Barutcigil Ç, Yýldýz M. Intrinsic and extrinsic discoloration of dimethacrylate and silorane based composites. J Dent 2012;40 Suppl 1:e57-63. |
|26.||Sato Y, Fusayama T. Removal of dentin by fuchsin staining. J Dent Res 1976;55:678-83. |
|27.||Fusayama T, Terachima S. Differentiation of two layers of carious dentin by staining. J Dent Res 1972;51:866. |
|28.||Ansari G, Beeley JA, Reid JS, Foye RH. Caries detector dyes - An in vitro assessment of some new compounds. J Oral Rehabil 1999;26:453-8. |
|29.||Bonser GM, Clayson DB, Jull JW. The induction of tumours of the subcutaneous tissues, liver and intestine in the mouse by certain dye-stuffs and their intermediates. Br J Cancer 1956;10:653-67. |
|30.||Samra AP, Pereira SK, Delgado LC, Borges CP. Color stability evaluation of aesthetic restorative materials. Braz Oral Res 2008;22:205-10. |
[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]
[Table 1], [Table 2]