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Kang CM, Hsu WC, Chen MS, Wu HY, Mine Y, Peng TY. Fracture characteristics and translucency of multilayer monolithic zirconia crowns of various thicknesses. J Dent 2024; 145:105023. [PMID: 38670331 DOI: 10.1016/j.jdent.2024.105023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 04/22/2024] [Accepted: 04/23/2024] [Indexed: 04/28/2024] Open
Abstract
OBJECTIVES Multilayer monolithic zirconia (M-Zr) crowns can be engineered to achieve gradational translucency and color intensity. However, this modification may compromise the mechanical strength, raising concerns regarding the ability of M-Zr crowns to withstand occlusal stresses. The effects of M-Zr crown thickness on translucency and ability to endure occlusal forces were investigated at different tooth positions (incisors, premolars, and molars). The objective was to determine the minimal thickness of M-Zr crowns used in tooth preparation to meet aesthetic and functional demands. METHODS M-Zr samples (Vita A1) with four thicknesses (0.5, 1.0, 1.5, and 2.0 mm) were prepared and subjected to translucency testing using a digital colorimeter by 3-third and 9-square division methods. Crown-shaped M-Zr samples with three thicknesses (1.0, 1.5, and 2.0 mm) and three tooth positions (incisor, premolar, and molar) were digitally designed, and 2.0 mm metal abutments were fabricated. The samples were bonded to the abutments; their fracture characteristics were evaluated using a universal testing machine, and their fracture surfaces examined using an optical microscope. Statistical analyses included the Shapiro-Wilk test, Pearson correlation, and one-way and two-way ANOVA with a post hoc Tukey HSD test (α = 0.05). RESULTS Color analysis results revealed a significant negative correlation between thickness and translucency (r < -0.96, P < 0.01), with the highest values in the incisal region. Cross-sectional profiles confirmed the uniform thickness and morphology of the digitally designed M-Zr crowns. The results of fracture strength analysis showed position-dependent variability, a strong positive correlation with thickness (r > 0.96, P < 0.01), and fracture strengths consistently exceeding 1200 N across all tooth positions. Fracture patterns indicated that thinner crowns at the incisors and molars were more prone to cracking, whereas those at the premolars demonstrated significantly higher strength (4872.51 N, P < 0.05), only with crack or even no fracture occurring at 2.0 mm. CONCLUSIONS Thickness significantly influenced both the translucency and fracture strength of M-Zr, with the tooth position playing an additional role, albeit to a lesser extent. Although thinner crowns exhibited lower strength at each tooth position, even at a thickness of 1.0 mm, fracture strength exceeding 1200 N was maintained, surpassing the typical occlusal forces. Thus, it can be asserted that M-Zr crowns with a minimum thickness of 1.0 mm can meet both aesthetic and functional requirements.
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Affiliation(s)
- Chien-Ming Kang
- Huayi Dental Laboratory, Taipei, Taiwan; School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Wen-Chieh Hsu
- School of Dentistry, College of Oral Medicine, Chung Shan Medical University, Taichung, Taiwan; Department of Oral Hygiene, Hsin Sheng Junior College of Medical Care and Management, Taoyuan, Taiwan; Research Center of Precision Biomedical Implants, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - May-Show Chen
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan; Division of Prosthodontics, Department of Dentistry, Taipei Medical University Hospital, Taipei, Taiwan
| | - Hsuan-Yu Wu
- School of Dental Technology, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan
| | - Yuichi Mine
- Department of Medical Systems Engineering, Graduate School of Biomedical and Health Sciences, Hiroshima University, Hiroshima, Japan; Project Research Center for Integrating Digital Dentistry, Hiroshima University, Hiroshima, Japan
| | - Tzu-Yu Peng
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
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Wu Z, Wei D, Tian J, Zhang Y, Lin Y, Di P. Quantitative analysis of the color in six CAD-CAM dental materials of varied thickness and surface roughness: An in vitro study. J Prosthet Dent 2024; 131:292.e1-292.e9. [PMID: 37978004 DOI: 10.1016/j.prosdent.2023.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 10/27/2023] [Accepted: 10/27/2023] [Indexed: 11/19/2023]
Abstract
