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Li Q, Zhan N, Ng T, Swain MV, Wan B, Jian Y, Wang X, Zhao K. The influence of hygroscopic expansion of resin supporting dies on the fracture resistance of ceramic restorations during thermal cycling. Dent Mater 2024; 40:1231-1243. [PMID: 38853105 DOI: 10.1016/j.dental.2024.06.011] [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: 02/19/2024] [Accepted: 06/05/2024] [Indexed: 06/11/2024]
Abstract
OBJECTIVES To evaluate the hygroscopic expansion characterization of resin composite dies during thermal cycling, and their influence on the fracture resistance of dental ceramic materials as well as the effect of pre-immersion on these measurements. METHODS Disc-shaped specimens (φ = 15.0 mm, h = 1.2 mm) and anatomical crown dies of four resin composites (epoxy, Z350, P60, G10) were fabricated. Disc-shaped samples were continuously soaked in distilled water and the volume expansion was measured at different time point by Archimedes method. Disc-shaped samples were pre-immersed for 0, 7, or 30 days, elastic modulus and hardness were measured using Nanoindentation test; thermal cycling (TC) test was performed (5 °C-55 °C, 104 cycles), and volume expansion during TC was measured. Four kinds of resin die with pre-immersion for 0, 7, or 30 days were cemented to 5Y-Z crown, or epoxy dies without pre-immersion were cemented to 5Y-Z, 3Y-Z and lithium disilicate glass (LDG) crowns, and load-to-failure testing was performed before and after TC. Finite element analysis (FEA) and fractography analysis were also conducted. RESULTS The hygroscopic expansion was in the order: epoxy > Z350 > P60 > G10. Except for G10, the other three resin composites exhibited different degrees of hygroscopic expansion during TC. Only the elastic modulus and hardness of epoxy decreased after water storage. However, only the fracture loads of 5Y-Z and LDG crowns supported by epoxy dies were significantly decreased after TC. FEA showed a stress concentration at the cervical region of the crown after volume expansion of the die, leading to the increase of the peak stress at the crown during loading. SIGNIFICANCE Only the hygroscopic expansion of epoxy dies caused by TC led to the decrease in the fracture resistance of the 5Y-Z and LDG crown, which may be related to the decrease in the elastic modulus of the epoxy die and the tensile stress caused by it.
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Affiliation(s)
- Qiulan Li
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou 510055, China; Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China
| | - Ni Zhan
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou 510055, China; Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China
| | - Takkun Ng
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou 510055, China; Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China
| | - Michael V Swain
- Don State Technical University, Rostov-on-Don 344000, Russia; AMME, Sydney University, Sydney, Australia
| | - Boyang Wan
- School of Aerospace, Mechanical and Mechatronic Engineering (AMME), The University of Sydney, NSW 2006, Australia
| | - Yutao Jian
- Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China; Institute of Stomatology, Sun Yat-Sen University, Guangzhou 510055, China.
| | - Xiaodong Wang
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou 510055, China; Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China.
| | - Ke Zhao
- Hospital of Stomatology, Sun Yat-Sen University, Guangzhou 510055, China; Guangdong Provincial Key Laboratory of Stomatology, Guangzhou 510055, China.
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Abdelhady WA, Metwally MF, Haggag KM. Effect of thermomechanical loading on fracture resistance and failure mode of new pressable zirconia-reinforced lithium disilicate onlay restoration. J Dent Res Dent Clin Dent Prospects 2024; 18:29-36. [PMID: 38881646 PMCID: PMC11179138 DOI: 10.34172/joddd.40843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/29/2024] [Indexed: 06/18/2024] Open
Abstract
Background Insufficient information exists regarding the fracture resistance and failure pattern of newly developed zirconia-reinforced lithium disilicate (ZL, Vita Ambria) onlays. This in vitro study compared the fracture resistance of two types of onlays: monolithic lithium disilicate (LD) and monolithic ZL. Methods Forty-eight ceramic onlay restorations were fabricated on epoxy dies using a maxillary first premolar model. The samples were divided into two main groups: LD and ZL. Half of each group was subjected to thermomechanical fatigue loading (TML) using a chewing simulator. All the samples were cemented with self-adhesive resin cement. Subsequently, they were loaded until failure in a universal testing machine, and the fracture patterns and resistance were recorded. Results Before TML, ZL demonstrated the highest statistically significant mean fracture resistance (499.76±34.14N) compared to LD (470.40±27.38N). After TML, ZL showed the highest non-statistically significant mean fracture resistance (429.27±131.42N), while LD's mean fracture resistance decreased (377.31±62.18N). Conclusion Monolithic zirconia-reinforced onlays demonstrated higher fracture resistance and a more favorable failure mode compared to LD. However, the impact of thermomechanical aging resulted in reduced fracture resistance for both materials, with a notable preference observed for ZL.
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Affiliation(s)
- Walid A Abdelhady
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
| | - Mohamed F Metwally
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
| | - Khaled M Haggag
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
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Sayed Ahmed A, Lawson NC, Fu CC, Bora PV, Kee E, Nejat AH. The Effect of Die Material on the Crown Fracture Strength of Zirconia Crowns. MATERIALS (BASEL, SWITZERLAND) 2024; 17:1096. [PMID: 38473568 DOI: 10.3390/ma17051096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Revised: 02/16/2024] [Accepted: 02/26/2024] [Indexed: 03/14/2024]
Abstract
BACKGROUND Determination of the eligibility of several tooth analog materials for use in crown fracture testing. METHODS A standardized premolar crown preparation was replicated into three types of resin dies (C&B, low modulus 3D printed resin; OnX, high modulus 3D printed resin composite; and highest modulus milled resin composite). 0.8 mm zirconia crowns were bonded to the dies and the maximum fracture load of the crowns was tested. Twelve extracted human premolars were prepared to a standardized crown preparation, and duplicate dies of the prepared teeth were 3D printed out of C&B. Zirconia crowns were bonded to both the dies and natural teeth, and their fracture load was tested. RESULTS There was no statistical difference between the fracture load of zirconia crowns bonded to standardized dies of C&B (1084.5 ± 134.2 N), OnX (1112.7 ± 109.8 N) or Lava Ultimate (1137.5 ± 88.7 N) (p = 0.580). There was no statistical difference between the fracture load of crowns bonded to dentin dies (1313 ± 240 N) and a 3D-printed resin die (C&B, 1156 ± 163 N) (p = 0.618). CONCLUSIONS There was no difference in the static fracture load of zirconia crowns bonded to standardized resin dies with different moduli or between a low modulus resin die and natural dentin die.
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Affiliation(s)
- Akram Sayed Ahmed
- Department of Dental Biomaterials, Faculty of Dentistry, Tanta University, Tanta 6624033, Egypt
- Division of Biomaterials, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA
| | - Nathaniel C Lawson
- Division of Biomaterials, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA
| | - Chin-Chuan Fu
- Division of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA
| | - Pranit V Bora
- Division of Biomaterials, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA
| | - Edwin Kee
- Division of Prosthodontics, LSU School of Dentistry, New Orleans, LA 70119, USA
| | - Amir H Nejat
- Division of Prosthodontics, LSU School of Dentistry, New Orleans, LA 70119, USA
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AboElhassan RG, Watts DC, Alamoush RA, Elraggal A. Biomechanical behavior and Weibull survival of CAD-CAM endocrowns with different marginal designs: A 3D finite element analysis. Dent Mater 2024; 40:227-235. [PMID: 37977990 DOI: 10.1016/j.dental.2023.11.012] [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: 09/05/2023] [Revised: 11/04/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023]
Abstract
OBJECTIVES To evaluate and compare the effect of tooth preparation designs and different CADCAM. materials on stress distribution and Weibull survival probability of endocrowns. applied to root canal-treated lower first permanent molar using the 3D finite element. analysis method. METHODS A root canal-treated lower first permanent molar was prepared for endocrowns with a. butt joint or with a ferrule design by placing, circumferentially, a 1-mm wide shoulder. finish line. The prepared molar was scanned for the two designs and modeled on a 3D. Finite element model. Monolithic zirconia (IPS e.max ZirCAD MT, FCZ), lithium. disilicate (IPS e.max CAD, EX), and nano-ceramic resin composite (Lava Ultimate, LU). CAD-CAM materials were used for each preparation to design the virtual endocrown. A. total of six models were built according to the different tooth preparation designs and. endocrown materials. An occlusal load of 600 N and a transverse load of 20 N in. magnitude that simulates the average occlusal load was directed toward the occlusal. surfaces. von Mises and maximum principle values were evaluated Weibull risk-ofrupture. analysis was used to analyze the survival probability of the restorations and. tooth in the different models. RESULTS The highest von Mises were found in the butt joint design for FCZ, EX, and LU (45.3. MPa, 35.2 MPa, and 24.2 MPa, respectively) compared to the ferrule design for the. same materials (42.6 MPa, 31.2 MPa, and 23.6 MPa, respectively). For von Mises. stress distribution in the remaining part of tooth structure (dentin), the highest stresses. were found in LUFerrule which was closely similar to LUButt joint (135.4 MPa and. 134.7 MPa, respectively), followed by EXFerrule and FCZFerrule (132.2 MPa and. 131.7 MPa, respectively), while the lowest stresses were found in EXButt joint and. FCZButt joint (129.0 MPa and 128.4 MPa, respectively). Shear stresses within the. resin cement were the highest in FCZ and EX compared to LU. EX was found to be the. most reliable material with the highest survival probability, while FCZ showed the. lowest survival probability according to the Weibull risk-of-fracture results. SIGNIFICANCE Materials with high elastic modulus transfer more stresses to the endocrown and less. to the remaining tooth structure. Endocrown tooth preparation with ferrule design has. better stress distribution and magnitude compared to the butt joint design.
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Affiliation(s)
- Rewaa G AboElhassan
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - David C Watts
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Rasha A Alamoush
- Department of Fixed and Removable Prosthodontics, School of Dentistry, the University of Jordan, Amman, Jordan
| | - Alaaeldin Elraggal
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt; Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
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Chen PH, Elamin E, Sayed Ahmed A, Givan DA, Fu CC, Lawson NC. The Effect of Restoration Thickness on the Fracture Resistance of 5 mol% Yttria-Containing Zirconia Crowns. MATERIALS (BASEL, SWITZERLAND) 2024; 17:365. [PMID: 38255531 PMCID: PMC10817558 DOI: 10.3390/ma17020365] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Revised: 01/04/2024] [Accepted: 01/08/2024] [Indexed: 01/24/2024]
Abstract
BACKGROUND To determine what thickness of 5 mol% yttria zirconia (5Y-Z) translucent crowns cemented with different cements and surface treatments would have equivalent fracture resistance as 3 mol% yttria (3Y-Z) crowns. METHODS The study included 0.8 mm, 1.0 mm, and 1.2 mm thickness 5Y-Z (Katana UTML) crowns and 0.5 and 1.0 mm thickness 3Y-Z (Katana HT) crowns as controls. The 5Y-Z crowns were divided among three treatment subgroups (n = 10/subgroup): (1) cemented using RMGIC (Rely X Luting Cement), (2) alumina particle-abraded then luted with the same cement, (3) alumina particle-abraded and cemented using a resin cement (Panavia SA Cement Universal). The 3Y-Z controls were alumina particle-abraded then cemented with RMGIC. The specimens were then loaded in compression at 30° until failure. RESULTS All 5Y-Z crowns (regardless of thickness or surface treatment) had a similar to or higher fracture force than the 0.5 mm 3Y-Z crowns. Only the 1.2 mm 5Y-Z crowns with resin cement showed significantly similar fracture force to the 1 mm 3Y-Z crowns. CONCLUSION In order to achieve a similar fracture resistance to 0.5 mm 3Y-Z crowns cemented with RMGIC, 5Y-Z crowns may be as thin as 0.8 mm. To achieve a similar fracture resistance to 1.0 mm 3Y-Z crowns cemented with RMGIC, 5Y-Z crowns must be 1.2 mm and bonded with resin cement.
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Affiliation(s)
- Po-Hsu Chen
- Division of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA; (P.-H.C.); (E.E.); (D.A.G.); (C.-C.F.)
| | - Esra Elamin
- Division of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA; (P.-H.C.); (E.E.); (D.A.G.); (C.-C.F.)
| | - Akram Sayed Ahmed
- Faculty of Dentistry, Department of Dental Biomaterials, Tanta University, Tanta 31527, Egypt;
| | - Daniel A. Givan
- Division of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA; (P.-H.C.); (E.E.); (D.A.G.); (C.-C.F.)
| | - Chin-Chuan Fu
- Division of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA; (P.-H.C.); (E.E.); (D.A.G.); (C.-C.F.)
| | - Nathaniel C. Lawson
- Division of Prosthodontics, University of Alabama at Birmingham School of Dentistry, Birmingham, AL 35209, USA; (P.-H.C.); (E.E.); (D.A.G.); (C.-C.F.)
