Staining Susceptibility of Microhybrid and Nanohybrid Composites on Exposure to Different Color Solutions

Citation: Mohamad-Kharib, A.; Chamorro-Petronacci, C.; Pérez-Jardón, A.; Castelo-Baz, P.; Martin-Biedma, B.; Ginzo-Villamayor, M.J.; García-García, A. Staining Susceptibility of Microhybrid and Nanohybrid Composites on Exposure to Different Color Solutions. Appl. Sci. 2023,13, 11211. https:// doi.org/10.3390/app132011211 Academic Editor: Andrea Scribante Received: 6 September 2023 Revised: 9 October 2023 Accepted: 10 October 2023 Published: 12 October 2023 Copyright: © 2023 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). applied sciences Article Staining Susceptibility of Microhybrid and Nanohybrid Composites on Exposure to Different Color Solutions Azheen Mohamad-Kharib 1,* , Cintia Chamorro-Petronacci 1,2 , Alba Pérez-Jardón1,2,* , Pablo Castelo-Baz 3, Benjamín Martin-Biedma 3, María JoséGinzo-Villamayor 4and Abel García-García1,2 1 Oral Medicine, Oral Surgery and Implantology Unit (MedOralRes Group), Faculty of Medicine and Dentistry, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; [email protected] (C.C.-P.); [email protected] (A.G.-G.) 2Health Research Institute of Santiago de Compostela (IDIS) (ORALRES Group), 15706 Santiago de Compostela, Spain 3 Oral Sciences Research Group, Endodontics and Restorative Dentistry Unit, School of Medicine and Dentistry, Universidade de Santiago de Compostela, Health Research Institute of Santiago de Compostela (IDIS), 15706 Santiago de Compostela, Spain; [email protected] (P.C.-B.); [email protected] (B.M.-B.) 4 Department of Statistics, Mathematical Analysis and Optimization, Universidade de Santiago de Compostela, 15782 Santiago de Compostela, Spain; [email protected] *Correspondence: [email protected] (A.M.-K.); [email protected] (A.P.-J.) Abstract: Composite discoloration is considered one of the most significant disadvantages of dental restorations. The purpose of our study was to assess the color susceptibility of two esthetic composite filling materials, microhybrid composite (ValuxTM Plus) and nanohybrid composite (FiltekTM Z250 XT), to different solutions and compare the results among different measuring methods (Intraoral scanner, Easyshade spectrophotometer, and Vita classical shade guide). A total of 100 specimens were fabricated in this experimental study. Each sample was soaked in either Coca-Cola, orange juice, tea, coffee, or distilled water for 30 days. Color measurement was performed using the spectrophotometer, IOS 3Shape Trios, and Vita classical shade guide. L*a*b* values were recorded to determine the color changing ( ∆ E00). The significance level was p< 0.05. All samples showed clinically visible color changes after immersion in coffee, tea, orange juice, and Coca-Cola. The nanohybrid composite showed high color change when placed in tea ( ∆ E00 = 12.5) measured by the Intraoral scanner, spectrophotometer ( ∆ E00 = 23.21), and by Vita classical shade guide ( ∆ E00 = 25). Less color discoloration was perceptible in the microhybrid composite when immersed in Coca-Cola ( ∆ E00 = 1.78) measured by spectrophotometer, intraoral scanner ( ∆ E00 = 2.85), and measured by Vita classical shade ( ∆ E00 = 3.2). The results showed that measurements with the spectrophotometer and Vita classical shade guide were correlated. The results were analyzed using the chi-square and Wilcoxon signed-rank tests, and there was a significant difference (p< 0.001) in both composite resins for all the solutions, with microhybrid being more color stable. Microhybrid composite had more color stability than nanohybrid composite, especially when immersed in tea and coffee. The spectrophotometer with Vita classical shade guide showed better interrater agreement than with the intraoral scanner. Keywords: color stability; composite resins; dentistry; staining; solutions; method comparison 1. Introduction Dental composite resins are the materials most commonly used in dental clinics due to their superior esthetic properties and ability to bond with dental surfaces [ 1 ]. They differ in terms of the resin matrix type, particle size, filler particle type, and quantity [ 2 ]. In recent years, technological advancements have