J Bagh College Dentistry Vol. 29(2), June 2017 Discoloration of Pedodontics, Orthodontics and Preventive Dentistry 97 Discoloration of Stretched Clear Elastomeric Chains by Dietary Media (An in vitro study) Athraa A. Abass B.D.S, M.Sc. (1) Akram F. Alhuwaizi B.D.S., M.Sc., Ph.D. (2) ABSTRACT: Background: With the increasing demand on esthetic orthodontic appliances, discoloration of clear elastomeric chains and modules remains an issue which concerns both orthodontics and patients. This in vitro study was conducted to evaluate the effect of exposing stretched clear elastomeric chains from six different companies (Ortho Technology, Ormco, Ortho Organizer, American Orthodontics, Opal and G&H companies) to three types of dietary media (tea, coffee and turmeric). Materials and methods: A total of 960 lengths of six modules were cut from short type elastomeric chain; 160 pieces from each brand. The specimens were stretched 50%, placed on plastic boards, and incubated in water at 37°C for 1 day, 7 days, 14 days and 28 days. Once a day, the specimens were immersed for ten minutes in the testing dietary media, washed and then returned back to the water container. Color measurements were made before and after incubation of the specimens. Digital image were taken by an SLR digital camera and the color changes were calculated according to CIE L*a*b* color space system by Adobe Photoshop program. The resulting data were statistically analyzed using ANOVA and LSD tests. Result: Elastomeric chains from AO, Opal and G&H companies were the most brands prone to discoloration. Ortho Organizers and Ortho Technology chains were the least prone to discoloration. Tea, coffee and turmeric solutions discolored elastomeric chains from all companies in a variable degree, however turmeric caused significantly more discoloration, followed by tea and least by coffee. The amount of discoloration caused by tea and coffee increases gradually to peak at 28 days, while most of the discoloration caused by turmeric was in the first day and reached a plateau in a week. Conclusion: To decrease the discoloration of clear elastomeric chains the consumption of colored dietary media especially spices like turmeric are to be discouraged. Key words: Clear elastomeric chains, discoloration, and dietary media. . (J Bagh Coll Dentistry 2017; 29(2):97-103 INTRODUCTION Orthodontic patients, including a growing population of adults, not only want an improved smile, but they are also increasingly demanding better aesthetics during treatment. The development of appliances that combine both acceptable aesthetics for the patient and adequate technical performance for the clinician is the ultimate goal. This problem was partially solved by the introduction of aesthetic transparent brackets made of ceramic or composite (1). However, while most of these brackets were resistant to stain, clear elastomeric chains used to retract teeth or to close spaces discolored if patients ate certain dietary media like coffee, tea and turmeric (2). It is difficult to measure the colour of elastomerics using a spectrophotometer or a colorimeter because of their small size and curved geometry. Recent advances in digital cameras and imaging software encouraged their use in colour measurement for clinical dentistry. Moreover, a statistically significant correlation was found between a digital camera with an appropriate calibration protocol and a spectrophotometer (3). There is some concern regarding the quality of elastomers and which company is superior to (1) Orthodontist, Karbala Specialized Dental Center, Ministry of Health. (2) Professor. Department of Orthodontics. College of Dentistry, University of Baghdad. the others in efficacy or cost-effectiveness. Many studies have been carried out on the force decay of elastomeric chains (4,5). However, the literature is very scares on studies on their color stability. MATERIALS AND METHODS Six brands of clear orthodontic elastomeric chains were investigated (Ortho Technology, Ormco, Ortho Organizer, AO, Opal and G&H). from each brand 160 pieces of 6 modules were cut. These had initial lengths of 16-19mm which when stretched 50% become 