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Hajhamid B, Bozec L, Moghadam H, Tenenbaum H, De Souza GM, Somogyi-Ganss E. Validation of clinically related aging models based on enamel wear. J Prosthodont 2024. [PMID: 39118276 DOI: 10.1111/jopr.13903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Accepted: 06/06/2024] [Indexed: 08/10/2024] Open
Abstract
PURPOSE Physiological and erosive wear reported in clinical studies were reviewed, and in vitro aging models were developed to simulate and compare the effect of aging on human teeth with the review data obtained from clinical studies. METHODS A review of clinical studies and randomized clinical trials that quantify enamel wear was performed in the PubMed database. The first in vitro analysis evaluated the effect of mechanical chewing simulation only. Enamel specimens were aged in the chewing simulator (up to 1.2 million cycles) with two occlusal loads (30 and 50 N). In the second in vitro analysis, specimens were aged in two aging models. The first model (MT) simulated mechanical and thermal oral challenges: MT1- 240,000 chewing and 10,000 thermal cycles, MT2- 480,000 chewing and 20,000 thermal cycles, MT3- 1.2 million chewing and 50,000 thermal cycles. The second model (MTA) simulated mechanical, thermal, and acidic oral challenges as follows: MTA1- 240,000 chewing, 10,000 thermal and 3-h acidic cycles; MTA2: 480,000 chewing, 20,000 thermal and 6-h acidic cycles, MTA3- 1.2 million chewing, 50,000 thermal and 15-h acidic cycles. RESULTS The review included 13 clinical studies evaluating tooth wear (eight physiological and five erosive). The results estimated the annual average physiological wear as 38.4 µm (9.37-51). In comparison, the MT1 showed wear of 60 (24) µm. Also, the average annual erosive wear in the literature was 179.5 µm (70-265) compared to MTA1-induced wear of 209 (14) µm. CONCLUSION There was wide variation in tooth wear reported in clinical studies, suggesting a critical need for more accurate studies, possibly based on scanning technologies. Despite this, the data reported using the novel aging models are within a range to be considered consistent with and to simulate tooth wear measured in vivo.
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Affiliation(s)
- Beshr Hajhamid
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Laurent Bozec
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Hassan Moghadam
- The Ottawa Hospital, Faculty McGill University, Montreal, Quebec, Canada
| | - Howard Tenenbaum
- Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Grace M De Souza
- Department of Comprehensive Dentistry, School of Dentistry, University of Louisville, Louisville, Kentucky, USA
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Samran A, Hashem AW, Ali S, Al-Akhali M, Wille S, Kern M. Influence of post material and ferrule thickness on the fracture resistance of endodontically treated premolars: A laboratory study. J Prosthet Dent 2024:S0022-3913(24)00055-6. [PMID: 38402134 DOI: 10.1016/j.prosdent.2024.01.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2023] [Revised: 01/24/2024] [Accepted: 01/26/2024] [Indexed: 02/26/2024]
Abstract
STATEMENT OF PROBLEM The influence of the ferrule thickness and post materials on the fracture resistance of endodontically treated teeth remains unclear. PURPOSE The purpose of this laboratory study was to evaluate the influence of post material and ferrule thickness on the fracture resistance of endodontically treated mandibular premolars. MATERIAL AND METHODS Sixty-four extracted and endodontically treated mandibular first premolars were used and divided into 4 test groups (n=16) depending on the ferrule thickness: F-0: without a ferrule, F-0.5: with a 0.5-mm ferrule thickness, F-1: with a 1-mm ferrule thickness, and F-1.5: with a 1.5-mm ferrule thickness. In groups with ferrules, the height ranged from 2 mm buccally/lingually to 1 mm proximally. Teeth in subgroups (n=8) were restored with either prefabricated glass fiber (FF) or titanium posts (FT) (ISO size 70 and length of 7.5 mm) and then adhesively restored with composite resin foundation materials. After foundation procedures, each specimen was restored with a cobalt chromium crown which was cemented with glass-ionomer cement. All specimens were subjected to dynamic loading in a masticatory simulator for 1 200 000 loading cycles with a nominal load of 5 Kg at 1.2 Hz and simultaneous thermocycling (5 to 55 °C). Specimens were then quasistatically loaded at 30 degrees in a universal testing machine until fracture. Fracture loads were analyzed by using 2-way ANOVA followed by the Tukey honestly significant difference test (α=.05). RESULTS Fracture loads ranged from 610 ±45 N (no ferrule - glass fiber post) to 1216 ±169 N (1.5 mm ferrule thickness - glass fiber post). A statistically significant increase in fracture resistance was observed with increasing ferrule thickness (P<.001). However, post materials did not show a statistically significant influence (P=.977). CONCLUSIONS Under the conditions of this laboratory study, increasing the ferrule thickness had a significant effect on the fracture resistance of endodontically treated teeth after thermomechanical fatigue, irrespective of post materials.
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Affiliation(s)
- Abdulaziz Samran
- Visiting Associate Professor, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany; Associate Professor, Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh, Saudi Arabia; and Associate Professor, Department of Prosthodontics, College of Dentistry, Ibb University, Ibb, Yemen.
| | - Ahmed Wagdy Hashem
- Visiting Assistant Professor, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany; and Lecturer, Faculty of Dentistry, October University for Modern Sciences and Arts, Cairo, Egypt
| | - Shurouk Ali
- Assistant Professor, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany
| | - Majed Al-Akhali
- Visiting Assistant Professor, Department of Prosthodontics, Propaedeutics and Dental Materials, Dental School, Christian-Albrechts University, Kiel, Germany; and Assistant Professor, Department of Prosthodontics, College of Dentistry, Ibb University, Ibb, Yemen
| | - Sebastian Wille
- Research Associate, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany
| | - Matthias Kern
- Professor and Chairman, Department of Prosthodontics, Propaedeutics and Dental Materials, School of Dentistry, Christian-Albrechts University, Kiel, Germany
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Bataineh K, Al Janaideh M. Fatigue behavior of three thin CAD/CAM all-ceramic crown materials. Int Biomech 2023; 10:1-8. [PMID: 38205926 PMCID: PMC10786422 DOI: 10.1080/23335432.2024.2303121] [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: 03/23/2020] [Accepted: 01/03/2024] [Indexed: 01/12/2024] Open
Abstract
The purpose of this study was to study the effect of crown thickness on the fatigue life of CAD/CAM ceramic materials. CAD/CAM ceramic materials for the crown were virtually designed with three thickness designs of (a) ultra-thin occlusal crown average 0.7 mm thick (group A), (b) thin occlusal crown 1.1 mm average thick (group B), (c) thick occlusal crown 1.5 mm thick. The materials are: zirconia Cercon ZC and IPS e.max CAD (LD). Finite Element Analysis (FEA) simulations were carried out to estimate the fatigue lives of restorative materials. The lives for groups B and C under fatigue load were not significantly different from each other for Zirconia. The predicted lives for group A zirconia crowns, under fatigue load 50 N, 100 N, 120 N is 24 years, 4.3 years, 1.9 years, respectively. Results for crowns made of LD can be summarized as follows: under load 50 N, all groups have survived longer than 5 respectively, while under the load of 100 N, only group C survived longer than 5 years. 0.7 mm thick full contour Zirconia crowns possessed adequate endurance strength to survive under physiologic conditions. On the other hand, the crown made of LD should have at least 1.5 mm thickness to survive longer than 5 years.
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Affiliation(s)
- Khaled Bataineh
- Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Mohammad Al Janaideh
- Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
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Altitinchi A, Schweizer A, Dean K, Lawson N, Sulaiman T, Fouad AF. An Ex-Vivo Model for Investigating Bacterial Extrusion from Infected Root Canals during Masticatory Function. J Endod 2023; 49:1553-1558. [PMID: 37611655 DOI: 10.1016/j.joen.2023.08.008] [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: 01/25/2021] [Revised: 07/24/2023] [Accepted: 08/13/2023] [Indexed: 08/25/2023]
Abstract
INTRODUCTION The extrusion of bacteria from infected root canals may lead to increase in symptoms, expansion of periapical lesions, and contribution to systemic diseases. The aim of this study is to investigate a potential proof-of-concept model to study the extent to which bacteria can escape from infected root canals under dynamic loading (simulated chewing). METHODS The study was completed in 2 experiments performed at 2 institutions. Biofilms of Streptococcus intermedius in the first experiment and S. intermedius and Actinomyces naeslundii were allowed to grow in root canals of single-rooted extracted teeth for 3 weeks. The roots of the teeth were suspended in a small chamber containing dental transport medium and were mounted on a lower sample holder of a chewing simulator. In the experimental group, simulated chewing cycles equivalent to 1 year of function were conducted, and then bacterial migration was quantified and compared with stationary teeth. RESULTS All experimental samples of the loading group revealed bacterial penetration in both experiments. Several of the unloaded samples revealed no bacterial penetration. In the first experiment, a significantly higher number of bacteria were able to escape into the periapex of the loaded group compared with the unloaded group (P = .017). In the second experiment, there was no significant difference between the 2 bacterial species used in the amount of extruded bacteria; however, there was a highly significant effect for occlusal loading (P = .0001). CONCLUSIONS The potential for occlusal forces to enhance bacterial extrusion from infected root canals should be further explored.
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Affiliation(s)
- Ali Altitinchi
- Department of Endodontics, School of Dentistry, University of Alabama at Birmingham, Birmingham, Alabama
| | - Andrew Schweizer
- Department of Endodontics, School of Dentistry, University of Alabama at Birmingham, Birmingham, Alabama
| | - Kimberly Dean
- Department of Endodontics, School of Dentistry, University of Alabama at Birmingham, Birmingham, Alabama
| | - Nathaniel Lawson
- Division of Biomaterials, School of Dentistry, University of Alabama at Birmingham, Birmingham, Alabama
| | - Taiseer Sulaiman
- Division of Comprehensive Oral Health, Adams School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina
| | - Ashraf F Fouad
- Department of Endodontics, School of Dentistry, University of Alabama at Birmingham, Birmingham, Alabama.
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García-Sala Bonmatí F, Bustamante-Hernández N, Alonso Pérez-Barquero J, Maneiro-Lojo J, Fons-Badal C, Labaig-Caturla C, Fernández-Estevan L, Agustín-Panadero R. Implant-Supported Fixed Partial Dentures with Posterior Cantilevers: In Vitro Study of Mechanical Behavior. MATERIALS (BASEL, SWITZERLAND) 2023; 16:6805. [PMID: 37895786 PMCID: PMC10608170 DOI: 10.3390/ma16206805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2023] [Revised: 10/19/2023] [Accepted: 10/19/2023] [Indexed: 10/29/2023]
Abstract
Rehabilitation with dental implants is not always possible due to the lack of bone quality or quantity, in many cases due to bone atrophy or the morbidity of regenerative treatments. We find ourselves in situations of performing dental prostheses with cantilevers in order to rehabilitate our patients, thus simplifying the treatment. The aim of this study was to analyze the mechanical behavior of four types of fixed partial dentures with posterior cantilevers on two dental implants (convergent collar and transmucosal internal connection) through an in vitro study (compressive loading and cyclic loading). This study comprised four groups (n = 76): in Group 1, the prosthesis was screwed directly to the implant platform (DS; n = 19); in Group 2, the prosthesis was screwed to the telescopic interface on the implant head (INS; n = 19); in Group 3, the prosthesis was cemented to the telescopic abutment (INC; n = 19); and in Group 4, the prosthesis was cemented to the abutment (DC; n = 19). The sets were subjected to a cyclic loading test (80 N load for 240,000 cycles) and compressive loading test (100 KN load at a displacement rate of 0.5 mm/min), applying the load until failure occurred to any of the components at the abutment-prosthesis-implant interface. Subsequently, an optical microscopy analysis was performed to obtain more data on what had occurred in each group. Results: Group 1 (direct screw-retained prosthesis, DS) obtained the highest mean strength value of 663.5 ± 196.0 N. The other three groups were very homogeneous: 428.4 ± 63.1 N for Group 2 (INS), 486.7 ± 67.8 N for Group 3 (INC), and 458.9 ± 38.9 N for Group 4 (DC). The mean strength was significantly dependent on the type of connection (p < 0.001), and this difference was similar for all of the test conditions (cyclic and compressive loading) (p = 0.689). Implant-borne prostheses with convergent collars and transmucosal internal connections with posterior cantilevers screwed directly to the implant connection are a good solution in cases where implant placement cannot avoid extensions.