contributed significantly to the field, enabling the creation of innovative dental restoration materials that offer enhanced durability and esthetic performance. Color stability is essential in esthetic composite, which Appl. Sci. 2023,13, 11211. https://doi.org/10.3390/app132011211 https://www.mdpi.com/journal/applsci Appl. Sci. 2023,13, 11211 2 of 14 permits maintaining the esthetic appearance over time. Internal and external factors can influence resin composite color and cause composite discoloration. Important factors are the composition of composite materials and the polymerization processes, which include the photo-initiator, resin matrixes, and polymerization intensity [ 3 ]. The usage of (Bis– GMA) bisphenol glycidyl dimethacrylate, invented by Bowen in 1962, was a significant advancement in composite materials. Minimizing volatility and transmission into the tissues, raising cross-linking capability, lowering polymerization contraction, and faster hardening under oral conditions are all benefits of (Bis-GMA) that have been proved over conventional polymethyl methacrylate [ 4 ]. The particle size of the filler is decreased from macro to micro and then to hybrids over time. The strength and handling qualities are improved by combining micro and mini fillers. Thus, the manufacturer’s objective is to maximize filler loading while minimizing filler size, as with hybrids [ 5 ]. Recently, nanotechnology was used to develop resin composites with superior esthetic and mechanical properties [ 6 , 7 ]; hydration sorption, the roughness of the surfaces, and the eating habits of the patient also influence staining of the restorative material [ 3 , 8 ]. The quality of the restorations can be affected by the drinking of some beverages, such as tea, coffee, Coke, orange juice, and even fluoridated water. Because diets contain a variety of colored foods and beverages, they have the potential to change the colors of composite restorations over time through absorption and adsorption of colorants [9]. Many studies have shown that several types of color solutions, including coffee, red wine, and others, can stain light-cured composite resins to different levels [ 10 , 11 ], and the potential of staining differs considerably among them [ 11 , 12 ]. Furthermore, there is a growing interest in exploring the effects of various beverages and food items on the color stability of dental composites, considering the wide-ranging dietary preferences of patients. Nanohybrid composites showed lower color stability of nanocomposite resin after exposure to coffee, tea, and wines than microcomposite resin in previous studies [ 13 , 14 ]. Kora´c et al. evaluated the color stability of composites following immersion in Coca-Cola, coffee, and tea, and found that coffee and tea induced clinically detectable discoloration in microhybrid and nanocomposite [ 15 ]. A recent study compared the color stability of three different types of nanohybrid composite after exposure to coffee, and chlorhexidine reported more discoloration [16]. Advancements in measurement techniques have also played a crucial role in assessing color stability in dental composites. Color measurement in dentistry is determined in two ways: visually or by using an instrument. The most common method is visual color determination, traditionally with the Vita shade guide. Several factors influence measurement findings with this method, including age, eye fatigue, color vision, and experience. It is also a subjective procedure with some limitations, including a lack of standardization and inconsistent results [ 17 , 18 ]. Colorimeters, spectrophotometers, spectroradiometers, 3D Shape software, and digital cameras are used to measure color. In recent years, the usage of a digital camera and subsequent analysis by software has grown in popularity. The fact that this approach examines color across an image’s complete surface rather than one point is an advantage, as are the method’s low cost and suitability for use in universities [19]. Spectrophotometers have frequently been used as a reference device in numerous recent studies about color measurement [ 20 , 21 ]. Depending on the measuring geometry and illuminant used, color measurements