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Silva SEGD, Silva NRD, Santos JVDN, Moreira FGDG, Özcan M, Souza RODAE. Accuracy, adaptation and margin quality of monolithic zirconia crowns fabricated by 3D printing versus subtractive manufacturing technique: A systematic review and meta-analysis of in vitro studies. J Dent 2024; 147:105089. [PMID: 38772449 DOI: 10.1016/j.jdent.2024.105089] [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: 02/03/2024] [Revised: 04/28/2024] [Accepted: 05/18/2024] [Indexed: 05/23/2024] Open
Abstract
OBJECTIVE The purpose of this systematic review and meta-analysis was to evaluate the accuracy (trueness and precision), marginal and internal adaptation, and margin quality of zirconia crowns made by additive manufacturing compared to subtractive manufacturing technology. METHODS The investigation adhered to the PRISMA-ScR guidelines for systematic reviews and was registered at the Prospero database (n°CRD42023452927). Four electronic databases, including PubMed, Scopus, Embase, and Web of Science and manual search was conducted to find relevant studies published until September 2023. In vitro studies that assessed the trueness and precision, marginal and internal adaptation, and margin quality of printed crowns compared to milled ones were included. Studies on crowns over implants, pontics, temporary restorations, laminates, or exclusively experimental materials were excluded. RESULTS A total of 9 studies were included in the descriptive reporting and 7 for meta-analysis. The global meta-analysis of the trueness (P<0.74,I2=90 %) and the margin quality (P<0.61,I2=0 %) indicated no significant difference between the root mean square of printed and milled zirconia crowns. The subgroup analysis for the printing system showed a significant effect (P<0.01). The meta-analysis of the crown areas indicated no significant difference in most of the areas, except for the marginal (favoring milled crowns) and axial (favoring printed crowns) areas. For precision and adaptation, both methods showed a clinically acceptable level. CONCLUSIONS Additive manufacturing technology produces crowns with trueness and margin quality comparable to subtractive manufacturing. Both techniques have demonstrated the ability to produce crowns with precision levels, internal discrepancy, and marginal fit within clinically acceptable limits. CLINICAL SIGNIFICANCE 3D printing emerges as a promising and potentially applicable alternative method for manufacturing zirconia crowns, as it shows trueness and margin quality comparable to restorations produced by the subtractive method.
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Affiliation(s)
- Sarah Emille Gomes da Silva
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, CEP 59056-000, Brazil
| | - Nathalia Ramos da Silva
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, CEP 59056-000, Brazil
| | - João Vitor do Nascimento Santos
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, CEP 59056-000, Brazil
| | - Fernanda Gurgel de Gois Moreira
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, CEP 59056-000, Brazil
| | - Mutlu Özcan
- University of Zurich, Clinic for Masticatory Disorders and Dental Biomaterials, Center for Dental Medicine, Zentrum für Zahnmedizin, Plattenstrasse, 11, 8032 Zurich, Switzerland
| | - Rodrigo Othávio de Assunção E Souza
- Federal University of Rio Grande do Norte (UFRN), Department of Dentistry, Av. Salgado Filho, 1787, Lagoa Nova, Natal, RN, CEP 59056-000, Brazil.
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Mosaddad SA, Peláez J, Panadero RA, Ghodsi S, Akhlaghian M, Suárez MJ. Do 3D-printed and milled tooth-supported complete monolithic zirconia crowns differ in accuracy and fit? A systematic review and meta-analysis of in vitro studies. J Prosthet Dent 2024:S0022-3913(24)00283-X. [PMID: 38772783 DOI: 10.1016/j.prosdent.2024.04.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2023] [Revised: 04/03/2024] [Accepted: 04/04/2024] [Indexed: 05/23/2024]
Abstract
STATEMENT OF PROBLEM Additive (3-dimensional printing) and subtractive (milling) methods are digital approaches to fabricating zirconia restorations. Comparisons of their resultant fabrication accuracy and restoration fit are lacking. PURPOSE The purpose of this systematic review and meta-analysis was to evaluate the accuracy and fit of monolithic zirconia crowns fabricated by 3-dimensional printing and milling. MATERIAL AND METHODS The PubMed (Medline), Scopus, Embase, Web of Science, Cochrane Library, and Google Scholar databases were searched up to August 2023. Eligible records were included, and the standardized mean difference (SMD) analyzed 4 outcomes: marginal fit, intaglio fit, trueness, and precision. Publication bias was analyzed with Trim-and-fill, the Egger regression test, and Begg funnel plot. Methodological quality was rated using the QUIN tool. RESULTS A total of 15 publications were found eligible out of the initial 6539 records. The 3-dimensional printing group demonstrated a lower marginal fit (SMD=1.46, 95% CI=[0.67, 2.26], P<.001; I2=83%, P<.001) and trueness (SMD=0.69, 95% CI=[0.20, 1.18], P=.006; I2=88%, P<.001) and a significantly higher precision (SMD=-2.19, 95% CI=[-2.90, -1.48], P<.001; I2=56%, P=.045). The intaglio fit did not differ significantly across the study groups (SMD=0.77, 95% CI=[-0.22, 1.77], P=.127; I2=87%, P<.001). CONCLUSIONS Given the high degree of heterogeneity, it can be cautiously concluded that while 3-dimensional printing led to greater precision, the outcomes of the 2 accuracy and adaptation parameters most crucial to the longevity of the restorations-trueness and marginal fit-showed the superiority of the milling technique.