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Bolaca A, Erdoğan Y. Fracture resistance evaluation of CAD/CAM zirconia and composite primary molar crowns with different occlusal thicknesses. J Appl Biomater Funct Mater 2024; 22:22808000241235994. [PMID: 38420920 DOI: 10.1177/22808000241235994] [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: 03/02/2024] Open
Abstract
OBJECTIVE To evaluate the effect of different CAD/CAM materials and occlusal thicknesses on the fracture resistance of primary molar crowns. METHODS Sixty extracted primary molar teeth were prepared and randomly divided into six experimental groups according to the material and thickness. Primary molar crowns with a central groove thickness of 0.3 and 0.5 mm were fabricated from CAD/CAM zirconia (group Z), zirconia-reinforced lithium silicate (group ZLS), and pre-polymerized composite resin blocks (group C). Each crown was cemented with self-adhesive resin cement on the prepared tooth. All specimens were subjected to fracture tests until fracture. Fracture load values were recorded in Newtons (N). Data were statistically analyzed using a two-way analysis of variance (ANOVA) followed by Tukey multiple comparison test. RESULTS The highest fracture load values were obtained in group Z at 0.5 mm occlusal thickness and were significantly higher compared with the other experimental groups (p < 0.05). Although the lowest fracture load values were obtained in group ZLS at 0.3 mm occlusal thickness, all the tested CAD/CAM primary molar crowns at both thicknesses demonstrated fracture load values exceeding reported chewing force in pediatric patients. CONCLUSION CAD/CAM primary molar crowns with reduced occlusal thickness may be used for the full-coverage restoration of primary molar teeth.
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Affiliation(s)
- Arif Bolaca
- Department of Pediatric Dentistry, Faculty of Dentistry, Pamukkale University, Denizli, Turkey
| | - Yıldırım Erdoğan
- Department of Pediatric Dentistry, Faculty of Dentistry, Pamukkale University, Denizli, Turkey
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Elmokadem MI, Haggag KM, Mohamed HR. Effect of Thermo-mechanical Cycling on Fracture Resistance of Different CAD/CAM Crowns: An In Vitro Study. J Contemp Dent Pract 2024; 25:29-34. [PMID: 38514428 DOI: 10.5005/jp-journals-10024-3619] [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: 03/23/2024]
Abstract
AIM To evaluate the effect of thermo-mechanical cycling (TMC) on fracture resistance of different computer-aided design/computer-aided manufacture (CAD/CAM) crowns. MATERIALS AND METHODS A total of 42 CAD/CAM crowns were fabricated on epoxy resin maxillary first premolar teeth and divided into three groups (n = 14) according to the material used: IPS e.max CAD (Ivoclar Vivadent) lithium disilicate (LD), Vita ENAMIC (VE) (VITA Zahnfabrik), Tetric CAD (Ivoclar Vivadent). Also, each group was subdivided into two equal subgroups according to TMC (n = 7). Subgroups (O) without TMC and subgroup (W) with TMC (5-55°C, 30 second, 75,000 cycles). All samples in each group were cemented with a universal bond (Tetric N bond universal) and adhesive resin cement (Variolink Esthetic DC) (Ivoclar Vivadent). Subsequently, the samples were loaded to failure in a universal testing machine at a crosshead speed of 1 mm/min, and the fracture pattern and the fracture resistance in each group were recorded. RESULTS Fracture resistance was analyzed by one-way analysis of variance (ANOVA) test, followed by Tukey's post hoc test for pairwise comparison. Fracture resistance showed a significant difference between the tested groups before and after TMC; IPS e.max CAD has the highest value (1233.35 ± 97.72, 1165.73 ± 199.54 N) followed by Tetric CAD (927.62 ± 42.5, 992.04 ± 53.46 N) and Vita ENAMIC has lowest value (506.49 ± 74.24, 354.69 ± 90.36 N). CONCLUSION Thermo-mechanical cycling affected the fracture resistance of both polymer-based CAD/CAM crowns. CLINICAL SIGNIFICANCE For dental practitioners, both IPS e.max CAD and Tetric CAD can be used clinically for posterior teeth, providing satisfactory results and resistance to fracture. How to cite this article: Elmokadem MI, Haggag KM, Mohamed HR. Effect of Thermo-mechanical Cycling on Fracture Resistance of Different CAD/CAM Crowns: An In Vitro Study. J Contemp Dent Pract 2024;25(1):29-34.
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Affiliation(s)
- Mohamed I Elmokadem
- Department of Crown and Bridge, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt, Phone: +20 1005840669, e-mail: , Orcid: https://orcid.org/0009-0007-6672-5994
| | - Khaled M Haggag
- Department of Crown and Bridge, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt
| | - Hussein Ramadan Mohamed
- Department of Crown and Bridge, Faculty of Dental Medicine, Al-Azhar University, Cairo, Egypt
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Golrezaei M, Mahgoli HA, Yaghoobi N, Niakan S. The Effect of Modified Framework Design on the Fracture Resistance of IPS e.max Press Crown after Thermocycling and Cyclic Loading. J Contemp Dent Pract 2024; 25:79-84. [PMID: 38514436 DOI: 10.5005/jp-journals-10024-3621] [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: 03/23/2024]
Abstract
AIM This study aimed to investigate the effect of modified framework (MF) design on the fracture resistance of IPS e.max Press anterior single crown after thermocycling and cyclic loading. MATERIALS AND METHODS Two types of IPS e.max Press frameworks were designed (n = 10); standard framework (SF) with a 0.5 mm uniform thickness and MF with a lingual margin of 1 mm in thickness and 2 mm in height connected to a proximal strut of 4 mm height and a 0.3 mm wide facial collar. The crowns were cemented to resin dies, subjected to 5,000 cycles of thermocycling, and loaded 10,000 cycles at 100 N. A universal testing machine was used to load specimens to fracture, and the modes of failure were determined. RESULTS The mean and standard deviation (SD) of fracture resistance were 219.24 ± 110.00 N and 216.54 ±120.02 N in the SF and MF groups. Thus, there was no significant difference (p = 0.96). Mixed fracture was the most common failure mode in both groups. We found no statistically significant difference between the groups (p = 0.58). CONCLUSION The MF design did not increase the fracture resistance of IPS e.max Press crown. CLINICAL SIGNIFICANCE Framework design is an essential factor for the success of all-ceramic restorations and its modification might be regarded as an approach to increase fracture resistance. Furthermore, the modified design was evaluated in metal-ceramic or zirconia crowns while less attention was paid to the IPS e.max Press crowns. How to cite this article: Golrezaei M, Mahgoli HA, Yaghoobi N, et al. The Effect of Modified Framework Design on the Fracture Resistance of IPS e.max Press Crown after Thermocycling and Cyclic Loading. J Contemp Dent Pract 2024;25(1):79-84.
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Affiliation(s)
- Mahnaz Golrezaei
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Hossein Ali Mahgoli
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Negin Yaghoobi
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran
| | - Somayeh Niakan
- Department of Prosthodontics, School of Dentistry, Tehran University of Medical Sciences, Tehran, Iran, Phone: +98 9126727694, e-mail:
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Işisağ Ö, Pektaş N. Comparison of the fracture strengths of single-unit metal-ceramic and monolithic zirconium restorations in the molar region: a systematic review and meta-analysis. Odontology 2023:10.1007/s10266-023-00878-x. [PMID: 38103151 DOI: 10.1007/s10266-023-00878-x] [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: 05/12/2023] [Accepted: 11/17/2023] [Indexed: 12/17/2023]
Abstract
Despite the success of monolithic zirconia restorations (MZ), metal-ceramic restorations (MC) are still considered the gold standard for fixed prosthetics in the posterior region. This systematic review and meta-analysis aimed to compare the fracture strengths of single-unit MC and MZ in the molar region. This review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA, 2020) statement. All articles were searched from the PubMed and Web of Science databases until November 18, 2022. All in vitro studies evaluating the fracture strengths of MC and MZ were also included. Statistical analysis was performed with the Comprehensive Meta-Analysis program, with a significance level of 0.05. Out of 753 studies, five were selected. The fracture strengths of MZ and MC did not show any statistically significant difference for both tooth (95% CI - 1.589: 2.118, p = 0.779, z = 0.280) and implant (95% CI - 2.215: 2.191, p = 0.992 z = - 0.010) supported restorations. However, different abutment materials (p < 0.001) and aging treatments (p < 0.001) in tooth-supported restorations displayed a significant statistical difference. Additionally, a significant difference was also observed in subgroup analysis considering different cements (p = 0.001) and load speeds (p = 0.001) in implant-supported restorations. Fracture strengths of MZ and MC did not show a significant statistical difference in implant or tooth-supported single-unit posterior restorations. MZ may be a suitable alternative to MC in single-unit posterior restorations. The results should be interpreted with caution, as the included studies were in vitro.
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Affiliation(s)
- Özer Işisağ
- Department of Prosthodontics, Faculty of Dentistry, Afyonkarahisar Health Sciences University, Inonu Boulevard No: 4, Afyonkarahisar, Turkey.
| | - Nur Pektaş
- Department of Prosthodontics, Faculty of Dentistry, Afyonkarahisar Health Sciences University, Inonu Boulevard No: 4, Afyonkarahisar, Turkey
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Choo SS, Ko KH, Huh YH, Park CJ, Cho LR. Fatigue resistance of anterior monolithic crowns produced from CAD-CAM materials: An in vitro study. J Prosthet Dent 2023; 130:620-628. [PMID: 34980473 DOI: 10.1016/j.prosdent.2021.09.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2020] [Revised: 09/29/2021] [Accepted: 09/29/2021] [Indexed: 10/19/2022]
Abstract
STATEMENT OF PROBLEM Lithium disilicate and 5 mol% yttria partially stabilized zirconia (5Y-PSZ) are commonly used for anterior restorations. However, studies comparing the durability of 5Y-PSZ and lithium disilicates are sparse. PURPOSE The purpose of this in vitro study was to investigate the fracture load of anterior monolithic crowns made of 2 lithium disilicates and a 5Y-PSZ under dynamic loading. MATERIAL AND METHODS Titanium abutments of the maxillary incisors were prepared (N=48, 8 for each group). Monolithic anterior crowns were made from the lithium disilicates (e.max CAD, Rosetta SM) and 5Y-PSZ (Katana UTML). After cementation, the specimens were stored in water for 24 hours and then thermocycled 10 000 times. Dynamic loading (70 N, 200 000 cycles, 1 Hz) was applied to half the specimens. The fracture load was measured by using a universal testing machine. The fracture patterns were analyzed and fractography applied. Two-way ANOVA and the Fisher exact test were used for statistical analysis (α=.05). RESULTS The material and dynamic loading affected the fracture load of the anterior monolithic crowns (P<.05). However, there was no interaction between the material and the dynamic loading (P=.079). Both lithium disilicates had higher fracture loads than 5Y-PSZ (P<.05). The fracture load of each specimen was reduced after dynamic loading (P<.05). Lithium disilicate showed marginal and bulk fractures, and 5Y-PSZ presented catastrophic fractures (P<.001). CONCLUSIONS 5Y-PSZ materials with large grains and low flexural strength may be less resistant to fractures under dynamic loading than lithium disilicates.
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Affiliation(s)
- Seung-Sik Choo
- Graduate student, Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Kyung-Ho Ko
- Assistant Professor, Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Yoon-Hyuk Huh
- Associate Professor, Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Chan-Jin Park
- Professor, Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea
| | - Lee-Ra Cho
- Professor, Department of Prosthodontics and Research Institute of Oral Science, College of Dentistry, Gangneung-Wonju National University, Gangneung, Republic of Korea.
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Refaie A, Bourauel C, Fouda AM, Keilig L, Singer L. The effect of cyclic loading on the fracture resistance of 3D-printed and CAD/CAM milled zirconia crowns-an in vitro study. Clin Oral Investig 2023; 27:6125-6133. [PMID: 37615777 PMCID: PMC10560138 DOI: 10.1007/s00784-023-05229-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/17/2023] [Indexed: 08/25/2023]
Abstract
OBJECTIVES The aim of this study was to evaluate the effect of cyclic mechanical loading on the fracture resistance of 3D-printed zirconia crowns in comparison to milled zirconia crowns. MATERIALS AND METHODS Monolithic zirconia crowns (n = 30) were manufactured using subtractive milling (group M) and 3D additive printing (group P). Nine samples of each group were fractured under one-time loading while the other 6 samples were subjected to cyclic loading for 1.2 million cycles before being subjected to one-time loading until fracture. Scanning electron microscope (SEM) fractographic analysis was carried out on fractured fragments of representative samples. RESULTS The mean for fracture resistance of group M was 1890 N without cyclic loading and 1642 N after being subjected to cyclic loading, and they were significantly higher than that of group P (1658 N and 1224 N respectively). CONCLUSIONS The fabrication technique and cyclic loading affect the fracture resistance of zirconia crowns. Although the fracture resistance values for the 3D-printed crowns were lower than those of the milled, still they are higher than the masticatory forces and thus could be considered being clinically acceptable. CLINICAL RELEVANCE Concerning fracture resistance, 3D-printed crowns can withstand the masticatory forces for the long term without any cracks or failure.