STATEMENT OF PROBLEM Computer-aided design and computer-aided manufacturing (CAD-CAM) monochromatic restorative materials are gaining popularity because of their convenience and efficiency. However, studies that quantitatively analyzed color change associated with thickness and surface roughness are sparse. PURPOSE The purpose of this in vitro study was to quantitatively evaluate the color of 6 CAD-CAM monochromatic materials of different thickness and surface roughness using the CIELab color system. MATERIAL AND METHODS A total of 150 12×12-mm square specimens of 6 different CAD-CAM monochromatic materials (VITA Enamic HT [VE], IPS e.max CAD HT [LS], LAVA Ultimate HT [LU], Telio CAD HT [TE], VITA Suprinity HT [VS], and Celtra Duo HT [CD]) in shade A2 and 5 different thicknesses (from 0.5 mm to 2.5 mm, with 0.5-mm increments) were fabricated (n=5). After 3 different surface treatments (polished, roughened by SiC P800-grit, and P300-grit), CIELab color parameters (L*, a* and b*) were measured using a spectrophotometer (VITA Easyshade V), and surface roughness was measured with a profilometer (VK-X200). Color variation was quantified by ΔE00 and 50:50% acceptability and perceptibly thresholds. Data analyses were performed using MANOVA, 2-way ANOVA, post hoc Tukey-Kramer test, and the 1-sample t test (α=.05). RESULTS The L*, a*, and b* of the monochromatic specimens were significantly influenced by material type, thickness, and surface roughness (P<.001). An overall increase in the L* (from 61.90 to 82.2), a* (from -4.22 to 1.16), and b* (from 5.48 to 43.22) of the specimens was observed with increased thickness. The roughened specimens exhibited lower L* and higher a* and b* than the polished ones (P<.001). The use of P300-grit for roughening resulted in greater ΔE00 compared with P800-grit (P<.001). As thickness decreased or surface roughness increased, the ΔE00 increased and exceeded the acceptability and perceptibly thresholds for color difference. CONCLUSIONS Material type, thickness, and surface roughness were major factors affecting the color of CAD-CAM monochromatic materials. Variations in thickness of 0.5 mm or more, as well as roughening treatments, may lead to clinically unacceptable color changes.
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Affiliation(s)
- Zhengda Wu
- Lecturer, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - Donghao Wei
- Lecturer, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - Jiehua Tian
- Lecturer, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - Yifan Zhang
- Lecturer, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - Ye Lin
- Professor, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China
| | - Ping Di
- Professor, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, PR China.
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Park C, Giap HV, Kwon JS, Kim KH, Choi SH, Lee JS, Lee KJ. Dimensional accuracy, mechanical property, and optical stability of zirconia orthodontic bracket according to yttria proportions. Sci Rep 2023; 13:20418. [PMID: 37990080 PMCID: PMC10663543 DOI: 10.1038/s41598-023-47827-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2023] [Accepted: 11/18/2023] [Indexed: 11/23/2023] Open
Abstract
This in vitro study evaluated comprehensively the performances of zirconia brackets with varying yttria proportions in manufacturing advanced orthodontic brackets. Three experimental groups of zirconia brackets were fabricated using yttria-stabilized zirconia (YSZ) materials with different yttria proportions-3 mol% yttria (3Y-YSZ), 4 mol% yttria (4Y-YSZ), and 5 mol% yttria (5Y-YSZ) (Tosoh Ceramic, Japan). A polycrystalline alumina ceramic bracket (3M™ Clarity™ Advanced, MBT 0.022-in. slot) was employed as the control group. Morphological properties, including slot surface structure and dimensions, were examined using scanning electron microscopy and surface profiler analysis. Manufacturing accuracy was assessed with root mean square calculations of trueness and precision. Mechanical properties were tested, encompassing static and kinetic frictional resistance (FR) and fracture strength. Optical stability was evaluated through 20,000 cycles of thermocycling and a 7-day immersion in various coloring agents. Within the limitations of this study, zirconia brackets containing 3 to 5 mol% YSZ presented enhanced reliability in terms of dimensional accuracy and demonstrated favorable optical stability. Notably, owing to its advantageous mechanical properties, the 3Y-YSZ variant showed remarkable potential as an advanced material for fabricating orthodontic brackets.
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Affiliation(s)
- Changbum Park
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, No. 723, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Hai-Van Giap
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, No. 723, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Jae-Sung Kwon
- Department and Research Institute for Dental Biomaterials and Bioengineering, Yonsei University College of Dentistry, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Kyung-Ho Kim
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, No. 723, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Sung-Hwan Choi
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, No. 723, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Joon Sang Lee
- Department of Mechanical Engineering, Yonsei University, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea
| | - Kee-Joon Lee
- Department of Orthodontics, Institute of Craniofacial Deformity, Yonsei University College of Dentistry, No. 723, 50-1 Yonsei-ro, Seodaemun-gu, Seoul, 03722, Republic of Korea.