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Affiliation(s)
- Seyed Ali Mosaddad
- Researcher, Department of Conservative Dentistry and Bucofacial Prosthesis, Faculty of Odontology, Complutense University of Madrid, Madrid, Spain; and Adjunct Faculty Member, Department of Research Analytics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences, Saveetha University, Chennai, India.
| | - Jesús Peláez
- Adjunct Professor, Department of Conservative Dentistry and Bucofacial Prosthesis, Faculty of Odontology, Complutense University of Madrid, Madrid, Spain.
| | - Rubén Agustín Panadero
- Professor, Department of Stomatology, Faculty of Medicine and Dentistry, Valencia University, Valencia, Spain
| | - Safoura Ghodsi
- Associate Professor, Dental Research Center, Dentistry Research Institute, Department of Prosthodontics, Tehran University of Medical Sciences, Tehran, Iran
| | - Marzieh Akhlaghian
- Assistant Professor, Department of Prosthodontics, School of Dentistry, Shiraz University of Medical Sciences, Shiraz, Iran
| | - María J Suárez
- Professor, Department of Conservative Dentistry and Bucofacial Prosthesis, Faculty of Odontology, Complutense University of Madrid, Madrid, Spain
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Espona J, Roig E, Ali A, Vidal C, Garcia-Font M, Roig M, Figueras O. Optical impressions assessment for overlay restorations with rubber dam: A clinical trial. J Dent 2024; 143:104825. [PMID: 38157974 DOI: 10.1016/j.jdent.2023.104825] [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: 04/12/2023] [Revised: 12/13/2023] [Accepted: 12/26/2023] [Indexed: 01/03/2024] Open
Abstract
OBJECTIVE The possibility of making impressions of teeth prepared with a rubber dam in place has been proposed; however, this requires trimming and rescanning the mesh, which has been described as a cause of accuracy loss. This study aims to clinically determine whether overlay restorations obtained from a scan with a rubber dam in place have equivalent marginal fit, contact points, and occlusal fit to the same type of restorations obtained from a scan without a rubber dam. MATERIAL AND METHODS Thirty patients who underwent overlay restoration of a molar with at least one neighbouring tooth were selected. After tooth preparation, two scans were performed: one without a rubber dam and the other with a rubber dam. Restorations were randomly created from one scan or another. The marginal fit, interproximal contact points, and occlusal fit were evaluated clinically. Two meshes, with and without rubber dams, were also compared. RESULTS No significant differences were observed in the clinical evaluation of the overlays made of the two meshes. The trueness of the mesh from the impression made with a rubber dam with respect to the mesh without a rubber dam was about 40 µm in the critical areas of the preparation (margins, intaglio, and interproximal contact points). CONCLUSIONS The results of this study show that under the conditions performed and with the equipment used, there are no significant clinical differences between overlay restorations made from a scan with a rubber dam and those made from a scan without a rubber dam. CLINICAL SIGNIFICANCE Scanning with a rubber dam in place may be a valid option for certain types of restorations under certain clinical conditions.
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Affiliation(s)
- José Espona
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Elena Roig
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain; Department of Endodontics, Universitat Internacional de Catalunya, Barcelona, Spain.
| | - Akram Ali
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Carla Vidal
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Marc Garcia-Font
- Department of Endodontics, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Miguel Roig
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain
| | - Oscar Figueras
- Department of Restorative Dentistry, Universitat Internacional de Catalunya, Barcelona, Spain
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Kim HY, Cho JH, Yoon HI, Lee JH, Choi S, Han JS, Yeo ISL. Topographical and crystalline change on surface by sandblasting improve flexural and shear bond strength of niobia-modified yttria-stabilized tetragonal zirconia polycrystal. Dent Mater J 2024; 43:216-226. [PMID: 38417860 DOI: 10.4012/dmj.2023-225] [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] [Indexed: 03/01/2024]
Abstract
This study aimed to investigate the effects of sandblasting on the physical properties and bond strength of two types of translucent zirconia: niobium-oxide-containing yttria-stabilized tetragonal zirconia polycrystals ((Y, Nb)-TZP) and 5 mol% yttria-partially stabilized zirconia (5Y-PSZ). Fully sintered disc specimens were either sandblasted with 125 µm alumina particles or left as-sintered. Surface roughness, crystal phase compositions, and surface morphology were explored. Biaxial flexural strength (n=10) and shear bond strength (SBS) (n=12) were evaluated, including thermocycling conditions. Results indicated a decrease in flexural strength of 5Y-PSZ from 601 to 303 MPa upon sandblasting, while (Y, Nb)-TZP improved from 458 to 544 MPa. Both materials significantly increased SBS after sandblasting (p<0.001). After thermocycling, (Y, Nb)-TZP maintained superior SBS (14.3 MPa) compared to 5Y-PSZ (11.3 MPa) (p<0.001). The study concludes that (Y, Nb)-TZP is preferable for sandblasting applications, particularly for achieving durable bonding without compromising flexural strength.
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Affiliation(s)
- Ha-Young Kim
- Department of Prosthodontics, Seoul National University School of Dentistry
| | - Jun-Ho Cho
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University
| | - Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University
| | - Jae-Hyun Lee
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University
| | - Sunyoung Choi
- Department of Prosthodontics, One-Stop Specialty Center, Seoul National University Dental Hospital
| | - Jung-Suk Han
- Department of Prosthodontics, Seoul National University School of Dentistry
| | - In-Sung Luke Yeo
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University
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Sun H, Tabrizian P, Qambrani A, Jargalsaikhan U, Sui T, Ireland T, Su B. Bio-inspired nacre-like zirconia/PMMA composites for chairside CAD/CAM dental restorations. Dent Mater 2024; 40:307-317. [PMID: 38040580 DOI: 10.1016/j.dental.2023.11.017] [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: 09/14/2023] [Revised: 11/14/2023] [Accepted: 11/23/2023] [Indexed: 12/03/2023]
Abstract
OBJECTIVES To introduce a versatile fabrication process to fabricate zirconia/PMMA composites for chairside CAD/CAM dental restorations. These zirconia composites have nacre-like lamellar microstructures, competent and tooth-matched mechanical properties, as well as crack resistance behaviours. METHODS Bi-directional freeze casting was used to fabricate ceramic green bodies with highly aligned lamellar structure. Pressure was then applied to control the ceramic volume fraction. PMMA was infiltrated into the ceramic scaffold. Mechanical tests including 3-point bending, Vickers hardness, and fracture toughness were performed on the composites. The machinability of the composites was also characterised. RESULTS Two types of nacre-like zirconia/PMMA composites, i.e., 3Y-YZP/PMMA and 5Y-PSZ/PMMA composites were fabricated. The microstructure created was similar to the 'brick and mortar' structure of nacre. Excellent flexural strength (up to 400 MPa and 290 MPa for 3Y-TZP/PMMA and 5Y-PSZ/PMMA composite, respectively), tuneable hardness and elastic modulus within the range similar to enamel, along with improved crack-resistance behaviour were demonstrated on both zirconia composites. In addition, both zirconia/PMMA composites showed acceptable machinability, being easy to mill, as would be required to produce a dental crown. SIGNIFICANCE Nacre-like zirconia/PMMA composites therefore exhibit the potential for use in the production of chairside CAD/CAM dental restorations.