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Affiliation(s)
- Fernando García-Sala Bonmatí
- Department of Dental Medicine, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain (J.M.-L.); (C.F.-B.); (R.A.-P.)
| | - Naia Bustamante-Hernández
- Department of Stomatology, Faculty of Medicine and Dentistry, University of Basque Country, 48940 Leioa, Spain;
| | - Jorge Alonso Pérez-Barquero
- Department of Dental Medicine, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain (J.M.-L.); (C.F.-B.); (R.A.-P.)
| | - Jesús Maneiro-Lojo
- Department of Dental Medicine, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain (J.M.-L.); (C.F.-B.); (R.A.-P.)
| | - Carla Fons-Badal
- Department of Dental Medicine, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain (J.M.-L.); (C.F.-B.); (R.A.-P.)
| | - Carla Labaig-Caturla
- Department of Dental Medicine, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain (J.M.-L.); (C.F.-B.); (R.A.-P.)
| | - Lucía Fernández-Estevan
- Department of Dental Medicine, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain (J.M.-L.); (C.F.-B.); (R.A.-P.)
| | - Rubén Agustín-Panadero
- Department of Dental Medicine, Faculty of Medicine and Dentistry, Universitat de València, 46010 Valencia, Spain (J.M.-L.); (C.F.-B.); (R.A.-P.)
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Yao KT, Chang TY, Huang GJ, Fang HW, Wang DH, Hsu ML. Survival of Four Conical Implant Abutment Connections After Removal of the Abutment Screw and Simulated Cyclic Loading: An In Vitro Comparative Study. J ORAL IMPLANTOL 2023; 49:393-400. [PMID: 37527179 DOI: 10.1563/aaid-joi-d-22-00037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2022] [Revised: 04/22/2023] [Accepted: 05/29/2023] [Indexed: 08/03/2023]
Abstract
This in vitro study evaluated the mechanical behavior of different conical connection implant systems after abutment screw withdrawal. Four conical connection systems were selected based on different conical half-angles: Ankylos (5.7°), Cowell (7.0°), Straumann (7.5°), and Astra (11.0°). In each system, 5 implants and abutments were used (n = 5). According to the recommended value, each abutment screw was torqued to settle the abutment and then withdrawn through a predesigned hole of the cemented crown. The retentiveness of the abutment was evaluated by the following mechanical testing. All specimens were subjected to cyclic loading of 20-200 N, 30°, and 4-mm off-axis to the implant axis, for 106 cycles. The pullout forces and axial displacements of the abutments were measured. The data of the Cowell system was obtained from our previous work. All groups other than Astra group, in which abutment loosened after abutment screw withdrawal, passed the cyclic loading test. Straumann group demonstrated a significantly lower pullout force (27.4 ± 21.1 N) than Ankylos (160.1 ± 41.4 N) and Cowell (183.7 ± 30.5 N) groups. All groups showed abutment rebound after screw withdrawal except Straumann group. In addition, Ankylos, Cowell, and Straumann groups demonstrated axial displacement after cyclic loading. In terms of the retentiveness of the abutment after abutment screw withdrawal examined in this study, Ankylos and Cowell groups had much higher retentiveness than Straumann group, while Astra group had none. Conical angle could be a key design parameter to make abutment screw withdrawal after conical abutment settlement feasible, but more studies must be conducted for clinical application.
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Affiliation(s)
- Kuang-Ta Yao
- School of Dentistry, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Tsai-Yu Chang
- School of Dentistry, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Guan-Jhong Huang
- School of Dentistry, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Hsu-Wei Fang
- Department of Chemical Engineering and Biotechnology & Institute of Chemical Engineering, National Taipei University of Technology, Taipei, Taiwan
| | - Ding-Han Wang
- School of Dentistry, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Ming-Lun Hsu
- School of Dentistry, National Yang Ming Chiao Tung University, Taipei, Taiwan
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Bein L, Rauch A, Schmidt M, Rosentritt M. In vitro fatigue and fracture testing of temporary materials from different manufacturing processes in implant-supported anterior crowns. Clin Oral Investig 2023; 27:4215-4224. [PMID: 37133699 DOI: 10.1007/s00784-023-05038-7] [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: 03/14/2023] [Accepted: 04/22/2023] [Indexed: 05/04/2023]
Abstract
OBJECTIVES The aim of this study was to investigate the in vitro fatigue and fracture force of temporary implant-supported anterior crowns made of different materials with different abutment total occlusal convergence (TOC), with/without a screw channel, and with different types of fabrication. MATERIALS AND METHODS One hundred ninety-two implant-supported crowns were manufactured (4° or 8° TOC; with/without screw channel) form 6 materials (n = 8; 2 × additive, 3 × subtractive, 1 × automix; reference). Crowns were temporarily cemented, screw channels were closed (polytetrafluoroethylene, resin composite), and crowns were stored in water (37 °C; 10 days) before thermal cycling and mechanical loading (TCML). Fracture force was determined. STATISTICS Kolmogorov-Smirnov, ANOVA; Bonferroni; Kaplan-Meier; log-rank; α = 0.05. RESULTS Failure during TCML varied between 0 failures and total failure. Mean survival was between 1.8 × 105 and 4.8 × 105 cycles. The highest impact on survival presented the material (η2 = 0.072, p < .001). Fracture forces varied between 265.7 and 628.6 N. The highest impact on force was found for the material (η2 = 0.084, p < .001). CONCLUSION Additively and subtractively manufactured crowns provided similar or higher survival rates and fracture forces compared to automix crowns. The choice of material is decisive for the survival and fracture force. The fabrication is not crucial. A smaller TOC led to higher fracture force. Manually inserted screw channels had negative effects on fatigue testing. CLINICAL RELEVANCE The highest stability has been shown for crowns with a low TOC, which are manufactured additively and subtractively. In automix-fabricated crowns, manually inserted screw channels have negative effects.
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Affiliation(s)
- Laila Bein
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany
| | - Angelika Rauch
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany
| | - Michael Schmidt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, 93042, Regensburg, Germany.
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Rosentritt PDM, Bollin D, Schmidt DMDMB, Rauch MDA. Stability and wear of zirconia crowns with micro-layering. J Dent 2023; 135:104560. [PMID: 37263411 DOI: 10.1016/j.jdent.2023.104560] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2023] [Revised: 05/02/2023] [Accepted: 05/22/2023] [Indexed: 06/03/2023] Open
Abstract
OBJECTIVES To investigate stability and wear of tooth-supported zirconia single crowns with micro-layering in-vitro. MATERIALS AND METHODS Molar crowns and specimens were fabricated from 5Y-TZP zirconia (Gen-X, Amann-Girrbach). Three groups were investigated: ML I: 0.1 mm cutback/painted/glazed (MiYO, Jensen); ML II: occlusal 0.3 mm cutback/painted/veneered/glazed (MiYO), and a monolithic control group (polished). After thermal cycling and mechanical loading (TCML), crowns were loaded to failure in a universal testing machine. Two-body wear test was performed. Wear (mean, maximum, antagonist) and roughness (Ra, Rz) were determined with a 3D laser-scanning-microscope. RESULTS All crowns survived TCML. In the control (2501.5 N) and ML II group (1775.3 N) significantly lower fracture forces were observed than in ML I (3636.4 N) (p ≤ 0.003). Significant wear differences were found (p ≤ 0.001) but not for antagonist wear (p ≥ 0.202). Lowest wear was observed in the control group 10.2±1.5 µm/28.8±6.4 µm, ML I 112.8±37.3 µm/152.9±42.8 µm, and ML II 192.4±49.1 µm/340.7±54.2 µm. Roughness was characterized by a Ra from 1.6 µm (control) to 3.0 µm (ML II), and a Rz from 11.8 µm (Control) to 24.0 µm (ML II). Roughness significantly differed between control group and ML I (p = 0.002) as well as ML I and ML II (p = 0.020). CONCLUSIONS Good in-vitro performance and fracture stability without chipping or fracture were found for all systems. Wear and roughness were comparable to conventional ceramic veneering systems. CLINICAL RELEVANCE The micro-layering of zirconia restorations can be recommended, yet the micro-layering could be worn during clinical application.
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Affiliation(s)
- Prof Dr Martin Rosentritt
- Department of Dental Prosthetics, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.
| | - Dirk Bollin
- Department of Dental Prosthetics, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | | | - Med Dent Angelika Rauch
- Department of Dental Prosthetics, University Hospital Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
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Rosentritt M, Rauch A, Hahnel S, Schmidt M. In-vitro performance of subtractively and additively manufactured resin-based molar crowns. J Mech Behav Biomed Mater 2023; 141:105806. [PMID: 37001248 DOI: 10.1016/j.jmbbm.2023.105806] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023]
Abstract
PURPOSE To compare the in-vitro performance and wear behavior of additively or subtractively fabricated resin-based composite molar crowns for temporary and permanent application. MATERIALS AND METHODS Identical molar crowns (n = 8 per group) were manufactured from materials for temporary or permanent application (3x temporary additive fabrication, 3x additive permanent fabrication, 1x temporary subtractive fabrication, 1x permanent subtractive fabrication). All crowns were adhesively bonded (Calibra Universal, Dentsply Sirona, USA) on standardized resin-based composite molars (FDI 46, P Pro temporary Crown & Bridge). Thermal cycling and mechanical loading (2 × 3000 × 5°C/55 °C, 2min, H20 dist., 1.2 × 106 force 50N) were performed and fracture force was determined (v = 1 mm/min, Z010, Zwick, Germany). Mean wear, maximum wear, and roughness were investigated on polished (P1200) specimens (n = 8 per group, d = 8 mm) in a pin-on-block test (50N; 120000 cycles; 1.6Hz; H2O). Statistics were performed by using one-way ANOVA, Bonferroni post-hoc-tests, and Pearson-correlation (α = 0.05). RESULTS All crowns survived TCML without failures. Fracture forces ranged from 1362.4 ± 182.4N to 2354.1 ± 373.3N for the additive temporary crowns, from 1680.4.4 ± 525.1N to 2601.6 ± 403.7N for the additive permanent crowns, and reached values of 2988.5 ± 604.7N for subtractive temporary crowns and 3092.0 ± 307.6 N for subtractive permanent crowns. Significant (p < 0.001) differences were identified between the various additively manufactured systems, but not for the subtractively fabricated systems (p = 0.673). Mean wear of the additive temporary crowns ranged between 114.5 ± 25.8 μm and 163.8 ± 21.4 μm without significant differences (p = 0.061). Mean wear of the additive permanent crowns ranged between 120.0 ± 27.5 μm and 171.3 ± 31.8 μm with significant differences (p = 0.004). No statistically significant differences were identified between temporary and permanent subtractively manufactured specimens, with mean wear ranging between 140.5 ± 51.1 μm and 176.6 ± 26.8 μm (p = 0.673). Maximum wear of additive temporary specimens ranged between 221.4.5 ± 53.3 μm and 322.1 ± 50.6 μm; significant differences were identified between the groups (p = 0.016). Maximum wear of additive permanent specimens ranged between 246.3 ± 47.3 μm and 337.4 ± 61.4 μm, and significant differences were identified between the groups (p = 0.006). Mean wear of the subtractive group (permanent and temporary) showed no differences in maximum wear from 277.9 ± 79.7.1 μm to 316.4 ± 58.1 μm (p = 0.288). Ra roughness ranged from 0.7 ± 0.2 μm to 3.6 ± 1.3 μm with significant differences (p < 0.001) and Rz reference between 65.9 ± 26.2 μm and 16.8 ± 6.3 μm. CONCLUSION Temporary and permanent molar crowns provided at least acceptable in-vitro performance and fracture force for clinical mid-term application. Laboratory wear stability of the resin-based materials appeared sufficient, but should be verified under clinical conditions.
