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Hiraba H, Nishio K, Takeuchi Y, Ito T, Yamamori T, Kamimoto A. Application of one-piece endodontic crowns fabricated with CAD-CAM system to molars. JAPANESE DENTAL SCIENCE REVIEW 2024; 60:81-94. [PMID: 38303746 PMCID: PMC10830429 DOI: 10.1016/j.jdsr.2023.12.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/04/2023] [Accepted: 12/26/2023] [Indexed: 02/03/2024] Open
Abstract
Computer-aided design-computer-aided manufacturing (CAD-CAM) systems have been widely used as a fabrication method for restorations because of their high efficiency and accuracy, which significantly reduces fabrication time. However, molars with insufficient clearance or short clinical crown lengths require retention holes or grooves on the preparation, making it difficult to replicate the shapes with the CAM milling system. In these cases, restorations using the lost-wax method are selected. This article focuses on one-piece endodontic crowns (endocrowns) fabricated with a CAD-CAM system (CAD-CAM endocrowns), in which their posts and crowns are integrated. Articles from July 2012 to August 2023 were searched in PubMed with the keyword "endocrown". This review discusses the application of CAD-CAM endocrowns to molars from the viewpoint of model experiment (fracture resistance, adaptation) and clinical research. This technique, which allows margins and internal gaps to be set within the clinically acceptable range, is reported to be an effective way of restoring molars with high survival rates in clinical research.
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Affiliation(s)
- Haruto Hiraba
- Department of Dental Materials, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
- Division of Biomaterials Science, Dental Research Center, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Kensuke Nishio
- Department of Complete Denture Prosthodontics, Nihon University School of Dentistry, 1-8-13 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Yoshimasa Takeuchi
- Department of Comprehensive Dentistry and Clinical Education, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
| | - Takashi Ito
- Center of Innovative Clinical Medicine, Okayama University Hospital, 2-5-1 Shikata-cho, Kita-ku, Okayama 700-8525, Japan
| | - Tetsuo Yamamori
- Department of Prosthetic Dentistry, School of Dentistry, Ohu University School of Dentistry, 31-1 Misumido, Tomita, Koriyama, Fukushima 963-8611, Japan
| | - Atsushi Kamimoto
- Department of Comprehensive Dentistry and Clinical Education, Nihon University School of Dentistry, 1-8-13, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8310, Japan
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M. S. Alqahtani W, A. Yousief S, Tammam R, M. Galal R, Brakat A, Mohamed El Sayed H, Kamal A, Noushad M, Nassani MZ. Biomechanics of Central Incisor Endocrowns with Different Lengths and Milled Materials after Static and Vertical Loading: A Finite Element Study. Int J Dent 2024; 2024:4670728. [PMID: 38585251 PMCID: PMC10999285 DOI: 10.1155/2024/4670728] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2024] [Revised: 03/02/2024] [Accepted: 03/14/2024] [Indexed: 04/09/2024] Open
Abstract
Purpose The aim of this study was to compare and assess the stress distribution and failure possibility of endodontically treated central incisor protected with endocrowns with different heights, with various CAD-CAM blocks such as IPS e.max CAD, Katana Zirconia, and Zolid Fx Zirconia. Materials and Methods A root canal-treated central incisor (plastic model) restored with an endocrown was scanned with a laser scanner to prepare a control model with a CAD software and then transferred to an FEA software. Proposed crown heights were 2, 4, and 6 mm. The model that was duplicated and restored with CAD-CAM blocks, IPS e.max CAD, Katana Zirconia, and Zolid Fx Zirconia were tested as endocrown materials. Bone geometry was simplified to be two coaxial cylinders in all models. Stress distributions under 50 N axial and oblique (with 135° angle from the vertical plane) loading were analyzed. Each model was then subjected to two occlusal loading conditions-the lingual slope of the incisal edge and the junction between incisal and middle thirds. Eighteen runs and calculations were performed to determine the endocrown height and material effect. Results The results showed a minor or negligible effect of changing the endocrown material. Increasing endocrown height was shown to reduce stresses and deformations on most of the model components (bone, gutta-percha, periodontal ligament, and endocrown), except root and cement. Differences in deformations and stresses between the two models of 4 and 6 mm were relatively smaller (ranged between 1% and 30%) compared to those between the 2 and 4 mm models (ranged between 10% and 400%). Conclusions The material used to fabricate endocrowns did not show considerable effect on the underlying structures. However, the endocrown design (2, 4, and 6 mm height) was shown to affect all components of the studied systems. Increasing endocrown height is recommended for bone, periodontal ligaments, and endocrown body, as it reduces stresses and deformations. On the other hand, it dramatically increases stresses on the root and cement layer. Smaller endocrown sizes represent an acceptable treatment option when there is a healthy periodontal state, while using larger sizes will be more suitable when there is a periodontal compromise with bone loss.
