1
|
Chen Z, Zhang M, Zhang R, Hao P. Effect of the coloring liquid shade and dipping time on the color, transparency, and flexural strength of monolithic zirconia. J Prosthet Dent 2024; 132:229.e1-229.e8. [PMID: 38604904 DOI: 10.1016/j.prosdent.2024.03.035] [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: 08/30/2023] [Revised: 03/04/2024] [Accepted: 03/05/2024] [Indexed: 04/13/2024]
Abstract
STATEMENT OF PROBLEM The impact of different coloring liquid shades and dipping times on the color, transparency, and flexural strength of monolithic zirconia ceramics is unclear. PURPOSE The purpose of this in vitro study was to evaluate the effects of different coloring liquid shades (A2, 3M2, and 5M2) and dipping times (no dipping, 30 seconds, 60 seconds, and 90 seconds) on the color difference (ΔE00), relative translucency parameter (ΔRTP00), and 3-point flexural strength (σ) of monolithic zirconia ceramics. MATERIAL AND METHODS Yttria-stabilized zirconia (3Y-TZP, 3 mol%) was cut into Ø16×1.2-mm plates (n=10) and 25×4×1.2-mm bars (n=15), which were colored using 3 shades of coloring liquid at 4 dipping times. Color coordinates were measured on a gray background by using a digital spectrophotometer with an integrating sphere attachment. The color and translucency differences were evaluated using 50:50% perceptibility (PT00 and TPT00) and acceptability (AT00 and TAT00) thresholds. The 3-point flexural strengths of the bar-shaped specimens were measured using a universal testing machine and analyzed using the Weibull distribution to calculate the Weibull modulus (m) and characteristic fracture strength (σ0). The data were analyzed with the 2-way ANOVA, Kruskal-Wallis, and LSD post hoc tests (α=.05). RESULTS Both shade and dipping time significantly affected the color and translucency of monolithic zirconia (P<.001). The ΔE00 was above the PT00 for all groups, with only 3M2-90 and A2-60 being below the AT00. The main cause of color differences was the difference in lightness. Only A2 showed ΔRTP00 below the TPT00 (A2-30 (ΔRTP00=0.26), A2-60 (ΔRTP00=0.29), and A2-90 (ΔRTP00=0.46)). All experimental groups showed translucency differences below TAT00. In addition, only the dipping time had a significant effect on the flexural strength of zirconia (P<.001). CONCLUSIONS The optical properties of monolithic zirconia ceramics were affected by the shade and dipping time of the coloring liquid. The mismatch in lightness was the main reason for the color difference. The dipping time affects the flexural strength of monolithic zirconia, whereas the shade of the coloring liquid did not seem to influence flexural strength.
Collapse
Affiliation(s)
- Zijie Chen
- Graduate student, Dental Technology, School of Stomatology, Binzhou Medical University, Yantai, PR China
| | - Mengmeng Zhang
- Graduate student, Dental Technology, School of Stomatology, Binzhou Medical University, Yantai, PR China
| | - Rimei Zhang
- Graduate student, Yantai Stomatological Hospital of Binzhou Medical University, Yantai, PR China
| | - Pengjie Hao
- Associate Professor, Department of Prosthodontics, Yantai Stomatological Hospital of Binzhou Medical University, Yantai, PR China.
| |
Collapse
|
2
|
Su C, Lu ZC, Ji X, Yu H. Optical properties of recycled zirconia for dental applications. J Prosthet Dent 2024; 131:1237.e1-1237.e7. [PMID: 38418303 DOI: 10.1016/j.prosdent.2024.02.001] [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: 11/30/2023] [Revised: 02/05/2024] [Accepted: 02/07/2024] [Indexed: 03/01/2024]
Abstract
STATEMENT OF PROBLEM While waste zirconia can be recycled, whether the optical properties of recycled zirconia match those of commercially available zirconia is unclear. PURPOSE The purpose of this in vitro study was to evaluate the optical properties of recycled zirconia by assessing its color, translucency, and opalescence across different thicknesses and shades. MATERIAL AND METHODS Sixty specimens were prepared from 3 mol% yttria-stabilized tetragonal zirconia polycrystal blocks (Lava Plus; 3M ESPE) (group C); 60 other specimens were prepared from waste blocks of the same zirconia (group R). The specimens were further categorized into 4 subgroups (n=15) based on their thicknesses (1.0 mm or 1.5 mm) and shades (A1 or A3). Specimen color was measured with a spectrophotometer (Easyshade Advance 4.0; Vita ZahnFabrik). The parameters of color difference (ΔE00), translucency (TP), contrast ratio (CR), and opalescence (OP) were calculated. Grain size analysis was performed using scanning electron microscopy. Data were analyzed with analysis of variance (ANOVA) (α=.05). RESULTS Significant differences in translucency and opalescence were observed between groups C and R in all specimens (P<.001). Group R exhibited a range of TP (4.89 to 11.27), CR (0.74 to 0.91), and OP (3.36 to 8.65) values. The ΔE00 values between groups C and R ranged from 13.99 to 21.31. Both thickness and shade significantly affected the ΔE00 values (P<.001). The grain size in group C was not significantly different from that in group R (F=0.364, df=1, P=.555). The TP and OP values of group R decreased with increasing thickness (P<.001). CONCLUSIONS Recycled zirconia was less translucent and opalescent than commercially available zirconia. The color difference between commercially available and recycled zirconia exceeded the acceptable threshold, even when using the same staining procedure. Recycled zirconia exhibited reduced translucency and opalescence with increasing thickness.
