November, 2009
Color Stability of Commonly Used Orthodontic Bonding Resins
Adhesive bonding is important for orthodontics, especially in terms of the fixation of brackets to teeth. This situation involves the joining of solid substrates or adherents by an intervening layer of adhesive agent.
Dr. Rajkumar S. Alle BDS, MDS, DNB and Dr. Rajat Sharma BDS, MDS
ABSTRACT
Adhesive bonding is important for orthodontics, especially in terms of the fixation of brackets to teeth. This situation involves the joining of solid substrates or adherents by an intervening layer of adhesive agent. The surface characteristics are crucial to the success of the bond, as are the inherent properties of the adhesive. Many aspects of the situation are rather general. That is, they are not entirely restricted to the orthodontic context itself.
It is important foremost to have sufficient background of adhesive science to facilitate appreciation for the necessary properties of dental orthodontic adhesives.
This study was aimed at investigating the colour stability of the commonly used orthodontic bonding resins when exposed to light for the equivalent of 30 days, which was deemed adequate since the labial surfaces of crowns are not exposed to ambient light under ordinary conditions. And whether, the change in colour was of any clinical significance.
Classification (On the basis of polymerization initiation mechanism) [1]
- Chemically activated / Auto – cured / Self cured
- Two paste
- One paste
- Visible Light Cure / Photo – Cured
- Dual Cured
- Thermo – cured
TYPES OF ORTHODONTIC ADHESIVES
During the last quarter of the twentieth century there were two competitive categories of non – metallic direct restorative biomaterials. They may be denoted as the Salt matrix and the Resin matrix that originated in the United Kingdom and the United States respectively.
During the 1990,s a major development had been the hybridization of the technology underlying resin composites (RC) and glass ionomer cements (GIC). That is, components from both systems have been combined in various ways with the aim of developing materials that will ideally exhibit characteristics of each parent.
Salt Matrix Adhesive
These may be categorized into three groups:
- RM – GIC (Resin Modified Glass Ionomer’s)
- Compomers
- Ionomer Modified Composites
Resin Matrix Adhesives
The major category of orthodontic resins systems is based upon resin components. The orthodontic adhesive formulations share much in common with that of the restorative resins. They consist of two main components, an organic matrix and a powdered ceramic, such as, barium aluminoborate silica glass. Particles ranging in the size of 0.004 to 5 microns in diameter and the volume fraction may range from 30% to 75%.
OBJECTIVE OF THE STUDY
To evaluate the colour stability of commercially available orthodontic bonding resins, and to compare the colour stability of ten commonly used orthodontic bonding resins.
MATERIALS AND METHODS
This study was designed to compare the change in colour of Ten commercially available orthodontic bonding resins after exposure to light and then comparing them to the unexposed samples of the same resin. These ten commercially available resin samples of ten each were divided into two groups of ten samples each and labeled A, B, C, D, E, F, G, H, I, and J respectively for the commercially available orthodontic resins (as listed in Table 1).
The disc shaped samples of resins were cured using a metallic ring of 10 mm diameter with the inner surfaces of the ring coated with petroleum jelly, so that the resin buttons would come out easily. The top and bottom surfaces of the ring were covered with cellulose strips, which were pressed between glass flats to remove excess resin. The light curable samples were photo polymerized in the rings for 20 seconds with a light curing lamp, whereas, the chemical curable samples were cured as per the manufacturer’s guidelines and then removed from the rings respectively.
Button shaped samples prepared from each of the commercially available bonding resin systems were divided into two groups of five samples from each. The first group (e.g. A- EXP) were subjected to accelerated artificial photoaging with the use of a light emitting apparatus (XenotestTM 150 S, Atlas material testing technology, Geluhausen, Germany), involving exposure of the resin surfaces to a continuous radiation of 24 hours at 56 MJ/m2 with λ < 800 nm. This procedure induces aging equivalent to 30 days of exposure to sunlight in the Indian subcontinent which was deemed adequate because the labial surfaces of crowns are not exposed to ambient light during ordinary conditions. The control group (e.g. A- ORG) was prepared just prior to colorimetric evaluation. The adhesive resin button was polished and placed on a tray of standard background with 75% reflectance. The buttons were colorimetrically evaluated with a colorimeter (Greta Macbeth Color i TM 5 Spectrophotometer).
All the specimens were stored in a dark environment throughout the procedure except when cured and colour evaluated. After photo aging, a second colour determination was performed on the second group. Colour parameters were averaged for each group, and colour differences (δ E) induced by photo aging were calculated using the equation:
The δ E values derived from the two colour recordings for the materials were analyzed with a one-way analysis of variance (ANOVA). The difference among groups was further investigated using Tukey multiple comparison test. To establish the statistical significance of the difference of the δ E values of each adhesive and the δ E threshold for clinical detection a paired t-test was used.