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Affiliation(s)
- Waleed M. S. Alqahtani
- Department of Prosthetic Dentistry, College of Dentistry, King Khalid University, Abha, Saudi Arabia
| | - Salah A. Yousief
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh 13313, Saudi Arabia
- Department of Crown and Bridge, Faculty of Oral and Dental Medicine, Al Azhar University, Assuit Branch, Cairo 71524, Egypt
| | - Raafat Tammam
- Department of Prosthodontics, Faculty of Dentistry, Assiut University, Assiut 71515, Egypt
| | - Rami M. Galal
- Department of Fixed and Removable Prosthodontics, National Research Centre, Cairo, Egypt
| | - Ali Brakat
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh 13313, Saudi Arabia
| | - Hend Mohamed El Sayed
- Restorative Dentistry Conservative Dentistry Department, Faculty of Dentistry, Cairo University, 11 EL-Saraya Street Manial, Cairo 11553, Egypt
| | - Ala'a Kamal
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh 13313, Saudi Arabia
| | - Mohammed Noushad
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh 13313, Saudi Arabia
| | - Mohammad Zakaria Nassani
- Department of Restorative and Prosthetic Dental Sciences, College of Dentistry, Dar Al Uloom University, Riyadh 13313, Saudi Arabia
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Zhu J, Li S, Wang D, Li D, Wang X, Rong Q. Effect of remaining pericervical dentin on biomechanical behavior of endocrown-restored molars with different materials: Three-dimensional finite element and Weibull analyses. Dent Mater J 2023; 42:683-691. [PMID: 37612061 DOI: 10.4012/dmj.2023-015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
To evaluate the effect of remaining pericervical dentin (PCD) on the biomechanical behavior of endocrown-restored molars with different materials, six three-dimensional finite element (FE) models were reconstructed with different thicknesses and heights of pulp-chamber lateral dentinal wall (PCLDW). IPS Empress 2, In-Ceram Zirconia, and Lava Ultimate were selected as the materials. Compared with the Lava Ultimate FE models, the maximum tensile stress in the FE models using ceramics was higher in the endocrown and lower in the PCD surrounding it, and the overall failure probabilities with different PCLDW thicknesses and heights were similar, ranging from 9.8% to 12.9% under the normal lateral masticatory force, which were lower than the FE models using Lava Ultimate (ranging from 13.4% to 15.1%). Considering the bonding properties of ceramics, endocrown-restored molars using etchable lithium disilicate-reinforced glass ceramic exhibit superior longevity due to the stress shielding effect, regardless of the thickness and height of PCLDW.
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Affiliation(s)
- Junxin Zhu
- Second Dental Center, Peking University School and Hospital of Stomatology
| | - Shiying Li
- Second Dental Center, Peking University School and Hospital of Stomatology
| | - Dongmei Wang
- Second Dental Center, Peking University School and Hospital of Stomatology
| | - Deli Li
- Second Dental Center, Peking University School and Hospital of Stomatology
| | - Xiaoyan Wang
- Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology
| | - Qiguo Rong
- Department of Mechanics and Engineering Science, College of Engineering, Peking University
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Capobianco V, Baroudi K, Santos MJMC, Rubo JH, Rizkalla AS, Dal Piva AMDO, Vitti RP, Tribst JPM, Santos GC. Post-fatigue fracture load, stress concentration and mechanical properties of feldspathic, leucite- and lithium disilicate-reinforced glass ceramics. Heliyon 2023; 9:e17787. [PMID: 37449193 PMCID: PMC10336509 DOI: 10.1016/j.heliyon.2023.e17787] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 06/09/2023] [Accepted: 06/28/2023] [Indexed: 07/18/2023] Open
Abstract
Objective To evaluate the mechanical properties of different CAD/CAM ceramic systems and the post-fatigue fracture and stress distribution when used as cemented crowns. Materials and methods Sixty (60) CAD/CAM monolithic crowns were milled using three different ceramic materials (FD - Feldspathic [Vita Mark II]), LE - Leucite-based ceramic [IPS Empress CAD] and LD - Lithium Disilicate [IPS e.max CAD]) and adhesively cemented on resin composite dyes. Specimens were stored in distillated water (37 °C) for 7 days. After, half of the crowns were submitted to immediate fracture load test while the other half was submitted to fatigue cycling. The average cement layer of approximately 80 μm was assessed using scanning electron microscopy (SEM). The average thickness was used in the three-dimensional (3D) Finite Element Analysis (FEA). For each ceramic material, the density, Poisson ratio, shear modulus, Young modulus, fracture toughness, and true hardness were assessed (n = 3). The data was used to assess the Maximum Principal Stress throughout 3D-FEA according to each material during load to fail and post-fatigue. Data were submitted to two-way ANOVA and Tukey test (α = 0.05). Results LD showed the highest compression load, density, shear modulus, Young modulus, fracture toughness and true hardness values. While LE presented the lowest mechanical properties values. There is no difference in the Poisson ratio between the evaluated ceramics. Conclusion LD was susceptible to aging process but presented stronger physicomechanical properties, showing the highest post-fatigue fracture load and highest stress magnitude.