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Affiliation(s)
- Huijun Sun
- Biomaterials Engineering Group, Bristol Dental School, University of Bristol, UK
| | - Parinaz Tabrizian
- Biomaterials Engineering Group, Bristol Dental School, University of Bristol, UK
| | - Aqsa Qambrani
- Department of Mechanical Engineering Sciences, University of Surrey, UK
| | | | - Tan Sui
- Department of Mechanical Engineering Sciences, University of Surrey, UK
| | - Tony Ireland
- Biomaterials Engineering Group, Bristol Dental School, University of Bristol, UK
| | - Bo Su
- Biomaterials Engineering Group, Bristol Dental School, University of Bristol, UK.
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Lim YA, Kim JM, Choi Y, Park S. Evaluation of Fitness and Accuracy of Milled and Three-Dimensionally Printed Inlays. Eur J Dent 2023; 17:1029-1036. [PMID: 36599450 PMCID: PMC10756847 DOI: 10.1055/s-0042-1758796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
OBJECTIVE This article compares and evaluates the marginal and internal fitness and three-dimensional (3D) accuracy of class II inlays fabricated using Tescera (TS) resin, milling of hybrid and zirconia blocks, and 3D printing with NextDent C&B. MATERIALS AND METHODS Fifty-two mesio-occlusal inlays were fabricated using conventional method with TS, milling of Lava Ultimate (LU), milling of Zolid Fx multilayer (ZR), and 3D printing (n = 13 each). The marginal and internal fitness were evaluated at six points in the mesio-distal section of a replica under a digital microscope (160× magnification), and the accuracy was evaluated using 3D software. Analyses were conducted using t-test, one-way analysis of variance (ANOVA) and two-way ANOVA, while Duncan's multiple range test was used for post hoc analyses (α = 0.05). RESULTS The marginal and internal fitness of the 3D and ZR were significantly superior to that of the TS and LU. For LU, ZR, and 3D, a significant discrepancy between the marginal gap and internal gap was observed (p < 0.05). On evaluating accuracy, trueness was significantly higher in ZR than in TS and LU; precision was significantly higher in 3D and ZR than in TS and LU (p < 0.05). CONCLUSION The marginal and internal fitness and the accuracy of TS, ZR, and 3D were within the clinically acceptable range. The marginal and internal fitness and accuracy of 3D were better than those of TS and LU, which are commonly used in dentistry. There is immense potential for using 3D-printed inlays in routine clinical practice.
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Affiliation(s)
- Yoen Ah Lim
- Department of Conservative Dentistry, School of Dentistry, Wonkwang University, Iksan, Republic of Korea
| | - Jeong Mi Kim
- Wonkwang University Dental Hospital, Central Dental Laboratory, Iksan, Republic of Korea
| | - Yoorina Choi
- Department of Conservative Dentistry, School of Dentistry, Wonkwang University, Iksan, Republic of Korea
| | - Sujung Park
- Department of Conservative Dentistry, School of Dentistry, Wonkwang University, Iksan, Republic of Korea
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Pan Y, Lin H, Wang Y, Jiang L, Cheng Y, Yu H, Cheng H. Comparison of occlusal contact errors of 6 chairside CAD/CAM crowns: a self-controlled clinical study. Clin Oral Investig 2023; 27:1301-1310. [PMID: 36333533 DOI: 10.1007/s00784-022-04764-8] [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: 07/19/2022] [Accepted: 10/20/2022] [Indexed: 11/07/2022]
Abstract
OBJECTIVES The purpose of this self-controlled clinical study was to evaluate the trueness of occlusal contacts of chairside CAD/CAM crowns fabricated using different ceramic materials. MATERIALS AND METHODS Ten volunteers (8 females, 2 males, average aged 20-30) were recruited in this study registered in the Clinical Trials Registry (#NCT05346744). After tooth preparation on tooth 36 or 46, an optical scan unit (CEREC Omnicam, Sirona Dental Systems, Germany) was utilized to perform the intraoral scanning. For each volunteer, 6 crowns were fabricated via the chairside CAD/CAM process (CEREC, Sirona Dental Systems, Germany) using the following materials: InCoris TZI (ZIR), Celtra Duo (CD), e.max CAD (EMA), UP.CAD (UP), Enamic (ENA) and Hyramic (HY). The microhardness of the milled surfaces was measured through a Vickers hardness Tester (HVS-50Z, Trojan, China). Together with the amount of occlusal adjustment, the occlusal contact trueness at both milling and postprocessing stages were quantitatively analyzed by using a high-precision scanner (ATOS, GOM Technologies, USA) and a reverse engineering software (Geomagic Control, 3D Systems, Rock Hill, SC). The times of chairside occlusal adjustment were also recorded. Data were analyzed by one-way analysis of variance (ANOVA) and ANOVA with randomized block design followed by Bonferroni test (p = 0.05). RESULTS Significant differences were found in surface microhardness of the materials tested (CD > EMA ~ UP > ENA > HY > ZIR, p < 0.05). Regarding the occlusal contact trueness at milling stage, ZIR showed the lowest (p < 0.05), while no significant difference was found among others (p > 0.05). At postprocessing stage, except for ENA, the occlusal contact trueness of ZIR was significantly lower than that of others (p < 0.05). As for occlusal adjustment amount, ZIR was lower than CD and ENA (p < 0.05). In addition, ENA, HY and ZIR required fewer times of occlusal adjustment than EMA, UP and CD. CONCLUSIONS The type of chairside CAD/CAM ceramic materials affected the occlusal contact trueness throughout the process of manufacturing and the amount of clinical occlusal adjustment as well. Zirconia exhibited the worst occlusal contact trueness at both milling and postprocessing stages, while the amount of occlusal adjustment was the least, which recommended the least occlusal compensation. CLINICAL RELEVANCE For better trueness, different negative occlusal offsets are suggested to be applied in the design process, so as to suit the material of the restoration.