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Pongtongkham P, Pleumsamran N, Suttiat K. Effect of CAD/CAM Position and Thickness of Ultra-Translucent Multilayered Zirconia on Color Aspects. Int J Dent 2023; 2023:5000800. [PMID: 37635898 PMCID: PMC10460285 DOI: 10.1155/2023/5000800] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/20/2023] [Accepted: 07/27/2023] [Indexed: 08/29/2023] Open
Abstract
Background Ultra-translucent multilayered zirconia restorations fabricated using computer-aided design and computer-aided manufacturing (CAD/CAM) technology have recently gained popularity. Their esthetic appeal is crucially dependent on the color accuracy, influenced by prosthesis thickness and multilayer composition due to CAD/CAM milling positions. This study comprehensively investigated how these two factors impacted color accuracy, thereby enhancing our understanding of color outcomes. Materials and Methods One hundred monolithic multilayer zirconia specimens with 10 × 10 mm square shape were milled in four different positions and five different thicknesses (1.0, 1.5, 2.0, 2.5, and 3.0 mm). The specimens were placed on an A3 shade resin composite substrate, and CIELAB values (L ∗, a ∗, and b ∗) were measured using a spectrophotometer. Delta E (ΔE) values were calculated to quantify the color differences between the specimens and the A3 VITA classical shade tab and compared with the perceptibility and acceptability thresholds of ΔE = 1.2 and 2.7, respectively. Pearson correlation, two-way ANOVA, and Tukey multiple comparisons (α = 0.05) were performed. Results The proportion of the dentin layer was positively correlated with the a ∗ and b ∗ values, while specimen thickness was positively correlated with the a ∗ value and negatively correlated with the L ∗ and b ∗ values. Significant difference in ΔE value due to different CAD/CAM positions was not observed within the same specimen thickness. Perceptible color differences were observed in specimens with thicknesses greater than 1 mm, while specimens with 1 mm thickness fell within the clinically acceptable range. Highest ΔE value was found in the specimen with 1 mm thickness. Conclusions Different compositions of multilayers in the final restoration due to different CAD/CAM positions do not significantly affect the color appearance of ultra-translucent multilayer zirconia, with color only influenced by specimen thickness.
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Affiliation(s)
- Palanupap Pongtongkham
- Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Nathawat Pleumsamran
- Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand
| | - Kullapop Suttiat
- Department of Prosthodontics, Faculty of Dentistry, Chiang Mai University, Chiang Mai 50200, Thailand
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Sutejo IA, Kim J, Zhang S, Gal CW, Choi YJ, Park H, Yun HS. Fabrication of color-graded feldspathic dental prosthetics for aesthetic and restorative dentistry. Dent Mater 2023:S0109-5641(23)00089-1. [PMID: 37088587 DOI: 10.1016/j.dental.2023.03.021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2023] [Revised: 03/22/2023] [Accepted: 03/31/2023] [Indexed: 04/25/2023]
Abstract
OBJECTIVE Feasibility investigation of natural teeth shades replication on dental prosthetics fabricated via functionally graded additive manufacturing (FGAM) using combination of feldspathic porcelain (FP) and yttrium aluminum garnet cerium (Y3Al5O12:Ce, YAG:Ce) as a promising esthetic restoration option. METHODS Color-graded feldspathic crown fabrication parameter through FGAM method was comprehensively examined from the slurry rheology, cure depth, debinding to sintering temperature. Effect of light absorbent also checked towards overcuring reaction during UV exposure by the shape comparison. Lastly, the flexural bending strength measured following ISO 6872:2015 to assure the applicability. Applying the studied parameter, natural teeth shades then imitated and investigated by alteration of FP and FP + 0.1 wt% YAG:Ce (Y-FP). Generated color across the structure captured through mobile camera, interpreted through the CIELAB coordinate and the gradation confirmed by the color differences (ΔE00) calculated using CIEDE2000 formula. RESULT Parameter study indicated that 70 wt% of FP slurry with 3 wt% dispersant and 0.2 wt% light absorbent is favored. It produces excellent flowability in our FGAM system with less overcuring justified by edge margin reduction from 95.65° to 90.00° after UV exposure on rectangle shapes masking. The obtain structure also offers adequate flexural bending strength of 106.26 MPa (FP) and 101.36 MPa (Y-FP) after sintering at 780 °C. This validated the materials as class 2 dental prosthetics citing ISO 6872:2015. Color gradation was verified by the yellow b* value reduction (14.8 to -3.33) as it shifted from cervical to incisal area while ΔE00 further affirmed the differences from each segment in comparison with the FP and Y-FP. SIGNIFICANCE Color gradation was successfully replicated by FP and YAG:Ce composition shift via FGAM technique. This result highlights the potential of FGAM as an alternative for fabricating dental prosthetics with high efficiency and improved esthetic appeal.