taken with spectrophotometers may show variations. As a result, when using such instruments to measure color, the resulting color values are highly dependent on the method used [ 22 ]. Instead of focusing on a single location, this approach’s advantages include color analysis for all sections of a specimen [ 23 ]. Another study assessing SR Nexco composite’s color stability reported that turmeric solution causes more discoloration, followed by Cola-Cola and coffee solution [24]. Addressing color stability concerns remains a priority in dental research, and continued efforts are necessary to enhance our understanding of the interplay between composite materials, patient habits, and measurement techniques. Furthermore, conducting comprehensive studies with larger specimen sizes and a variety of measurement methods will be Appl. Sci. 2023,13, 11211 3 of 14 essential to further validate color stability assessments and contribute to the advancement of dental shade matching. The objectives of this study were (1) to assess color stability following staining solutions of microhybrid and nanohybrid composite resins; (2) to evaluate which solution causes more composite staining after immersion of the composite in the discoloration media; and (3) to compare color measurement results between the IOS 3Shape Trios, Easyshade spectrophotometer, and Vita classical shade guide. 2. Materials and Methods 2.1. Sampling Preparation Based on the mean and standard deviation of color variation for direct composites and indirect composites for immersion in distilled water from previous studies [ 25 ], the sample size for one immersion media was 10. There were five immersion media, or 50 per resin type. Fifty specimens were fabricated of the composites Filtek Z250 XT nanohybrid (3M ESPE Dental Products, St. Paul, CA, USA) and Valux Plus microhybrid (3M ESPE Dental Products, St. Paul, CA, USA), as shown in Figure 1. The specimens were made using metallic molds with dimensions of 8 mm × 2 mm to correspond to the polymerization units’ diameter, as determined by Kumari et al. [ 26 ] The mold usually contained a resin composite, which was sandwiched between two glass slabs. From the top, the specimens were exposed to light with a light-emitting diode (dentist wireless LED 1200 m/w dental curing light, USA) for 40 s [ 27 ]. The sample size was calculated using a digital caliper gauge (Sichuan Mighty Machinery Co. Ltd., Work zone, Chengdu, China) [26,28]. Appl. Sci. 2023, 13, x FOR PEER REVIEW 3 of 14 Addressing color stability concerns remains a priority in dental research, and continued efforts are necessary to enhance our understanding of the interplay between composite materials, patient habits, and measurement techniques. Furthermore, conducting comprehensive studies with larger specimen sizes and a variety of measurement methods will be essential to further validate color stability assessments and contribute to the advancement of dental shade matching. The objectives of this study were (1) to assess color stability following staining solutions of microhybrid and nanohybrid composite resins; (2) to evaluate which solution causes more composite staining after immersion of the composite in the discoloration media; and (3) to compare color measurement results between the IOS 3Shape Trios, Easyshade spectrophotometer, and Vita classical shade guide. 2. Materials and Methods 2.1. Sampling Preparation Based on the mean and standard deviation of color variation for direct composites and indirect composites for immersion in distilled water from previous studies [25], the sample size for one immersion media was 10. There were five immersion media, or 50 per resin type. Fifty specimens were fabricated of the composites Filtek Z250 XT nanohybrid (3M ESPE Dental Products, St Paul, CA, USA) and Valux Plus microhybrid (3M ESPE Dental Products, St Paul, CA, USA), as shown in Figure 1. The specimens were made using metallic molds with dimensions of 8 mm × 2 mm to correspond to the polymerization units’ diameter, as determined by Kumari et al. [26] The mold usually contained a resin composite, which was sandwiched between two glass slabs. From the top, the specimens were exposed to light with a light-emitting