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Affiliation(s)
- Yu Pan
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, 88 Jiaotong Road, Fuzhou, 350004, Fujian, China
| | - Honglei Lin
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, 88 Jiaotong Road, Fuzhou, 350004, Fujian, China
| | - Yinghui Wang
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, 88 Jiaotong Road, Fuzhou, 350004, Fujian, China
| | - Lei Jiang
- Institute of Stomatology & Research Center of Dental Esthetics and Biomechanics, School and Hospital of S tomatology, Fujian Medical University, 246 Yangqiao Zhong Road, Fuzhou, 350002, Fujian, China
| | - Yiling Cheng
- Institute of Stomatology & Research Center of Dental Esthetics and Biomechanics, School and Hospital of S tomatology, Fujian Medical University, 246 Yangqiao Zhong Road, Fuzhou, 350002, Fujian, China
| | - Hao Yu
- Institute of Stomatology & Research Center of Dental Esthetics and Biomechanics, School and Hospital of S tomatology, Fujian Medical University, 246 Yangqiao Zhong Road, Fuzhou, 350002, Fujian, China
| | - Hui Cheng
- Fujian Key Laboratory of Oral Diseases & Fujian Provincial Engineering Research Center of Oral Biomaterial & Stomatological Key Lab of Fujian College and University, School and Hospital of Stomatology, Fujian Medical University, 88 Jiaotong Road, Fuzhou, 350004, Fujian, China.
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Cho JH, Yoon HI, Oh JH, Kim DH. Effect of maximum support attachment angle on intaglio surface trueness of anatomic contour monolithic prostheses manufactured by digital light processing and zirconia suspension. J Prosthet Dent 2023; 129:478-485. [PMID: 36621357 DOI: 10.1016/j.prosdent.2022.12.003] [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: 07/13/2022] [Revised: 12/03/2022] [Accepted: 12/05/2022] [Indexed: 01/07/2023]
Abstract
STATEMENT OF PROBLEM Support structures are essential for the quality of resin-based prostheses made by the digital light processing (DLP), but few studies have evaluated the effect of support structure on the accuracy of zirconia-based anatomic contour prostheses. PURPOSE The purpose of this in vitro study was to evaluate the effect of maximum support attachment angle (MSA) on the intaglio surface trueness of anatomic contour prostheses made by DLP and compare the trueness of 2-unit anatomic contour prostheses with that of those produced by milling. MATERIAL AND METHODS Anatomic contour single-unit prostheses were manufactured using DLP and a suspension with 3-mol% yttria-stabilized zirconia. Four different conditions of MSA values to the vertical axis of the object (50, 55, 60, and 65 degrees) were applied (n=10). After printing, postprocessing, and sintering, all successfully produced prostheses were evaluated for intaglio surface trueness by considering the root mean square (RMS). Using the MSA showing the highest trueness, the 2-unit prostheses made by DLP (DLP group) were compared with milled (MIL group) prostheses in terms of intaglio accuracy (n=10). One-way analysis of variance and a post hoc pairwise comparison or independent t test were used for trueness analysis (α=.05). RESULTS Three MSA groups (50, 55, and 60 degrees) were successfully produced with significant differences between the trueness of the single-unit prostheses for the groups with different MSA values (P<.05). The highest trueness was in the 50-degree MSA group. The 2-unit prostheses of the DLP group with 50-degree MSA showed significantly lower trueness than those of the MIL group (P<.05); however, the RMS values of both groups were lower than 50 μm. CONCLUSIONS The intaglio surface trueness of anatomic contour DLP-generated prostheses can be improved by changing the MSA. The 50-degree MSA was beneficial for the accuracy of both single-unit and 2-unit DLP-generated prostheses, produced within clinically acceptable limits.
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Affiliation(s)
- Jun-Ho Cho
- Research Associate, Department of Prosthodontics, Seoul National University School of Dentistry and Dental Research Institute, Seoul, Republic of Korea
| | - Hyung-In Yoon
- Associate Professor, Department of Prosthodontics, Seoul National University School of Dentistry and Dental Research Institute, Seoul, Republic of Korea.
| | - Jin-Ho Oh
- Principal Researcher, Research and Development Center, Mother-of-Pearl (M.O.P) Ltd, Seoul, Republic of Korea
| | - Do-Hyun Kim
- Principal Researcher, Research and Development Center, Mother-of-Pearl (M.O.P) Ltd, Seoul, Republic of Korea
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Yoo SK, Jo YH, Yeo ISL, Yoon HI, Lee JH, Ahn JS, Han JS. Analysis of surface characteristics of (Y, Nb)-TZP after finishing and polishing. J Adv Prosthodont 2022; 14:335-345. [PMID: 36685792 PMCID: PMC9832147 DOI: 10.4047/jap.2022.14.6.335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/25/2022] [Accepted: 10/27/2022] [Indexed: 12/28/2022] Open
Abstract
PURPOSE This in vitro study aimed to evaluate the surface characteristics of a full veneer crown fabricated chairside (CS) from a (Y, Nb)-TZP zirconia block in response to conventional zirconia grinding and polishing. MATERIALS AND METHODS Zirconia crowns (n = 40) were first prepared and divided into two groups of materials: Labside (LS) and CS, after which each specimen went through a five-step grinding and polishing procedure. Following each surface treatment, surface characteristics were analyzed using confocal laser microscopy (CLSM), average surface roughness (Ra) values were processed from the profile data through Gaussian filtering, and X-ray diffraction pattern analysis was performed to evaluate the monoclinic (M) phase content. Then, a representative specimen was selected for field-emission scanning electron microscopy (FE-SEM), followed by a final analysis of the roughness and X-ray diffraction of the specimens using the independent t-test and repeated measures analysis of variance (RM-ANOVA). RESULTS In every group, polishing significantly reduced the Ra values (P < .001). There was no significant difference in Ra between the polished state CS and LS. Furthermore, CLSM and FE-SEM investigations revealed that even though grain exposure was visible in CS specimens throughout the as-delivered and ground states, the exposure was reduced after polishing. Moreover, while no phase transformation was visible in the LS, phase transformation was visible in CS after every surface treatment, with the M phase content of the CS group showing a significant reduction after polishing (P < .001). CONCLUSION Within the limits of this study, clinically acceptable level of surface finishing of (Y, Nb)-TZP can be achieved after conventional zirconia polishing sequence.