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Graphene-Doped Polymethyl Methacrylate (PMMA) as a New Restorative Material in Implant-Prosthetics: In Vitro Analysis of Resistance to Mechanical Fatigue. J Clin Med 2023; 12:jcm12041269. [PMID: 36835805 PMCID: PMC9960587 DOI: 10.3390/jcm12041269] [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: 12/21/2022] [Revised: 01/26/2023] [Accepted: 02/01/2023] [Indexed: 02/09/2023] Open
Abstract
BACKGROUND AND PURPOSE Provisional prostheses in restorations over several implants with immediate loading in completely edentulous patients increase the risk of frequent structural fractures. An analysis was performed of the resistance to fracture of prosthetic structures with cantilevers using graphene-doped polymethyl methacrylate (PMMA) resins and CAD-CAM technology. METHODS A master model was produced with four implants measuring 4 mm in diameter and spaced 3 mm apart, over which 44 specimens representing three-unit fixed partial prostheses with a cantilever measuring 11 mm were placed. These structures were cemented over titanium abutments using dual cure resin cement. Twenty-two of the 44 units were manufactured from machined PMMA discs, and 22 were manufactured from PMMA doped with graphene oxide nanoparticles (PMMA-G). All of the samples were tested in a chewing simulator with a load of 80 N until fracture or 240,000 load applications. RESULTS The mean number of load applications required for temporary restoration until the fracture was 155,455 in the PMMA-G group versus 51,136 in the PMMA group. CONCLUSIONS Resistance to fracture under cyclic loading was three times greater in the PMMA-G group than in the PMMA group.
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Kaya Büyükbayram I, Güven ME, Ayman D, Şener Yamaner ID, Cakan EF. Fracture resistance of resin endocrowns with and without fiber reinforced composite base material: A preliminary study. J Appl Biomater Funct Mater 2023; 21:22808000231151832. [PMID: 36708253 DOI: 10.1177/22808000231151832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
OBJECTIVE The aim of this study was to investigate the effects of fiber-reinforced composite base material on fracture resistance and fracture pattern of endodontically treated maxillary premolars restored with endocrowns using two different resin nanoceramic computer-aided design and computer-aided manufacturing (CAD/CAM) restorative material. METHODS Forty extracted sound maxillary premolars with an occlusal reduction of 2 mm above the cementoenamel junction (CEJ) was performed following root canal treatment. Mesial interproximal box was prepared for each tooth at the margin of the CEJ and randomly distributed into four groups (n = 10) as follows: Group A, no resin build-up in the pulp chamber; Group B, 2 mm of fiber-reinforced composite (FRC) build-up (EverX Posterior, GC).; Group C, no resin build-up in pulp chamber; Group D, 2 mm of FRC build-up. Groups A and B were prepared with resin nanoceramic (RNC) consisting ceramic nanofillers (Lava Ultimate 3 M ESPE), while Group C and D were prepared with RNC consisting ceramic nanohybrid fillers (Cerasmart GC Corp). All samples were subjected to 1,200,000 chewing cycles (1.6 Hz, 50 N) and 5000 thermal cycles (5°C-55°C) for artificial aging on a chewing simulator with thermal cycles (CSTC). Samples that survived the CSTC test without being damaged were subjected to a load-to-fracture test. RESULTS The highest mean fracture strength was found in Group D (936.0 ± 354.7) and lowest in Group A (684.2 ± 466.9). Fracture strength was higher in groups where FRC was used as a base material than plain restorations. However, there were no significant differences between the Lava and Cerasmart groups with and without FRC (p > 0.05). Most of the samples were irreparably fractured under CEJ. CONCLUSION Using short FRCs as a resin base material did not significantly improve fracture resistance. Cerasmart and Lava blocks had similar fracture resistance and fracture pattern.
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Affiliation(s)
- Işıl Kaya Büyükbayram
- Department of Endodontics, School of Dentistry, İstanbul Aydın University, Küçükçekmece, İstanbul, Turkey
| | - Mehmet Esad Güven
- Department of Prosthodontics, School of Dentistry, Necmettin Erbakan University, Konya, İstanbul, Turkey
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Güleç C, Sarıkaya I. The influence of aging on the fracture load of milled monolithic crowns. BMC Oral Health 2022; 22:516. [PMCID: PMC9675227 DOI: 10.1186/s12903-022-02529-z] [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: 02/15/2022] [Accepted: 10/24/2022] [Indexed: 11/21/2022] Open
Abstract
Background This in-vitro study was conducted to assess the effect of aging on the fracture load of molar crowns fabricated with monolithic CAD/CAM materials. Methods The crown restorations were produced from Cerasmart, Vita Enamic, and IPS e.max CAD blocks. Aging was applied to the 10 samples each of monolithic CAD/CAM materials (n = 10). Dual-axis chewing simulator (50 N, 1.1 Hz, lateral movement: 1 mm, mouth opening: 2 mm, 1,200,000 cycles) and thermocycling (± 5–55 °C, 6000 cycles) were applied as an aging procedure. 10 samples each of monolithic CAD/CAM materials without aging (n = 10) were considered the control group. 6 tested groups were obtained. Then, all samples were evaluated in a universal testing machine to determine the fracture loading values’. Results There was not a statistically significant difference between the fracture load values before and after aging for all samples of Cerasmart, Vita Enamic, and IPS e.max CAD (p > 0.005). In a comparison of the monolithic materials together, a statistically significant difference was found between the fracture load values of IPS e.max CAD and Vita Enamic crowns before aging (p = 0.02). Also, Vita Enamic crowns (1978,71 ± 364,05 N) were found different from the IPS e.max CAD (p = 0.005) and Cerasmart crowns (p = 0.041) after aging. Conclusions Dynamic aging with 1.200.000 cycles was found to have no effect to fracture loading on milled Cerasmart, Vita Enamic, and IPS e.max CAD monolithic crowns.
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Affiliation(s)
- Ceyda Güleç
- grid.411550.40000 0001 0689 906XDepartment of Prosthodontics, Faculty of Dentistry, Tokat Gaziosmanpasa University, Ali Şevki Erek Campus, 60100 Tokat, Turkey
| | - Işıl Sarıkaya
- grid.411550.40000 0001 0689 906XDepartment of Prosthodontics, Faculty of Dentistry, Tokat Gaziosmanpasa University, Ali Şevki Erek Campus, 60100 Tokat, Turkey
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Buyukerkmen EB, Bozkurt DA, Terlemez A. Effect of surface treatment, ferrule height, and luting agent type on pull-out bond strength of monolithic zirconia endocrowns. J Oral Sci 2022; 64:279-282. [PMID: 35989297 DOI: 10.2334/josnusd.22-0147] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022]
Abstract
PURPOSE To evaluate the effect of different surface treatments, ferrule heights, and luting agents on the pull-out bond strength (PBS) of computer-aided design/computer-aided manufacturing (CAD-CAM) monolithic endocrowns. METHODS After endodontic treatment and preparation for two endocrown designs (ferrule height 0 mm or 2 mm), CAD-CAM monolithic zirconia endocrowns were fabricated for 80 mandibular molars. Each endocrown design group was then divided on the basis of surface treatment into two groups: half were air-abraded and half were air-abraded/laser-irradiated. Then, all treated groups were further divided into two subgroups (n = 10) and cemented to teeth with either a 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing resin luting agent (Panavia SA) or a combination of MDP-containing primer and MDP-free resin luting agent (Monobond Plus/Multilink Automix). PBS was measured with a universal test machine after simulated chewing and thermocycling. Three-way ANOVA and the post-hoc Bonferroni test were used for statistical analysis. RESULTS PBS was significantly associated with type of surface treatment, type of luting agent, and ferrule height. Air-abraded/laser-irradiated endocrowns with a 2-mm ferrule that were cemented with Monobond Plus/Multilink Automix had the highest PBS (P < 0.05). CONCLUSION Surface treatment with air abrasion/laser irradiation, presence of a ferrule, and priming with an MDP-containing primer increased the PBS of monolithic zirconia endocrowns.
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Affiliation(s)
- Emine B Buyukerkmen
- Department of Prosthodontics, Faculty of Dentistry, Necmettin Erbakan University
| | - Durmuş A Bozkurt
- Department of Endodontics, Faculty of Dentistry, Necmettin Erbakan University
| | - Arslan Terlemez
- Department of Endodontics, Faculty of Dentistry, Necmettin Erbakan University
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Messer-Hannemann P, Samadi M, Böttcher H, Duy S, Duy D, Albrecht N, Schwendicke F, Effenberger S. Evaluation of a Method to Determine Wear Resistance of Class I Tooth Restorations during Cyclic Loading. MATERIALS (BASEL, SWITZERLAND) 2022; 15:5440. [PMID: 35955375 PMCID: PMC9369466 DOI: 10.3390/ma15155440] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 07/08/2022] [Accepted: 07/29/2022] [Indexed: 06/15/2023]
Abstract
The aim of this study was the development of a test regime to determine the wear resistance and predict the clinical performance of conventional glass ionomer cement (GIC) restorations in Class I tooth cavities. Cavities were prepared in excised human teeth and restored using three conventional glass ionomer restorative materials: DeltaFil, Fuji IX GP and Ketac Universal. The restored teeth were mechanically and thermally stressed using a chewing simulator with a maximum number of 1,200,000 load cycles. Besides determining the number of cycles achieved, the abrasion volume after termination of the chewing simulation was calculated using µCT images. All teeth restored with DeltaFil reached 1,200,000 cycles without any restoration failure. Only 37.5% of the restorations each with Ketac Universal and Fuji IX GP were able to achieve the maximum cycle number. A significant lower abrasion volume for restorations with DeltaFil compared to Ketac Universal (p = 0.0099) and Fuji IX GP (p = 0.0005) was found. Laboratory chewing simulations are a useful tool to study basic wear mechanisms in a controlled setting with in-vivo related parameters. DeltaFil shows an improved wear resistance compared to other conventional GICs, indicating the high potential of this material for long-lasting Class I restorations.
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Affiliation(s)
| | - Mariam Samadi
- DMG Dental-Material Gesellschaft mbH, 22547 Hamburg, Germany
| | - Henrik Böttcher
- DMG Dental-Material Gesellschaft mbH, 22547 Hamburg, Germany
| | - Sebastian Duy
- SD Mechatronik GmbH, 83620 Feldkirchen-Westerham, Germany
| | - Daniela Duy
- SD Mechatronik GmbH, 83620 Feldkirchen-Westerham, Germany
| | | | - Falk Schwendicke
- Department of Oral Diagnostics, Digital Health and Health Services Research, Charité-Universitätsmedizin Berlin, 14197 Berlin, Germany
| | - Susanne Effenberger
- DMG Dental-Material Gesellschaft mbH, 22547 Hamburg, Germany
- Department of Oral Diagnostics, Digital Health and Health Services Research, Charité-Universitätsmedizin Berlin, 14197 Berlin, Germany
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Micovic Soldatovic D, Liebermann A, Huth KC, Stawarczyk B. Fracture load of different veneered and implant-supported 4-UNIT cantilever PEEK fixed dental prostheses. J Mech Behav Biomed Mater 2022; 129:105173. [DOI: 10.1016/j.jmbbm.2022.105173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/04/2022] [Accepted: 03/07/2022] [Indexed: 11/16/2022]
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Nawar NN, Kataia M, Omar N, Kataia EM, Kim HC. Biomechanical behavior and life span of maxillary molar according to the access preparation and pericervical dentin preservation: finite element analysis. J Endod 2022; 48:902-908. [DOI: 10.1016/j.joen.2022.03.013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 03/29/2022] [Accepted: 03/31/2022] [Indexed: 10/18/2022]
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Badr Z, Culp L, Duqum I, Lim CH, Zhang Y, A. Sulaiman T. Survivability and fracture resistance of monolithic and multi‐yttria‐layered zirconia crowns as a function of yttria content: A mastication simulation study. J ESTHET RESTOR DENT 2022; 34:633-640. [DOI: 10.1111/jerd.12907] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2022] [Revised: 02/28/2022] [Accepted: 03/13/2022] [Indexed: 11/30/2022]
Affiliation(s)
- Zaid Badr
- Department of Adult Restorative Dentistry University of Nebraska Medical Center, College of Dentistry Lincoln Nebraska USA
| | - Lee Culp
- Sculpture Studios Cary North Carolina USA
| | - Ibrahim Duqum
- Division of Comprehensive Oral Health University of North Carolina at Chapel Hill Adams School of Dentistry Chapel Hill North Carolina USA
| | - Chek Hai Lim
- Department of Preventive and Restorative Sciences, School of Dental Medicine University of Pennsylvania Philadelphia Pennsylvania USA
| | - Yu Zhang
- Department of Preventive and Restorative Sciences, School of Dental Medicine University of Pennsylvania Philadelphia Pennsylvania USA
| | - Taiseer A. Sulaiman
- Division of Comprehensive Oral Health University of North Carolina at Chapel Hill Adams School of Dentistry Chapel Hill North Carolina USA
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Physicochemical Properties of Dentine Subjected to Microabrasive Blasting and Its Influence on Bonding to Self-Adhesive Prosthetic Cement in Shear Bond Strength Test: An In Vitro Study. MATERIALS 2022; 15:ma15041476. [PMID: 35208013 PMCID: PMC8875517 DOI: 10.3390/ma15041476] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Revised: 02/06/2022] [Accepted: 02/14/2022] [Indexed: 12/10/2022]
Abstract
The aim of this in vitro study was to assess the influence of microabrasive blasting on the physicochemical properties of dentine and shear bond strength (SBS) of self-adhesive resin cement (Maxcem Elite, Kerr, Orange, CA, USA) bonded to the dentine surface. Ninety cylindrical specimens with exposed dentine of human teeth were prepared and divided into three randomized, parallel sample sets A, B, and C. Groups B and C were subjected to abrasive blasting using a micro-sandblasting device (Microetcher IIa, Danville Materials, Carlsbad, CA, USA) with two gradations of Al2O3 abrasives (Group B, abrasion with a gradation of 50 μm; group C, abrasion with a gradation of 27 μm). SEM imaging, profilometry, chemical composition analysis, contact angle measurements, surface free energy, and SBS tests were performed. The resulting data were statistically analyzed using the Statistica software (ver. 13.3, Tibco Software Inc., Palo Alto, CA, USA). Microabrasive blasting caused changes in surface topography, structural features, and the connection strength between the dentin surface and self-adhesive prosthetic cement. Air microabrasion through the multifactorial positive reorganization of the treated surface of dentine is recommended as a pretreatment method in fixed prosthodontics adhesive cementation protocols.