Collapse
Affiliation(s)
- Chen Su
- Postgraduate student, Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, PR China
| | - Zhi-Cen Lu
- PhD Candidate, Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, PR China
| | - Xiong Ji
- Postgraduate student, Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Laboratory of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, PR China
| | - Hao Yu
- Associate Professor and Associate Dean, School and Hospital of Stomatology, Fujian Medical University, Fuzhou, Fujian, PR China, and Adjunct Associate Professor, Department of Applied Prosthodontics, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan.
| |
Collapse
|
3
|
Ateş G, Demirel M, Donmez MB, Dayan SÇ, Sülün T. Effect of material and antagonist type on the wear of occlusal devices with different compositions fabricated by using conventional, additive, and subtractive manufacturing. J Prosthet Dent 2024; 131:1235.e1-1235.e8. [PMID: 38594086 DOI: 10.1016/j.prosdent.2024.03.026] [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: 10/04/2023] [Revised: 03/18/2024] [Accepted: 03/19/2024] [Indexed: 04/11/2024]
Abstract
STATEMENT OF PROBLEM Additive (AM) and subtractive (SM) manufacturing have become popular for fabricating occlusal devices with materials of different chemical compositions. However, knowledge on the effect of material and antagonist type on the wear characteristics of occlusal devices fabricated by using different methods is limited. PURPOSE The purpose of this in vitro study was to evaluate the effect of material and antagonist type on the wear of occlusal devices fabricated by using conventional manufacturing, AM, and SM. MATERIAL AND METHODS Two-hundred and forty Ø10×2-mm disk-shaped specimens were fabricated by using heat-polymerized polymethylmethacrylate (control, CM), AM clear device resin fabricated in 3 different orientations (horizontal [AMH], diagonal [AMD], and vertical [AMV]), SM polymethylmethacrylate (SMP), and SM ceramic-reinforced polyetheretherketone (SMB) (n=40). Specimens were then divided into 4 groups based on the antagonists: steatite ceramic (SC); multilayered zirconia (ZR); lithium disilicate (EX); and zirconia-reinforced lithium silicate (ZLS) used for thermomechanical aging (n=10). After aging, the volume loss (mm3) and maximum wear depth (μm) were digitally evaluated. Data were analyzed with 2-way analysis of variance and Tukey honestly significant difference tests (α=.05). RESULTS The interaction between the device material and the antagonist affected volume loss and maximum depth of wear (P<.001). AMH had volume loss and depth of wear that was either similar to or higher than those of other materials (P≤.044). When SC was used, CM had higher volume loss and depth of wear than AMV, and, when EX was used, AMD had higher volume loss and depth of wear than SMP (P≤.013). SC and ZR led to higher volume loss of CM and AMH than EX and led to the highest depth of wear for these materials, while ZR also led to the highest volume loss and depth of wear of AMD and AMV (P≤.019). EX led to the lowest volume loss and depth of wear of AMV and SMP and to the lowest depth of wear of AMH (P≤.021). Regardless of the antagonist, SMB had the lowest volume loss and depth of wear (P≤.005). CONCLUSIONS AMH mostly had higher volume loss and depth of wear, while SMB had the lowest volume loss, and its depth of wear was not affected by the tested antagonists. ZR mostly led to higher volume loss and maximum depth of wear, while EX mostly led to lower volume loss and maximum depth of wear of the tested occlusal device materials.