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Affiliation(s)
- Seong-keun Yoo
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Ye-Hyeon Jo
- Dental Research Institute, Seoul National University School of Dentistry, Seoul, Republic of Korea
| | - In-Sung Luke Yeo
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Jae-Hyun Lee
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Jin-Soo Ahn
- Department of Dental Biomaterials Science and Dental Research Institute, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Jung-Suk Han
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
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Abualsaud R, Alalawi H. Fit, Precision, and Trueness of 3D-Printed Zirconia Crowns Compared to Milled Counterparts. Dent J (Basel) 2022; 10:dj10110215. [PMID: 36421402 PMCID: PMC9689223 DOI: 10.3390/dj10110215] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Revised: 11/08/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022] Open
Abstract
Precise fit of a crown and accurate reproduction of the digital design are paramount for successful treatment outcomes and preservation of clinician and technician time. The study aimed to compare the internal fit, marginal adaptation, precision, and trueness of 3D-printed zirconia crowns compared to their milled counterpart. A total of 20 monolithic 3 mol% yttria stabilized-zirconia crowns (n = 10) were made using computer-assisted design (CAD) followed by additive (3D-printed) and subtractive (milled) manufacturing. Digital scanning of the master die with and without a fit checker followed by image superimposition, and analysis was performed to evaluate internal and marginal adaptation in four areas (occlusal, axial, marginal, and overall). ISO 12836:2015 standard was followed for precision and trueness evaluation. Statistical analysis was achieved using a t-test at α = 0.05. Internal fit and marginal adaptation revealed no significant difference between the two test groups (p > 0.05). The significant difference in trueness (p < 0.05) was found between the two groups in three areas (occlusal, axial, and internal). The best and worst trueness values were seen with 3D-printed crowns at occlusal (8.77 ± 0.89 µm) and Intaglio (23.90 ± 1.60 µm), respectively. The overall precision was statistically better (p < 0.05) in the 3D-printed crowns (9.59 ± 0.75 µm) than the milled (17.31 ± 3.39 µm). 3D-printed and milled zirconia crowns were comparable to each other in terms of internal fit and marginal adaptation. The trueness of the occlusal and axial surfaces of 3D-printed crowns was better, whereas the trueness of fitting surface of milled crowns was better. 3D-printed crowns provided a higher level of precision than milled crowns. Although the internal and marginal fit of both production techniques were comparable, 3D printing of zirconia produced more precise crowns.
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Turkyilmaz I, Wilkins GN, Yun S. Moving from analogue to digital workflows in dentistry: Understanding undermilling and overmilling as detrimental factors in fabricating CAD/CAM crowns. Prim Dent J 2022; 11:59-61. [PMID: 35658655 DOI: 10.1177/20501684221100938] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Due to the limitations caused by the specific dimensions of milling burs, milling machines may inaccurately fabricate restorations by either over-reducing or under-reducing restorative material, respectively known as "overmilling" and "undermilling". Overmilling occurs when the bur is unable to accommodate areas smaller than the size of the bur, especially at cusp tips and sharp line angles. This results in excess cement space and a weaker restoration. Undermilling occurs when small concavities are ignored by the larger milling bur, particularly at the margins. This results in inadequate seating of the restoration and open margins due to premature binding, which can lead to restorative failure. To prevent these processing errors, clinicians should ensure that all incisal edges and cusp tips are flattened and rounded, verify that there are no undercuts, and prepare teeth with 1mm thick, smooth finish lines. Furthermore, clinicians may use the preparation check and milling simulation step of computer-aided design/computer-aided manufacturing (CAD/CAM) software to confirm the preparation is adequate and the restorative design does not have potential areas that will lead to overmilling.
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Affiliation(s)
- Ilser Turkyilmaz
- Clinical Professor, Prosthodontics, New York University College of Dentistry, Department of Prosthodontics, New York, USA
| | | | - Sarah Yun
- New York University College of Dentistry, New York, USA
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Kim YK, Yoon HI, Kim DJ, Han JS. Comparative analysis on intaglio surface trueness, wear volume loss of antagonist, and fracture resistance of full-contour monolithic zirconia crown for single-visit dentistry under simulated mastication. J Adv Prosthodont 2022; 14:173-181. [PMID: 35855321 PMCID: PMC9259349 DOI: 10.4047/jap.2022.14.3.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 11/10/2022] Open
Abstract
PURPOSE This analysis aimed to evaluate the intaglio surface trueness, antagonist’s wear volume loss, and fracture resistance of full-contour crowns of (Y, Nb)-stabilized fully-sintered zirconia (FSZ), 4 mol% or 5 mol% yttria-stabilized partially sintered zirconia (4YZ or 5YZ) with high-speed sintering. MATERIALS AND METHODS A total of 42 zirconia crowns were separated into three groups: FSZ, 4YZ, and 5YZ (n = 14). The intaglio surface trueness of the crowns was evaluated at the inner surface, occlusal, margin, and axial areas and reported as root-mean-square, positive and negative average deviation. Half of the specimens were aged for 120,000 cycles in the chewing simulator, and the wear volume loss of antagonist was measured. Before and after chewing, the fracture load was measured for each group. The trueness values were analyzed with Welch's ANOVA, and the wear volume loss with the Kruskal-Wallis tests. Effect of the zirconia type and aging on fracture resistance of crowns was tested using two-way ANOVA. RESULTS The intaglio surface trueness measured at four different areas of the crown was less than 50 µm, regardless of the type of zirconia. No significant P in wear volume loss of antagonists were detected among the groups (P > .05). Both the type of zirconia and aging showed statistically significant effects on fracture resistance (P < .05). CONCLUSION The full-contour crowns of FSZ as well as 4YZ or 5YZ with high-speed sintering were clinically acceptable, in terms of intaglio surface trueness, antagonist’s wear volume loss, and fracture resistance after simulated mastication.