diode (dentist wireless LED 1200 m/w dental curing light, USA) for 40 s [27]. The sample size was calculated using a digital caliper gauge (Sichuan Mighty Machinery Co. Ltd., Work zone, Chengdu, China) [26,28]. Figure 1. (A) Fifty specimens of (Filtek™ Z250 XT) nanohybrid composite resin. (B) Fifty specimens of (Valux™ Plus) microhybrid composite resin. A Sof-Lex polishing kit (coarse, medium, fine and super fine) (Sof-Lex 3M ESPE Dental Products, St Paul, CA, USA) was used to polish the superior as well as lateral surface areas of specimens and discs, and a low-speed handpiece was used for finishing and polishing for 30 s each. Water was used to rinse the specimens for 10 s and they were dried with a paper towel after each polishing phase [26]. The specimens were immersed in purified water for one week. After that, specimens were divided into five subgroups (Figure 2) and exposed to tea (Lipton yellow label tea, Dubai, UAE) coffee (Nestle, Switzerland), orange juice (Almarai 100% natural, Saudi Arabian), Coca-Cola (Coca Cola Co., Ltd., Dubai, UAE), and distilled water (Nove medic, Jonkoping, Sweden), as a control group. The results were evaluated by three different color measurement methods. Figure 1. ( A ) Fifty specimens of (Filtek ™ Z250 XT) nanohybrid composite resin. ( B ) Fifty specimens of (Valux™ Plus) microhybrid composite resin. A Sof-Lex polishing kit (coarse, medium, fine and super fine) (Sof-Lex 3M ESPE Dental Products, St. Paul, CA, USA) was used to polish the superior as well as lateral surface areas of specimens and discs, and a low-speed handpiece was used for finishing and polishing for 30 s each. Water was used to rinse the specimens for 10 s and they were dried with a paper towel after each polishing phase [26]. The specimens were immersed in purified water for one week. After that, specimens were divided into five subgroups (Figure 2) and exposed to tea (Lipton yellow label tea, Dubai, UAE) coffee (Nestle, Switzerland), orange juice (Almarai 100% natural, Saudi Arabian), Coca-Cola (Coca Cola Co., Ltd., Dubai, UAE), and distilled water (Nove medic, Jonkoping, Sweden), as a control group. The results were evaluated by three different color measurement methods. 2.2. Staining Solution Preparation Solution media with composition and brands are described in Table 1. The coffee solution was produced in 300 mL of boiling water in which (3.6 g) of coffee powder was dissolved, waiting till the coffee’s temperature reached the normal drinking temperature of 70 degrees Celsius [ 29 ]. For tea preparation using 300 mL of boiling water, two Lipton yellow teabags (2 × 2 g) were steeped for three minutes. Specimens were immersed in Appl. Sci. 2023,13, 11211 4 of 14 solutions completely in a vertical position [ 30 , 31 ]. All specimen-containing solutions were then kept in an incubator at 37 degrees Celsius. A daily refreshment of solutions was made. Strict adherence to preparedness protocols was carried out. Appl. Sci. 2023, 13, x FOR PEER REVIEW 4 of 14 Figure 2. Sample distribution and color media with measurement methods. 2.2. Staining Solution Preparation Solution media with composition and brands are described in Table 1. The coffee solution was produced in 300 mL of boiling water in which (3.6 g) of coffee powder was dissolved, waiting till the coffee’s temperature reached the normal drinking temperature of 70 degrees Celsius [29]. For tea preparation using 300 mL of boiling water, two Lipton yellow teabags (2 × 2 g) were steeped for three minutes. Specimens were immersed in solutions completely in a vertical position [30,31]. All specimen-containing solutions were then kept in an incubator at 37 degrees Celsius. A daily refreshment of solutions was made. Strict adherence to preparedness protocols was carried out. Table 1. Solution media with composition and brand. Solutions Compositions Brand Tea Caffeine, tannins, theophylline, vitamin, glucose. Lipton yellow label tea, Dubai, UAE Coffee Zinc, copper, magnesium, potassium, caffeine. Nescafe, Nestle, Vevey, Switzerland Orange juice Ascorbic acid, potassium, citric acid, and folic acid. Almarai, 100% orange juice (natural), Riyadh , Saudi Arabian Figure 2. Sample distribution and color media with