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Affiliation(s)
- Ashraf Refaie
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany.
- Department of Fixed Prosthodontics, Faculty of Dentistry, Fayoum University, Faiyum, Egypt.
| | - Christoph Bourauel
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
| | - Ahmed Mahmoud Fouda
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
- Suez Canal University, Ismailia, Egypt
| | - Ludger Keilig
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
- Department of Prosthodontics, Preclinical Education and Dental Materials Science, Dental School, Medical Faculty, University Hospital of Bonn, 53111, Bonn, North Rhine-Westphalia, Germany
| | - Lamia Singer
- Oral Technology, Dental School, Medical Faculty, University Hospital of Bonn, Welschnonnenstr. 17, 53111, Bonn, North Rhine-Westphalia, Germany
- Department of Orthodontic, Dental School, Medical Faculty, University Hospital of Bonn, 53111, Bonn, North Rhine-Westphalia, Germany
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12
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Delikan E, Çaliskan S, Çalışkan A, Özdemir C. Does repeated autoclave sterilization cause changes in the color and fragility of fiberglass reinforced resin crowns? BMC Oral Health 2023; 23:533. [PMID: 37528379 PMCID: PMC10394804 DOI: 10.1186/s12903-023-03254-x] [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: 04/10/2023] [Accepted: 06/22/2023] [Indexed: 08/03/2023] Open
Abstract
BACKGROUND Since the effects of sterilization on the Fiberglass Reinforced Resin Crowns (FRRCs) is not well-known the aim of current study was to evaluate the effects of autoclave sterilization on the fracture resistance, color stability, and surface composition of FRRCs. METHODS A total of 48 crowns were used. The crowns were divided into three groups according to the sterilization number: no sterilization (Control Group), one sterilization (Group 1), and four sterilizations (Group 2). The microstructure of the three crowns from each group was evaluated using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) spectroscopy. Thirteen FRRCs from each group were first used for color stability testing and then for the fracture resistance analysis. One-way analysis of variance (ANOVA), one-way repeated measures ANOVA, and paired t-tests were used in the statistical analysis. RESULTS EDX results revealed that the weight% of surface silicon atoms in group 2 was significantly higher. Some crack lines could be observed on the SEM images. Statistically significant differences were found in color stability following the first and fourth sterilization cycles (p < .01). The increase in the sterilization cycle did not statistically decrease the fracture resistance of the FRRCs (p = .055); however, overall, a decreasing trend was observed in fracture resistance as the sterilization cycle increased. CONCLUSIONS Autoclave sterilization caused some changes in the surface elemental composition and surface morphology of FRRCs. Avoiding unnecessary FRRC trials is important to reduce the number of sterilizations.
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Affiliation(s)
- Ebru Delikan
- Department of Pediatric Dentistry, Faculty of Dentistry, Nuh Naci Yazgan University, Kayseri, Turkey
| | - Seçil Çaliskan
- Department of Pediatric Dentistry, Faculty of Dentistry, Eskişehir Osmangazi University, Eskişehir, Turkey.
| | - Ahmet Çalışkan
- Special Uzman Diş Grup Oral and Dental Health Polyclinic, İzmit, Turkey
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13
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Erdinç G, Bülbül M, Özcan M. Fracture strength and energy-dispersive spectroscopy analysis of 3-unit fixed partial dentures fabricated from different monolithic zirconia materials. J Prosthet Dent 2023:S0022-3913(23)00178-6. [PMID: 37024356 DOI: 10.1016/j.prosdent.2023.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 03/08/2023] [Accepted: 03/09/2023] [Indexed: 04/08/2023]
Abstract
STATEMENT OF PROBLEM Mastication forces in different regions affect the survival of multiunit posterior restorations. The fracture strength of 3-unit posterior monolithic zirconia fixed partial dentures (FPDs) and their fracture patterns require investigation. PURPOSE The purpose of this in vitro study was to evaluate and compare the fracture strength and fracture pattern of 3-unit posterior FPDs fabricated from different monolithic zirconia materials. MATERIAL AND METHODS Thirty 3-unit FPDs were fabricated from BruxZir, FireZr, and Upcera (n=10 per group). Energy-dispersive spectroscopy analysis was performed on 2 selected specimens from each group. All specimens were exposed to a mastication simulator for 1.2×106 cycles and then monotonically loaded to fracture at a crosshead speed of 1 mm/min. The surfaces of a selected fractured specimen were examined at magnifications of ×25 and ×500 with scanning electron microscopy. Conformity to normal distribution was evaluated with the Shapiro-Wilk test. One-way analysis of variance was used to compare the normally distributed initial crack formation load F initial (Fi) and catastrophic failure strength F maximum (Fm) means by group. Weibull statistics were calculated by using the maximum likelihood estimation method. The chi-square test was used to compare shape and scale parameters (α=.05). RESULTS The mean Fm values were fail1878.9 N for Upcera, 2177.8 N for BruxZir, and 2229.4 N for FireZr. Upcera and BruxZir showed statistically significant differences for the Fm mean values (P=.039). The differences between the fracture type distributions according to the groups were statistically similar (P>.05). For Fi, Upcera presented the highest Weibull modulus value (2.199), FireZr had the lowest (1.594), while for Fm, BruxZir had the highest Weibull modulus value (9.267) and FireZr the lowest (6.572). CONCLUSIONS Using the zirconia materials BruxZir, FireZr, and Upcera resulted in high Fm values after aging procedures. With all materials, the fractures were most commonly found in the connector areas in the tested FPDs.
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Affiliation(s)
- Gülbahar Erdinç
- Assistant Professor, Department of Prosthodontics, Faculty of Dentistry, Karabük University, Karabük, Turkey.
| | - Mehmet Bülbül
- Professor, Department of Prosthodontics, Faculty of Dentistry, İstanbul Aydin University, İstanbul, Turkey
| | - Mutlu Özcan
- Professor and Head, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Center for Dental and Oral Medicine, University of Zurich, Zurich, Switzerland
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Kudo H, Wakabayashi K, Sasaki JI, Tamiya S, Ishigaki S. Fracture strength and behavior of resin-faced CAD/CAM anterior crowns. Dent Mater J 2023; 42:86-91. [PMID: 36288943 DOI: 10.4012/dmj.2022-127] [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: 02/03/2023]
Abstract
The fracture strength and behavior of a novel resin-faced computer-aided design/computer-aided manufacturing (CAD/CAM) crown were investigated to evaluate application to the anterior teeth. Resin-faced CAD/CAM crowns were fabricated by arranging a resin composite on a frame prepared from a CAD/CAM resin block. The fracture strength was evaluated after 24 h of complete polymerization (day 0) and after water immersion for 30 days (day 30). Uniaxial loading was applied to the center point between the incisal edge and cingulum (loading point 1) or at 1.5 mm from the incisal edge (loading point 2). There was no significant difference in the fracture strength of the resin-faced CAD/CAM crowns between day 0 and 30 at loading point 1. At loading point 2, they exhibited decreased fracture strength after water immersion; however, the mean strength was still >1 kN. This novel crown showed good mechanical properties to serve as a prosthesis for the anterior teeth.
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Affiliation(s)
- Hiroki Kudo
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry
| | | | - Jun-Ichi Sasaki
- Department of Biomaterials Science, Osaka University Graduate School of Dentistry
| | - Shingo Tamiya
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry
| | - Shoichi Ishigaki
- Department of Fixed Prosthodontics, Osaka University Graduate School of Dentistry
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15
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Skjold A, Schriwer C, Gjerdet NR, Øilo M. Fractographic analysis of 35 clinically fractured bi-layered and monolithic zirconia crowns. J Dent 2022; 125:104271. [PMID: 36041673 DOI: 10.1016/j.jdent.2022.104271] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2022] [Revised: 07/12/2022] [Accepted: 08/25/2022] [Indexed: 10/15/2022] Open
Abstract
OBJECTIVES The aim of this retrieval study was to analyze the fracture features and identify the fracture origin of zirconia-based single crowns that failed during clinical use. METHODS Thirty-five fractured single crowns were retrieved from dental practices (bi-layered, n=15; monolithic, n=20). These were analyzed according to fractographic procedures by optical and scanning electron microscopy to identify fracture patterns and fracture origins. The fracture origins were closely examined. The crown margin thickness and axial wall height were measured. RESULTS Three types of failure modes were observed: total fractures, marginal semilunar fractures, and incisal chippings. Most of the crowns (23) had fracture origins at the crown margin and seven of them had defects in the fracture origin area. The exact fracture origin was not possible to identify due to missing parts in four crowns. The crown wall thickness was 20% thinner and wall height 30% shorter in the fracture origin area compared to the opposite side. CONCLUSIONS The findings in this study show that fractography can reveal fracture origins and fracture modes of both monolithic and bi-layered dental zirconia. The findings indicate that the crown margin on the shortest axial wall is the most common fracture origin site. CLINICAL SIGNIFICANCE Crown design factors such as material thickness at the margin, axial wall height and preparation type affects the risk of fracture. It is important to ensure that the crown margins are even and flawless.
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Affiliation(s)
- Anneli Skjold
- Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Aarstadveien 19. N-5009 Bergen, Norway.
| | - Christian Schriwer
- Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Aarstadveien 19. N-5009 Bergen, Norway.
| | - Nils Roar Gjerdet
- Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Aarstadveien 19. N-5009 Bergen, Norway.
| | - Marit Øilo
- Department of Clinical Dentistry, Faculty of Medicine, University of Bergen, Aarstadveien 19. N-5009 Bergen, Norway.
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Ordoñez Balladares A, Abad-Coronel C, Ramos JC, Martín Biedma BJ. Fracture Resistance of Sintered Monolithic Zirconia Dioxide in Different Thermal Units. MATERIALS 2022; 15:ma15072478. [PMID: 35407810 PMCID: PMC8999687 DOI: 10.3390/ma15072478] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 03/16/2022] [Accepted: 03/22/2022] [Indexed: 01/27/2023]
Abstract
The purpose of this study was to compare the fracture strength of monolithic zirconium dioxide subjected to a sintering process in two different furnaces: InFire HTC Speed and CEREC SpeedFire. Methods: Forty restorations were designed and machined using a computer aided design / computer aidded machine (CAD/CAM) system. The restorations were randomly assigned to two groups of 20 samples each, Group 1 for the SpeedFire furnace (fast sintering) and Group 2 for the InFire furnace (slow sintering). Each of the crowns was subjected to a maximum compression load recorded in Newtons (N) and a displacement control with a speed of 1 mm/min. Results: Group 1 presented an average of 1222.8 N and a standard deviation of 136.91 N. Group 2 obtained a mean of 1068.5 N and a standard deviation of 316.39 N. Conclusions: There were no significant differences between the two groups, and the mechanical strength of the material was not affected, which would imply a saving of clinical and laboratory time when performing rapid sintering on monolithic translucent zirconium dioxide restorations. However, rapidly sintered restorations have limited reliability.