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Affiliation(s)
- Yong-Kyu Kim
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Dae-Joon Kim
- Department of Dentistry, VASIC Research Center, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
| | - Jung-Suk Han
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul, Republic of Korea
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13
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Koenig N, Choi JY, McCray J, Hayes A, Schneider P, Kim KB. Comparison of dimensional accuracy between direct-printed and thermoformed aligners. Korean J Orthod 2022; 52:249-257. [PMID: 35466087 PMCID: PMC9314211 DOI: 10.4041/kjod21.269] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2021] [Revised: 01/18/2022] [Accepted: 01/19/2022] [Indexed: 11/19/2022] Open
Abstract
Objective The purpose of this study was to evaluate and compare the dimensional accuracy between thermoformed and direct-printed aligners. Methods Three types of aligners were manufactured from the same reference standard tessellation language (STL) file thermoformed aligners were manufactured using Zendura FLXTM (n = 12) and Essix ACETM (n = 12), and direct-printed aligners were printed using Tera HarzTM TC-85DAP 3D Printer UV Resin (n = 12). The teeth were not manipulated with any tooth-moving software in this study. The samples were sprayed with an opaque scanning spray, scanned, imported to Geomagic® Control XTM metrology software, and superimposed on the reference STL file by using the best-fit alignment algorithm. Distances between the aligner meshes and the reference STL file were measured at nine anatomical landmarks. Results Mean absolute discrepancies in the Zendura FLXTM aligners ranged from 0.076 ± 0.057 mm to 0.260 ± 0.089 mm and those in the Essix ACETM aligners ranged from 0.188 ± 0.271 mm to 0.457 ± 0.350 mm, while in the direct-printed aligners, they ranged from 0.079 ± 0.054 mm to 0.224 ± 0.041 mm. Root mean square values, representing the overall trueness, ranged from 0.209 ± 0.094 mm for Essix ACETM, 0.188 ± 0.074 mm for Zendura FLXTM, and 0.140 ± 0.020 mm for the direct-printed aligners. Conclusions This study showed greater trueness and precision of direct-printed aligners than thermoformed aligners.
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Affiliation(s)
- Nickolas Koenig
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Jin-Young Choi
- Department of Orthodontics, Graduate School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Julie McCray
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Andrew Hayes
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Patricia Schneider
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
| | - Ki Beom Kim
- Department of Orthodontics, Saint Louis University, Saint Louis, MO, USA
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Study of Wear Phenomenon of a Dental Milling Cutter by Statistical-Mathematical Modeling Based on the Experimental Results. MATERIALS 2022; 15:ma15051903. [PMID: 35269133 PMCID: PMC8911949 DOI: 10.3390/ma15051903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Revised: 02/14/2022] [Accepted: 02/25/2022] [Indexed: 02/01/2023]
Abstract
The wear phenomenon of a dental milling cutter is studied based on experimental results and data and validated by statistical–mathematical modeling. The results of the statistical–mathematical modeling by the interpolation of the experimental results (data) regarding the wear of the dental milling cutter analyzed and obtained in the work process are presented in this paper. These results (data) are important because they lead to polynomial functions which by interpolation approximate very well the dependent parameter, specifically the wear process (mass lost due to dental milling cutter wear, mw), considered in the experimental program. The polynomial interpolation functions are valid, only during the experimental testing range of the dental milling cutter, to describe the wear phenomenon; the extrapolations do not lead to satisfactory results. However, by using a controlled interpolation function with an exponential component, the extrapolation of the results is possible. Therefore, the purpose of this paper is the statistical–mathematical modeling by the interpolation of the experimental results of the mass lost due to dental milling cutter wear, mw, using the deterministic differential model for the work process of it. Thus, interesting conclusions can be drawn relating to the phenomenon. In support of these statements come the results of the statistical–mathematical modeling by the interpolation of the experimental data obtained in the work process of the dental milling cutters, leading to practical applications, such as the extension of the life of dental milling cutter, useful even for its operation optimization; determination of possible criteria for replacing the worn dental milling cutters; the extension of the life of the materials from which dental milling cutters are built; or the provision of ideas for constructive solutions. Based on the modeling results by interpolation, it was found that the dental milling cutter during the milling operation works with high efficiency (mass loss due to wear is very reduced) in the first 11 h of operation, i.e., about a 10% increase in lifetime. After 11 h of operation, mass loss due to wear of the dental milling cutter increases relatively exponentially; thus, it is recommended that, in the normal way, the dental milling cutter be replaced with a new one to ensure high standards of materials processing.