measurement methods. Table 1. Solution media with composition and brand. Solutions Compositions Brand Tea Caffeine, tannins, theophylline, vitamin, glucose. Lipton yellow label tea, Dubai, UAE Coffee Zinc, copper, magnesium, potassium, caffeine. Nescafe, Nestle, Vevey, Switzerland Orange juice Ascorbic acid, potassium, citric acid, and folic acid. Almarai, 100% orange juice (natural), Riyadh, Saudi Arabian Coca-Cola Sugar, caramel, caffeine, orthophosphoric acid, water. Coca-Cola, Dubai, UAE Water Distilled water 2.3. Color Assessment Color measurement was performed with an Easyshade spectrophotometer, IOS 3shape Trios, and Vita classical shade guide. 1. Easyshade spectrophotometer (Vita Easyshade, 4.0, Vita Zahnfabrik, Bad Sackingen, Germany): After the device was adjusted in accordance with the manufacturer’s Appl. Sci. 2023,13, 11211 5 of 14 guidelines prior to each test, color measurement was done after the spectrophotometer was positioned on the specimen at the same angle (90◦) in the sample’s middle [32]. 2. Intraoral scanner (IOS) 3Shape Trios (SoftwareTrios 4, version 19.2.5, Copenhagen, Denmark): The shade calibration was performed in accordance with the manufacturer’s instructions [ 32 ]. The color assessment was immediately created after specimen scanning. The intraoral scanner gave two different measures: Vita classical and 3D Master Guide. The device recorded both measurements, and we converted them to L, a, and b values to compare results using a conversion table. 3. Vita classical shade guide (Vita Zahnfabrik, Germany). Three calibrated dentists were asked to categorize the specimens from lightest to darkest, grouping specimens of comparable hues in that order according to their personal criteria. The shade value of the Vita classical shade guide was converted into numerical data using a conversion table [32]. 2.4. Calculation of the Color Difference For all the color measurements using the CIEDE2000 color difference (E00) and the CIE lab (E ab), the following equations were used: ∆E00 =s∆L∗ kLsL2 +∆C∗ kCsC2 +∆H∗ kHsH2 +RT∆C∗ kCsC∆H∗ kHsH C∗=q(a∗)2+(b∗)2 H∗=tan−1b∗ a∗ ∆E ab = [(∆L*) 2 +(∆a*) 2 + (∆b*) 2]1/2 In this approach, L* stands for lightness, with values ranging from 0 (dark) to 100 (bright), a* for red-green chromatism, and b* for yellow-blue chromatism. The threshold values used to interpret results to determine visual acceptability and perceptibility as described by Paravina et al. were: ∆ E00 ≤ 0.8 indicates clinically unnoticeable, 0.8 < ∆ E00 ≤ 1.8 is clinically acceptable, 1.8 < ∆ E00 ≤ 3.6 considering moderately unacceptable, and 3.6 < ∆ E00 ≤ 5.4 is obviously unacceptable, ∆ E00 > 5.4 severely unacceptable [ 33 ]. Various studies have observed that ∆ E values between 1 and 3 seem to be detectable to the human eye, while ∆E levels greater than 3.3 are clinically significant [6,34]. 2.5. Statistical Analysis Color variables were collected on a database and analyzed statistically with the R package v.4.0.3. Variables recorded were the type of composite, immersion solution, measurement method, and L, a, b values. The mean value of each measurement was calculated, and then their standard deviation was calculated. Means were compared using the chi square test, and the variable water was considered the baseline. Wilcoxon signed-rank tests were used to assess the difference in color measurement methods. The significance level was set at p< 0.05. 3. Results A total of 100 specimens were evaluated in this study. The meticulous examination involved assessing color changes in five different solutions, and these changes were measured by three different methods. The descriptive results of the color values for each solution and composite resin are summarized in Table 2. Appl. Sci. 2023,13, 11211 6 of 14 Table 2. Descriptive data of L, a, and b values of composite resin and staining solution (* clinically significant, e.g., ∆E more than 3.3). Easyshade Spectrophotometer L a b (Composite) (Media) (Mean) (SD) (Mean) (SD) (Mean) (SD) (∆E_ab) Nanohybrid Filtek Z250 XT 3M ESPE Coffee 63.83 0.81 4.34 0.29 32.36 0.86 16.32 * Coca-Cola 81.98 0.62 2.20 0.07 27.64 0.39 6.11 * Orange 82.18 0.66 2.01 0.14 28.36 0.78 6.69 * Tea 61.30 0.95 5.07 0.26 32.37 0.50 