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Affiliation(s)
- Imam Akbar Sutejo
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Jeehwan Kim
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; Pusan National University (PNU), Busan, Republic of Korea
| | - Sinuo Zhang
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Chang Woo Gal
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea
| | - Yeong-Jin Choi
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea
| | - Honghyun Park
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea
| | - Hui-Suk Yun
- Korea Institute of Materials Science (KIMS), Changwon, Republic of Korea,; University of Science and Technology (UST), Daejeon, Republic of Korea.
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Shirani M, Emami M, Mosharraf R, Savabi O, Akhavankhaleghi M, Azadbakht K. Comparing the color match of monolithic CAD-CAM dental ceramics with the VITA Classical shade guide. J Prosthet Dent 2022:S0022-3913(22)00463-2. [PMID: 36115709 DOI: 10.1016/j.prosdent.2022.06.024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 06/17/2022] [Accepted: 06/21/2022] [Indexed: 10/14/2022]
Abstract
STATEMENT OF PROBLEM Matching the shade selected and the final color of a ceramic restoration is challenging, and studies on matching monolithic ceramics to the shade selected are lacking. PURPOSE The purpose of this in vitro study was to compare the color match of monolithic lithium disilicate (LDS), zirconia-reinforced lithium silicate (ZLS), presintered zirconia-reinforced lithium silicate (PS-ZLS), polymer-infiltrated ceramic network (PICN), and multilayer zirconia with the 3 modes of the VITA Classical shade guide. MATERIAL AND METHODS This study was performed on 50 rectangular plates (14×12×1 mm) of 5 types of ceramics with A2 shade (n=10). Zirconia specimens were evaluated in 3 locations: incisal, medial, and cervical thirds. The color coordinates of the specimens of all 7 groups were measured on #3 and #8 Ivoclar Natural Die Color material by using a reflective spectrophotometer. The color coordinates of A2 VITA shade were measured in 5 modes: without backing placed in specimen holder, shade tab on the backgrounds #3 and #8, and 1-mm-thick shade tab on the backgrounds #3 and #8. The color difference of each specimen with 3 modes of A2 shade (without backing and on similar backgrounds) was calculated by using the ΔE00 formula, and comparison among groups was performed by using 2-way ANOVA and Tamhane post hoc tests. The comparison of ΔE00 between the values obtained from backgrounds #3 and #8 was performed by using the independent t test (α=.05). RESULTS In both backgrounds, statistically significant differences were found between the studied groups and VITA shade (P<.001). In most situations, the amount of color difference was lowest for the "shade tab on the backgrounds" mode. On background #3, the highest color difference was related to ZLS (6.48 ±0.23), and the lowest values were observed in the PICN group (1.02 ±0.31). On background #8, the highest color difference was related to ZLS compared with the "without backing" mode (8.62 ±0.27), and the lowest values were reported for ZLS compared with the "shade tab on the backgrounds" mode (1.27 ±0.44). The independent t test showed a statistically significant color difference on the 2 different backgrounds for all situations (P<.001). CONCLUSIONS Color selection of monolithic ceramics with the VITA Classical shade guide is improved by placing the VITA tabs on a similar background. Background color has a significant effect on the final shade of the monolithic ceramics. Choosing the correct color for LDS, ZLS, and PS-ZLS requires more care than for PICN and zirconia.
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Affiliation(s)
- Mohammadjavad Shirani
- Assistant Professor, Department of Prosthodontics, School of Dentistry, Lorestan University of Medical Sciences, Khorramabad, Iran
| | - Maryam Emami
- Instructor, Dentist, student Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Ramin Mosharraf
- Professor of Prosthodontics, Dental Materials Research Center, Department of Prosthodontics, Dental Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Omid Savabi
- Professor of Prosthodontics, Dental Materials Research Center, Department of Prosthodontics, Dental Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran; Professor of Prosthodontics, Dental Research Center, Dental Research Institute, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mehrdad Akhavankhaleghi
- Assistant Professor, Department of Prosthodontics, School of Dentistry, Shahrekord University of Medical Sciences, Shahrekord, Iran
| | - Kamran Azadbakht
- Assistant Professor, Department of Prosthodontics, School of Dentistry, Lorestan University of Medical Sciences, Khorramabad, Iran.