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Physical properties and wear behavior of CAD/CAM resin composite blocks containing S-PRG filler for restoring primary molar teeth. Dent Mater 2021; 38:158-168. [PMID: 34872741 DOI: 10.1016/j.dental.2021.11.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 11/05/2021] [Indexed: 11/21/2022]
Abstract
OBJECTIVES This study aimed to develop computer-aided design/computer-aided manufacturing (CAD/CAM) resin composite blocks (RCBs) containing surface pre-reacted glass-ionomer (S-PRG) filler for primary molar teeth and evaluate their physical properties and wear resistance. METHODS Experimental CAD/CAM RCBs containing S-PRG filler for primary molar teeth (EB), a commercial CAD/CAM RCB (HC), two resin composites for primary teeth (BKP and BKZ) and one for permanent teeth (BⅡ) were used. Hardness tests, three-point bending tests, fracture toughness tests, and water absorption tests were conducted. Wear tests were conducted for these materials and stainless steel crowns (SSCs). RESULTS The Vickers hardness of EB was lower than that of HC (p < 0.05), and there was no significant difference among BKZ, BKP, and BⅡ (p > 0.05). After 1 week of water immersion, EB and HC showed greater flexural strength than the other materials (p < 0.05). EB showed greater fracture toughness than the other materials (p < 0.05). The water absorption of EB was lower than that of HC, BKZ, and BKP (p < 0.05), and greater than that of BⅡ (p < 0.05). Antagonist wear was significantly smaller in EB than in HC and BⅡ (p < 0.05), and significantly greater than in BKZ (p < 0.05). Antagonist wear could not be measured in SSC because of excessive wear that was out of range of the surface roughness tester. SIGNIFICANCE The CAD/CAM RCBs containing S-PRG filler for primary molar teeth developed in this study demonstrated adequate physical properties and wear performance, suggesting that they are suitable for restoration of primary molar teeth and could function in place of SSCs.
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20
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Tobar C, Rodriguez V, Lopez-Suarez C, Pelaez J, Suarez MJ. Influence of Digital Technologies and Framework Design on the Load to Fracture of Co-Cr Posterior Fixed Partial Denture Frameworks. J Prosthodont 2021; 31:606-613. [PMID: 34860426 DOI: 10.1111/jopr.13458] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/25/2021] [Indexed: 12/01/2022] Open
Abstract
PURPOSE To compare the load to fracture of cobalt-chromium (Co-Cr) 3-unit posterior fixed partial denture (FPD) frameworks manufactured by conventional and digital techniques and to evaluate the influence of the framework design on the fracture load. MATERIAL AND METHODS Eighty 3-unit Co-Cr posterior FPD frameworks were fabricated with two designs: intermediate pontic (n = 40) and cantilever (n = 40). Each design was randomly divided into four groups (n = 10): casting, direct metal laser sintering, soft metal milling, and hard metal milling. After thermal cycling, all specimens were subjected to a 3-point bending test until fracture. Data were statistically analyzed using one-way ANOVA, Welch and Brown-Forsythe test, Ryan-Einot-Gabriel-Welsch F and Tamhane T2 post hoc test, Student's t test, and Weibull statistics (α = 0.05). RESULTS Significant differences (p < 0.001; F = 39.59) were found among intermediate pontic frameworks (except between laser sintering and hard metal milling), and cantilevered frameworks (F = 36.75) (except between laser sintering and hard metal milling, and casting and soft metal milling). The cantilever groups showed load to fracture values significantly lower than those of the intermediate pontic (p < 0.001; F = 28.29). The Weibull statistics corroborated the results. CONCLUSIONS Hard metal milling and laser sintered frameworks exhibited the highest load to fracture values. However, all tested frameworks demonstrated clinically acceptable load to fracture values. The framework design directly affected the fracture load, with drastically lower values in cantilevered frameworks.
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Affiliation(s)
- Celia Tobar
- Department of Conservative Dentistry and Buccofacial Prostheses, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain
| | - Veronica Rodriguez
- Department of Conservative Dentistry and Buccofacial Prostheses, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain
| | - Carlos Lopez-Suarez
- Department of Conservative Dentistry and Buccofacial Prostheses, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain
| | - Jesus Pelaez
- Department of Conservative Dentistry and Buccofacial Prostheses, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain
| | - Maria J Suarez
- Department of Conservative Dentistry and Buccofacial Prostheses, Faculty of Odontology, University Complutense of Madrid, Madrid, Spain
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Elkholy MMA, Nawar NN, Ha WN, Saber SM, Kim HC. Impact of Canal Taper and Access Cavity Design on the Life Span of an Endodontically Treated Mandibular Molar: A Finite Element Analysis. J Endod 2021; 47:1472-1480. [PMID: 34139264 DOI: 10.1016/j.joen.2021.06.009] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Revised: 06/05/2021] [Accepted: 06/08/2021] [Indexed: 12/27/2022]
Abstract
INTRODUCTION This study investigated the impact of different canal tapers and access cavity designs on the life span of endodontically treated mandibular first molars using the finite element method. METHODS Finite element analysis was performed on simulated models with 3 access cavity designs (traditional, conservative, and truss). The mesial canals were prepared to either constant tapers of 25/.04 and 25/.06 or a variable taper corresponding to the cumulative canal preparation shapes of TruNatomy Prime (Dentsply Sirona, Charlotte, NC) and ProTaper Gold F2 (Dentsply Sirona). The distal canals in all models had a 40/.04 preparation. Using occlusal fingerprint analysis, all models were subjected to cyclic occlusal loading until model failure. The number of cycles until failure, the location of failure, stress distribution patterns, and the maximum von Mises stresses were assessed. RESULTS The traditional access models showed a lower life span than the conservative and truss models regardless of the canal taper, whereas there was not a notable difference in the conservative and truss models. The stresses migrated apically along the root surface and remarkably on the mesial aspect of the mesial root and the furcation area's outer surface. After root canal preparation with different tapers, there were no evident changes in the pattern and magnitude of the stresses distributed along the root surface. CONCLUSIONS The life span of the tooth is affected more significantly by the access cavity design than the root canal preparation taper. Because stress patterns migrate apically rather than concentrate in the pericervical area, crack initiation and propagation might occur anywhere on the root surface.
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Affiliation(s)
- Mostafa M A Elkholy
- Department of Endodontics, Faculty of Dentistry, The British University in Egypt, Cairo, Egypt.
| | - Nawar Naguib Nawar
- Department of Endodontics, Faculty of Dentistry, The British University in Egypt, Cairo, Egypt
| | - William Nguyen Ha
- University of Adelaide, Adelaide Dental School, Adelaide, South Australia, Australia
| | - Shehabeldin Mohamed Saber
- Department of Endodontics, Faculty of Dentistry, The British University in Egypt, Cairo, Egypt; Department of Endodontics, Ain Shams University, Cairo, Egypt
| | - Hyeon-Cheol Kim
- Department of Conservative Dentistry, Pusan National University School of Dentistry, Dental Research Institute, Dental and Life Science Institute, Gyeongnam, Korea.
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Schönhoff LM, Lümkemann N, Buser R, Hampe R, Stawarczyk B. Fatigue resistance of monolithic strength-gradient zirconia materials. J Mech Behav Biomed Mater 2021; 119:104504. [PMID: 33845296 DOI: 10.1016/j.jmbbm.2021.104504] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 03/24/2021] [Accepted: 03/29/2021] [Indexed: 11/18/2022]
Abstract
PURPOSE Evaluation of the effect of three different dynamic fatigue protocols on the fracture resistance of two monolithic strength-gradient zirconia materials. MATERIALS AND METHODS A total of 240 specimens (3 × 4 × 45 mm) was milled from two different layers (incisal and middle) of two types of strength-gradient zirconia blanks (IPS e. max ZirCAD MT Multi A2 vs. IPS e. max ZirCAD Prime A2), resulting in 60 specimens per material and layer group (IPS e. max ZirCAD MT Multi A2: incisal (MI), middle (MM); IPS e. max ZirCAD Prime A2: incisal (PI), middle (PM)). Each group was divided into one static (n = 15) and three dynamic fatigue protocols (N = 45, n = 15): i. 50 N increase every 5000 cycles ii. Increase by 5% of static fracture load every 5000 cycles iii. 10 N increase every 1000 cycles until facture. All specimens were loaded until facture in CeraTest 2 k. Kaplan-Meier, Log-Rank and Chi-squared-test as well as Weibull statistics were performed. A fractographic analysis was performed. The specimens were classified according to the number of crack origins and evaluated using the Ciba-Geigy table. RESULTS With regard to the fracture load, in the static loading MI and PI showed a higher fracture load and in dynamic fatigue protocol 2 PI showed a lower fracture load. The number of cycles until fracture only differed within three groups: MM and MI survived a higher number of cycles in dynamic fatigue protocol 2; PI survived a higher number of cycles in dynamic fatigue protocol 2 than in protocol 1. Within dynamic fatigue protocols, PM resisted the highest number of cycles in protocol 1 and 3 and MI in protocol 2. Comparing groups, Weibull modulus differed only within the static loading, with PI showing lower values than MM and MI. Within the material groups, MI showed higher values in static loading than in dynamic fatigue protocol 1 and 2, and PI showed higher values in the dynamic fatigue protocol 3 than in static loading. With regard to fracture patterns, no differences were found between the groups. CONCLUSIONS Dynamic fatigue protocols provide clinically relevant information on the long-term stability and reliability of monolithic strength-gradient zirconia materials. However, no definitive instructions for dynamic testing can be provided from this investigation.
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Affiliation(s)
- Lisa Marie Schönhoff
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Nina Lümkemann
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Ramona Buser
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany; Department of Reconstructive Dentistry and Gerodontology, School of Dental Medicine, University of Bern, Bern, Switzerland
| | - Rüdiger Hampe
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany
| | - Bogna Stawarczyk
- Dental Material Unit, Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336, Munich, Germany.