24-27.5mm long. This distance approximated the distance between the hook of the lateral bracket and the hook of the first molar tooth for en-masse retraction of the anterior teeth. A total of 960 elastomeric chain specimens were tested, 240 for each dietary medium (distilled water, tea, coffee and turmeric) where distilled water served as a positive control. Holding blocks were made by inserting 24 stainless steel pins perpendicularly into a plastic board making 12 pairs set at a distance of 50% more than the original length of the elastomeric chains (Fig. 1). All the test specimens were placed on the holding blocks and incubated in water containers for 1, 7, 14 or 28 days at 37°C. Once each day, all the plastic holding blocks with their elastomeric J Bagh College Dentistry Vol. 29(2), June 2017 Discoloration of Pedodontics, Orthodontics and Preventive Dentistry 98 specimens were removed from water containers and immersed for ten minutes in the testing dietary media containers. After that, the holding blocks were removed from the dietary media containers and rinsed with copious amount of water to wash out any remnants of the dietary solutions and returned back and incubated in the water containers until the next day (6). Figure 1: Plastic holding block. Color measurements were made before and after immersion. A commercial SLR camera, Nikon D40 (Nikon Corp., Japan) with Tamron SP AF 18-55mm with 1:1 Macro lens (Saitama, Japan) were used. The digital camera was set to manual mode, which allowed total control of the shutter speed and aperture size. The shutter speed was set at 1/5 seconds with an aperture of F32, and the film sensitivity was set at International Organization for Standardization 200 sensitivity mode (7). Digital images were taken in a darkroom with a ring fluorescent tube (OPPLE/ 40W, 6500K) as a light source. The fluorescent tube was perpendicularly fixed at a distance of 45cm from the platform where the elastomeric chains were placed. A standard grey card (DGK color tools) was used because neutral light grey was considered to be the ideal background for shade matching which had 17.68 % reflectance (7). The digital image files were opened in Adobe Photoshop program (version 7.0; Adobe Systems Inc., San Jose, California, USA). Four areas (average 5 × 5 pixels) were randomly selected using the ‘eyedropper’ tool. The CIE L*, a*, and b* values of each area were obtained using the ‘Lab sliders’ in the software. L* is in the range of 0-100 and a* and b* in the range of -120 to 120. The L*, a*, and b* values were calculated by averaging the four areas of each specimen. The three- dimensional CIE Lab color order system provided a useful standardization technique for color difference assessments. The system included three color co-ordinates. CIE L* corresponded to the value (degree of lightness) in the Munsell system, and a* and b* co-ordinates designate the positions on the red/green and yellow/blue axes, respectively (+a= red, -a= green; +b= yellow, -b= blue). Color difference ∆E*= ∆L*2 +∆a*2+∆b*2 2 (8). Statistical analysis Data was collected and analyzed by using statistical package of social science program (SPSS, Chicago, Illinois, USA). Mean and standard deviation (SD) values were computed. One-way analysis of variance (ANOVA) and least significant difference (LSD) tests were used to test the differences between brands and the effect of different dietary media. P values of less than 0.05 were regarded as statistically significant. RESULTS Color changes (∆E* ab) after immersion in the dietary media are displayed in table 1. Difference between brands: The difference of ∆E*values of elastomeric chains between different companies was minimal for the specimens immersed in water but was more evident for those immersed in tea, coffee and turmeric solutions (Fig. 2). All the readings were comparable for all brands immersed in water. However, at 14 days ANOVA test showed a significant difference and LSD test showed that AO chains had a significant less ∆E*values than Ormco, Ortho Organizers and Opal chains (Table 2). The highest color change caused by tea was for Opal (ΔE*=40.6), followed by AO (ΔE*=39.4), G&H (ΔE*=39.1), Ormco (ΔE*=38.9), Ortho Technology (ΔE*=35.1) and least was for Ortho Organizers (ΔE*=30.9). However, at 7, 14 and 28 days ANOVA test showed significant differences and LSD test showed significant differences between all brands (Table 2). The highest color change caused by coffee was for Ormco (ΔE*=27.2), followed by G&H (ΔE*=26.3), Ortho Technology (ΔE*=24.8), Opal (ΔE*=23.8), AO (ΔE*=23.5), and least was for Ortho Organizers (ΔE*=22.2). However, at 1, 7 and 14 days ANOVA test showed significant differences and LSD test showed significant differences between all brands (Table 2). The highest color change for the turmeric solution was for AO (ΔE*=57.5), followed by G&H (ΔE*=56.4), Opal (ΔE*=55.9), Ortho Organizers (ΔE*=53.4), Ormco (ΔE*=53.2), and least was for Ortho Technology (ΔE*=52.1). However, at all time intervals ANOVA test showed significant differences and LSD test showed significant differences between all brands (Table 2). J Bagh College Dentistry Vol. 29(2), June 2017 Discoloration of Pedodontics, Orthodontics and Preventive Dentistry 99 Difference between dietary media For all brands, chains immersed in turmeric showed highest color change peaking at 28 days followed by tea then coffee and lastly water which showed only minimal color change (Fig. 3). For all brands, ANOVA test showed significant differences for all media and all time intervals (Table 3). LSD test for the specimens immersed in water showed significant differences from those immersed in tea or coffee for 7 to 28 days but not for 1-day. But for those immersed in turmeric solution the difference was significant from day 1 to 28 days. LSD test for the specimens immersed in tea showed significant differences from those immersed in coffee for all brands and at all time intervals except at 1-day. LSD test for the specimens immersed in turmeric solution showed significant differences from those immersed in tea or coffee for all brands and at all time intervals. DISCUSSION The color change values were recorded for test periods of 1, 7, 14 and 28 days in order to measure the relative changes occurring throughout the whole time period between visits. A digital camera was used to assess the amount of color change because of its reliability and accuracy. Jarad et al. (3) used a 5-megapixel camera and found a highly significant correlation between a spectrophotometer and digital camera for all CIE L*a*and b* coordinates (9). The CIE L*a* and b* color space was used for assessment of color changes. This system was commonly used for assessment of small color differences (10). The discoloring effect of tea and coffee on elastomeric modules had been extensively researched, but turmeric was added to this investigation because of its widespread use in cooking. Recent researches had evaluated the discoloration caused by turmeric on esthetic brackets and elastomeric modules (11-14). Difference between brands From the result of this study, no clear pattern was found regarding the susceptibility of a particular brand of elastomeric chain to discoloration but these general points could be noted: • Elastomeric chains from AO, Opal and G&H companies were the most discolored brands. • Elastomeric chains from Ortho Organizers and Ortho Technology companies were the least discolored brands. These differences might be because of several factors like the chemical composition and details of manufacturing and processing. The polyurethane used to make the elastomeric chains was made by several chemical reactions involving many compounds making products with different chemical compositions which affected the configuration of the chains of the elastomer and their ability to withstand deterioration from external agents and processing conditions (15). The surface characteristics such as texture and porosity could be different (12). To the authors’ knowledge, there is no published report on the discoloration of elastomeric chains, therefore the comparison with other researches is not possible. However, previous researches on the discoloration of elastomeric modules also show a diversity in the intensity of discoloration caused by different media on the different