Table 1. Samples used in the study
Figure 1. Preparation of button shaped samples
Figure 2. Mounted samples for aging
Figure 3. XenotestTM 150 S, Atlas material testing machine, Geluhausen, Germany
Figure 4. Greta Macbeth Color i TM on 5 Spectrophotometer
Figure 5. Mounted sample the spectrophotometer
Figure 6. Sample as seen from inside for colorimetric evaluation
RESULTS
Study design: A comparative study consisting of 100 samples randomized into 10 groups is undertaken to compare the colour changes observed after photo – aging in ten commonly available orthodontic bonding resins with freshly prepared samples.
Table 2. Mean pattern δE values between 10 groups
Table 3. Pair wise comparison
Statistical Methods: Analysis of variance has been used to find the significant difference of δE values between the 10 groups. The Post hoc Tukey test has been used to find the pair wise significance of δE values between the groups. Student t test was used to test the significance of δ E values from the threshold value.
1. Analysis of Variance: F test for K Population means
Objective: To test the hypothesis that K samples from K Populations with the same mean.
Limitations: It is assumed that populations are normally distributed and have equal variance. It is also assumed that samples are independent of each other.
Method: Let the jth sample contain nj elements (j=1, 2…K). Then the total number of elements is
F=S22/S12 which follows F distribution (K-1, N-K)
2. Tukey test
, N is the total number of subjects and MSE is the mean square error in ANOVA, J is the number of groups to be compared.
3. Student t – test
Student t test was used to test the significance of δ E values from the threshold value of 3.7. (P< 0.05/0.01) All δ E values of the samples evaluated are significantly less than the δ E threshold for clinical detection 3.7 (P<0.01**) This test indicates that no group exhibited colour alterations above the detection limit
Statistical software: The Statistical software namely SPSS 11.0 and Systat 8.0 were used for the analysis of the data and Microsoft word and Excel have been used to generate graphs, tables etc.
SUMMARY
Colour alteration of adhesive during treatment and after debonding may be implicated in long-term enamel discolouration. The aim of this study was to assess the colour stability of light-cured and chemically cured adhesives subjected to artificial photoaging. Disk-shaped specimens of adhesives were colorimetrically evaluated before and after artificial photoaging using a colorimeter. The measurement variable was the colour change (δ E) of adhesives induced by artificial, accelerated photoaging.
The δ E values derived from the two color recordings for the materials at pre- and post-aging intervals were statistically analyzed with a one-way analysis of variance (ANOVA), with the adhesive brand serving as a discriminating variable. Differences among groups were further investigated using the Tukey multiple comparisons test. To establish the statistical significance of the difference of the δ E values of each adhesive and the δ E threshold for clinical detection, a paired t-test was used.
All the adhesives exhibited color change which, in none of the cases, exceeded the clinically detectable color change limit. The extent of the colour alterations of aged bonding systems may contribute to enamel discoloration after treatment.
Thus, it can be concluded that all the ten orthodontic bonding systems used in this study can be used for orthodontic bonding without significant risk of discolouration owing to photo aging.
BIBLIOGRAPHY
1. Eliades T. and Brantley W. A. Orthodontic Materials Scientific and Clinical Aspects: Thieme; 2001.
2. Lee HL, Orlowski JA, Rogers BJ. A comparison of ultraviolet-curing and self-curing polymers in preventive, restorative and orthodontic dentistry. Int Dent J. 1976 Jun; 224.
3. Powers JM, Dennison JB, Koran A. Color stability of restorative resins under accelerated aging. J Dent Res. 1978 Nov-Dec; 57(11-12):964-70.
4. Miyagawa Y, Dennison JB, Powers JM. Testing of color stability of composites. Shika Rikogaku Zasshi. 1980 Jul; 21(55):222-7.
5. Powers JM, Fan PL, Raptis CN. Color stability of new composite restorative materials under accelerated aging. J Dent Res. 1980 Dec; 59(12):2071-4.
6. Viohl J. Clinical assessment of the colour stability of resin filling materials. Int Dent J. 1981 Mar; 31(1):39-44.
7. Asmussen E. Factors affecting the color stability of restorative resins. Acta Odontol Scand. 1983; 41(1):11-8.
8. St. Germain H, Swartz ML, Phillips RW, Moore BK, Roberts TA. Properties of microfilled composite resins as influenced by filler content. J Dent Res. 1985 Feb; 64(2):155-60.
9. Wozniak WT, Moser JB, Willis E, Stanford JW. Ultraviolet light stability of composite resins. J Prosthet Dent. 1985 Feb; 53(2):204-9.
10. Cook WD and Chong MP. Colour stability and visual perception of dimethacrylate based dental composite resins. Biomaterials. 1985 Jul; 6(4):257-64.