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Zadeh PN, Stawarczyk B, Hampe R, Liebermann A, Mayinger F. Edge chipping resistance of veneering composite resins. J Mech Behav Biomed Mater 2021; 116:104349. [PMID: 33561676 DOI: 10.1016/j.jmbbm.2021.104349] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 01/14/2021] [Accepted: 01/19/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To investigate the edge chipping resistance (ECR) of six veneering composite resins after different treatment protocols. MATERIALS AND METHODS Rectangular bar specimens were manufactured from Ceramage Incisal (CER; Shofu), dialog Vario Occlusal (DIA; Schütz Dental), Gradia Plus Heavy Body Enamel (GRA; GC Europe), in:joy incisal (INJ; Dentsply Sirona Deutschland), SR Nexco Paste Incisal (SRN; Ivoclar Vivadent), and Signum composite enamel (SIG; Kulzer). ECR was determined after five treatment protocols: (1) no treatment, (2) after storage in distilled water at 37 °C for 7 days, (3) storage in distilled water with an additional 10 000 thermal cycles (5 °C/55 °C), and hydrothermal treatment at 134 °C at a water vapor pressure of 0.2 MPa for a duration of (4) 3.5 min or (5) 23.5 min. Force was applied with the universal testing machine ZHU 0.2 (Zwick Roell) mounted with a Vickers diamond indenter until the chip fractured off the specimen and ECR values were computed by dividing the applied maximum force by the distance to the center of the applied force. Fracture analysis was performed employing light microscope imaging. Univariate and one-way ANOVA, Scheffé and Tukey-B post hoc, and partial eta squared (ƞp2) were computed (p < 0.05). RESULTS DIA presented consistently high ECR values, while CER showed low results. For some groups, seven days' storage in water and hydrothermal treatment for 3.5 min led to higher ECR results than observed in the initial state, while an additional 10 000 thermal cycles and hydrothermal treatment for 23.5 min resulted in lower ECR values. CONCLUSIONS The examined veneering composite resins differed in regard to their mechanical properties, with DIA possessing the highest resistance to chipping. While post-processing can initially increase a material's edge chipping resistance, intensified treatment protocols reduced the mechanical properties of veneering composite resins.
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Affiliation(s)
- Parissa Nassary Zadeh
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Rüdiger Hampe
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Anja Liebermann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany
| | - Felicitas Mayinger
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336, Munich, Germany.
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Two-body wear and fracture behaviour of an experimental paediatric composite crown in comparison to zirconia and stainless steel crowns dependent on the cementation mode. Dent Mater 2021; 37:264-271. [DOI: 10.1016/j.dental.2020.11.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2020] [Revised: 07/17/2020] [Accepted: 11/18/2020] [Indexed: 11/21/2022]
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Reliability and aging behavior of three different zirconia grades used for monolithic four-unit fixed dental prostheses. Dent Mater 2020; 36:e329-e339. [DOI: 10.1016/j.dental.2020.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 07/16/2020] [Accepted: 08/07/2020] [Indexed: 11/23/2022]
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Griffis E, Abd Alraheam I, Boushell L, Donovan T, Fasbinder D, Sulaiman TA. Tooth-cusp preservation with lithium disilicate onlay restorations: A fatigue resistance study. J ESTHET RESTOR DENT 2020; 34:512-518. [PMID: 33009726 DOI: 10.1111/jerd.12666] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Revised: 09/12/2020] [Accepted: 09/15/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This study examined the in vitro fatigue resistance of maxillary premolars with 2 mm or 3 mm preserved cusp thicknesses restored with lithium disilicate onlays. MATERIALS AND METHODS Premolars(N = 48) were divided into six groups. Onlays for groups 1 to 4 preserved a 3 mm functional (G1), 2 mm functional (G2), 3 mm nonfunctional (G3), or 2 mm nonfunctional (G4) buccal-lingual cusp width. Onlays for group 5 (G5, control) replaced both cusps. Group 6 (G6) samples were identical to G1 with added retentive boxes. Lithium disilicate onlays were exposed to thermocycling (10 000 cycles, 5°C-55°C, 30s/cycle) and mechanical loading (1.2 million cycles at 1.4 Hz and 70 N). All samples were examined for onlay debonding or cusp or onlay fracture. RESULTS Failure rates were 75%(G1), 0.0%(G2), 12.5%(G3), 0.0%(G4), 0.0%(G5), and 0.0%(G6). The difference in percent failure between the groups preserving the functional cusps (37.5%) and the groups preserving the nonfunctional cusps (6.3%) was statistically significant (P = .04; 95%CI:2.11-55.66). No cusp or restoration fractures were observed; all failures were due to debonding of the restoration. CONCLUSION Teeth with thin remaining cusps that were restored with bonded lithium disilicate onlay restorations were not prone to fracture. Retentive preparation features that physically eliminated lateral displacement prevented onlay debonding even though the ceramic-enamel margin was directly at the occlusal contact. CLINICAL SIGNIFICANCE The use of adhesively retained lithium disilicate ceramic onlays may be a viable alternative to full coverage restorations and may challenge traditionally accepted principals related to preparation resistance and retention form of ceramic partial coverage restorations.
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Affiliation(s)
| | | | - Lee Boushell
- Division of Comprehensive Oral Health, Adams School of Dentistry, University of Chapel Hill, Chapel Hill, North Carolina, USA
| | - Terrence Donovan
- Division of Comprehensive Oral Health, Adams School of Dentistry, University of Chapel Hill, Chapel Hill, North Carolina, USA
| | - Dennis Fasbinder
- Department of Cariology and Restorative Sciences and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan, USA
| | - Taiseer A Sulaiman
- Division of Comprehensive Oral Health, Adams School of Dentistry, University of Chapel Hill, Chapel Hill, North Carolina, USA
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Impact of Coping Veneering Techniques on the Survival of Implant-Supported Zirconia-Based-Crowns Cemented to Hybrid-Abutments: An-In-Vitro Study. Bioengineering (Basel) 2020; 7:bioengineering7040117. [PMID: 32992792 PMCID: PMC7712862 DOI: 10.3390/bioengineering7040117] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Revised: 09/14/2020] [Accepted: 09/20/2020] [Indexed: 11/17/2022] Open
Abstract
The objective of this study is to investigate the influence of veneering technique (hand-layering vs. milling) on the fracture resistance of bi-layer implant-supported zirconia-based hybrid-abutment crowns. Mandibular molar copings were anatomically designed and milled. Copings were then veneered by hand-layering (HL) (n = 20) and milling using the Cad-On technique (LD) (n = 20). Crowns were cemented to zirconia hybrid-abutments. Ten samples of each group acted as a control while the remaining ten samples were subjected to fatigue in a chewing simulator. Crowns were loaded between 50 and 100 N for 1.2 million cycles under simultaneous temperature fluctuation between 5 and 55 °C. Crowns were then subjected to static load a to fracture test. Data were statistically analysed using the one-way ANOVA. Randomly selected crowns from each group were observed under scanning electron microscopy to view fractured surfaces. Study results indicate that during fatigue, LD crowns had a 100% survival rate; while HL crowns had a 50% failure rate. Fracture resistance of LD crowns was statistically significantly higher than that of HL crowns at the baseline and after fatigue (p ≤ 0.05). However, fatigue did not cause a statistically significant reduction in fracture resistance in both LD and HL groups (p > 0.05). Copings fractured in the LD crowns only and the fracture path was different in both LD and HL groups. According to the results, it was concluded that milled veneer implant-supported hybrid-abutment crowns exhibit significantly higher fracture resistance, and better withstand clinical masticatory loads in the posterior region compared to the hand-layered technique. Also, fatigue application and artificial aging caused no significant strength reduction in both techniques. Clinical significance: Different veneering techniques and materials (hand-layering or milling) act differently to clinical forces and environment and may be prone to early chipping during service. Therefore, practitioners are urged to consider the appropriate veneering protocol for posterior implant-supported hybrid-abutment restorations.
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In vitro performance and fracture resistance of interim conventional or CAD-CAM implant-supported screw- or cement-retained anterior fixed partial dentures. J Prosthet Dent 2020; 126:575-580. [PMID: 32962835 DOI: 10.1016/j.prosdent.2020.08.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 08/05/2020] [Accepted: 08/05/2020] [Indexed: 11/21/2022]
Abstract
STATEMENT OF PROBLEM Interim restorations represent an essential clinical treatment step; however, limited information is available concerning the performance of computer-aided design and computer-aided manufacturing (CAD-CAM) interim materials. PURPOSE The purpose of this in vitro study was to evaluate the performance and fracture load of resin anterior implant-supported interim fixed partial dentures (IFPDs). MATERIAL AND METHODS Identical anterior resin IFPDs (maxillary central incisor to canine; n=16 per material) were milled from polymethylmethacrylate (PMMA) or di-methacrylate (DMA) systems with different filler content. The IFPD groups were split to simulate a chairside (cemented implant-supported prosthesis) or laboratory procedure (screw-retained implant-supported prosthesis). A cartridge DMA material served as a control. After interim cementation, combined thermocycling and mechanical loading (TCML) was performed on all restorations to approximate a maximum of 2.5 years of clinical function. Behavior during TCML and fracture force was determined, and failures were analyzed. The data were statistically investigated (Kolmogorov-Smirnov test, 1-way-ANOVA; post hoc Bonferroni, Kaplan-Meier survival, α=.05). RESULTS Drop out during TCML varied between no failures and complete failure during loading. For most systems, failure occurred between 120 000 and 600 000 mechanical loading cycles. For IFPDs without a screw channel fracture, values varied between 644 ±263 N and 987 ±101 N. Those with a screw channel fracture failed between 493 ±89 N and 951 ±248 N. Individual IFPDs had significantly higher mean fracture loads (P<.002), but the mean fracture values between IFPDs with and without a screw channel were not significantly different (P>.137). Failures were characterized by fracture of the connector (n=53) followed by mixed failures (n=22) or fractures at the abutment (n=21). CONCLUSIONS These interim materials are sufficiently fracture resistant for the fabrication of implant-supported anterior IFPDs and are expected to survive between 6 months and 2 years before failure. The stability of IFPDs depended on the type of material but not on the restoration design (with or without a screw channel).
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Nawafleh N, Bibars AR, Elshiyab S, Janzeer Y. In vitro Simulation of Periodontal Ligament in Fatigue Testing of Dental Crowns. Eur J Dent 2020; 14:380-385. [PMID: 32645731 PMCID: PMC7440937 DOI: 10.1055/s-0040-1713953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
OBJECTIVE Fatigue testing of restorative material has been appreciated as an appropriate method to evaluate dental restorations. This study aims to investigate the influence of periodontal ligament (PDL) simulation on fatigue and fracture tests results of zirconia crowns. MATERIALS AND METHODS A standard tooth preparation for all ceramic zirconia crown was made on a typodont mandibular molar. The prepared master die was duplicated using epoxy resin to produce 40 replicas. PDL simulation was made by surrounding the root of 20 dies with a 0.3-mm thick silicon layer. The other 20 specimens had no PDL simulation. Zirconia crowns were fabricated using computer-aided design/computer-aided manufacturing technology and cemented to the epoxy resin dies. Ten crowns from each group were subject to chewing simulation with simultaneous thermocycling (5-55°C). All specimens were then loaded until failure in universal testing machine. STATISTICAL ANALYSIS Statistical analysis was conducted using SPSS software. Shapiro-Wilk test confirmed the normal distribution of data. Descriptive statistic was performed and differences between the groups were analyzed using paired samples t-test. RESULTS All fatigued crowns survived chewing simulation; no failure was observed after finishing simulation. The highest mean fracture load recorded was 3,987 ± 400 N for the no fatigue/no periodontal simulation group. Comparing the mean fracture load of the two groups with periodontal simulation and the two groups with no periodontal simulation showed no statistically significant difference (p > 0.5). CONCLUSION Considering the testing set-up applied in this study, simulating PDL using resilient materials does not affect the in vitro survival and fracture resistance 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
| | - Shareen Elshiyab
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Yasmeen Janzeer
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
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Sari T, Usumez A, Strasser T, Şahinbas A, Rosentritt M. Temporary materials: comparison of in vivo and in vitro performance. Clin Oral Investig 2020; 24:4061-4068. [PMID: 32583239 PMCID: PMC8275555 DOI: 10.1007/s00784-020-03278-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Accepted: 04/08/2020] [Indexed: 11/30/2022]
Abstract
OBJECTIVE The aim of this investigation was to compare clinical performance and in vitro wear of temporary CAD/CAM and cartridge crowns. This study is an approach to estimate the influence of in vivo use and laboratory simulation on temporary crowns. MATERIALS AND METHODS A total of 90 crowns were fabricated from each temporary CAD/CAM or cartridge material. Also, 10 crowns of each material were clinically applied for 14 days, and 80 identical duplicate restorations were investigated in the laboratory after storage in water (14 days; 37 °C) and subsequent thermal cycling and mechanical loading (TCML, 240.000 × 50N ML, 600 × 5°C/55 °C). After in vivo application or in vitro aging, facture force, superficial wear (mean and maximum), surface roughness (Ra, Rz), thermal weight loss (TGA), and heat of reaction (DSC) were determined for all crowns. STATISTICS Bonferroni post hoc test; one-way analysis of variance (ANOVA); α = 0.05). RESULTS The fracture resistance of the temporary materials varied between 1196.4 (CAD in vivo) and 1598.3 N (cartridge crown in vitro). Mean (maximum) wear data between 204.7 (386.7 μm; cartridge in vitro) and 353.0 μm (621.8 μm; CAD in vitro) were found. Ra values ranged between 4.4 and 4.9 μm and Rz values between 36.0 and 40.8 μm. DSC and TG analysis revealed small differences between the materials but a strong influence of the aging process. CONCLUSIONS Comparison of in vivo and in vitro aging led to no significant differences in fracture force and wear but differences in roughness, DSC, and TGA. SEM evaluation confirmed comparability. Comparison of CAD/CAM and cartridge temporary materials partially showed significant differences. CLINICAL RELEVANCE In vitro aging methods might be helpful to estimate materials' properties before principal clinical application. CAD/CAM and cartridge temporary materials provided comparable good clinical performance.