brands of modules (4,12,14,16-18). Difference between dietary media In the present study, turmeric caused significantly more discoloration than tea and coffee. This agrees with previous studies (13) but disagrees with the findings of other studies (15) who found more discoloration of elastomeric modules caused by coffee than turmeric. The difference with Bhandari et al. (14) may be because of the different response of modules than chains and the variable company brands. In the present study, tea caused significantly more discoloration than coffee. However, this disagrees with the findings of other studies carried out on elastomeric modules (12,14,16). The difference may be because of the different chemical composition and manufacturing technique between elastomeric chains and modules. Comparison between immersion times Since all elastomeric brands tested underwent color change in all solutions over time, the storage period was taken to assess the degree of staining. It was seen that the storage time influenced the amount of color change of the elastomeric chains and this was agreement with Kim and Lee (8) and Bhandari et al. (14). Exposure to water led to chemical degradation of polyester polyurethane. Substances leached from the polymer over time so that pigments and other compounds from dietary media could penetrate deep into elastomeric chains and cause discoloration (19,20). Thus when the elastomeric chains were stretched, the stretching affected the color stability of elastomeric chains giving a significant difference between the readings of 1 day, 7 days, 14 days and 28 days after immersion in dietary media for all groups. This was in agreement with J Bagh College Dentistry Vol. 29(2), June 2017 Discoloration of Pedodontics, Orthodontics and Preventive Dentistry 100 Bhandari et al. (14) who found the amount of discoloration increased as the amount of immersion time increased. The amount of discoloration caused by tea and coffee increased gradually to peak at 28 days. This agrees with the findings of Bhandari et al. (14) who found similar findings on elastomeric modules. This disagree with the findings of Lew (21) who found the amount of discoloration of elastomeric modules increased rapidly. Most of the discoloration caused by turmeric was in the first day. After this period, there was trend towards saturation and reached a plateau at 7 days. This agrees with the findings of Bhandari et al. (14) who found the same outcome on elastomeric modules. Limitations of the study: Reader should be cautious when interpreting this data to the clinical condition. In vivo staining differs from that found in vitro because of the lack of bacteria, abrasion from occlusion, eating and brushing, salivary mucins and proteins and the dilution effect of saliva on the ingested dietary media. Furthermore, the technique to assess color change needs further development because of the small surface area, clear color, and geometry of the elastomeric chains. Clinical consideration: 1. The orthodontic patient should be advised to minimize the consumption of coloring foods like turmeric, tea and coffee to keep the esthetic appliance clear with minimum amount of discoloration to get benefit from choosing this type of appliance. 2. The orthodontist should use the clear elastomeric chains with the best color stability to minimize their discoloration to satisfy the patient. CONCLUSION 1. Elastomeric chains from AO, Opal and G&H companies were the most brands prone to discoloration, while elastomeric chains from Ortho Organizers and Ortho Technology companies were the least ones. 2. Tea, coffee and turmeric solutions discolored elastomeric chains from all companies in a variable degree, however turmeric caused significantly more discoloration, followed b y tea and least by coffee. The amount of discoloration caused by tea and coffee increased gradually to peak at 28 days, while most of the discoloration caused by turmeric was in the first day and reaches a plateau at 7 days. Table 1: Mean and standard deviation of the color changes (∆ E* ab) of all brands after immersion in the dietary media. 