Collapse
Affiliation(s)
- Gökçen Ateş
- Postdoctoral Research Associate, Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey; and ITI Scholar, Department of Prosthodontics, University of São Paulo (USP), São Paulo, Brazil
| | - Münir Demirel
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Biruni University, Istanbul, Turkey
| | - Mustafa Borga Donmez
- Associate Professor, Department of Prosthodontics, Faculty of Dentistry, Istinye Univeristy, İstanbul, Turkey; and ITI Scholar, Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland.
| | - Süleyman Çağatay Dayan
- Associate Professor, Program of Dental Technicians, Istanbul University-Cerrahpasa, Istanbul, Turkey
| | - Tonguç Sülün
- Professor, Department of Prosthodontics, Faculty of Dentistry, Istanbul University, Istanbul, Turkey
| |
Collapse
|
4
|
Zenthöfer A, Ilani A, Schmitt C, Rammelsberg P, Hetzler S, Rues S. Biaxial flexural strength of 3D-printed 3Y-TZP zirconia using a novel ceramic printer. Clin Oral Investig 2024; 28:145. [PMID: 38351386 PMCID: PMC10864574 DOI: 10.1007/s00784-024-05533-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2023] [Accepted: 01/29/2024] [Indexed: 02/16/2024]
Abstract
OBJECTIVES To compare the strength and reliability of 3D-printed 3Y-TZP zirconia manufactured with various printing orientations and staining. MATERIALS AND METHODS A total of one-hundred cylindrical zirconia specimens were designed and fabricated using 3D printing and processed according to ISO 6872 standards. Of these specimens, 80 were 3D printed using the new ZIPRO-D (ZD) 3D ceramic printer. In this ZD group, 60 specimens were printed in a vertical orientation and were either stained after debinding (ZD1, x-orientation, n = 20) or not stained (ZD2, x-orientation, n = 20; ZD3, y-orientation, n = 20) and the remaining 20 specimens out of n = 80 were printed in a horizontal orientation (ZD4). Further 20 specimens out of the entire sample N = 100 were printed vertically with the CeraFab7500 3D ceramic printer (LC). All completed specimens were loaded until fracture using a universal testing machine. Biaxial flexural strengths and Weibull parameters were computed for the ZD groups and for the LC group. Group and sub-group effects were evaluated using Welch ANOVA (alpha = 0.05). RESULTS The mean (standard deviation, SD) biaxial flexural strengths of vertically oriented ZD samples with (ZD1) and without (ZD2/ZD3) staining were 811 (197) and 850 (152) MPa, respectively (p > 0.05). The ZD4 (horizontally printed), 1107 (144) MPa, and LC (1238 (327)) MPa samples had higher mean (SD) flexural strengths than the ZD1-3 specimens. No difference was observed between the ZD4 and LC group (p > 0.05). Weibull moduli were between m = 4.6 (ZD1) and 9.1 (ZD4) in the ZD group and m = 3.5 in the LC group. CONCLUSIONS All tested 3D-printed zirconia specimens exceeded the flexural strengths required for class 5 restorations according to ISO 6872 standards. While the flexural strengths of zirconia printed using the novel ZD device in the vertical orientation are lower than those of zirconia printed using the LC printer, the ZD printer shows at least comparable reliability. CLINICAL RELEVANCE 3D-printing of zirconia is a new technology in dental application. Based on the presented strengths values, clinical application of 3D-printed zirconia for fixed dental protheses can be recommended.
Collapse
Affiliation(s)
- Andreas Zenthöfer
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany.
| | - Ali Ilani
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Clemens Schmitt
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Peter Rammelsberg
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Sebastian Hetzler
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| | - Stefan Rues
- Department of Prosthodontics, University Clinic Heidelberg, University of Heidelberg, 69120, Heidelberg, Germany
| |
Collapse
|
5
|
Alghazzawi TF, Janowski GM, Eberhardt AW. An experimental study of flexural strength and hardness of zirconia and their relation to crown failure loads. J Prosthet Dent 2024; 131:320-328. [PMID: 35995603 DOI: 10.1016/j.prosdent.2022.04.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 04/04/2022] [Accepted: 04/05/2022] [Indexed: 11/23/2022]
Abstract
STATEMENT OF PROBLEM Dental zirconia is often marketed and selected for restorative use based upon the biaxial flexural strength of prefabricated specimens (disks) without considering other mechanical and physical properties. PURPOSE The purpose of this in vitro study was to test whether 4-point flexural strength, biaxial flexural strength, and/or hardness may correlate with failure loads for crowns made of different zirconia materials. MATERIAL AND METHODS Three brands of zirconia (BruxZir, Cercon, and Katana) were used to fabricate anatomically contoured crowns, rectangular bars, and circular disks. The sample size was n=15 specimens per zirconia brand and specimen shape. The bars were tested for 4-point flexural strength by using the 4-point bending (4PB) test and Vickers hardness (VH), while the disks were tested for biaxial flexural strength by using a piston-on-3 ball (POB) test. Crowns were attached to resin abutments and compressed with a steel spherical indenter through a polyethylene sheet to assess the failure loads by using the "crunch the crown" (CTC) test. One-way ANOVA (α=.05) was used to test for statistically significant differences between groups, and Weibull analysis was used to assess the variability of the measured flexural strengths, failure load, and hardness. RESULTS Statistical differences (P<.001) were found in comparing Cercon, BruxZir, and Katana ([4260 N=4186 N]>3195 N, respectively) with the CTC test and (396 MPa>[281 MPa=275 MPa], respectively) the 4PB test. No statistical differences (P=.084) were found among the zirconia brands (Cercon [384 MPa]=Bruxzir [359 MPa]=Katana [416 MPa]) for the POB test. No significant correlations (P>.05) were found between the 4PB, POB, or VH tests and the corresponding CTC test. The Weibull modulus varied for the different specimen geometries. CONCLUSIONS The piston-on-3 ball, 4-point bending, and Vickers hardness test results were not correlated with the corresponding crunch-the-crown test.