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Altan B, Cinar S. Effect of Repeated Firings and Thickness on Optical Properties of Variable Preshaded and Shaded Novel Translucent Zirconia Blocks. BIOMED RESEARCH INTERNATIONAL 2022; 2022:8572782. [PMID: 36017380 PMCID: PMC9398792 DOI: 10.1155/2022/8572782] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 08/05/2022] [Indexed: 11/18/2022]
Abstract
Objective The purpose of this study was to examine the optical properties of translucent zirconia with different thickness during multiple firings. Materials and Methods Three different types of translucent zirconia (Vita YZ HT (HT), Vita YZ ST (ST), Vita YZ XT (XT)) with thickness of 0.5, 1, and 1.5 mm were used in the study. 180 disk-shaped specimens (n = 10) were prepared from preshaded and nonshaded blocks. The coloring liquid (A2, Vita Shade Liquid) was applied with a synthetic nylon brush in the nonshaded group. Then, the specimens were then subjected to 1, 3, and 5 firing times. After consecutive firings, color differences (ΔE) and translucency parameter (TP) were measured. Statistical analysis was carried out by using repeated measure ANOVA followed by Tukey test. Results ANOVA analysis reveals that TP and ΔE were significantly affected by the repeated firings. The highest TP was seen in 0.5 mm XT specimen. For all specimens, TP decreases from 1st to 3rd firing cycles, despite TP increases from 3rd to 5th firing cycles. Although there is a significant change in TP values in 0.5 mm thickness, there is no significant change between firing cycles for 1 and 1.5 mm thickness specimens. The highest ΔE value was observed for shaded specimens between 1st and 5th firings. ΔE values were not significantly different between 1 and 3 firings. Conclusions Changes in thickness and repeated firings of zirconia specimens affected final color and translucency of zirconia specimens. HT blocks are more affected by consecutive firings than ST and XT blocks. ΔE increased as the thicknesses decreased for both types of translucent zirconia specimens tested.
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Affiliation(s)
- Bike Altan
- Department of Prosthodontics, Faculty of Dentistry, University of Health Sciences, Uskudar, Istanbul, Turkey
| | - Sevki Cinar
- Department of Prosthodontics, Faculty of Dentistry, University of Health Sciences, Uskudar, Istanbul, Turkey
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Hsu WC, Peng TY, Kang CM, Chao FY, Yu JH, Chen SF. Evaluating the Effect of Different Polymer and Composite Abutments on the Color Accuracy of Multilayer Pre-Colored Zirconia Polycrystal Dental Prosthesis. Polymers (Basel) 2022; 14:polym14122325. [PMID: 35745899 PMCID: PMC9229389 DOI: 10.3390/polym14122325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2022] [Revised: 06/03/2022] [Accepted: 06/07/2022] [Indexed: 12/25/2022] Open
Abstract
With increasing aesthetic awareness and emphasis on time costs in today’s society, monolithic multilayer precolored zirconia ceramics (M-Zr) facilitate aesthetic restorations in a convenient and straightforward manner without the need for veneering porcelain to modify the color. However, the effect of abutment materials on the final color of M-Zr remains unclear. Herein, we placed Vita A1 Shade M-Zr on six different abutment materials, zirconia (Y-TZP), 3D printed composite resin (CR), dental model resin (MR), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and cobalt−chromium alloy (Co−Cr), to evaluate their effect on the color accuracy of M-Zr. The color attributes (L*, a*, and b*) were measured using a dental spectrophotometer. The translucency parameter (TP), contrast ratio, color difference (ΔE) between each background substrate and the Vita A1 Shade Guide, and chroma values (C) were calculated to evaluate the color accuracy of M-Zr. A statistical analysis was performed using one-way analysis of variance and post hoc Tukey’s HSD tests (α = 0.05). The experimental results indicate that the TP values and contrast ratio of the M-Zr samples were 14.85 and 0.83, respectively. Co−Cr had the highest ΔE (6.08) and lowest C value (7.52); PEKK had the lowest ΔE (2.60), and PEEK had the highest C value (12.23) (p < 0.05). Notably, the ΔE values of CR (3.13), PEEK (2.86), and PEKK were within clinical indicators (ΔE < 3.7). Based on these results, it can be concluded that the abutment material has a significant effect on the final color of the M-Zr, and PEEK or PEKK resulted in good color accuracy. When choosing the dental MR, traditional zirconia, or metals as abutment materials, colored or opaque cement might be required to eliminate color distortion and achieve desirable optical properties.