11. Gatti AM. UV-radiation aging test on composite materials for dental restorations. J Biomed Mater Res. 1987 May; 21(5):603-12.
12. Ogaard B, Rolla G, Arends J. Orthodontic brackets and enamel demineralization. Part 1 – Lesion development. Am J Orthod Dentofacial Orthop. 1988; 94; 68 – 73.
13. Suarez Quintanilla J, Segade LA.An experimental study of the colour changes in composite resins. Stoma (Lisb). 1989; 2(14):19-20, 22.
14. Ogaard B. Prevalence of white spot lesions in 19 year olds: a study of untreated and orthodontically treated persons 5 years after treatment. Am J Orthod and Dentofacial Orthop, 1989; 96: 423 – 427.
15. Placek M. The color fastness of composite fillings for the anterior teeth. Schweiz Monatsschr Zahnmed. 1990; 100(4):420-4.
16. Peutzfeldt A, Asmussen E. Color stability of three composite resins used in the inlay/onlay technique. Scand J Dent Res. 1990 Jun; 98(3):257-60.
17. Chang YG, Swartz ML, Moore BK, Cochran MA, Lund MR. Color stability of composite resins. Gaoxiong Yi Xue Ke Xue Za Zhi. 1990 Oct; 6(10):538-45.
18. Setz J, Lin W, Pfeifer H. Color stability of light curing composites. Dtsch Zahnarztl Z. 1990 Oct; 45(10):666-8.
19. Khokhar ZA, Razzoog ME, Yaman P. Color stability of restorative resins. Quintessence Int. 1991 Sep; 22(9):733-7.
20. Tyas MJ.Colour stability of composite resins: a clinical comparison. Aust Dent J. 1992. Apr; 37(2):88-90.
21. 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 Nov; 10(6):353-62.
22. Davis BA, Friedl KH, Powers JM. Color stability of hybrid ionomers after accelerated aging. J Prosthodont. 1995 Jun; 4(2):111-5.
23. Eldiwany M, Friedl KH, Powers JM. Color stability of light-cured and post-cured composites. Am J Dent. 1995 Aug; 8(4):179-81.
23. Eldiwany M, Friedl KH, Powers JM. Color stability of light-cured and post-cured composites. Am J Dent. 1995 Aug; 8(4):179-81.
24. Waes v. H, Matter T, Kreji I. Three dimensional measurement of enamel loss caused by bonding and debonding of orthodontic brackets. Am J Orthod and Dentofacial Orthop, 1997; 112: 666 – 669.
25. Hasegawa A, Hamano T, Miwa M, Nagasaka S. A method of predicting color stability of autopolymerizing acrylic resins using electron spin resonance. Dent Mater J. 1999 Sep; 18(3):207-17.
26. Canay S, Hersek N, Tulunoglu I, Uzun G. Evaluation of colour and hardness changes of soft lining materials in food colorant solutions. J Oral Rehabil. 1999 Oct; 26(10):821-9.6(2):134-51.
27. Douglas RD. Color stability of new-generation indirect resins for prosthodontic application. J Prosthet Dent. 2000 Feb; 83(2):166-70.
28. Lee YK, El Zawahry M, Noaman KM, Powers JM. Effect of mouthwash and accelerated aging on the color stability of esthetic restorative materials. Am J Dent. 2000 Jun; 13(3):159-61.
29. Iazzetti G, Burgess JO, Gardiner D, Ripps A. Color stability of fluoride-containing restorative materials. Oper Dent. 2000 Nov-Dec; 25(6):520-5.
30. Arikawa H, Kanie T, Fujii K, Shinohara N, Takahashi H, Inoue K. A method for evaluating color stability of light-cured composite resins using an experimental filter. Dent Mater J. 2000 Dec; 19(4):338-45.
31. Stober T, Gilde H, Lenz P. Color stability of highly filled composite resin materials for facings. Dent Mater. 2001 Jan; 17(1):87-94.
32. Eliades T. A. Kakaboura. G. Eliades T. G. Bradley. Comparison of enamel changes associated with orthodontis bonding using two different adhesives. Eur J Orthod. 2001 23(1)85-90.
33. Heydecke G, Zhang F, Razzoog ME. In vitro color stability of double-layer veneers after accelerated aging. J Prosthet Dent. 2001 Jun; 85(6):551-7.
34. Lim BS, Moon HJ, Baek KW, Hahn SH, Kim CW. Color stability of glass-ionomers and polyacid-modified resin-based composites in various environmental solutions. Am J Dent. 2001 Aug; 14(4):241-6.
35. Koishi Y, Tanoue N, Atsuta M, Matsumura H. Influence of visible-light exposure on colour stability of current dual-curable luting composites. J Oral Rehabil. 2002 Apr;29(4):387-93.