1 day 7 days 14 days 28 days Mean SD Mean SD Mean SD Mean SD W at er Ortho Technology 6.578 4.376 6.849 3.375 6.649 1.706 6.887 1.943 Ormco 5.492 2.044 4.815 1.714 4.884 3.129 6.202 1.867 Ortho Organizers 8.508 4.215 6.932 2.8 6.202 2.531 7.717 3.851 AO 8.011 2.689 8.414 3.86 8.873 3.246 7.856 3.99 Opal 7.543 1.92 5.12 2.375 5.348 2.244 6.631 2.01 G&H 8.189 5.076 7.679 3.204 7.375 3.82 7.437 4.021 T ea Ortho Technology 9.515 3.534 17.097 2.126 24.933 3.027 35.088 4.685 Ormco 7.539 2.467 17.097 1.074 29.462 1.578 38.9 2.028 Ortho Organizers 9.781 3.271 14.963 2.699 27.625 4.182 30.876 4.657 AO 9.944 2.773 20.932 4.844 25.627 5.73 39.428 4.458 Opal 8.265 3.189 16.208 3.434 20.247 4.361 40.56 2.716 G&H 11.616 5.637 23.61 3.744 29.782 5.3 39.081 6.05 C of fe e Ortho Technology 9.116 3.385 12.637 2.622 14.95 2.252 24.79 5.194 Ormco 11.469 1.582 12.795 2.731 17.463 1.294 27.232 2.305 Ortho Organizers 12.015 3.474 12.732 2.359 13.495 2.637 22.191 3.275 AO 11.838 4.823 14.94 3.429 15.714 1.596 23.533 3.392 Opal 14.575 1.753 13.481 2.825 14.312 1.681 23.831 3.487 G&H 13.575 3.403 17.368 2.389 18.67 6.666 26.294 4.625 T ur m er ic Ortho Technology 25.756 3.478 41.511 4.392 49.911 2.235 52.116 3.632 Ormco 23.959 1.423 43.675 1.771 52.987 1.942 53.233 2.362 Ortho Organizers 26.483 4.867 41.298 5.782 50.001 4.653 53.392 2.072 AO 28.706 4.267 53.34 3.725 57.023 6.141 57.531 4.735 Opal 23.928 2.088 44.607 2.186 51.33 5.449 55.898 2.415 G&H 26.27 2.537 46.753 3.053 50.715 4.279 56.388 4.705 J Bagh College Dentistry Vol. 29(2), June 2017 Discoloration of Pedodontics, Orthodontics and Preventive Dentistry 101 Figure 2: Color changes of elastomeric chains (Ortho Technology, Ormco, Ortho Organizer, AO, Opal and G&H) after immersion in water, tea, coffee, and turmeric. Table 2: Difference between the color changes of the elastomeric chains of different companies. Days ANOVA LSD Test A A A A A B B B B C C C D D E B C D E F C D E F D E F E F F W at er 1 NS 7 NS 14 * NS NS NS NS NS NS ** NS NS * NS NS ** NS NS 28 NS T ea 1 NS 7 *** NS NS * NS *** NS * NS *** *** NS *** ** NS *** 14 *** * NS NS * * NS NS *** NS NS *** NS ** * *** 28 *** NS * * ** * *** NS NS NS *** *** *** NS NS NS C of fe e 1 * NS NS NS *** ** NS NS * NS NS NS NS NS NS NS 7 *** NS NS ** NS *** NS ** NS ** ** NS ** * NS ** 14 ** NS NS NS NS * * * * NS NS NS ** NS ** ** 28 NS T ur m er ic 1 * NS NS NS NS NS NS ** NS NS NS NS NS ** NS NS 7 *** NS NS *** NS ** NS *** NS NS *** NS ** *** *** NS 14 ** NS NS ** NS NS NS * NS NS ** NS NS ** ** NS 28 ** NS NS ** * ** NS ** NS NS * NS NS NS NS NS A. Ortho Technology, B. Ormco, C. Ortho Organizers, D. AO, E. Opal, F. G&H NS= non-significant, * = p<0.05, ** = p<0.01, *** = p<0.001 J Bagh College Dentistry Vol. 29(2), June 2017 Discoloration of Pedodontics, Orthodontics and Preventive Dentistry 102 Figure 3: Mean color change of clear elastomeric chains from Ortho Technology, Ormco, Ortho Organizer, AO, Opal and G&H companies after immersion in water, tea, coffee, and turmeric. Table 3: Statistical difference between the color changes of the clear elastomeric chains immersed in different dietary media. Days ANOVA LSD Test Water Water Water Tea Tea Coffee Tea Coffee Turmeric Coffee Turmeric Turmeric Ortho Technology 1 *** NS NS *** NS *** *** 7 *** *** *** *** ** *** *** 14 *** *** *** *** *** *** *** 28 *** *** *** *** *** *** *** Ormco 1 *** * *** *** *** *** *** 7 *** *** *** *** *** *** *** 14 *** *** *** *** *** *** *** 28 *** *** *** *** *** *** *** Ortho Organizers 1 *** NS NS *** NS *** *** 7 *** *** ** *** NS *** *** 14 *** *** *** *** *** *** *** 28 *** *** *** *** *** *** *** AO 1 *** NS * *** NS *** *** 7 *** *** *** *** * *** *** 14 *** *** * *** *** *** *** 28 *** *** *** *** *** *** *** Opal 1 *** NS *** *** *** *** *** 7 *** *** *** *** * *** *** 14 *** *** *** *** ** *** *** 28 *** *** *** *** *** *** *** G&H 1 *** NS ** *** NS *** *** 7 *** *** *** *** *** *** *** 14 *** *** *** *** *** *** *** 28 *** *** *** *** *** *** *** NS= non-significant, * = p<0.05, ** = p<0.01, *** = p<0.001 J Bagh College Dentistry Vol. 29(2), June 2017 Discoloration of Pedodontics, Orthodontics and Preventive Dentistry 103 References 1. 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