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Affiliation(s)
- Tuğrul Sari
- Faculty of Dentistry, Department of Prosthodontics, Istanbul Aydın University, Istanbul, Turkey
| | | | - Thomas Strasser
- Department of Prosthetic Dentistry, Regensburg University Medical Center, D-93042, Regensburg, Germany
| | - Abdurrahman Şahinbas
- Faculty of Dentistry, Department of Prosthodontics, Bezmialem Vakif University, İstanbul, Turkey
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, Regensburg University Medical Center, D-93042, Regensburg, Germany.
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Brunner KC, Özcan M. Load bearing capacity and Weibull characteristics of inlay-retained resin-bonded fixed dental prosthesis made of all-ceramic, fiber-reinforced composite and metal-ceramic after cyclic loading. J Mech Behav Biomed Mater 2020; 109:103855. [PMID: 32543415 DOI: 10.1016/j.jmbbm.2020.103855] [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: 04/13/2020] [Revised: 05/06/2020] [Accepted: 05/10/2020] [Indexed: 10/24/2022]
Abstract
PURPOSE The objectives of this study were to evaluate the load bearing capacity of RBFDPs made of different materials after cyclic loading, and classify the failure types after loading. MATERIALS AND METHODS Sound human mandibular first premolars and first molar pairs (N = 60 per tooth type, n = 10 per group) were randomly divided into six experimental groups to receive one of the following inlay-retained RBFDP types: RC: Resin composite only, DFRC: Direct E-glass fiber-reinforced composite (FRC), IFRC: Indirect E-glass FRC, LS: Lithium disilicate glass-ceramic, ZR: Yttria-stabilized tetragonal zirconia, MC: Metal-ceramic. Box preparations were made in abutment teeth using diamond burs followed by standardized ultrasonic burs. The teeth were conditioned employing an etch-and-rinse adhesive system and the indirect RBFDPs were cemented adhesively. The specimens were subjected to cyclic loading for x1.200.000 in distilled water alternating between 5 and 55 °C (Zurich Chewing Simulator). They were then loaded to failure from the occlusal surface in the Universal Testing Machine (cross-head speed: 1 mm/min). Failure types were classified as repairable or irreparable depending on the location and size. Data were analyzed using Welch and Tamhane's T2 post-hoc tests (α = 0.05). Weibull modulus for each group was calculated based on parametric distribution analysis of censored data for maximum fracture load. RESULTS Mean load bearing capacity (N) of Groups LS (1274 ± 270), ZR (1567 ± 363) and MC (1544 ± 787) were significantly higher than those of other groups (p < 0.05). RC, DFRC, IFRC (601 ± 130 - 819 ± 270) and MC did not show significant difference (p > 0.05). Weibull modulus (m) was the highest in Group LS (m = 5.3) followed by Group RC (m = 5.1). Other groups presented Weibull moduli ranging between 1.4 and 3.3. Only in Group ZR, 2 early debonding occurred during cyclic loading. While in this group predominantly irreparable failures (debonding with without tooth fracture) were observed (8 out of 10), all other groups presented mainly single or a combination of repairable failures (chipping in the veneering material). DFRC, IDRC and MC did not show any debonding from the abutment teeth. CONCLUSION Considering load bearing capacity, repairable failure types and Weibull moduli, lithium disilicate seem to be more durable than those of other material options for posterior inlay-retained RBFDPs. Due to early debondings and catastrophic irreparable failure types, zirconia RBFDPs should be indicated with caution in the posterior region.
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Affiliation(s)
- Kim-Chi Brunner
- University of Zürich, Center for Dental and Oral Medicine, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Zurich, Switzerland
| | - Mutlu Özcan
- University of Zürich, Center for Dental and Oral Medicine, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Zurich, Switzerland.
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Wiedenmann F, Pfefferle R, Reichert A, Jerman E, Stawarczyk B. Impact of high-speed sintering, layer thickness and artificial aging on the fracture load and two-body wear of zirconia crowns. Dent Mater 2020; 36:846-853. [PMID: 32414506 DOI: 10.1016/j.dental.2020.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 03/18/2020] [Accepted: 04/13/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE To investigate the impact of high-speed sintering, layer thickness and artificial aging in a chewing simulator on the fracture load (FL) and two-body wear (2BW) of 4Y-TZP crowns. METHODS 4Y-TZP crowns (Ceramill Zolid HT+, Amann Girrbach AG) in three different layer thicknesses (0.5, 1.0, 1.5; N=192, n=64/group) were manufactured using CAD/CAM technology and sintered at 1580°C (high-speed sintering) or 1450°C (control group). Specimens were polished in two-steps and bonded to standardized CoCr abutments with Multilink Automix (Ivoclar Vivadent). 2BW after 6000 thermo- and 1,200,000 chewing-cycles employing enamel antagonists was determined using best fit machining. FL was tested before and after artificial aging. Univariate ANOVAs, post hoc Scheffé, unpaired t-, Kruskal-Wallis- and Mann-Whitney-U-test were computed (p<0.05). RESULTS High-speed sintering resulted in less 2BW of the zirconia than the control group (p=0.013). High-speed sintering (p=0.001-0.006) and an increase in layer thickness (p<0.001-0.012) resulted in higher FL values, while artificial aging led to a reduction of FL (p<0.001). SIGNIFICANCE As high-speed sintering resulted in less two-body wear of the zirconia and comparable or even higher fracture load results than the control group, this cost- and time efficient alternative presents promising mechanical results.
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Affiliation(s)
- Felicitas Wiedenmann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336 Munich, Germany.
| | - Regina Pfefferle
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336 Munich, Germany
| | - Axel Reichert
- Research & Development, Amann Girrbach GmbH, Herrschaftswiesen 1, 6842 Koblach, Austria
| | - Eva Jerman
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336 Munich, Germany
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestraße 70, 80336 Munich, Germany
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Lümkemann N, Pfefferle R, Jerman E, Sener B, Stawarczyk B. Translucency, flexural strength, fracture toughness, fracture load of 3-unit FDPs, Martens hardness parameter and grain size of 3Y-TZP materials. Dent Mater 2020; 36:838-845. [PMID: 32370908 DOI: 10.1016/j.dental.2020.03.027] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 01/31/2020] [Accepted: 03/30/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVE This investigation tested pre-shaded 3Y-TZP materials on optical, mechanical and structural properties and calculated correlations between these properties. METHODS Seven A2-shaded 3Y-TZP zirconia materials were investigated on translucency (T) via UV-vis-spectrophotometer, fracture load of 3-unit FDPs (FL), biaxial flexural strength (FS), Chevron-Notch Beam (CNB), fracture toughness (KIC) and Martens parameter (hardness: HM and indentation modulus: EIT). FL, FS and KIC were measured in a universal testing machine. The grain size was evaluated by scanning electron microscopy (SEM). Data was analyzed using one-way ANOVA followed by post hoc Scheffé, Kruskal-Wallis-, Mann-Whitney-U- and Pearson-test (p<0.05). RESULTS For translucency, negative correlations were found with results of facture load (R=-0.444, p<0.001) and KIC (R=-0.503, p<0.001). While a positive correlation was found between translucency and flexural strength (R=0.238, p=0.019), between fracture load and EIT (R=0.227, p<0.029), between fracture load and KIC (R=0.362, p<0.001) as well as between fracture load and the grain size (R=0.598, p=0.007). While the grain size positively correlated with EIT (R=0.534, p=0.017) as well as EIT with HM (R=0.720, p<0.001). SIGNIFICANCE Despite of being based on the same raw material, tested zirconia materials significantly differed regarding optical, mechanical (except biaxial flexural strength and Martens hardness) and structural properties. Materials with highest optical properties were those with lowest mechanical properties (CER, COP).
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Affiliation(s)
- Nina Lümkemann
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Regina Pfefferle
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Eva Jerman
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany
| | - Beatrice Sener
- Periodontics and Cardiology, Clinic for Preventive Dentistry, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
| | - Bogna Stawarczyk
- Department of Prosthetic Dentistry, University Hospital, LMU Munich, Goethestrasse 70, 80336 Munich, Germany.
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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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Rosentritt M, Schumann F, Krifka S, Preis V. Influence of zirconia and lithium disilicate tooth- or implant-supported crowns on wear of antagonistic and adjacent teeth. J Adv Prosthodont 2020; 12:1-8. [PMID: 32128080 PMCID: PMC7040450 DOI: 10.4047/jap.2020.12.1.1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 01/22/2020] [Accepted: 01/23/2020] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To investigate the influence of crown material (lithium-disilicate, 3Y-TZP zirconia) and abutment type (rigid implant, resin tooth with artificial periodontium) on wear performance of their antagonist teeth and adjacent teeth. MATERIALS AND METHODS A mandibular left first molar (#36) with adjacent human teeth (mandibular left second premolar: #35, mandibular left second molar: #37) and antagonistic human teeth (maxillary left second premolar: #25, maxillary left first molar: #26, maxillary left second molar: #27) was prepared simulating a section of the jaw. Samples were made with extracted human molars (Reference), crowned implants (Implant), or crowned resin tooth analogues (Tooth). Crowns (tooth #36; n = 16/material) were milled from lithium-disilicate (Li, IPS e.max CAD) or 3Y-TZP zirconia (Zr, IPS e.max ZirCAD, both Ivoclar Vivadent). Thermal cycling and mechanical loading (TCML) in the chewing simulator were applied simulating 15 years of clinical service. Wear traces were analyzed (frequency [n], depth [µm]) and evaluated using scanning electron pictures. Wear results were compared by one-way-ANOVA and post-hoc-Bonferroni (α = 0.05). RESULTS After TCML, no visible wear traces were found on Zr. Li showed more wear traces (n = 30–31) than the reference (n = 21). Antagonistic teeth #26 showed more wear traces in contact to both ceramics (n = 27–29) than to the reference (n = 21). Strong wear traces (> 350 µm) on antagonists and their adjacent teeth were found only in crowned groups. Abutment type influenced number and depth of wear facets on the antagonistic and adjacent teeth. CONCLUSION The clinically relevant model with human antagonistic and adjacent teeth allowed for a limited comparison of the wear situation. The total number of wear traces and strong wear on crowns, antagonistic and adjacent teeth were influenced by crown material.
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Affiliation(s)
- Martin Rosentritt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Frederik Schumann
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Stephanie Krifka
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Verena Preis
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
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Cometa S, Bonifacio MA, Ferreira AM, Gentile P, De Giglio E. Surface Characterization of Electro-Assisted Titanium Implants: A Multi-Technique Approach. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E705. [PMID: 32033256 PMCID: PMC7040792 DOI: 10.3390/ma13030705] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 01/17/2020] [Accepted: 01/22/2020] [Indexed: 12/20/2022]
Abstract
The understanding of chemical-physical, morphological, and mechanical properties of polymer coatings is a crucial preliminary step for further biological evaluation of the processes occurring on the coatings' surface. Several studies have demonstrated how surface properties play a key role in the interactions between biomolecules (e.g., proteins, cells, extracellular matrix, and biological fluids) and titanium, such as chemical composition (investigated by means of XPS, TOF-SIMS, and ATR-FTIR), morphology (SEM-EDX), roughness (AFM), thickness (Ellipsometry), wettability (CA), solution-surface interactions (QCM-D), and mechanical features (hardness, elastic modulus, adhesion, and fatigue strength). In this review, we report an overview of the main analytical and mechanical methods commonly used to characterize polymer-based coatings deposited on titanium implants by electro-assisted techniques. A description of the relevance and shortcomings of each technique is described, in order to provide suitable information for the design and characterization of advanced coatings or for the optimization of the existing ones.