36. Poiurovskaia IIa, Makeeva IM, Emilenko EA. Comparative in vitro evaluation of color and color stability of composite and ceramic ionomer materials for esthetic repair of teeth. Stomatologiia (Mosk). 2002; 81(2):4-7.
37. Gurdal P, Akdeniz BG, Hakan Sen B. The effects of mouthrinses on microhardness and colour stability of aesthetic restorative materials. J Oral Rehabil. 2002 Sep; 29(9):895-901.
38. De Lillo A, Lombardo S, Chiado Cutin D, Pirri F, Carossa S. In vitro evaluation of chromatic stability in new-generation composites. Minerva Stomatol. 2002 Sep; 51(9):371-6.
39. Eliades T, Christiana G, Matthew H, Eliades G. Margarita M. Color stability of orthodontic resins. Angle Orthod. 2003; 74(3) 391- 393.
40. Schulze KA, Marshall SJ, Gansky SA, Marshall GW. Color stability and hardness in dental composites after accelerated aging. Dent Mater. 2003 Nov; 19(7):612-9.
41. Mussig E, Lux CJ, Staehle HJ, Stellzig-Eisenhauer A, Komposch G. Applications for direct composite restorations in orthodontics. J Orofac Orthop. 2004 Mar; 65(2):164-79.
42. Patel SB, Gordan VV, Barrett AA, Shen C. The effect of surface finishing and storage solutions on the color stability of resin-based composites. J Am Dent Assoc. 2004 May; 135(5):587-94; quiz 654.
43. Sham AS, Chu FC, Chai J, Chow TW. Color stability of provisional prosthodontic materials. J Prosthet Dent. 2004 May; 91(5):447-52.
44. Vichi A, Ferrari M, Davidson CL. Color and opacity variations in three different resin-based composite products after water aging. Dent Mater. 2004 Jul; 20(6):530-4.
45. Tanoue N, Koishi Y, Yanagida H, Atsuta M, Shimada K, Matsumura H. Color stability of acrylic resin adhesives with different initiation modes. Dent Mater J. 2004 Sep; 23(3):368-72.
46. Tanoue N, Soeno K, Kawasaki K, Atsuta M. Influence of acidulated phosphate fluoride solution on the color stability of indirect composites. J Prosthet Dent. 2004 Oct; 92(4):343-7.
47. Autio-Gold JT, Barrett AA. Effect of fluoride varnishes on color stability of esthetic restorative materials. Oper Dent. 2004 Nov-Dec; 29(6):636-41.
48. Ozkan Y, Arikan A, Akalin B, Arda T. A study to assess the colour stability of acetal resins subjected to thermocycling. Eur J Prosthodont Restor Dent. 2005 Mar; 13(1):10-4.
49. Janda R, Roulet JF, Latta M, Steffin G, Ruttermann S. Color stability of resin-based filling materials after aging when cured with plasma or halogen light. Eur J Oral Sci. 2005 Jun; 113(3):251-7.
50. Gaintantzopoulou M, Kakaboura A, Vougiouklakis G..Colour stability of tooth-coloured restorative materials. Eur J Prosthodont Restor Dent. 2005 Jun; 13.
51. Yoshimoto N, Akasaka A, Warita K, Ishiura Y, Higuchi D, Hu S, Kawawa T. Study on color stability of composite resins for a facing crown polymerized with high output photo-curing unit. Nihon Hotetsu Shika Gakkai Zasshi. 2005 Jun; 49(3):488-97.
52. Mutlu-Sagesen L, Ergun G, Ozkan Y, Semiz M Color stability of a dental composite after immersion in various media. Dent Mater J. 2005 Sep; 24(3):382-90.
53. Hino DM, Mendes FM, de Figueiredo JL, Gomide KL, Imparato JC . Effects of plaque disclosing agents on esthetic restorative materials used in pediatric dentistry. J Clin Pediatr Dent. 2005 Winter; 29(2):143-6.
54. Kolbeck C, Rosentritt M, Lang R, Handel G . Discoloration of facing and restorative composites by UV-irradiation and staining food. Dent Mater. 2006 Jan; 22(1):63-8.
55. Begum Turker S, Kocak A, Esra A. Effect of five staining solutions on the colour stability of two acrylics and three composite resins based provisional restorations. Eur. J. Prosthodont. Restor. Dent. 2006 Mar; 14(1):2-6.
56. Bernard Rosner. Fundamentals of Biostatistics, 5th Edition, Duxbury; 2000.
57. M. Venkataswamy Reddy .Statistics for Mental Health Care Research, NIMHANS publication (INDIA); 2002.
Contributed by:
Dr. Rajkumar S. Alle BDS, MDS, DNB.
Dr. Rajat Sharma BDS, MDS.