18.61 * Water 77.34 3.36 1.03 0.45 23.84 1.34 Microhybrid Valux Plus 3M ESPE Coffee 72.47 0.80 1.35 0.11 27.08 1.27 8.65 * Coca-Cola 81.25 0.92 0.69 0.16 23.55 0.90 1.46 Orange 80.14 1.16 0.60 0.07 24.15 0.55 1.24 Tea 70.78 0.45 2.50 0.27 28.21 0.56 10.64 * Water 80.73 3.29 1.62 0.54 24.55 4.06 3Shape Trios L a b (Composite) (Media) (Mean) (SD) (Mean) (SD) (Mean) (SD) (∆E_ab) Nanohybrid Filtek Z250 XT 3M ESPE Coffee 69.59 0.21 2.34 0.37 22.27 1.09 9.20 * Coca-Cola 76.27 1.16 0.98 0.00 17.97 0.00 4.71 * Orange 76.09 2.33 1.11 0.23 20.40 1.71 5.14 * Tea 66.84 1.91 3.40 0.53 22.13 0.66 11.24 * Water 75.47 1.24 1.12 0.5 15.29 2.7 Microhybrid Valux Plus 3M ESPE Coffee 69.43 0.05 2.66 0.04 18.88 3.06 6.97 * Coca-Cola 75.67 1.39 1.23 0.62 13.29 1.40 2.80 Orange 78.80 0.00 0.97 0.00 19.34 0.00 3.00 Tea 69.39 0.00 2.69 0.00 21.25 0.00 7.69 * Water 76.13 1.53 0.98 0.00 17.97 0.00 Vita Classical Shade Guide L a b (Composite) (Media) (Mean) (SD) (Mean) (SD) (Mean) (SD) (∆E_ab) Nanohybrid Filtek Z250 XT 3M ESPE Coffee 40.61 6.08 7.01 0.24 12.88 0.01 19.95 * Coca-Cola 58.54 3.51 6.17 0.91 10.37 2.95 3.02 Orange 60.09 0.59 6.43 0.72 10.91 2.00 1.71 Tea 34.92 0.00 7.23 0.00 12.87 0.00 25.63 * Water 60.55 0 6.99 0 12.46 0 Microhybrid Valux Plus 3M ESPE Coffee 51.96 3.61 8.12 0.25 16.04 0.93 9.37 * Coca-Cola 62.13 0.78 6.53 0.62 11.74 1.66 1.80 Orange 61.13 1.06 6.17 0.48 11.74 1.66 1.24 Tea 49.66 2.28 8.44 0.17 15.59 0.35 11.42 * Water 60.55 0.00 6.99 0.00 12.46 0.00 Appl. Sci. 2023,13, 11211 7 of 14 When applied to each of the resin materials, tea had the greatest staining impact. Coffee exhibited the second most pronounced staining, while both composites suffered the least color change when exposed to Coca-Cola and orange juice, as illustrated in Figures 3and 4. Appl. Sci. 2023, 13, x FOR PEER REVIEW 7 of 14 When applied to each of the resin materials, tea had the greatest staining impact. Coffee exhibited the second most pronounced staining, while both composites suffered the least color change when exposed to Coca-Cola and orange juice, as illustrated in Figures 3 and 4. Figure 3. Average color change values for nanohybrid composite resin (3M FiltekTM Z250 XT), by three measurement methods after immersion of staining solutions. Figure 4. Average color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) by three measurement methods after immersion on staining solutions. The ΔE00 values of both composite resins (microhybrid and nanohybrid) were determined with reference to the Vita classical shade guide. ΔE00 of coffee (14.1–20.19) and in tea (15.6–25), followed by ΔE00 values from the Easyshade spectrophotometer for coffee (11–20.7) and tea (14.24–23.21), then by 3Shape Trios for coffee (5.14–9.7) and tea (6.5–12.5), were all clinically severely unacceptable. In contrast, ΔE00 results obtained by the Vita classical shade guide for Coca-Cola (3.2–3.75) and orange Juice (3.9–4.19) indicated clinically clearly unacceptable levels. At the same time, ΔE00 results demonstrated by spectrophotometer and 3Shape Trios were indicated as moderately unacceptable, including ΔE00 values measured by the spectrophotometer for Coca-Cola (1.78–3) and orange Juice (2.56–2.82), as well as the Figure 3. Average color change values for nanohybrid composite resin (3M FiltekTM Z250 XT), by three measurement methods after immersion of staining solutions. Appl. Sci. 2023, 13, x FOR PEER REVIEW 7 of 14 When applied to each of the resin materials, tea had the greatest staining impact. Coffee exhibited the second most pronounced staining, while both composites suffered the least color change when exposed to Coca-Cola and orange juice, as illustrated in Figures 3 and 4. Figure 3. Average color change values for nanohybrid composite resin (3M FiltekTM Z250 XT), by three measurement methods after immersion of staining solutions. Figure 4. Average color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) by three measurement methods after immersion on staining solutions. The ΔE00 values of both composite resins (microhybrid and nanohybrid) were determined with reference to the Vita classical shade guide. ΔE00 of coffee (14.1–20.19) and in tea (15.6–25), followed by ΔE00 values from the Easyshade spectrophotometer