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Affiliation(s)
| | - Maria A. Bonifacio
- Jaber Innovation s.r.l., 00144 Rome, Italy;
- Department of Chemistry, University of Bari “Aldo Moro”, 70126 Bari, Italy;
| | - Ana M. Ferreira
- School of Engineering, Newcastle University, Newcastle NE1 7RU, UK; (A.M.F.); (P.G.)
| | - Piergiorgio Gentile
- School of Engineering, Newcastle University, Newcastle NE1 7RU, UK; (A.M.F.); (P.G.)
| | - Elvira De Giglio
- Department of Chemistry, University of Bari “Aldo Moro”, 70126 Bari, Italy;
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de Kuijper MCFM, Cune MS, Tromp Y, Gresnigt MMM. Cyclic loading and load to failure of lithium disilicate endocrowns: Influence of the restoration extension in the pulp chamber and the enamel outline. J Mech Behav Biomed Mater 2020; 105:103670. [PMID: 32090891 DOI: 10.1016/j.jmbbm.2020.103670] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2019] [Revised: 02/02/2020] [Accepted: 02/03/2020] [Indexed: 01/22/2023]
Affiliation(s)
- Maurits C F M de Kuijper
- The University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry and Biomaterials, Groningen, the Netherlands.
| | - Marco S Cune
- The University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry and Biomaterials, Groningen, the Netherlands; St. Antonius Hospital Nieuwegein, Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, Nieuwegein, the Netherlands; University Medical Center Utrecht, Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, Utrecht, the Netherlands
| | - Youp Tromp
- The University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry and Biomaterials, Groningen, the Netherlands
| | - Marco M M Gresnigt
- The University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry and Biomaterials, Groningen, the Netherlands; Martini Hospital, Department of Special Dental Care, Groningen, the Netherlands
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Chai SY, Bennani V, Aarts JM, Lyons K. Incisal preparation design for ceramic veneers: A critical review. J Am Dent Assoc 2019; 149:25-37. [PMID: 29304908 DOI: 10.1016/j.adaj.2017.08.031] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2017] [Revised: 08/23/2017] [Accepted: 08/26/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND The authors reviewed and identified the evidence for the various incisal preparation designs for ceramic veneers. TYPES OF STUDIES REVIEWED The authors searched MEDLINE with PubMed and Ovid to identify any articles in the English language related to the topic up through March 2017 using a combination of key words: "porcelain veneer or ceramic veneer or dental veneer or labial veneer" AND "preparation," NOT "composite veneer," NOT "crown," NOT "implant," NOT "fixed partial denture or bridge or denture," NOT "porcelain-fused-to-metal," NOT "marginal gap or fit." RESULTS In vitro studies showed that the palatal chamfer preparation design increases the risk of developing ceramic fractures. The butt joint preparation design had the least effect on the strength of the tooth. CONCLUSIONS Surveys show the 2 most common incisal preparation designs provided are butt joint and feathered-edge. Clinical studies have identified that incisal ceramic is the most common location of ceramic fracture. In addition, there is a lack in standardization of the modeling structures and type of finite element analysis. PRACTICAL IMPLICATIONS The evidence seems to support the use of butt joint over palatal chamfer incisal preparation design. Fracture or chipping is the most frequent complication and the risk increases with time. Incisal ceramic is the most common location of ceramic fracture.
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Rosentritt M, Koenig A, Kolbeck C, Krifka S, Hahnel S. Validating laboratory simulation with resin-based materials for temporary fixed denture prostheses - Results from clinical and laboratory trials. J Mech Behav Biomed Mater 2019; 101:103431. [PMID: 31585349 DOI: 10.1016/j.jmbbm.2019.103431] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 09/02/2019] [Accepted: 09/12/2019] [Indexed: 11/13/2022]
Abstract
The aim of the current study was to relate an artificial aging protocol for the analysis of dental materials to their clinical performance. 20 fixed interim restorations (crowns and fixed denture prostheses (FDPs)) fabricated from two commercially available resin-based composites (RBCs) and a previous clinical trial served as templates for the fabrication of duplicate restorations. Duplicates were subjected to artificial aging using thermal cycling and mechanical loading. Subsequent to wear analysis, templates and duplicates were loaded to fracture and were examined using thermal gravimetric analysis (TG) and differential scanning calorimetry (DSC). For both RBCs, a relevant uptake of water was identified, which was more pronounced in the duplicates. Tribological analyses indicated relevant signs of wear in both templates and duplicates. While qualitative analyses indicated macroscopically similar wear traces in templates and duplicates, data showed that wear of FDPs was underrated in the laboratory analyses. The results of the current study suggest that chewing simulation allows a proper estimation of aging processes in materials for the fabrication of fixed interim restorations. However, simulation parameters should be continuously improved using data derived from clinical settings to enhance the quality of the simulation protocols.
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Affiliation(s)
- Martin Rosentritt
- Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg, Germany
| | - Andreas Koenig
- Department of Prosthodontics and Materials Science, University of Leipzig, Leipzig, Germany
| | - Carola Kolbeck
- Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg, Germany
| | - Stephanie Krifka
- Department of Prosthetic Dentistry, Regensburg University Medical Center, Regensburg, Germany
| | - Sebastian Hahnel
- Department of Prosthodontics and Materials Science, University of Leipzig, Leipzig, Germany.
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Sorrentino R, Navarra CO, Di Lenarda R, Breschi L, Zarone F, Cadenaro M, Spagnuolo G. Effects of Finish Line Design and Fatigue Cyclic Loading on Phase Transformation of Zirconia Dental Ceramics: A Qualitative Micro-Raman Spectroscopic Analysis. MATERIALS 2019; 12:ma12060863. [PMID: 30875849 PMCID: PMC6470560 DOI: 10.3390/ma12060863] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2019] [Revised: 02/28/2019] [Accepted: 03/12/2019] [Indexed: 11/16/2022]
Abstract
Objectives: Stresses produced during the fabrication of copings and by chewing activity can induce a tetragonal-to-monoclinic (t–m) transformation of zirconia. As a consequence, in the m-phase, the material is not able to hinder possible cracks by the favorable mechanism known as “transformation toughening”. This study aimed at evaluating if different marginal preparations of zirconia copings can cause a premature phase transformation immediately after manufacturing milling and after chewing simulation. Methods: Ninety copings using three commercial zirconia ceramics (Nobel Procera Zirconia, Nobel Biocare Management AG; Lava Classic, 3M ESPE; Lava Plus, 3M ESPE) were prepared with deep-chamfer, slight-chamfer, or feather-edge finish lines (n = 10). Specimens were tested in a chewing simulator (CS-4.4, SD Mechatronik) under cyclic occlusal loads simulating one year of clinical service. Raman spectra were acquired and analyzed for each specimen along the finish lines and at the top of each coping before and after chewing simulation, respectively. Results: Raman analysis did not show any t–m transformation both before and after chewing simulation, as the typical monoclinic bands at 181 cm−1 and 192 cm−1 were not detected in any of the tested specimens. Conclusions: After a one-year simulation of chewing activity, irrespective of preparation geometry, zirconia copings did not show any sign of t–m transformation, either in the load application areas or at the margins. Consequently, manufacturing milling even in thin thickness did not cause any structural modification of zirconia ceramics “as received by manufacturers” both before and after chewing simulation.
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Affiliation(s)
- Roberto Sorrentino
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, Division of Prosthodontics and Digital Dentistry, University of Naples "Federico II", via S. Pansini 5, 80131 Naples, Italy.
| | - Chiara Ottavia Navarra
- Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34129 Trieste, Italy.
| | - Roberto Di Lenarda
- Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34129 Trieste, Italy.
| | - Lorenzo Breschi
- Department of Biomedical Science and Neuromotor Sciences, DIBINEM, University of Bologna, Via San Vitale 59, 40123 Bologna, Italy.
| | - Fernando Zarone
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, Division of Prosthodontics and Digital Dentistry, University of Naples "Federico II", via S. Pansini 5, 80131 Naples, Italy.
| | - Milena Cadenaro
- Department of Medical Sciences, University of Trieste, Piazza dell'Ospitale 1, 34129 Trieste, Italy.
| | - Gianrico Spagnuolo
- Department of Neurosciences, Reproductive and Odontostomatological Sciences, Division of Prosthodontics and Digital Dentistry, University of Naples "Federico II", via S. Pansini 5, 80131 Naples, Italy.
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Preis V, Hahnel S, Behr M, Rosentritt M. In vitro performance and fracture resistance of novel CAD/CAM ceramic molar crowns loaded on implants and human teeth. J Adv Prosthodont 2018; 10:300-307. [PMID: 30140397 PMCID: PMC6104500 DOI: 10.4047/jap.2018.10.4.300] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/07/2018] [Accepted: 05/08/2018] [Indexed: 11/25/2022] Open
Abstract
PURPOSE To investigate the fatigue and fracture resistance of computer-aided design and computer-aided manufacturing (CAD/CAM) ceramic molar crowns on dental implants and human teeth. MATERIALS AND METHODS Molar crowns (n=48; n=8/group) were fabricated of a lithium-disilicate-strengthened lithium aluminosilicate glass ceramic (N). Surfaces were polished (P) or glazed (G). Crowns were tested on human teeth (T) and implant-abutment analogues (I) simulating a chairside (C, crown bonded to abutment) or labside (L, screw channel) procedure for implant groups. Polished/glazed lithium disilicate (E) crowns (n=16) served as reference. Combined thermal cycling and mechanical loading (TC: 3000×5℃/3000×55℃; ML: 1.2×106 cycles, 50 N) with antagonistic human molars (groups T) and steatite spheres (groups I) was performed under a chewing simulator. TCML crowns were then analyzed for failures (optical microscopy, SEM) and fracture force was determined. Data were statistically analyzed (Kolmogorow-Smirnov, one-way-ANOVA, post-hoc Bonferroni, α=.05). RESULTS All crowns survived TCML and showed small traces of wear. In human teeth groups, fracture forces of N crowns varied between 1214±293 N (NPT) and 1324±498 N (NGT), differing significantly (P≤.003) from the polished reference EPT (2044±302 N). Fracture forces in implant groups varied between 934±154 N (NGI_L) and 1782±153 N (NPI_C), providing higher values for the respective chairside crowns. Differences between polishing and glazing were not significant (P≥.066) between crowns of identical materials and abutment support. CONCLUSION Fracture resistance was influenced by the ceramic material, and partly by the tooth or implant situation and the clinical procedure (chairside/labside). Type of surface finish (polishing/glazing) had no significant influence. Clinical survival of the new glass ceramic may be comparable to lithium disilicate.
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Affiliation(s)
- Verena Preis
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Sebastian Hahnel
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Michael Behr
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
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Elshiyab SH, Nawafleh N, Walsh L, George R. Fracture resistance and survival of implant-supported, zirconia-based hybrid-abutment crowns: Influence of aging and crown structure. ACTA ACUST UNITED AC 2018; 9:e12355. [PMID: 30105895 DOI: 10.1111/jicd.12355] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 05/18/2018] [Indexed: 11/29/2022]
Abstract
AIM The aim of the present study was to investigate fracture resistance of implant-supported zirconia-based crowns (monolayer vs bilayer) cemented to hybrid abutments. METHODS Monolayer and bilayer zirconia crowns were constructed and cemented to zirconia hybrid abutments. Crowns were divided into two subgroups: (a) untreated control group; and (b) experimental group, which underwent thermal-cycling mechanical loading in a chewing simulator. Up to 1.2 million stress cycles with simultaneous thermocycling (5 and 55°C) were applied. Samples were finally subjected to static load to fracture. Data were analyzed using one-way analysis of variance and t test. Fractured surfaces were observed using scanning electron microscopy. RESULTS Monolayer zirconia crowns had a 100% survival rate upon completion of the thermal mechanical loading, whereas bilayer zirconia crowns had a 50% survival rate. The fracture load of monolayer zirconia crowns was significantly higher than that of bilayer crowns. Moreover, the fracture load was significantly reduced in monolayer zirconia crowns after aging. Monolayer zirconia crowns showed bulk fracture within the monolayer, while bilayer crowns exhibited cohesive fracture within the veneering porcelain only. CONCLUSIONS Monolayer implant-supported hybrid-abutment crowns exhibit significantly higher fracture resistance compared to bilayer crowns, making them better suited to handle higher masticatory loads encountered in the posterior region of the mouth.