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Affiliation(s)
- Andrea Ordoñez Balladares
- Faculty of Dentistry, Universidad de Guayaquil, Guayaquil 090514, Ecuador;
- Faculty of Dentistry, Universidad de Santiago de Compostela, 15782 Galicia, Spain;
| | - Cristian Abad-Coronel
- Department of Digital Dentistry and CAD/CAM Materials, Faculty of Dentistry, Universidad de Cuenca, Cuenca 010107, Ecuador
- Faculty of Dentistry, Universidad San Francisco de Quito, Quito 170901, Ecuador
- Correspondence:
| | - Joao Carlos Ramos
- Faculty of Medicine, Universidad de Coimbra, 3000-370 Coimbra, Portugal;
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UCHIKURA K, MURAKAMI N, YAMAZAKI T, LYU H, NAGATA K, ONA M, IWASAKI N, TAKAHASHI H, WAKABAYASHI N. Fracture resistance of CAD/CAM restorative materials in mismatched removable partial denture rests: An <i>in vitro</i> experimental and finite element analysis. Dent Mater J 2022; 41:466-472. [DOI: 10.4012/dmj.2021-224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Keiichiro UCHIKURA
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Natsuko MURAKAMI
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Toshiki YAMAZAKI
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Huaxin LYU
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Kohji NAGATA
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masahiro ONA
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Naohiko IWASAKI
- Oral Health Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Hidekazu TAKAHASHI
- Oral Health Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Noriyuki WAKABAYASHI
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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Jian Y, Zhang T, Wang X, Kyaw L, Pow EHN, Zhao K. Effect of supporting dies' mechanical properties on fracture behavior of monolithic zirconia molar crowns. Dent Mater J 2021; 41:249-255. [PMID: 34866116 DOI: 10.4012/dmj.2021-090] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The aim of this study was to investigate the effects of supporting dies with different mechanical properties on the fracture strengths and failure modes of monolithic zirconia crowns, and identify a suitable die material for testing high-strength ceramic restorations. Thirty six dies from teeth, porous titanium and composite-resin with 36 zirconia crowns were fabricated based on 3D model. Crowns were cemented, then underwent load-to-fracture testing. Fractographic analysis was performed with scanning electron microscopy, and finite element analysis was made. During loading, a high stress concentration zone formed near the loading point and on surface of die. Cracks generated on failure penetrated the crown and extended to die in 9 teeth group specimens, while composite-resin samples exhibited fracture of both crowns and dies. All dies remained intact in porous titanium group. Fracture mode was undistinguishable in all groups. It was concluded that porous titanium appears suitable as die material for dental restorations with high fracture strength.
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Affiliation(s)
- Yutao Jian
- Institute of Stomatological Research, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-Sen University
| | - Tianyi Zhang
- Research Center for Stomatology, Peking University Shenzhen Hospital
| | - Xiaodong Wang
- Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-Sen University; Guangdong Engineering Research Center of Technology and Materials for Oral Reconstruction, Guangdong Provincial Key Laboratory of Stomatology
| | - Laina Kyaw
- Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-Sen University; Guangdong Engineering Research Center of Technology and Materials for Oral Reconstruction, Guangdong Provincial Key Laboratory of Stomatology
| | - Edmond Ho Nang Pow
- Prosthodontics, Faculty of Dentistry, The University of Hong Kong, Prince Philip Dental Hospital
| | - Ke Zhao
- Department of Prosthodontics, Guanghua School of Stomatology, Sun Yat-Sen University; Guangdong Engineering Research Center of Technology and Materials for Oral Reconstruction, Guangdong Provincial Key Laboratory of Stomatology
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Sadeqi HA, Baig MR, Al-Shammari M. Evaluation of Marginal/Internal Fit and Fracture Load of Monolithic Zirconia and Zirconia Lithium Silicate (ZLS) CAD/CAM Crown Systems. MATERIALS 2021; 14:ma14216346. [PMID: 34771872 PMCID: PMC8585271 DOI: 10.3390/ma14216346] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 10/15/2021] [Accepted: 10/20/2021] [Indexed: 11/24/2022]
Abstract
Fit accuracy and fracture strength of milled monolithic zirconia (Zi) and zirconia-reinforced lithium silicate (ZLS) crowns are important parameters determining the success of these restorations. This study aimed to evaluate and compare the marginal and internal fit of monolithic Zi and ZLS crowns, along with the fracture load, with and without mechanical aging. Thirty-two stone dies acquired from a customized master metal molar die were scanned, and ceramic crowns (16 Zi Ceramill Zolid HT+ and 16 ZLS Vita Suprinity) were designed and milled. Absolute marginal discrepancies (AMD), marginal gaps (MG), and internal gaps (IG) of the crowns, in relation to the master metal die, were evaluated using x-ray nanotomography (n = 16). Next, thirty-two metal dies were fabricated based on the master metal die, and crowns (16 Zi; 16 ZLS) cemented and divided into four groups of eight each; eight Zi with mechanical aging (MA), eight Zi without mechanical aging (WMA), eight ZLS (MA), and eight ZLS (WMA). Two groups of crowns (Zi-MA; ZLS-MA) were subjected to 500,000 mechanical cycles (200 ± 50 N, 10 Hz) followed by axial compressive strength testing of all crowns, until failure, and the values were recorded. Independent sample t tests (α = 0.05) revealed no significant differences between Zi and ZLS crowns (p > 0.05); for both internal and marginal gaps, however, there were significant differences in AMD (p < 0.005). Independent samples Mann–Whitney U and Kruskal–Wallis tests revealed significant differences between the two materials, Zi and ZLS, regardless of fatigue loading, and for the individual material groups based on aging (α = 0.05). Multiple comparisons using Bonferroni post-hoc analysis showed significant differences between Zi and ZLS material groups, with or without aging. Within the limitations of this study, the ZLS crown fit was found to be on par with Zi, except for the AMD parameter. As regards fracture resistance, both materials survived the normal range of masticatory forces, but the Zi crowns demonstrated greater resistance to fracture. The monolithic Zi and ZLS crowns seem suitable for clinical application, based on the fit and fracture strength values obtained.
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Affiliation(s)
- Haneen A. Sadeqi
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923,
Safat 13110, Kuwait; (H.A.S.); (M.A.-S.)
| | - Mirza Rustum Baig
- Department of Restorative Sciences (Prosthodontics), Faculty of Dentistry, Kuwait University, P.O. Box 24923,
Safat 13110, Kuwait
- Correspondence:
| | - Mohammad Al-Shammari
- Department of Bioclinical Sciences, Faculty of Dentistry, Kuwait University, P.O. Box 24923,
Safat 13110, Kuwait; (H.A.S.); (M.A.-S.)
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20
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Alberto Jurado C, Kaleinikova Z, Tsujimoto A, Alberto Cortés Treviño D, Seghi RR, Lee DJ. Comparison of Fracture Resistance for Chairside CAD/CAM Lithium Disilicate Crowns and Overlays with Different Designs. J Prosthodont 2021; 31:341-347. [PMID: 34297866 DOI: 10.1111/jopr.13411] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/21/2021] [Indexed: 11/27/2022] Open
Abstract
PURPOSE To determine the fracture resistance of chairside computer-aided design and computer-assisted manufacturing (CAD/CAM) lithium disilicate full coverage crowns and two different designs of overlay restorations for premolars. MATERIALS AND METHODS CAD/CAM lithium disilicate (IPS e.max CAD for CEREC/HT A1 C14, Ivoclar Vivadent) restorations (15 specimens/group) with 1.5 mm occlusal thickness and 1.0 mm chamfer were designed and fabricated with a chairside CAD/CAM system (CEREC, Dentsply Sirona). The restorations were prepared in three different designs: (1) full coverage crowns, (2) overlays with the margin located 2 mm above the gingiva, and (3) overlays with the margin located 4 mm above the gingiva. Restorations were cemented using conventional resin luting cement (Multilink, Ivoclar Vivadent) with primer system (Monobond Plus, Ivoclar Vivadent) to resin printed dies, load cycled (2,000,000 load cycles at 1 Hz with 275 N force), and then finally loaded with a steel indenter until failure. Scanning electron microscopy observations of fractured surfaces were also conducted. Group results were analyzed with one-way analysis of variance, and the medians were evaluated independently with Kruskal-Wallis. RESULTS The fracture force of CAD/CAM lithium disilicate restorations was significantly different (p < 0.001) depending on the design of the restoration. Full coverage crowns showed significantly higher force to fracture (1018.8 N) than both types of overlays (p = 0.002 for overlay 2.0 mm and p < 0.001 for overlay 4.0 mm above gingiva). Among the two overlays, the restoration with the margin located 2 mm above the gingiva showed significantly higher fracture force (813.8 N) than the overlay with margin at 4 mm above the gingiva (436.1 N; p < 0.001). The fracture appearance of the crowns was much more complex than that of the overlay restorations. CONCLUSIONS Full coverage chairside CAD/CAM lithium disilicate premolar crown showed higher fracture resistance than overlay restorations. Overlays with the margin located 2 mm above the margin demonstrated higher resistance than those with the margin located 4 mm above the gingiva.
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Affiliation(s)
- Carlos Alberto Jurado
- Woody L. Hunt School of Dental Medicine, Texas Tech University Health Sciences Center El Paso, El Paso, TX
| | - Zinaida Kaleinikova
- Comprehensive Care Unit, A.T. Still University Arizona School of Dentistry & Oral Health, Mesa, AZ
| | - Akimasa Tsujimoto
- Department of Operative Dentistry, University of Iowa College of Dentistry, Iowa City, IA
| | | | - Robert R Seghi
- Division of Restorative and Prosthetic Dentistry, The Ohio State University College of Dentistry, Columbus, OH
| | - Damian J Lee
- Advanced Prosthodontics Program, The Ohio State University College of Dentistry, Columbus, OH
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Chai SY, Bennani V, Aarts JM, Lyons K, Das R. Stress distribution within the ceramic veneer-tooth system with butt joint and feathered edge incisal preparation designs. J ESTHET RESTOR DENT 2020; 33:496-502. [PMID: 32937021 DOI: 10.1111/jerd.12655] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 08/27/2020] [Indexed: 12/01/2022]
Abstract
OBJECTIVE This in-vitro study aims to study the stress distribution within the ceramic veneer-tooth system with two incisal preparation designs-butt joint (BJ) and feathered edge (FE), and to correlate these findings to the results of our previous published load-to-failure study. METHODS Six photoelastic models were fabricated with an epoxy resin material (West System 105 Epoxy Resin/205 Fast Hardener, West System) to represent BJ and FE preparation configurations at 0° and 20° loading angulations. Lithium disilicate ceramic veneers (IPS e.max CAD, Ivoclar Vivadent) were bonded to the BJ and FE photoelastic models using resin cement (IPS Variolink Esthetic, Ivoclar Vivadent). Each model was loaded using an Instron Universal Testing Machine at the incisal edge at a cross-head speed of 0.25 mm/min till 100 N. RESULTS BJ photoelastic model had more uniform distribution compared with FE photoelastic models under 0° and 20° loading angulations. CONCLUSION Parallel to the results of our earlier load-to-failure published study, both incisal preparation designs affect stress distribution within the ceramic veneer-tooth system. BJ photoelastic model demonstrated a more uniform distribution compared with FE photoelastic model. CLINICAL SIGNIFICANCE BJ incisal preparation design has more uniform stress distribution than FE preparation design within the ceramic veneer-tooth system.
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Affiliation(s)
- Sy Yin Chai
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Vincent Bennani
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - John M Aarts
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Karl Lyons
- Department of Oral Rehabilitation, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Raj Das
- School of Engineering, RMIT University, Melbourne, Australia
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Arslan M, Tosun İ. Fracture load and microcrack comparison of crowns manufactured from tooth-shaped and traditional blocks. Microsc Res Tech 2020; 84:111-118. [PMID: 32845029 DOI: 10.1002/jemt.23571] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Revised: 06/09/2020] [Accepted: 07/21/2020] [Indexed: 11/12/2022]
Abstract
This study intended to analyze microcracks and fractographic markings on the surface of all ceramic crowns after milling and compare the fracture loads. 90 crowns were manufactured from two feldspathic (Priticrown-Pr and Vita Mark II-Vi) and a lithium disilicate (EmaxCAD-Em) blocks (n = 30). Two groups (n = 15) were prepared for each ceramic. In the first group, crowns were analyzed twice via the fluorescent penetrant method for microcrack detection, after the manufacturing process and thermal cycles. The load to fracture test was applied at a crosshead speed of 0.5 mm/min until catastrophic failure. Second group crowns were directly cemented onto the Co-Cr dies following the manufacturing process and loaded to fracture. Fractographic markings were analyzed through scanning electron microscope. Spearman correlation analysis, Kruskal-Wallis H test, Mann-Whitney U test, and Wilcoxon Signed Rank test were applied (α = .05). Fracture loads of Em crowns were higher than other groups (p < .05), with and without the aging procedure. Except for second group Pr (r = -.532), no significant relationship was found between microcrack numbers and fracture loads (p > .05). Thermal cycling did not affect microcrack numbers and fracture loads (p > .05). Tooth-shaped multilayered Pr blocks did not provide an advantage in terms of microcrack and fracture loads.