for coffee (11–20.7) and tea (14.24–23.21), then by 3Shape Trios for coffee (5.14–9.7) and tea (6.5–12.5), were all clinically severely unacceptable. In contrast, ΔE00 results obtained by the Vita classical shade guide for Coca-Cola (3.2–3.75) and orange Juice (3.9–4.19) indicated clinically clearly unacceptable levels. At the same time, ΔE00 results demonstrated by spectrophotometer and 3Shape Trios were indicated as moderately unacceptable, including ΔE00 values measured by the spectrophotometer for Coca-Cola (1.78–3) and orange Juice (2.56–2.82), as well as the Figure 4. Average color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) by three measurement methods after immersion on staining solutions. The ∆E00 values of both composite resins (microhybrid and nanohybrid) were determined with reference to the Vita classical shade guide. ∆ E00 of coffee (14.1–20.19) and in tea (15.6–25), followed by ∆ E00 values from the Easyshade spectrophotometer for coffee (11–20.7) and tea (14.24–23.21), then by 3Shape Trios for coffee (5.14–9.7) and tea (6.5–12.5), were all clinically severely unacceptable. In contrast, ∆ E00 results obtained by the Vita classical shade guide for Coca-Cola (3.2–3.75) and orange Juice (3.9–4.19) indicated clinically clearly unacceptable levels. At the same time, ∆ E00 results demonstrated by spectrophotometer and 3Shape Trios were indicated as moderately unacceptable, including ∆ E00 values measured by the spectropho- Appl. Sci. 2023,13, 11211 8 of 14 tometer for Coca-Cola (1.78–3) and orange Juice (2.56–2.82), as well as the results obtained by 3Shape Trios ∆E00 for Coca-Cola (2.85–2.9) and orange Juice (3–3.2) (Figures 5–7). Appl. Sci. 2023, 13, x FOR PEER REVIEW 8 of 14 results obtained by 3Shape Trios ΔE00 for Coca-Cola (2.85–2.9) and orange Juice (3–3.2) (Figures 5–7). Figure 5. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between Easyshade spectrophotometer and 3Shape Trios after immersion on staining solutions. Figure 6. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between Easyshade spectrophotometer and Vita classical shade guide after immersion on staining solutions. Figure 5. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between Easyshade spectrophotometer and 3Shape Trios after immersion on staining solutions. Appl. Sci. 2023, 13, x FOR PEER REVIEW 8 of 14 results obtained by 3Shape Trios ΔE00 for Coca-Cola (2.85–2.9) and orange Juice (3–3.2) (Figures 5–7). Figure 5. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between Easyshade spectrophotometer and 3Shape Trios after immersion on staining solutions. Figure 6. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between Easyshade spectrophotometer and Vita classical shade guide after immersion on staining solutions. Figure 6. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between Easyshade spectrophotometer and Vita classical shade guide after immersion on staining solutions. Although comparing the results obtained by the three different methods of both composites found that different values recorded by the Easyshade spectrophotometer and the 3Shape Trios were statistically significant p< 0.001. In contrast, the results obtained by comparing Easyshade spectrophotometer and Vita classical shade guide were near each other p> 0.01; comparing values obtained by 3Shape Trios and Vita’s classical shade guide showed different values p< 0.001 (Table 3). Appl. Sci. 2023,13, 11211 9 of 14 Appl. Sci. 2023, 13, x FOR PEER REVIEW 9 of 14 Figure 7. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between 3Shape Trios and Vita classical shade guide after immersion on staining solutions. Although comparing the results obtained by the three different methods of both composites found that different values recorded by the Easyshade spectrophotometer and the 3Shape Trios were statistically significant p < 0.001. In contrast, the results obtained by comparing Easyshade spectrophotometer and Vita classical shade guide were near each other p > 0.01; comparing values obtained by 3Shape Trios and Vita’s classical shade guide showed different values p < 0.001 (Table 3). Table 3. Statistical comparisons among three different color measurement methods (means and