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Affiliation(s)
- Wen-Chieh Hsu
- School of Dentistry, College of Dentistry, China Medical University, Taichung 40402, Taiwan;
| | - Tzu-Yu Peng
- School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei 11031, Taiwan;
| | | | - Fan-Yi Chao
- Department of Physiology and Biophysics, University of Colorado School of Medicine, Aurora, CO 80045, USA;
| | - Jian-Hong Yu
- School of Dentistry, College of Dentistry, China Medical University, Taichung 40402, Taiwan;
- Correspondence: (J.-H.Y.); (S.-F.C.); Tel.: +886-4-2205-3366 (ext. 2309) (S.-F.C.)
| | - Su-Feng Chen
- School of Dentistry, College of Dentistry, China Medical University, Taichung 40402, Taiwan;
- Correspondence: (J.-H.Y.); (S.-F.C.); Tel.: +886-4-2205-3366 (ext. 2309) (S.-F.C.)
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Wu Z, Tian J, Wei D, Di P, Lin Y. Quantitative analysis of color accuracy and bias in 4 dental CAD-CAM monolithic restorative materials with different thicknesses: An in vitro study. J Prosthet Dent 2022; 128:92.e1-92.e7. [PMID: 35595548 DOI: 10.1016/j.prosdent.2022.04.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 04/19/2022] [Accepted: 04/19/2022] [Indexed: 10/18/2022]
Abstract
STATEMENT OF PROBLEM Computer-aided design and computer-aided manufacturing (CAD-CAM) monolithic restorative materials have become a popular option because of advantages such as convenience and efficiency. However, studies that quantitatively analyzed their color accuracy and bias are lacking. PURPOSE The purpose of this in vitro study was to evaluate the color accuracy and bias of 4 CAD-CAM monolithic restorative materials with different thicknesses by using the CIELab color space. MATERIAL AND METHODS Four types of dental CAD-CAM monolithic restorative materials in shade A2, lithium disilicate glass-ceramic (IPS e.max CAD), infiltrated ceramic (VITA Enamic), resin-nano ceramic (LAVA Ultimate), and polymethyl methacrylate (Telio CAD), were prepared as 12×12-mm specimens of 10 different thicknesses (from 0.5 to 5.0 mm) (N=200, n=5). After polishing with SiC P1500-grit, CIELab color coordinate parameters of the specimens were measured with a spectrophotometer (VITA Easyshade V). The color accuracy and bias were described by ΔE00, ΔL∗, Δa∗, and Δb∗ in the CIELab color space, and the data were analyzed by using a 2-way ANOVA, post hoc Tukey-Kramer test, and the t test (α=.05). RESULTS The ΔE00, ΔL∗, Δa∗, and Δb∗ were significantly influenced by material type and thickness (P<.001). Specimens at a thickness of 0.5 mm represented the maximum ΔE00. The minimum ΔE00 was observed at a thickness of 2.0 mm for LAVA Ultimate, 1.5 mm for VITA Enamic and Telio CAD, and 4.0 mm for IPS e.max CAD. The ΔE00 of all specimens significantly exceeded the 50:50% acceptability threshold (1.8 unit) (P<.001). LU exhibited higher ΔE00, Δa∗, and Δb∗ than the other 3 materials in all thickness expect for 0.5 mm. For color bias, the ΔE00 was more influenced by Δb∗ and ΔL∗ than Δa∗. CONCLUSIONS The color accuracy and bias were significantly affected by material type and thickness. The color inaccuracy of the tested materials was statistically significant and clinically perceptible. Improved clinical outcomes may be expected from the 1.5-mm- to 2.0-mm-thick restorations.
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Affiliation(s)
- Zhengda Wu
- Postgraduate student, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Jiehua Tian
- Lecturer, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Donghao Wei
- Lecturer, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Ping Di
- Professor, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, China
| | - Ye Lin
- Professor, Department of Oral Implantology, Peking University School and Hospital of Stomatology, Beijing, China.
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