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Affiliation(s)
- Merve Arslan
- Kırıkkale University, Vocational School of Health Services, Yahşihan-Kırıkkale, Turkey
| | - İlgi Tosun
- Department of Prosthodontics, Faculty of Dentistry, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
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Fracture Load of CAD/CAM Feldspathic Crowns Influenced by Abutment Material. MATERIALS 2020; 13:ma13153407. [PMID: 32748827 PMCID: PMC7435702 DOI: 10.3390/ma13153407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2020] [Revised: 07/22/2020] [Accepted: 07/31/2020] [Indexed: 11/30/2022]
Abstract
In vitro studies investigating the mechanical properties of dental reconstructions use various materials to replicate prepared teeth. However, no uniform recommendation exists as to which material is most suitable for standardized testing. The purpose of this study was to identify a material that resembles human dentin in fracture load tests. Sixteen human teeth were scanned with an intraoral scanner to obtain copies of the original crown morphology and were then prepared for crowns. Replica dies of the prepared teeth including the root morphology were fabricated with a Computer-aided design and computer-aided manufacturing (CAD/CAM) system and divided into four groups: (A) reinforced composite (RC); (B) human dentin (HD); (C) polymethyl methacrylate (PM); and (D) hybrid ceramic (HC). Sixty-four feldspar ceramic crowns were designed with the biocopy mode, fabricated with a CAD/CAM system, luted on the dies, and then with the roots embedded in polymethyl methacrylate. Care was taken to position all specimens of the same morphology identically. Thermo-mechanical load cycling was performed in a chewing simulator followed by fractural loading of the crowns. A mixed effect linear model was fitted to the data, and pairwise contrasts were estimated on the marginal means and corrected for multiple testing according to Tukey (α = 0.05). The means for fracture load (N) were 2435 N (95% CI (2162, 2709)) for hybrid ceramic, 1838 N (95% CI (1565, 2112)) for reinforced composite, 1670 N (95% CI (1396, 1943)) for human tooth and 1142 N (95% CI (868, 1415)) for polymethyl methacrylate abutment materials. Post-hoc pairwise contrasts revealed a statistically significant (p < 0.05) difference among all groups except for reinforced composite and human dentin (p = 0.76). The results indicate that the mechanical properties of abutment dies play a significant role for a possible substitution of natural teeth in in vitro studies.
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Jasim HH, Findakly MB, Mahdi NA, Mutar MT. Effect of Reduced Occlusal Thickness with Two Margin Designs on Fracture Resistance of Monolithic Zirconia Crowns. Eur J Dent 2020; 14:245-249. [PMID: 32503065 PMCID: PMC7274823 DOI: 10.1055/s-0040-1709342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Objectives
The aim of this study was to compare the effects of two margin designs (shoulderless and slight chamfer) with two occlusal thicknesses on fracture resistance and failure mode of the monolithic zirconia crowns.
Materials and Methods
Forty nickel–chromium dies were duplicated from the previous two prepared teeth using a three-dimensional optical scanner. Nickel–chromium supporting dies were divided into two main groups (
n
= 20) according to the type of margin design: group A, slight chamfer margin design and group B, shoulderless margin design. These groups were further divided into two subgroups according to the occlusal thicknesses (0.5 and 1 mm). The digital imaging of each die was done using a three-dimensional optical scanner, then zirconia blocks were milled by 5-axis machine. The crowns were cleaned by alcohol, air dried, and cemented by resin cement. Next, the crowns were subjected to 500 hot and cold cycles (30 seconds for each cycle). The samples were subjected to a static load until failure using an electronic universal testing machine and fracture resistance was recorded in Newton (N).
Statistical Analysis
Data were analyzed using the test of normality (Shapiro–Wilk test) and two-way analysis of variance (ANOVA) test.
Results
The highest mean fracture load was recorded by the shoulderless (1 mm occlusal thickness) subgroup (3,992.5 N), followed by shoulderless (0.5 mm occlusal thickness) subgroup (3,244.4 N), and the slight chamfer (1 mm occlusal thickness) subgroup (2,811 N). The lowest mean of fracture load was recorded by slight chamfer (0.5 mm occlusal thickness) subgroup (1,632.9 N). The two-way ANOVA test revealed a significant difference between the four subgroups. Regarding the fracture mode, the slight chamfer subgroups showed a severe fracture of the restoration while the shoulderless subgroups showed a fracture through the midline of the restoration.
Conclusion
Within the limitation of the comparative study, shoulderless margin design has a more favorable outcome than a slight chamfer design in all thicknesses. Although the restoration with reduced occlusal thickness has lower fracture resistance than 1 mm occlusal thickness, the 0.5 mm restorations still can tolerate occlusal forces.
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Affiliation(s)
- Haider Hasan Jasim
- Department of Conservative Dentistry, College of Dentistry, Mustansiriyah University, Baghdad, Iraq
| | | | - Nada Ali Mahdi
- Department of Conservative Dentistry, College of Dentistry, Mustansiriyah University, Baghdad, Iraq
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Oguz Eİ, Kılıçarslan MA, Özcan M. Effect of endodontic access simulation on the fracture strength of lithium-disilicate and resin-matrix ceramic CAD-CAM crowns. J ESTHET RESTOR DENT 2020; 32:472-479. [PMID: 32369271 DOI: 10.1111/jerd.12591] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 04/03/2020] [Accepted: 04/13/2020] [Indexed: 12/01/2022]
Abstract
OBJECTIVES The purpose of this in vitro study was to compare the effect of simulated endodontic access preparation on the failure loads of lithium disilicate crowns and resin-matrix ceramic (RMC) crowns. MATERIALS AND METHODS Eighty maxillary first premolar crowns were manufactured by using four different CAD/CAM blocks (n = 20): lithium disilicate (LD; IPS e.max CAD), resin nanoceramic (RNC; Lava Ultimate), flexible nanaoceramic (FNC; GC Cerasmart), and polymer-infiltrated ceramic (PIC; VITA Enamic). Half of each group was accessed and repaired to simulate endodontic treatment. After cyclic loading, all specimens were loaded to failure. Data were analyzed with two-way ANOVA followed by Tukey-HSD test (α = .05). RESULTS The load to failure results showed significant differences for material types (P < .001), but not for endodontic access simulation (P = .09). The highest and lowest mean failure loads were obtained for LD (1546 N) and PIC (843 N), respectively. CONCLUSION The endodontic access preparation was not found to affect the fracture strength of LD and RMC crowns. The LD showed higher fracture strength than RMC crowns. Even though significant differences were noted for failure loads regarding different crown materials, all could reasonably withstand masticatory forces. CLINICAL SIGNIFICANCE The endodontic access preparation through a restoration is known to be a common challenge in clinical practice. Maintaining a repaired LD or RMC crown is feasible and replacement may not be necessary.
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Affiliation(s)
- Ece İrem Oguz
- Department of Prosthodontics, Faculty of Dentistry, Ankara University, Ankara, Turkey
| | | | - Mutlu Özcan
- University of Zürich, Division of Dental Biomaterials, Center for Dental and Oral Medicine, Clinic for Reconstructive Dentistry, Zürich, Switzerland
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Nawafleh N, Bibars AR, Al Twal E, Öchsner A. Influence of Antagonist Material on Fatigue and Fracture Resistance of Zirconia Crowns. Eur J Dent 2020; 14:200-205. [PMID: 32311751 PMCID: PMC7274834 DOI: 10.1055/s-0040-1708228] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Objective
This study investigates the influence of the most commonly used indenter materials on fatigue survival and fracture resistance of zirconia crowns.
Materials and Methods
A total of 40 zirconia crowns were prepared using computer-aided design (CAD)/computer-aided manufacturing (CAM) technology: 30 crowns were divided into three experimental groups of 10 specimens and the last 10 specimens acted as the control group. The experimental groups were subjected to chewing simulation with simultaneous thermocycling. Three indenter materials (steatite ceramic, stainless steel, and tungsten carbide) with identical diameter were used to load the specimens. All crowns were then subjected to single load to fracture test in universal testing machine. Load was applied vertically with a crosshead speed of 1 mm/min until failure, and fracture load was recorded.
Statistical Analysis
Normal distribution of data was confirmed using the Shapiro–Wilk test. Descriptive statistics including means and standard deviations were determined for all groups. Differences between groups were tested using Dunnett’s test and paired sample
t
-test.
Results
Chewing simulation for 1.2 million cycles resulted in 100% survival. The highest mean fracture load was recorded for the control group and the lowest one was for the group fatigued with stainless steel indenter. Chewing simulation statistically significantly (
p
< 0.05) reduced the mean fracture load of the crowns fatigued with stainless steel and steatite ceramic indenter. However, the mean fracture load for the crowns fatigued with tungsten carbide was not significantly different from that of the control group.
Conclusion
Steatite ceramic and stainless steel indenters produced close results and significantly reduced fracture load of zirconia crowns. However, tungsten carbide indenter caused nonsignificant reduction in the fracture load of zirconia crowns.
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Affiliation(s)
- Noor Nawafleh
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Abdel Raheem Bibars
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Elina Al Twal
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Andreas Öchsner
- Faculty of Mechanical Engineering, Esslingen University of Applied Sciences, Esslingen, Germany.,Faculty of Engineering and Built Environment, University of Newcastle, Newcastle, Australia
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Chai SY, Bennani V, Aarts JM, Lyons K, Lowe B. Effect of incisal preparation design on load-to-failure of ceramic veneers. J ESTHET RESTOR DENT 2020; 32:424-432. [PMID: 32270920 DOI: 10.1111/jerd.12584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 02/10/2020] [Accepted: 03/19/2020] [Indexed: 11/28/2022]
Abstract
OBJECTIVE This in vitro study aims to evaluate load-to-failure of ceramic veneers with butt joint (BJ) and feathered edge (FE) incisal preparation designs, and to correlate these results to the failure mode of the restorations. MATERIALS AND METHODS One hundred and forty-eight typodont teeth (customized Nissin A25A-UL19B) were divided into two different preparation configurations BJ and FE and two different loading angulations, 0° and 20°. Lithium disilicate ceramic veneers (IPS e.max CAD, Ivoclar Vivadent) were milled using computer-aided-design-and-computer-aided-manufacturing (CAD/CAM) techniques. Veneers were bonded to typodont teeth with resin cement (IPS Variolink Esthetic, Ivoclar Vivadent). Each group was loaded at the incisal edge using an Instron Universal Testing Machine at a crosshead speed of 0.01 mm/s till failure. RESULTS Pairwise comparison showed veneers from the BJ groups had a significantly higher load-to-failure value compared to the FE groups. Veneers with a FE preparation design loaded at 20° angulation had the lowest load-to-failure value. CONCLUSIONS Within the limitations of the present study, both incisal preparation designs and loading angulations have significant effects on the load-to-failure values of ceramic veneers. BJ group exhibits a significantly higher load-to-failure value compared to the FE group. CLINICAL SIGNIFICANCE BJ incisal preparation is preferred over FE preparation design.
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Affiliation(s)
- Sy Yin Chai
- Faculty of Dentistry, Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand
| | - Vincent Bennani
- Faculty of Dentistry, Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand
| | - John M Aarts
- Faculty of Dentistry, Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand
| | - Karl Lyons
- Faculty of Dentistry, Department of Oral Rehabilitation, University of Otago, Dunedin, New Zealand
| | - Bronwyn Lowe
- Department of Applied Sciences, University of Otago, Dunedin, New Zealand
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Findakly MB, Jasim HH. Influence of preparation design on fracture resistance of different monolithic zirconia crowns: A comparative study. J Adv Prosthodont 2019; 11:324-330. [PMID: 31897271 PMCID: PMC6933051 DOI: 10.4047/jap.2019.11.6.324] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/08/2019] [Accepted: 12/11/2019] [Indexed: 12/18/2022] Open
Abstract
PURPOSE The aim of the study was to evaluate and compare the fracture resistance and modes of fracture of monolithic zirconia crowns with two preparation designs. MATERIALS AND METHODS Forty human maxillary first premolar teeth were extracted for orthodontic purposes and divided into two main groups (n=20): Group A: monolithic traditional zirconia; Group B: monolithic translucent zirconia. The groups were further subdivided into two subgroups (n=10): (A1, B1) shoulder margin design; (A2, B2) feather-edge margin design. Teeth were prepared with either a 1 mm shoulder margin design or a feather-edge margin design. The prepared teeth were scanned using a digital intraoral scanner. The crowns were cemented using self-adhesive resin cement. All cemented teeth were stored in water for 7 days and thermocycling was done before testing. All samples were subjected to compressive axial loading until fracture. The fractographic analysis was done to assess the modes of fracture of the tested samples. RESULTS The highest mean values of fracture resistance were recorded in kilo-newton and were in the order of subgroup A1 (2.903); subgroup A2 (2.3); subgroup B1 (1.854) and subgroup B2 (1.523). One-way ANOVA showed a statistically significant difference among the 4 subgroups. Concerning modes of fracture, the majority of samples in subgroups A1 and B1 were fracture of restoration and/or tooth, while in subgroups A2 and B2, the majority of samples fractured through the central fossa. CONCLUSION Even though all the tested crowns fractured at a higher level than the maximum occlusal forces, the shoulder margin design was better than the feather-edge margin design and the monolithic traditional zirconia was better than the monolithic translucent zirconia in terms of fracture strength.