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15
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The occlusal precision of milled versus printed provisional crowns. J Dent 2021; 117:103924. [PMID: 34910962 DOI: 10.1016/j.jdent.2021.103924] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 11/12/2021] [Accepted: 12/10/2021] [Indexed: 11/22/2022] Open
Abstract
OBJECTIVES The aim of this study was to compare the occlusal precision of computer-aided-design/ computer-assisted-manufacturing (CAD/CAM) milled versus 3D printed polymethylmethacrylate (PMMA) temporary prosthetic crowns , starting from the same digital CAD design. MATERIALS AND METHODS The study sample included 34 patients presenting 34 premolars in need of prosthetic rehabilitation: a total of 68 temporary crowns were manufactured, 34 of which milled and 34 printed. Immediately after manufacturing, the milled and printed provisionals were scanned with a desktop scanner (E1, 3Shape) to obtain STL files, that were superimposed to the original CAD design in order to identify the occlusal trueness (Analysis A). A second occlusal comparison was performed by scanning both kind of provisional after being placed intraorally with Trios scanner (3 Shape); intraoral scans were obtained in order to compare STL files of provisionals before and after occlusal adjustments (Analysis B). The occlusal trueness was identified at three reference points, P1 (vestibular cusp), P2 (palatal / lingual cusp), P3 (central fossa). The statistical analysis was performed using the R 3.4.3 statistical software (The R Foundation for Statistical Computing), with a significance level of p <0.05. RESULTS Overall, the printed crowns showed lower occlusal differences than the milled crowns, when compared to the CAD design file, with a statistically significant difference in P1 (difference of 0.025 ± 0.046 mm), P2 (difference of 0.027 ± 0 0.044 mm) and P3 ( difference of 0.018 ± 0.050) for Analysis A (p <0.05). In the Analysis B the direct comparison between the degree of average difference between the pre-adjustment and the post-occlusal adjustment of the milled and printed crowns shows that the printed crowns have lower occlusal mean difference values in all three points compared to the milled ones (difference of 0.146 ± 0.273 mm in P1, 0.285 ± 0.360 mm in P2 and 0.257 ± 0.277 mm in P3). CONCLUSIONS Within the limitation of this study, the data obtained showed a better occlusal surface dimensional accuracy of the 3D printed provisional crowns, when compared to the milled ones. Comparing the results obtained, it is possible to assume that the intraoral scans also had a contribution to occlusion, beside the manufacturing method. 3D printing can be successfully applied for manufacturing temporary PMMA crowns.
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Hassan LA, Goo CL. Effect of cement space on marginal discrepancy and retention of CAD/CAM crown. Dent Mater J 2021; 40:1189-1195. [PMID: 34078778 DOI: 10.4012/dmj.2020-408] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
This research aimed to evaluate the effect of cement space on the marginal discrepancy and retention of computer-aided design/computer-aided manufacturing (CAD/CAM) crowns. A total of 30 premolar Frasaco teeth were machined to receive crowns with cement spaces of 70, 90, and 110 μm. The marginal discrepancy measurements were done before and after cementation. Pull-off test was conducted using universal testing machine (UTM). Data was analyzed using two-way mixed ANOVA with post-hoc Bonferroni test and Kruskal-Wallis test. The crowns with cement space of 70 μm showed a significantly higher absolute marginal discrepancy than those with 90 and 110 μm. No significant effect on the crown retention was found. Within the limitations of this study, modifying cement space to 90 μm and 110 μm may improve the marginal adaptation of CAD/CAM crown, whereas adjusting cement space from 70 to 110 μm did not significantly affect the crown retention.
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Affiliation(s)
- Laila Azwa Hassan
- Department of Restorative Dentistry, Faculty of Dentistry, The National University of Malaysia
| | - Chui Ling Goo
- Department of Restorative Dentistry, Faculty of Dentistry, The National University of Malaysia
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Jeong KW, Yoon HI, Lee JH, Yeo ISL, Kim DJ, Han JS. Clinical Feasibility of Fully Sintered (Y, Nb)-TZP for CAD-CAM Single-Unit Restoration: A Pilot Study. MATERIALS 2021; 14:ma14112762. [PMID: 34071077 PMCID: PMC8197114 DOI: 10.3390/ma14112762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 04/24/2021] [Accepted: 05/21/2021] [Indexed: 11/16/2022]
Abstract
Fifteen participants (9 male, 6 female) received a total of 15 monolithic single restorations made from fully sintered (Y, Nb)-TZP (tetragonal zirconia polycrystal) block. The restorations were clinically evaluated for survival, success rate, and periodontal probing depths 6 months after the insertion of the restorations. Esthetic, functional, and biological evaluations were also performed over a 6-month follow-up period. The survival and success rates of the single-unit restorations were 100%. The periodontal probing depth values ranged from 1 to 3 mm. No complications with regard to functional and biological properties were observed after 6 months. The postoperative sensitivity was only a transient phenomenon. The fully sintered (Y, Nb)-TZP single-unit restoration showed highly acceptable quality with successful clinical performance over 6 months.
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Affiliation(s)
- Ki-Won Jeong
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Korea; (K.-W.J.); (J.-H.L.); (I.-S.L.Y.); (J.-S.H.)
| | - Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Korea; (K.-W.J.); (J.-H.L.); (I.-S.L.Y.); (J.-S.H.)
- Correspondence: ; Tel.: +82-2-2072-4472
| | - Jae-Hyun Lee
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Korea; (K.-W.J.); (J.-H.L.); (I.-S.L.Y.); (J.-S.H.)
| | - In-Sung Luke Yeo
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Korea; (K.-W.J.); (J.-H.L.); (I.-S.L.Y.); (J.-S.H.)
| | - Dae-Joon Kim
- Department of Dentistry, VASIC Research Center, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Korea;
| | - Jung-Suk Han
- Department of Prosthodontics, School of Dentistry and Dental Research Institute, Seoul National University, Seoul 03080, Korea; (K.-W.J.); (J.-H.L.); (I.-S.L.Y.); (J.-S.H.)