Collapse
Affiliation(s)
- Tariq F Alghazzawi
- Associate Professor, Department of Substitutive Dental Sciences, Taibah University, Madina, Saudi Arabia; Fullbright Scholar, Department of Materials Science and Engineering, The University of Alabama at Birmingham, Birmingham, USA.
| | - Gregg M Janowski
- Professor, Department of Materials Science and Engineering, University of Alabama at Birmingham, Birmingham, Ala
| | - Alan W Eberhardt
- Professor and Associate Chair, Department of Biomedical Engineering, University of Alabama at Birmingham, Birmingham, Ala
| |
Collapse
|
6
|
Zenthöfer A, Schwindling FS, Schmitt C, Ilani A, Zehender N, Rammelsberg P, Rues S. Strength and reliability of zirconia fabricated by additive manufacturing technology. Dent Mater 2022; 38:1565-1574. [PMID: 35933222 DOI: 10.1016/j.dental.2022.07.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 06/29/2022] [Accepted: 07/20/2022] [Indexed: 11/13/2022]
Abstract
OBJECTIVES To test strength and reliability of 3D printed compared to milled zirconia. METHODS Cylindrical specimens were fabricated from milled (group G1; e.max ZirCAD LT) and from 3D printed (group G2; LithaCon 3Y 230) 3-mol% yttria-stabilized tetragonal zirconia polycrystal (3Y-TZP). While G1 and G2 were sintered in one step, a further series (G3) of 3D printed 3Y-TZP was sintered in two steps including intermediate color infiltration. In each group, two different conditioning strategies were applied (n ≥ 20 samples/subgroup): (1) final polishing with #1200 diamond discs according to ISO 6872, and (2) final polishing with #220 diamond discs resulting in imperfectly polished surfaces. All samples were tested to fracture with a universal testing device (cross-head speed: 1 mm/min). Characteristic strengths and Weibull moduli were calculated. Effects were analyzed by means of either ANOVA (homocedastic data) or Welch ANOVA (heterocedastic data). RESULTS For samples conditioned according to ISO 6872, mean flexural strengths were 1462 ± 105 MPa (G1), 1369 ± 280 MPa (G2), and 1197 ± 317 MPa (G3). For the imperfectly polished subgroups, strength values were 1461 ± 121 MPa (G1), 1349 ± 332 MPa (G2), and 1271 ± 272 MPa (G3). Although all groups showed high mean strength values, the reliability of milled zirconia (Weibull moduli 14 < m <16) outperformed that of the 3D-printed material (3 < m <6). SIGNIFICANCE Even after color infiltration in a partially sintered state, the tested 3D printed zirconia exceeded the ISO flexural strength criteria for all types of fixed ceramic restorations by far (800 MPa for class 6, ISO 6872), indicating its high potential for clinical use. Further optimization of the internal material structure after sintering might improve the reliability of 3D printed zirconia which is currently inferior to that of milled zirconia.
Collapse
Affiliation(s)
- Andreas Zenthöfer
- Department of Prosthodontics, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Franz Sebastian Schwindling
- Department of Prosthodontics, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Clemens Schmitt
- Department of Prosthodontics, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Ali Ilani
- Department of Prosthodontics, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Nathalie Zehender
- Department of Prosthodontics, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Peter Rammelsberg
- Department of Prosthodontics, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany
| | - Stefan Rues
- Department of Prosthodontics, University Hospital Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany.
| |
Collapse
|
7
|
Yılmaz Savaş T, Akın C. Effects of sintering protocol and dipping time on the optical properties of monolithic zirconia. J Prosthet Dent 2022; 127:801.e1-801.e8. [DOI: 10.1016/j.prosdent.2021.12.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 12/02/2021] [Accepted: 12/02/2021] [Indexed: 10/19/2022]
|