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Affiliation(s)
- Meelad Basil Findakly
- Department of Conservative Dentistry, College of Dentistry, Mustansiriyah University, Baghdad, Iraq
| | - Haider Hasan Jasim
- Department of Conservative Dentistry, College of Dentistry, Mustansiriyah University, Baghdad, Iraq
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Longhini D, Rocha C, de Oliveira LT, Olenscki NG, Bonfante EA, Adabo GL. Mechanical Behavior of Ceramic Monolithic Systems With Different Thicknesses. Oper Dent 2019; 44:E244-E253. [PMID: 31265354 DOI: 10.2341/18-083-l] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVES This study assessed the fully stabilized zirconia (FSZ) Prettau Anterior, the partially stabilized zirconia (PSZ) Prettau, and the lithium disilicate IPS e.max CAD (LD) through microstructural and mechanical characterization and effect of thickness on fracture load of the ceramics. METHODS AND MATERIALS Disk-shaped specimens (12 mm diameter and 1.2 mm thickness) were prepared for biaxial flexural strength (BFS) and Weibull statistics (n=30). For the fracture load static test (FLST) and Weibull statistics (n=30), disk-shaped specimens 12 mm in diameter and thicknesses of 0.5 mm, 1 mm, and 1.5 mm were cemented on an epoxy-resin substrate. RESULTS BFS (MPa) results were PSZ: 683.0 ± 70.23; FSZ: 438.6 ± 64.1; and LD: 248.6 ± 37.3. One-way analysis of variance (ANOVA) for BFS was significant (p<0.001), and the Tukey post hoc test showed differences among all ceramics. There was difference in characteristic strength, but there was no difference in Weibull modulus. Two-way ANOVA for FLST was significant for ceramic (p<0001), thickness (p<0001), and interaction (p<0001). There was no difference among all ceramics at the 0.5 mm thickness. PSZ had higher values for the 1.0 mm and 1.5 mm thicknesses. LD of 1.5 mm thickness exhibited a higher FLST than FSZ. CONCLUSIONS PSZ had the highest BFS, but when cemented on a substrate, all ceramics with 0.5 mm thickness behaved similarly. Despite the lower BFS, LD had a fracture load similar or superior to FSZ when cemented on a substrate.
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30
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Manchester JA, Chung KH, Brudvik JS, Ramos V, Chen YW. Fracture resistance of cingulum rest seats in CAD-CAM tooth-colored crowns for removable partial denture abutments. J Prosthet Dent 2019; 121:828-835. [DOI: 10.1016/j.prosdent.2018.08.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 08/28/2018] [Accepted: 08/29/2018] [Indexed: 11/16/2022]
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Kashkari A, Yilmaz B, Brantley WA, Schricker SR, Johnston WM. Fracture analysis of monolithic CAD‐CAM crowns. J ESTHET RESTOR DENT 2019; 31:346-352. [DOI: 10.1111/jerd.12462] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2018] [Revised: 01/19/2019] [Accepted: 02/13/2019] [Indexed: 11/30/2022]
Affiliation(s)
- Afnan Kashkari
- Restorative and Esthetic DentistryJohns Hopkins Aramco Healthcare Dhahran Saudi Arabia
| | - Burak Yilmaz
- Division of Restorative and Prosthetic DentistryThe Ohio State University, College of Dentistry Columbus Ohio
| | - William A. Brantley
- College of Dentistry, Division of Restorative and Prosthetic DentistryThe Ohio State University Columbus Ohio
| | - Scott R. Schricker
- College of Dentistry, Division of Restorative and Prosthetic DentistryThe Ohio State University Columbus Ohio
| | - William M. Johnston
- College of Dentistry, Division of Restorative and Prosthetic DentistryThe Ohio State University Columbus Ohio
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Nakamura K, Ankyu S, Nilsson F, Kanno T, Niwano Y, Vult von Steyern P, Örtengren U. Critical considerations on load-to-failure test for monolithic zirconia molar crowns. J Mech Behav Biomed Mater 2018; 87:180-189. [PMID: 30077077 DOI: 10.1016/j.jmbbm.2018.07.034] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2018] [Revised: 07/19/2018] [Accepted: 07/24/2018] [Indexed: 11/30/2022]
Abstract
Application of monolithic zirconia crowns (MZCs) with reduced thickness to the molar region has been proposed, but potential complications have yet to be fully evaluated in laboratory tests. The present study aimed to develop a clinically relevant load-to-failure test in combination with fatigue treatments involving thermal and mechanical cycling (TC and MC) to evaluate the fracture resistance of molar MZCs. MZCs with a minimal thickness of 0.5 mm were bonded to dies made of resin-based composite (RBC), epoxy resin (EP), or polyoxymethylene-copolymer (POM-C). The samples were either untreated (UT) or subjected to TC (5-55 °C for 1 × 105 cycles) and MC (300 N for 2.4 × 106 cycles). The stress generated by TC and MC was simulated by finite element modeling. The load-to-failure test was performed using an inverse V-shaped two-plane indenter and was followed by fractographic analysis. The median values of fracture load for MZC/RBC and MZC/EP in the TC group were significantly lower than those in the UT group. MC also decreased the median value of fracture load for MZC/RBC significantly, but not that for MZC/EP and MZC/POM-C. Fractography revealed that the fracture started in the cervical area in all groups, which is similar to clinically failed crowns. The simulation confirmed stress concentration at the cervical area in both TC and MC groups. The present study suggests that the load-to-failure test using a two-plane indenter could induce clinically relevant fracture of MZCs, the vulnerability of the MZCs depends largely on the die material employed, and MZCs are more likely to be damaged by thermal fatigue than mechanical fatigue.
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Affiliation(s)
- Keisuke Nakamura
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980 8575, Japan.
| | - Shuhei Ankyu
- Sweden Dental Sendai (private practice), 1-6-2 Tsutsujigaoka, Miyagino-ku, Sendai 983 0852, Japan
| | - Fritjof Nilsson
- Division of Polymeric Materials, Department of Fibre and Polymer Technology, School of Engineering Sciences in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, SE-100 44 Stockholm, Sweden
| | - Taro Kanno
- Department of Advanced Free Radical Science, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai 980 8575, Japan
| | - Yoshimi Niwano
- Faculty of Nursing, Shumei University, 1-1 Daigaku-cho, Yachiyo, Chiba 276-0003, Japan
| | - Per Vult von Steyern
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, SE-205 06 Malmö, Sweden
| | - Ulf Örtengren
- Department of Cariology, Institute of Odontology, Sahlgrenska Academy, University of Gothenburg, SE-405 30 Gothenburg, Sweden; Department of Clinical Dentistry/Faculty of Health Sciences, The Arctic University of Norway, Tromsø 9037, Norway
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Bakitian F, Seweryniak P, Papia E, Larsson C, Vult von Steyern P. Effect of different semimonolithic designs on fracture resistance and fracture mode of translucent and high-translucent zirconia crowns. Clin Cosmet Investig Dent 2018; 10:51-60. [PMID: 29628778 PMCID: PMC5878660 DOI: 10.2147/ccide.s157118] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Purpose The aim of this study was to describe different designs of semimonolithic crowns made of translucent and high-translucent zirconia materials and to evaluate the effect on fracture resistance and fracture mode. Methods One hundred crowns with different designs were produced and divided into five groups (n=20): monolithic (M), partially veneered monolithic (semimonolithic) with 0.3 mm buccal veneer (SM0.3), semimonolithic with 0.5 mm buccal veneer (SM0.5), semimonolithic with 0.5 mm buccal veneer supported by wave design (SMW), and semimonolithic with 0.5 mm buccal veneer supported by occlusal cap design (SMC). Each group was divided into two subgroups (n=10) according to the materials used, translucent and high-translucent zirconia. All crowns underwent artificial aging before loading until fracture. Fracture mode analysis was performed. Fracture loads and fracture modes were analyzed using two-way ANOVA and Fisher's exact probability tests (P≤0.05). Results SM0.3 design showed highest fracture loads with no significant difference compared to M and SMW designs (P>0.05). SM0.5 design showed lower fracture loads compared to SMW and SWC designs. Crowns made of translucent zirconia showed higher fracture loads compared to those made of high-translucent zirconia. M, SM0.3, and all but one of the SMC crowns showed complete fractures with significant differences in fracture mode compared to SMW and SM0.5 crowns with cohesive veneer fractures (P≤0.05). Conclusion Translucent and high-translucent zirconia crowns might be used in combination with 0.3 mm microcoating porcelain layer with semimonolithic design to enhance the esthetic properties of restorations without significantly decreasing fracture resistance of the crowns. If 0.5 mm porcelain layer is needed for a semimonolithic crown, wave design or cap design might be used to increase fracture resistance. In both cases, fracture resistance gained is likely to be clinically sufficient as the registered fracture loads were high in relation to expected loads under clinical use.
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Affiliation(s)
- Fahad Bakitian
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden.,Department of Restorative Dentistry, Faculty of Dentistry, Umm Al-Qura University, Makkah, Saudi Arabia
| | | | - Evaggelia Papia
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Christel Larsson
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden
| | - Per Vult von Steyern
- Department of Materials Science and Technology, Faculty of Odontology, Malmö University, Malmö, Sweden
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Komine F, Kamio S, Takata H, Yagawa S, Taguchi S, Taguchi K, Hashiguchi A, Matsumura H. Effect of framework design on fracture load after thermal cycling and mechanical loading of implant-supported zirconia-based prostheses. Dent Mater J 2018; 37:78-86. [PMID: 28883302 DOI: 10.4012/dmj.2017-057] [Citation(s) in RCA: 2] [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 study evaluated the effect of zirconia framework design on fracture load of implant-supported zirconia-based prostheses after thermal cycling and mechanical loading. Three different zirconia framework designs were investigated: uniform-thickness (UNI), anatomic (ANA), and supported anatomic (SUP) designs. Each framework was layered with feldspathic porcelain (ZAC group) or indirect composite material (ZIC group). The specimens then underwent fracture load testing after thermal cycling and cyclic loading. In the ZAC group, mean fracture load was significantly lower for UNI design specimens than for the other framework designs. In the ZIC group, there was no significant difference in mean fracture load between ANA design specimens and either UNI or SUP design specimens. To improve fracture resistance of implant-supported zirconia-based prostheses after artificial aging, uniformly thick layering material and appropriate lingual support with zirconia frameworks should be provided.
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Affiliation(s)
- Futoshi Komine
- Department of Fixed Prosthodontics, Nihon University School of Dentistry
| | - Shingo Kamio
- Department of Fixed Prosthodontics, Nihon University School of Dentistry
| | - Hiroki Takata
- Department of Fixed Prosthodontics, Nihon University School of Dentistry
| | - Shogo Yagawa
- Department of Fixed Prosthodontics, Nihon University School of Dentistry
| | - Serina Taguchi
- Department of Fixed Prosthodontics, Nihon University School of Dentistry
| | - Kohei Taguchi
- Department of Fixed Prosthodontics, Nihon University School of Dentistry
| | | | - Hideo Matsumura
- Department of Fixed Prosthodontics, Nihon University School of Dentistry
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Miura S, Kasahara S, Yamauchi S, Egusa H. Effect of finish line design on stress distribution in bilayer and monolithic zirconia crowns: a three-dimensional finite element analysis study. Eur J Oral Sci 2018; 126:159-165. [DOI: 10.1111/eos.12402] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Shoko Miura
- Division of Molecular and Regenerative Prosthodontics; Tohoku University Graduate School of Dentistry; Sendai Miyagi Japan
| | - Shin Kasahara
- Division of Molecular and Regenerative Prosthodontics; Tohoku University Graduate School of Dentistry; Sendai Miyagi Japan
| | - Shinobu Yamauchi
- Division of Molecular and Regenerative Prosthodontics; Tohoku University Graduate School of Dentistry; Sendai Miyagi Japan
| | - Hiroshi Egusa
- Division of Molecular and Regenerative Prosthodontics; Tohoku University Graduate School of Dentistry; Sendai Miyagi Japan
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Bakitian F, Seweryniak P, Papia E, Larsson C, Vult von Steyern P. Fracture strength of veneered translucent zirconium dioxide crowns with different porcelain thicknesses. ACTA BIOMATERIALIA ODONTOLOGICA SCANDINAVICA 2017; 3:74-83. [PMID: 29242815 PMCID: PMC5724800 DOI: 10.1080/23337931.2017.1403288] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/15/2017] [Revised: 10/26/2017] [Accepted: 11/07/2017] [Indexed: 11/28/2022]
Abstract
Objective: To evaluate fracture strength of veneered translucent zirconium dioxide crowns designed with different porcelain layer thicknesses. Materials and Methods: Sixty crowns, divided into six groups of 10, were used in this study. Groups were divided according to different thicknesses of porcelain veneer on translucent zirconium dioxide cores of equal thickness (0.5 mm). Porcelain thicknesses were 2.5, 2.0, 1.0, 0.8, 0.5 and 0.3 mm. Crowns were artificially aged before loaded to fracture. Determination of fracture mode was performed using light microscope. Results: Group 1.0 mm showed significantly (p ≤ .05) highest fracture loads (mean 1540 N) in comparison with groups 2.5, 2.0 and 0.3 mm (mean 851, 910 and 1202 N). There was no significant difference (p>.05) in fracture loads among groups 1.0, 0.8 and 0.5 mm (mean 1540, 1313 and 1286 N). There were significantly (p ≤ .05) more complete fractures in group 0.3 mm compared to all other groups which presented mainly cohesive fractures. Conclusions: Translucent zirconium dioxide crowns can be veneered with minimal thickness layer of 0.5 mm porcelain without showing significantly reduced fracture strength compared to traditionally veneered (1.0–2.0 mm) crowns. Fracture strength of micro-veneered crowns with a layer of porcelain (0.3 mm) is lower than that of traditionally veneered crowns but still within range of what may be considered clinically sufficient. Porcelain layers of 2.0 mm or thicker should be used where expected loads are low only.