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Al Hamad KQ, Al Rashdan RB, Al Rashdan BA, Al Quran FA. Effect of CAD-CAM tool deterioration on the trueness of ceramic restorations. J Prosthet Dent 2020; 127:635-644. [PMID: 33342613 DOI: 10.1016/j.prosdent.2020.09.035] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 09/08/2020] [Accepted: 09/09/2020] [Indexed: 11/19/2022]
Abstract
STATEMENT OF PROBLEM Tools will gradually deteriorate with repetitive milling. However, tool lifetime can vary depending on the type of milling machine, the hardness of the ceramic material, and the size of the restoration. Studies evaluating the effect of tool deterioration on the trueness of milled restorations are lacking. PURPOSE The purpose of this study was to evaluate the effect of tool deterioration on the trueness of milled restorations. MATERIAL AND METHODS A patient requiring a ceramic crown was recruited. Repetitive milling of zirconia crowns (inCoris TZI; Dentsply Sirona) with tungsten carbide rotary instruments and glass-ceramic crowns (VITABLOCS mark II; Vita Zahnfabrik) with diamond rotary instruments was performed by using a 5-axis milling machine (inLab MC X5; Dentsply Sirona) until the machine software indicated replacing the largest tool. The percentage of deterioration for the largest tool was recorded before each milling. The trueness for different crown areas was evaluated by using a 3-dimensional evaluation software (Geomagic Control X; 3D systems), and the crowns were clinically evaluated. The crowns were grouped into 4 quadrants as per the deterioration percentage. The Pearson correlation (r) between the deterioration percentage and trueness and linear contrast analysis (partial eta squared [η]) among the groups were performed. RESULTS Glass-ceramic crown areas had low correlation except for mesial (high, r=0.63, high, η=0.37) and distal (medium, r=0.42, high, η= 0.34) areas, whereas zirconia crowns had low correlation for inner and internal areas and medium to high correlation for mesial (r= -0.31, η=0.33), distal (r= -0.53, η=0.36), occlusal (r= -0.32, η=0.164), external (r= 0.69, η=0.52), and marginal (r= -0.44, η=0.19) areas. Zirconia crowns had excellent marginal fit and occlusal contact and light to excellent proximal contact, whereas glass-ceramic crowns had excellent marginal fit, minor to major occlusal correction, and heavy proximal contact. CONCLUSIONS The effect of tool deterioration on trueness depended on material type and crown area. Only proximal areas were affected in the glass-ceramic crowns, whereas external, proximal, occlusal, and marginal areas were affected in the zirconia crowns. Trueness did not necessarily reflect the clinical quality of the crown, as both crown types were clinically satisfactory. Although zirconia crowns were overmilled in comparison with the reference design and glass-ceramic crowns, they had better clinical quality.
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Affiliation(s)
- Khaled Q Al Hamad
- Professor, Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan.
| | | | | | - Firas A Al Quran
- Professor, Department of Prosthodontics, Faculty of Dentistry, Jordan University of Science and Technology, Irbid, Jordan
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Al Hamad KQ, Al-Rashdan RB, Al-Rashdan BA, Baba NZ. Effect of Milling Protocols on Trueness and Precision of Ceramic Crowns. J Prosthodont 2020; 30:171-176. [PMID: 32856358 DOI: 10.1111/jopr.13245] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2020] [Indexed: 12/01/2022] Open
Abstract
PURPOSE To investigate the effect of different milling protocols for different ceramic materials on the trueness and precision of milled ceramic crowns. MATERIALS AND METHODS A definitive impression from a patient requiring a ceramic crown was used to fabricate forty glass ceramic crowns (VITABLOCS mark II, Vita Zahnfabrik) milled with wet, hard milling protocol, and 40 zirconia crowns (inCoris TZI, Dentsply, Sirona) milled with dry, soft milling protocol, using a 5-axis milling machine (inLab MC X5; Dentsply Sirona). Trueness and precision for different crown areas were evaluated with a 3D evaluation software (Geomagic Control X, 3D systems). Statistical analysis was performed between the 2 crown types with independent t-test, and analysis of variances followed by Bonferroni tests among crown areas for each crown. RESULTS All areas of the glass ceramic crowns had higher trueness than the zirconia crown areas (p < 0.05). Crown areas of each crown type had significantly different trueness values (p < 0.001, F = 175.17 for glass crowns, p < 0.001, F = 35.04 for zirconia crowns). Glass crowns had 3.78 µm precision, while zirconia crowns had 4.12 µm precision, with a precision difference range between the 2 types of crowns from 0.32 µm for the inner surface to 6.5 µm for the marginal surface. CONCLUSIONS Type of ceramic material and milling protocol affected trueness of the milled crown, with higher trueness for the hardmilled glass crowns than the soft milled zirconia crowns. Soft milled zirconia crowns were generally overmilled in comparison with the reference design and glass crowns. However, glass crowns exhibited more undermilling in thin and deep areas. The crown area affected trueness, with external areas having better trueness than internal areas. The 5-axis milling machine had high precision, which was minimally affected by the ceramic type, milling protocol, or crown area.
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Affiliation(s)
- Khaled Q Al Hamad
- Department of Prosthodontics, Jordan University of Science & Technology, Irbid, Jordan
| | | | | | - Nadim Z Baba
- Advanced Specialty Education Program in Prosthodontics, Loma Linda University, School of Dentistry, Loma Linda, CA
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Ceramic Materials and Technologies Applied to Digital Works in Implant-Supported Restorative Dentistry. MATERIALS 2020; 13:ma13081964. [PMID: 32331379 PMCID: PMC7216107 DOI: 10.3390/ma13081964] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 04/14/2020] [Accepted: 04/20/2020] [Indexed: 12/17/2022]
Abstract
Computer-aided design and manufacturing technology has been closely associated with implant-supported restoration. The digital system employed for prosthodontic restorations comprises data acquisition, processing, and manufacturing using subtractive or additive methods. As digital implantology has developed, optical scanning, computer-based digital algorithms, fabricating techniques, and numerical control skills have all rapidly improved in terms of their accuracy, which has resulted in the development of new ceramic materials with advanced esthetics and durability for clinical application. This study reviews the application of digital technology in implant-supported dental restoration and explores two globally utilized ceramic restorative materials: Yttria-stabilized tetragonal zirconia polycrystalline and lithium disilicate glass ceramics.
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