SD). Easyshade SpectroPhotometer (a) IOS 3Shape Trios (b) Vita Classical Shade Guide (c) p-Value (a–b) p-Value (a–c) p-Value (b–c) Nanohybrid Filtek Z250 XT 3M ESPE Coffee 16.32 (0.86) 9.20 (1.09) 19.95 (0.01) 0.0007 0.2 0.0006 Coca-Cola 6.11 (0.39) 4.71 (0.00) 3.02 (2.95) 0.0002 0.7 0.0002 Orange 6.69 (0.78) 5.14 (1.71) 1.71 (2.00) 0.0001 0.7 0.0001 Tea 18.61 (0.50) 11.24 (0.66) 25.63 (0.00) 0.0003 0.1 0.0001 Microhybrid Valux Plus 3M ESPE Coffee 8.65 (1.27) 6.97 (3.06) 9.37 (0.93) 0.0006 0.1 0.0001 Coca-Cola 1.46 (0.90) 2.80 (1.40) 1.80 (1.66) 0.0003 0.7 0.0001 Orange 1.24 (0.55) 3.00 (0.00) 1.24 (1.66) 0.0002 0.5 0.0004 Tea 10.64 (0.56) 7.69 (0.00) 11.42 (0.35) 0.0001 0.1 0.0002 4. Discussion The objectives of this research were to evaluate color stability after staining solutions of two types of composite resin materials and to compare results from various color measuring methods. We decided to evaluate the A2 shade of both composite resins, microhybrid and nanohybrid, because it is the shade most popularly used in dental practice for esthetic treatments [28,31]. The findings revealed that microhybrid composites showed less staining after immersion in the color solutions than nanohybrid composites measured by Vita classical shade guide (ΔE00 tea: 15.6 vs. 25, coffee: 14.1 vs. 20.19, Coca-Cola: 3.2 vs. 3.75, and orange juice: 3.9 vs. 4.19). This agrees with the findings of previous research that observed that nanohybrids had a higher degree of discoloration and poorer color stability while having a higher degree of conversion than microhybrids, especially when immersions were in coffee or tea [10,14,35]. Meshki et al. found that microhybrid composite had greater discoloration resistance than nanohybrid composite after Figure 7. Comparing color change values for microhybrid composite resin (ValuxTM Plus 3M ESPE) between 3Shape Trios and Vita classical shade guide after immersion on staining solutions. Table 3. Statistical comparisons among three different color measurement methods (means and SD). Easyshade Spectro-Photometer (a) IOS 3Shape Trios (b) Vita Classical Shade Guide (c) p-Value (a–b) p-Value (a–c) p-Value (b–c) Nanohybrid Filtek Z250 XT 3M ESPE Coffee 16.32 (0.86) 9.20 (1.09) 19.95 (0.01) 0.0007 0.2 0.0006 Coca-Cola 6.11 (0.39) 4.71 (0.00) 3.02 (2.95) 0.0002 0.7 0.0002 Orange 6.69 (0.78) 5.14 (1.71) 1.71 (2.00) 0.0001 0.7 0.0001 Tea 18.61 (0.50) 11.24 (0.66) 25.63 (0.00) 0.0003 0.1 0.0001 Microhybrid Valux Plus 3M ESPE Coffee 8.65 (1.27) 6.97 (3.06) 9.37 (0.93) 0.0006 0.1 0.0001 Coca-Cola 1.46 (0.90) 2.80 (1.40) 1.80 (1.66) 0.0003 0.7 0.0001 Orange 1.24 (0.55) 3.00 (0.00) 1.24 (1.66) 0.0002 0.5 0.0004 Tea 10.64 (0.56) 7.69 (0.00) 11.42 (0.35) 0.0001 0.1 0.0002 4. Discussion The objectives of this research were to evaluate color stability after staining solutions of two types of composite resin materials and to compare results from various color measuring methods. We decided to evaluate the A2 shade of both composite resins, microhybrid and nanohybrid, because it is the shade most popularly used in dental practice for esthetic treatments [ 28 , 31 ]. The findings revealed that microhybrid composites showed less staining after immersion in the color solutions than nanohybrid composites measured by Vita classical shade guide ( ∆ E00 tea: 15.6 vs. 25, coffee: 14.1 vs. 20.19, Coca-Cola: 3.2 vs. 3.75, and orange juice: 3.9 vs. 4.19). This agrees with the findings of previous research that observed that nanohybrids had a higher degree of discoloration and poorer color stability while having a higher degree of conversion than microhybrids, especially when immersions were in coffee or tea [ 10 , 14 , 35 ]. Meshki et al. found that microhybrid composite had greater discoloration resistance than nanohybrid composite after immersion in different orange juices [ 36 ]. The study showed nanohybrid composite had less color stability than microhybrid composite resin following immersion in red wine and coffee [37]. Composites capable of absorbing water may also be capable of absorbing other fluids, which may cause the polymer matrix to dissolve, resulting in discoloration and a decrease in the powered properties of the composite [ 11 ]. Microhybrid composite stability can be