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Affiliation(s)
- Fahad Bakitian
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden.,Department of Restorative Dentistry, Faculty of Dentistry, Umm Al-Qura UniversityMakkahSaudi Arabia
| | | | - Evaggelia Papia
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden
| | - Christel Larsson
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden
| | - Per Vult von Steyern
- Department of Materials Science and Technology, Faculty of Odontology, Malmö UniversityMalmöSweden
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Nawafleh NA, Hatamleh MM, Öchsner A, Mack F. Fracture load and survival of anatomically representative monolithic lithium disilicate crowns with reduced tooth preparation and ceramic thickness. J Adv Prosthodont 2017; 9:416-422. [PMID: 29279760 PMCID: PMC5741444 DOI: 10.4047/jap.2017.9.6.416] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2017] [Revised: 06/17/2017] [Accepted: 07/04/2017] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To investigate the effect of reducing tooth preparation and ceramic thickness on fracture resistance of lithium disilicate crowns. MATERIALS AND METHODS Specimen preparation included a standard complete crown preparation of a typodont mandibular left first molar with an occlusal reduction of 2 mm, proximal/axial wall reduction of 1.5 mm, and 1.0 mm deep chamfer (Group A). Another typodont mandibular first molar was prepared with less tooth reduction: 1 mm occlusal and proximal/axial wall reduction and 0.8 mm chamfer (Group B). Twenty crowns were milled from each preparation corresponding to control group (n=5) and conditioned group of simultaneous thermal and mechanical loading in aqueous environment (n=15). All crowns were then loaded until fracture to determine the fracture load. RESULTS The mean (SD) fracture load values (in Newton) for Group A were 2340 (83) and 2149 (649), and for Group B, 1752 (134) and 1054 (249) without and with fatigue, respectively. Reducing tooth preparation thickness significantly decreased fracture load of the crowns at baseline and after fatigue application. After fatigue, the mean fracture load statistically significantly decreased (P<.001) in Group B; however, it was not affected (P>.05) in Group A. CONCLUSION Reducing the amount of tooth preparation by 0.5 mm on the occlusal and proximal/axial wall with a 0.8 mm chamfer significantly reduced fracture load of the restoration. Tooth reduction required for lithium disilicate crowns is a crucial factor for a long-term successful application of this all-ceramic system.
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Affiliation(s)
- Noor A Nawafleh
- School of Dentistry and Oral Health, Griffith University, Gold Coast, Australia.,Faculty of Applied Medical Sciences, Jordan University of Science and technology, Irbid, Jordan
| | - Muhanad M Hatamleh
- Maxillofacial Department, King's College Hospital NHS Foundation Trust, London, UK
| | - Andreas Öchsner
- School of engineering, Griffith University, Gold Coast, Australia
| | - Florian Mack
- School of Dentistry and Oral Health, Griffith University, Gold Coast, Australia
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Choi S, Yoon HI, Park EJ. Load-bearing capacity of various CAD/CAM monolithic molar crowns under recommended occlusal thickness and reduced occlusal thickness conditions. J Adv Prosthodont 2017; 9:423-431. [PMID: 29279761 PMCID: PMC5741445 DOI: 10.4047/jap.2017.9.6.423] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 04/19/2017] [Accepted: 04/20/2017] [Indexed: 11/24/2022] Open
Abstract
PURPOSE The goal of this study was to evaluate the fracture resistances of various monolithic crowns fabricated by computer-aided design and computer-aided manufacturing (CAD/CAM) with different thickness. MATERIALS AND METHODS Test dies were fabricated as mandibular molar forms with occlusal reductions using CAD/CAM. With different occlusal thickness (1.0 or 1.5 mm), a polymer-infiltrated ceramic network (Enamic, EN), and zirconia-reinforced lithium silicate (Suprinity, SU and Celtra-Duo, CD) were used to fabricate molar crowns. Lithium disilicate (e.max CAD, EM) crowns (occlusal: 1.5 mm) were fabricated as control. Seventy crowns (n=10 per group) were bonded to abutments and stored in water for 24 hours. A universal testing machine was used to apply load to crown until fracture. The fractured specimens were examined with a scanning electron microscopy. RESULTS The type of ceramics and the occlusal thickness showed a significant interaction. With a recommended thickness (1.5 mm), the SU revealed the mean load similar to the EM, higher compared with those of the EN and CD. The fracture loads in a reduced thickness (1.0 mm) were similar among the SU, CD, and EN. The mean fracture load of the SU and CD enhanced significantly when the occlusal thickness increased, whereas that of the EN did not. CONCLUSION The fracture loads of monolithic crowns were differently influenced by the changes in occlusal thickness, depending on the type of ceramics. Within the limitations of this study, all the tested crowns withstood the physiological masticatory loads both at the recommended and reduced occlusal
thickness.
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Affiliation(s)
- Sulki Choi
- Graduate School of Clinical Dentistry, Ewha Womans University, Seoul, Republic of Korea
| | - Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry, Seoul National University, Seoul, Republic of Korea
| | - Eun-Jin Park
- Department of Prosthodontics, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
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Halal R, Nohra J, Akel H. Conservative anterior treatment with CAD-CAM technology and polymer-infiltrated ceramic for a child with amelogenesis imperfecta: A 2-year follow-up. J Prosthet Dent 2017; 119:710-712. [PMID: 28967409 DOI: 10.1016/j.prosdent.2017.07.018] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2017] [Revised: 07/16/2017] [Accepted: 07/17/2017] [Indexed: 11/16/2022]
Abstract
Amelogenesis imperfecta is a genetic disorder that affects the structure of enamel and consequently the function, esthetics, and psychology of young patients. Restoring the dentition of a child with minimal tooth preparation is achievable with polymer-infiltrated ceramics. The treatment of a 12-year-old child presenting with amelogenesis imperfecta is described. An in-office computer-aided design and computer-aided manufacturing (CAD-CAM) system and polymer-infiltrated ceramic blocks were used in a noninvasive procedure. The definitive clinical outcome showed a major esthetic improvement and allowed for the normal eruption of the permanent dentition.
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Affiliation(s)
- Rozalio Halal
- Resident, Department of Esthetic and Prosthodontics, School of Dentistry, Saint Joseph University, Beirut, Lebanon.
| | - Johnny Nohra
- Senior Clinical Instructor, Department of Periodontology, School of Dentistry, Saint Joseph University, Beirut, Lebanon
| | - Hadi Akel
- Senior Clinical Instructor, Department of Esthetic and Prosthodontics, School of Dentistry, Saint Joseph University, Beirut, Lebanon; and Private practice, Hadi Akel Cosmetic Dentistry, Antelias, Lebanon
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Miura S, Kasahara S, Yamauchi S, Egusa H. Three-dimensional finite element analysis of zirconia all-ceramic cantilevered fixed partial dentures with different framework designs. Eur J Oral Sci 2017; 125:208-214. [PMID: 28303598 DOI: 10.1111/eos.12342] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/08/2017] [Indexed: 11/28/2022]
Abstract
The purpose of this study were: to perform stress analyses using three-dimensional finite element analysis methods; to analyze the mechanical stress of different framework designs; and to investigate framework designs that will provide for the long-term stability of both cantilevered fixed partial dentures (FPDs) and abutment teeth. An analysis model was prepared for three units of cantilevered FPDs that assume a missing mandibular first molar. Four types of framework design (Design 1, basic type; Design 2, framework width expanded buccolingually by 2 mm; Design 3, framework height expanded by 0.5 mm to the occlusal surface side from the end abutment to the connector area; and Design 4, a combination of Designs 2 and 3) were created. Two types of framework material (yttrium-oxide partially stabilized zirconia and a high precious noble metal gold alloy) and two types of abutment material (dentin and brass) were used. In the framework designs, Design 1 exhibited the highest maximum principal stress value for both zirconia and gold alloy. In the abutment tooth, Design 3 exhibited the highest maximum principal stress value for all abutment teeth. In the present study, Design 4 (the design with expanded framework height and framework width) could contribute to preventing the concentration of stress and protecting abutment teeth.
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Affiliation(s)
- Shoko Miura
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Shin Kasahara
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Shinobu Yamauchi
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Hiroshi Egusa
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Japan
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ALSADON O, PATRICK D, JOHNSON A, POLLINGTON S, WOOD D. Fracture resistance of zirconia-composite veneered crowns in comparison with zirconia-porcelain crowns. Dent Mater J 2017; 36:289-295. [PMID: 28190816 DOI: 10.4012/dmj.2016-298] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Affiliation(s)
- Omar ALSADON
- Academic Unit of Restorative Dentistry, The School of Clinical Dentistry, The University of Sheffield
- Department of Dental Health, College of Applied Medical Sciences, King Saud University
| | - David PATRICK
- Academic Unit of Restorative Dentistry, The School of Clinical Dentistry, The University of Sheffield
| | - Anthony JOHNSON
- Academic Unit of Restorative Dentistry, The School of Clinical Dentistry, The University of Sheffield
| | - Sarah POLLINGTON
- Academic Unit of Restorative Dentistry, The School of Clinical Dentistry, The University of Sheffield
| | - Duncan WOOD
- Academic Unit of Restorative Dentistry, The School of Clinical Dentistry, The University of Sheffield
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Aktas G, Yerlikaya H, Akca K. Mechanical Failure of Endocrowns Manufactured with Different Ceramic Materials: An In Vitro Biomechanical Study. J Prosthodont 2016; 27:340-346. [PMID: 27465810 DOI: 10.1111/jopr.12499] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/09/2016] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To evaluate the effect of different silica-based ceramic materials on the mechanical failure behavior of endocrowns used in the restoration of endodontically treated mandibular molar teeth. MATERIALS AND METHODS Thirty-six intact mandibular molar teeth extracted because of a loss of periodontal support received root canal treatment. The teeth were prepared with a central cavity to support the endocrowns, replacing the occlusal surface with mesial-lingual-distal walls. Data acquisition of the prepared tooth surfaces was carried out digitally with a powder-free intraoral scanner. Restoration designs were completed on manufactured restorations from three silicate ceramics: alumina-silicate (control), zirconia-reinforced (Zr-R), and polymer-infiltrated (P-I). Following adhesive cementation, endocrowns were subjected to thermal aging, and then, each specimen was obliquely loaded to record the fracture strength and define the mechanical failure. For the failure definition, the fracture type characteristics were identified, and further analytic measurements were made on the fractured tooth and ceramic structure. RESULTS Load-to-fracture failure did not differ significantly, and the calculated mean values were 1035.08 N, 1058.33 N, and 1025.00 N for control, Zr-R, and P-I groups, respectively; however, the stiffness of the restoration-tooth complex was significantly higher than that in both test groups. No statistically significant correlation was established in paired comparisons of the failure strength, restorative stiffness, and fractured tooth distance parameters. The failure mode for teeth restored with zirconia-reinforced glass ceramics was identified as non-restorable. The resin interface in the control and P-I groups presented similar adhesive failure behavior. CONCLUSION Mechanical failure of endocrown restorations does not significantly differ for silica-based ceramics modified either with zirconia or polymer.