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Affiliation(s)
- Shareen H Elshiyab
- School of Dentistry and Oral Health, Griffith University, Gold Coast, Australia.,Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Noor Nawafleh
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Laurence Walsh
- School of Dentistry, University of Queensland, Brisbane, Australia
| | - Roy George
- School of Dentistry and Oral Health, Griffith University, Gold Coast, Australia
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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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Weigl P, Sander A, Wu Y, Felber R, Lauer HC, Rosentritt M. In-vitro performance and fracture strength of thin monolithic zirconia crowns. J Adv Prosthodont 2018; 10:79-84. [PMID: 29713427 PMCID: PMC5917110 DOI: 10.4047/jap.2018.10.2.79] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Revised: 08/30/2017] [Accepted: 09/12/2017] [Indexed: 01/19/2023] Open
Abstract
PURPOSE All-ceramic restorations required extensive tooth preparation. The purpose of this in vitro study was to investigate a minimally invasive preparation and thickness of monolithic zirconia crowns, which would provide sufficient mechanical endurance and strength. MATERIALS AND METHODS Crowns with thickness of 0.2 mm (group 0.2, n=32) or of 0.5 mm (group 0.5, n=32) were milled from zirconia and fixed with resin-based adhesives (groups 0.2A, 0.5A) or zinc phosphate cements (groups 0.2C, 0.5C). Half of the samples in each subgroup (n=8) underwent thermal cycling and mechanical loading (TCML)(TC: 5℃ and 55℃, 2×3,000 cycles, 2 min/cycle; ML: 50 N, 1.2×106 cycles), while the other samples were stored in water (37℃/24 h). Survival rates were compared (Kaplan-Maier). The specimens surviving TCML were loaded to fracture and the maximal fracture force was determined (ANOVA; Bonferroni; α=.05). The fracture mode was analyzed. RESULTS In both 0.5 groups, all crowns survived TCML, and the comparison of fracture strength among crowns with and without TCML showed no significant difference (P=.628). Four crowns in group 0.2A and all of the crowns in group 0.2C failed during TCML. The fracture strength after 24 hours of the cemented 0.2 mm-thick crowns was significantly lower than that of adhesive bonded crowns. All cemented crowns provided fracture in the crown, while about 80% of the adhesively bonded crowns fractured through crown and die. CONCLUSION 0.5 mm thick monolithic crowns possessed sufficient strength to endure physiologic performance, regardless of the type of cementation. Fracture strength of the 0.2 mm cemented crowns was too low for clinical application.
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Affiliation(s)
- Paul Weigl
- Head of Department of Postgraduate Education, Carolinum Dental University Institute gGmbH, Department of Prosthetic Dentistry, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Anna Sander
- Department of Prosthetic Dentistry, Faculty of Oral and Dental Medicine at JW Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Yanyun Wu
- Department of Postgraduate Education, Faculty of Oral and Dental Medicine at JW Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Roland Felber
- Department of Postgraduate Education, Carolinum Dental University Institute gGmbH, Department of Prosthetic Dentistry, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Hans-Christoph Lauer
- Head of Department of Prosthetic Dentistry, Carolinum Dental University Institute gGmbH, Department of Prosthetic Dentistry, Goethe-University Frankfurt am Main, Frankfurt, Germany
| | - Martin Rosentritt
- Department of Prosthetic Dentistry, UKR University Hospital Regensburg, Regensburg, Germany
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Peroz I, Mitsas T, Erdelt K, Kopsahilis N. Marginal adaptation of lithium disilicate ceramic crowns cemented with three different resin cements. Clin Oral Investig 2018; 23:315-320. [PMID: 29663086 DOI: 10.1007/s00784-018-2438-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 04/09/2018] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The cementation process and cementation materials have an influence on the marginal adaptation of restorations. The gap could be affected by thermal and mechanical loading (TCML). The computerized x-ray microtomography (μCT) method offers the possibility of measuring the marginal gap without destruction of the restoration. The aim of this study was to evaluate the marginal gap (MG) and the absolute marginal discrepancy (AMD) before and after TCML. MATERIALS AND METHODS Thirty-nine human premolars were prepared for full ceramic crowns made of lithium disilicate. The crowns were cemented by three different resins-Panavia F 2.0, Variolink II, and Relyx Unicem. The MG and AMD were evaluated by μCT before and after TCML. RESULTS Panavia F 2.0 had the lowest MG (before 118 μm-after TMCL 124 μm) and AMD (before 145 μm-after TMCL 154 μm), followed by Relyx Unicem (MG: before 164 μm-after TCML 155 μm; AMD: before 213 μm-after TMCL 209 μm) and Variolink II (MG: before 317 μm-after TMCL 320 μm; AMD: before 412 μm-after TMCL 406 μm). The differences were statistically significant before and after TCML. Rather than TCML, it appeared the resin cement was responsible for differences between the MG and AMD before and after TCML. CONCLUSIONS μCT is an accurate technique for assessing cemented restorations. Panavia F 2.0 has the lowest MG and AMD before and after TCML. CLINICAL RELEVANCE The resin material that features a three-step protocol (Variolink II) produced higher MG and AMG values than the Panavia or Relyx Unicem varieties with less or no intermediate steps at all.
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Affiliation(s)
- Ingrid Peroz
- Department of Prosthodontics, Gerodontology and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, Aßmannshauserstraße 4-6, 14197, Berlin, Germany.
| | | | - Kurt Erdelt
- Department of Prosthodontics, Dental School of the Ludwig-Maximilians University, Munich, Germany
| | - Niko Kopsahilis
- Department of Prosthodontics, Gerodontology and Craniomandibular Disorders, Charité - Universitätsmedizin Berlin, CC3, Berlin, Germany
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Ossareh A, Rosentritt M, Kishen A. Biomechanical studies on the effect of iatrogenic dentin removal on vertical root fractures. J Conserv Dent 2018; 21:290-296. [PMID: 29899632 PMCID: PMC5977778 DOI: 10.4103/jcd.jcd_126_18] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Introduction The aim of this study was to understand the mechanism by which iatrogenic root dentin removal influences radicular stress distribution and subsequently affects the resistance to vertical root fractures (VRF) in endodontically treated teeth. Materials and Methods The experiments were conducted in two phases. Phase 1: freshly extracted premolar teeth maintained in phosphate-buffered saline were instrumented to simulate three different degrees of dentin removal, designated as low, medium, and extreme groups. Micro-Ct analyzes were performed to quantitatively determine: (a) the amount of dentin removed, (b) the remaining dentin volume, and (c) the moment of inertia of root dentin. The specimens were then subjected to thermomechanical cycling and continuous loading to determine (a) the mechanical load to fracture and (b) dentin microcracking (fractography) using scanning electron microscopy. Phase 2: Finite element analysis was used to evaluate the influence of dentin removal on the stress distribution pattern in root dentin. The data obtained were analyzed using one-way ANOVA and Tukey's post hoc test (P < 0.05). Results Phase 1: A significantly greater volume of dentin was removed from teeth in extreme group when compared to low group (P < 0.01). The mechanical analysis showed that the load to fracture was significantly lower in teeth from extreme group (P < 0.05). A linear relationship was observed between the moment of inertia and load to fracture in all experimental groups (R2 = 0.52). Fractography showed that most microcracks were initiated from the root canal walls in extreme group. Phase 2: The numerical analysis showed that the radicular stress distribution increased apically and buccolingually with greater degree of root canal dentin removal. Conclusions The combined experimental/numerical analyses highlighted the influence of remaining root dentin volume on the radicular bending resistance, stress distribution pattern, and subsequent propensity to VRF.
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Affiliation(s)
- A Ossareh
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Ontario M5G 1G6, Canada
| | - M Rosentritt
- Department of Prosthetic Dentistry, University Hospital Regensburg UKR, Regensburg, Germany
| | - A Kishen
- Dental Research Institute, Faculty of Dentistry, University of Toronto, Ontario M5G 1G6, Canada
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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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In Vitro Investigation of Wear of CAD/CAM Polymeric Materials Against Primary Teeth. MATERIALS 2017; 10:ma10121410. [PMID: 29232849 PMCID: PMC5744345 DOI: 10.3390/ma10121410] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 11/30/2017] [Accepted: 12/08/2017] [Indexed: 11/17/2022]
Abstract
The aim of the study was to evaluate the effects of polymeric computer-aided design/computer-aided manufacturing CAD/CAM materials on antagonistic primary tooth wear. Five CAD/CAM polymeric materials were examined: Vipi Block Monocolor (VBM), Yamahachi polymethylmethacrylate (PMMA) (YAP), Mazic Duro (MZD), Vita Enamic (ENA), and Pekkton (PEK). All of the specimens were tested in a thermomechanical loading machine with the primary canine as the antagonist (50 N, 1.2 × 105 cycles, 1.7 Hz, 5/55 °C). The wear losses of the antagonist tooth and the restorative materials were calculated using reverse modelling software and an electronic scale. VBM and ENA showed significantly higher antagonist tooth wear than PEK (p < 0.05), but there was no significant difference observed among VBM, YAP, MZD, and ENA (p > 0.05). PEK showed the largest value in both material volumetric and weight losses. In terms of material volumetric losses, there was no significant difference between all of the groups (p > 0.05). In terms of material weight losses, PEK was significantly larger than ENA (p < 0.05), but there was no significant difference between VBM, YAP, MZD, and ENA (p > 0.05). Volumetric and weight losses of materials showed similar wear behaviour. However, the wear patterns of antagonists and materials were different, especially in PEK.
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Zaugg LK, Meyer S, Rohr N, Zehnder I, Zitzmann NU. Fracture behavior, marginal gap width, and marginal quality of vented or pre-cemented CAD/CAM all-ceramic crowns luted on Y-TZP implants. Clin Oral Implants Res 2017; 29:175-184. [PMID: 29090511 DOI: 10.1111/clr.13075] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2017] [Indexed: 11/28/2022]
Abstract
OBJECTIVES To investigate the fracture behavior and marginal gap region of CAD/CAM fabricated lithium disilicate (L) and zirconium dioxide (Z) crowns using palatal venting (PV), pre-cementation with custom analogs (CA), or conventional cementation technique (SP) with adhesive cement (A) or resin-modified glass ionomer cement (B). MATERIAL AND METHODS Twelve groups (n = 6) were set according to material (L, Z), cement (A, B), and technique (PV, CA, SP). Specimens were thermo-mechanical aged (TML), loaded until fracture (LF) and fracture patterns recorded. Marginal gap width and quality were assessed and compared to replicas obtained before and after TML. RESULTS Crown material significantly influenced LF with a mean of 1037.6 ± 282.4 N in L and 5356.3 ± 1207.0 N in Z groups (p < .001). Neither cement material nor cementation method affected the outcome. Fractures occurred along the mesial-distal central fissure in both materials. Gap width before TML was 22.04 ± 13.42 μm for L and 19.98 ± 12.72 μm for Z specimens, with overall no influence of crown material, cement type, or method. Marginal cleanliness just below the polished implant shoulder reached 66.7%-88.9% with A, and 91.7%-100% with B, and tended to increase in all groups during TML indicating a decrease in excess cement. Implant-crown junctions were cleaner with B compared to A (p ≤ .001) and along Z crown surfaces compared to L (p ≤ .007). CONCLUSIONS Crown venting of lithium disilicate and zirconium dioxide crowns did not affect the fracture load and patterns. Complete cement removal was rare, and the observed particle ablation requires further clinical attention, particularly with submucosal margins.
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Affiliation(s)
- Lucia K Zaugg
- Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland.,Centre for Craniofacial and Regenerative Biology, Dental Institute, King's College London, London, UK
| | - Simon Meyer
- Department of Reconstructive Dentistry and Temporomandibular Disorders, Division of Dental Materials and Engineering, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Nadja Rohr
- Department of Reconstructive Dentistry and Temporomandibular Disorders, Division of Dental Materials and Engineering, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Isabella Zehnder
- Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
| | - Nicola U Zitzmann
- Department of Periodontology, Endodontology and Cariology, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland.,Department of Reconstructive Dentistry and Temporomandibular Disorders, Division of Dental Materials and Engineering, University Center for Dental Medicine Basel, University of Basel, Basel, Switzerland
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Rosentritt M, Preis V, Behr M, Hahnel S. Influence of preparation, fitting, and cementation on the vitro performance and fracture resistance of CAD/CAM crowns. J Dent 2017; 65:70-75. [DOI: 10.1016/j.jdent.2017.07.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Revised: 06/29/2017] [Accepted: 07/08/2017] [Indexed: 11/24/2022] Open
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