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Affiliation(s)
- Guliz Aktas
- Department of Prosthodontics, Hacettepe University, Ankara, Turkey
| | - Hatice Yerlikaya
- Department of Prosthodontics, Hacettepe University, Ankara, Turkey
| | - Kivanc Akca
- Department of Prosthodontics, Hacettepe University, Ankara, Turkey
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43
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Nawafleh N, Hatamleh MM, Öchsner A, Mack F. The Impact of Core/Veneer Thickness Ratio and Cyclic Loading on Fracture Resistance of Lithium Disilicate Crown. J Prosthodont 2016; 27:75-82. [PMID: 26965298 DOI: 10.1111/jopr.12473] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/29/2015] [Indexed: 11/28/2022] Open
Affiliation(s)
- Noor Nawafleh
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia
| | - Muhanad M Hatamleh
- Cranio-Maxillofacial Prosthetics Unit, King's College Hospital NHS Foundation Trust, London, UK
| | - Andreas Öchsner
- School of Engineering, Griffith University, Queensland, Australia
| | - Florian Mack
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia
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Nakamura K, Mouhat M, Nergård JM, Lægreid SJ, Kanno T, Milleding P, Örtengren U. Effect of cements on fracture resistance of monolithic zirconia crowns. ACTA BIOMATERIALIA ODONTOLOGICA SCANDINAVICA 2016; 2:12-19. [PMID: 27335900 PMCID: PMC4894086 DOI: 10.3109/23337931.2015.1129908] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 12/07/2015] [Indexed: 11/16/2022]
Abstract
Objectives The present study investigated the effect of cements on fracture resistance of monolithic zirconia crowns in relation to their compressive strength. Materials and methods Four different cements were tested: zinc phosphate cement (ZPC), glass-ionomer cement (GIC), self-adhesive resin-based cement (SRC) and resin-based cement (RC). RC was used in both dual cure mode (RC-D) and chemical cure mode (RC-C). First, the compressive strength of each cement was tested according to a standard (ISO 9917-1:2004). Second, load-to-failure test was performed to analyze the crown fracture resistance. CAD/CAM-produced monolithic zirconia crowns with a minimal thickness of 0.5 mm were prepared and cemented to dies with each cement. The crown–die samples were loaded until fracture. Results The compressive strength of SRC, RC-D and RC-C was significantly higher than those of ZPC and GIC (p < 0.05). However, there was no significant difference in the fracture load of the crown between the groups. Conclusion The values achieved in the load-to-failure test suggest that monolithic zirconia crowns with a minimal thickness of 0.5 mm may have good resistance against fracture regardless of types of cements.
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Affiliation(s)
- Keisuke Nakamura
- Department of Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, University of Gothenburg, Gothenburg, Sweden; Laboratory for Redox Regulation, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - Mathieu Mouhat
- Research Group for Biomaterials Used in Dentistry and Medicine, Department for Clinical Dentistry, Faculty of Health Sciences, the Arctic University of Norway , Tromsø , Norway
| | - John Magnus Nergård
- Research Group for Biomaterials Used in Dentistry and Medicine, Department for Clinical Dentistry, Faculty of Health Sciences, the Arctic University of Norway , Tromsø , Norway
| | - Solveig Jenssen Lægreid
- Research Group for Biomaterials Used in Dentistry and Medicine, Department for Clinical Dentistry, Faculty of Health Sciences, the Arctic University of Norway , Tromsø , Norway
| | - Taro Kanno
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry , Sendai , Japan
| | - Percy Milleding
- Department of Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, University of Gothenburg , Gothenburg , Sweden
| | - Ulf Örtengren
- Department of Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, University of Gothenburg, Gothenburg, Sweden; Research Group for Biomaterials Used in Dentistry and Medicine, Department for Clinical Dentistry, Faculty of Health Sciences, the Arctic University of Norway, Tromsø, Norway
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Correlation of flexural strength of coupons versus strength of crowns fabricated with different zirconia materials with and without aging. J Am Dent Assoc 2015; 146:904-912.e1. [DOI: 10.1016/j.adaj.2015.06.006] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2015] [Revised: 05/27/2015] [Accepted: 06/09/2015] [Indexed: 02/04/2023]
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Nawafleh N, Hatamleh M, Elshiyab S, Mack F. Lithium Disilicate Restorations Fatigue Testing Parameters: A Systematic Review. J Prosthodont 2015; 25:116-26. [PMID: 26505638 DOI: 10.1111/jopr.12376] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/07/2015] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To review laboratory studies that investigated fatigue resistance of lithium disilicate (LD) crowns and fixed dental prostheses (FDPs) to elucidate study designs and testing parameters. METHODS An electronic search was performed in PubMed, Scopus, and Ovid to identify in vitro studies that investigated fatigue resistance of LD crowns and FDPs. The search included all studies published in English in peer-reviewed journals in the period from 1998 to June 2014. The search followed a specific strategy that included combination of the following keywords: lithium disilicate, e.max, empress, all-ceramic, all ceramic, glass ceramic, fatigue, cyclic loading, dynamic loading, chewing simulator, fracture resistance, thermocycling, laboratory simulation, aging, crown, FDPs, FPDs, fixed partial denture, fixed dental prosthesis, and bridge. Studies were selected if mechanical and thermal loading parameters were clearly identified. Search results with abstracts were transferred into Endnote reference system, and duplicates were deleted. The remaining studies were then reviewed at three levels (title, abstract, full text) to further refine the articles. RESULTS The initial search retrieved 1044 eligible studies. After deduplication, 864 records were examined by titles and then abstracts; 826 were excluded, and 38 were assessed by full-text reading. In total, 19 articles met inclusion criteria and were included in this study. CONCLUSION The studies reviewed showed a level of heterogeneity, as testing parameters were considered through different setups. The current study demonstrated that various setting of the testing parameters and having a lack of testing standardization has likely led to inconsistency in the reported results. The obvious heterogeneity in the setting of testing variables-especially the magnitude of load and number of cycles applied-made it impractical to run direct comparisons between the reviewed studies. Therefore, specific international standardization of fatigue testing of dental restorations is urgently needed to ensure the delivery of consistent, indicative, and comparable data.
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Affiliation(s)
- Noor Nawafleh
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia
| | - Muhanad Hatamleh
- Cranio-Maxillofacial Prosthetics Unit, King's College Hospital NHS Foundation Trust, London, UK
| | - Shareen Elshiyab
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia
| | - Florian Mack
- School of Dentistry and Oral Health, Griffith University, Queensland, Australia
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Harada A, Nakamura K, Kanno T, Inagaki R, Örtengren U, Niwano Y, Sasaki K, Egusa H. Fracture resistance of computer-aided design/computer-aided manufacturing-generated composite resin-based molar crowns. Eur J Oral Sci 2015; 123:122-9. [PMID: 25683749 DOI: 10.1111/eos.12173] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/19/2015] [Indexed: 11/26/2022]
Abstract
The aim of this study was to investigate whether different fabrication processes, such as the computer-aided design/computer-aided manufacturing (CAD/CAM) system or the manual build-up technique, affect the fracture resistance of composite resin-based crowns. Lava Ultimate (LU), Estenia C&B (EC&B), and lithium disilicate glass-ceramic IPS e.max press (EMP) were used. Four types of molar crowns were fabricated: CAD/CAM-generated composite resin-based crowns (LU crowns); manually built-up monolayer composite resin-based crowns (EC&B-monolayer crowns); manually built-up layered composite resin-based crowns (EC&B-layered crowns); and EMP crowns. Each type of crown was cemented to dies and the fracture resistance was tested. EC&B-layered crowns showed significantly lower fracture resistance compared with LU and EMP crowns, although there was no significant difference in flexural strength or fracture toughness between LU and EC&B materials. Micro-computed tomography and fractographic analysis showed that decreased strength probably resulted from internal voids in the EC&B-layered crowns introduced by the layering process. There was no significant difference in fracture resistance among LU, EC&B-monolayer, and EMP crowns. Both types of composite resin-based crowns showed fracture loads of >2000 N, which is higher than the molar bite force. Therefore, CAD/CAM-generated crowns, without internal defects, may be applied to molar regions with sufficient fracture resistance.
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Affiliation(s)
- Akio Harada
- Division of Molecular and Regenerative Prosthodontics, Tohoku University Graduate School of Dentistry, Sendai, Japan
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Nakamura K, Harada A, Inagaki R, Kanno T, Niwano Y, Milleding P, Örtengren U. Fracture resistance of monolithic zirconia molar crowns with reduced thickness. Acta Odontol Scand 2015; 73:602-8. [PMID: 25635734 DOI: 10.3109/00016357.2015.1007479] [Citation(s) in RCA: 126] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVES The purpose of the present study was to analyze the relationship between fracture load of monolithic zirconia crowns and axial/occlusal thickness and to evaluate the fracture resistance of monolithic zirconia crowns with reduced thickness in comparison with that of monolithic lithium disilicate crowns with regular thickness. MATERIALS AND METHODS Monolithic zirconia crowns (Lava Plus Zirconia, 3M/ESPE) with specified axial/occlusal thicknesses and lithium disilicate crowns (IPS e.max press, Ivoclar/Vivadent) with regular thickness were fabricated using a dental CAD/CAM system and a press technique, respectively. The crowns cemented onto dies were loaded until fracture. Based on measurements of the crown thickness made by micro-CT and the fracture load, multiple regression analysis was performed. RESULTS It was revealed that the occlusal thickness significantly affected the fracture load (p < 0.01), but the axial thickness did not (p = 0.2828). Although the reduction of the occlusal thickness decreased the fracture resistance of the monolithic zirconia crowns, the fracture load of the zirconia crowns with the occlusal thickness of 0.5 mm (5558 ± 522 N) was significantly higher than that of lithium disilicate crowns with an occlusal thickness of 1.5 mm (3147 ± 409 N). CONCLUSION Within the limitations of the present study, it is suggested that monolithic zirconia crown with chamfer width of 0.5 mm and occlusal thickness of 0.5 mm can be used in the molar region in terms of fracture resistance.
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Affiliation(s)
- Keisuke Nakamura
- Department of Prosthetic Dentistry/Dental Materials Science, Institute of Odontology, University of Gothenburg , Gothenburg , Sweden
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Oilo M, Kvam K, Gjerdet NR. Simulation of clinical fractures for three different all-ceramic crowns. Eur J Oral Sci 2014; 122:245-50. [PMID: 24698209 PMCID: PMC4298035 DOI: 10.1111/eos.12128] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/01/2014] [Indexed: 11/27/2022]
Abstract
Comparison of fracture strength and fracture modes of different all-ceramic crown systems is not straightforward. Established methods for reliable testing of all-ceramic crowns are not currently available. Published in-vitro tests rarely simulate clinical failure modes and are therefore unsuited to distinguish between the materials. The in-vivo trials usually lack assessment of failure modes. Fractographic analyses show that clinical crowns usually fail from cracks initiating in the cervical margins, whereas in-vitro specimens fail from contact damage at the occlusal loading point. The aim of this study was to compare three all-ceramic systems using a clinically relevant test method that is able to simulate clinical failure modes. Ten incisor crowns of three types of all-ceramic systems were exposed to soft loading until fracture. The initiation and propagation of cracks in these crowns were compared with those of a reference group of crowns that failed during clinical use. All crowns fractured in a manner similar to fracture of the clinical reference crowns. The zirconia crowns fractured at statistically significantly higher loads than alumina and glass-ceramic crowns. Fracture initiation was in the core material, cervically in the approximal areas.
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Affiliation(s)
- Marit Oilo
- Department of Clinical Dentistry - Biomaterials, Faculty of Medicine and Dentistry, University of Bergen, Bergen, Norway
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Clinically relevant fracture testing of all-ceramic crowns. Dent Mater 2013; 29:815-23. [PMID: 23746750 DOI: 10.1016/j.dental.2013.04.026] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2012] [Revised: 04/23/2013] [Accepted: 04/25/2013] [Indexed: 11/20/2022]
Abstract
OBJECTIVES Fracture strength measured in vitro indicates that most all-ceramic crowns should be able to withstand mastication forces. Nevertheless, fractures are one of the major clinical problems with all-ceramic restorations. Furthermore, the fracture mode of all-ceramic crowns observed in clinical use differs from that found in conventional fracture strength tests. The aim of the present study was to develop and investigate a method that simulates clinical fracture behavior in vitro. METHODS 30 crowns with alumina cores were made to fit a cylindrical model with a molar-like preparation design. These crowns were randomly allocated to 3 tests groups (n=10). The crowns in group 1 were cemented to abutment models of epoxy and subsequently fractured by occlusal loading without contact damage. The crowns in group 2 were fractured by cementation with expanding cement. The crowns in group 3 were cemented on an abutment model of epoxy split almost in two and fractured by increasing the diameter of the model in the bucco-lingual direction. The fractured crowns were analyzed by fractographic methods and compared to a reference group of 10 crowns fractured in clinical use. RESULTS The fracture modes of all the in vitro crowns were similar to clinical fracture modes. The fracture modes in group 1 were most closely matched to the clinical fractures. These crowns also fractured at clinically relevant loads. CONCLUSION Laboratory tests that induce a distortion of the abutment model during occlusal loading without occlusal contact damage can simulate clinical fractures of all-ceramic crowns.
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