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Affiliation(s)
| | - Kusai Baroudi
- RAK College of Dental Sciences, RAK Medical & Health Sciences University, RAS Al Khaimah, United Arab Emirates
- School of Dentistry, University of Taubaté, Taubaté, SP, Brazil
| | | | | | - Amin S. Rizkalla
- Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
| | - Amanda Maria de Oliveira Dal Piva
- Department of Dental Materials, Academic Centre for Dentistry Amsterdam (ACTA),Universiteit van Amsterdam en Vrije Universiteit, Amsterdam, the Netherlands
| | - Rafael Pino Vitti
- School of Dentistry, Herminio Ometto University Center, Araras, SP, Brazil
| | - João Paulo Mendes Tribst
- Department of Reconstructive Oral Care, Academic Centre for Dentistry Amsterdam (ACTA),Universiteit van Amsterdam en Vrije Universiteit, Amsterdam, the Netherlands
| | - Gildo Coelho Santos
- Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON, Canada
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Lithium Disilicate Ceramic Endocrown Biomechanical Response According to Different Pulp Chamber Extension Angles and Filling Materials. MATERIALS 2021; 14:ma14051307. [PMID: 33803194 PMCID: PMC7963147 DOI: 10.3390/ma14051307] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 03/02/2021] [Accepted: 03/04/2021] [Indexed: 12/28/2022]
Abstract
The purpose of this study is to evaluate the effect of pulp chamber extension angles and filling material mechanical properties on the biomechanical response of a ceramic endocrown. A 3D model of maxillary molar that underwent endodontically treatment was exported to computer aided design software to conduct finite element analysis (FEA). The endocrown model was modified considering different pulp chamber extension angles (right angle; 6°, 12° and 18° of axial divergence). The solids were imported into the computer aided engineering software in Standard for the Exchange of Product Data (STEP) format. Nine different filling materials were simulated to seal the orifice of the root canal system under each endocrown restoration (resin composite, bulk-fill resin composite, alkasite, flowable resin composite, glass ionomer cement, autocured resin-reinforced glass ionomer cement, resin cement, bulk-fill flowable resin composite, zinc oxide cement), totaling 36 models. An axial load (300 N) was applied at the occlusal surface. Results were determined by colorimetric graphs of von-Misses stress (VMS) and Maximum Principal Stress (MPS) on tooth, cement layer, and endocrown restorations. VMS distribution showed a similar pattern between the models, with more stress at the load region for the right-angled endocrowns. The MPS showed that the endocrown intaglio surface and cement layer showed different mechanical responses with different filing materials and pulp chamber angles. The stress peaks plotted in the dispersion plot showed that the filling material stiffness is proportional to the stress magnitude in the endocrown, cement layer and tooth adhesive surface. In addition, the higher the pulp chamber preparation angle, the higher the stress peak in the restoration and tooth, and the lower the stress in the cement layer. Therefore, 6° and 12° pulp chamber angles showed more promising balance between the stresses of the adhesive interface structures. Under the conditions of this study, rigid filling materials were avoided to seal the orifice of root canal system when an endocrown restoration was planned as rehabilitation. In addition, the pulp chamber axial walls were prepared between 6° and 12° of divergence to balance the stress magnitude in the adhesive interface for this treatment modality.
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Tribst JPM, Borges ALS, Silva-Concílio LR, Bottino MA, Özcan M. Effect of Restorative Material on Mechanical Response of Provisional Endocrowns: A 3D-FEA Study. MATERIALS 2021; 14:ma14030649. [PMID: 33572533 PMCID: PMC7866804 DOI: 10.3390/ma14030649] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 01/22/2021] [Accepted: 01/26/2021] [Indexed: 12/14/2022]
Abstract
The goal of this study was to evaluate the stress distribution in an endocrown restoration according to different provisional restorative materials. An endodontically treated maxillary molar model was selected for conducting the finite element analysis (FEA), with a determined amount of dental remnant of 1.5 mm. The model was imported to the analysis software (ANSYS 19.2, ANSYS Inc., Houston, TX, USA) in STEP format. All contacts were considered perfectly bonded. The mechanical properties of each structure were considered isotropic, linear, elastic, and homogeneous. Three different provisional restorative materials were simulated (acrylic resin, bis-acrylic resin, and resin composite). An axial load (300 N) was applied at the occlusal surface in the center of the restoration. Results were determined by colorimetric stress maps of maximum principal stress, maximum shear stress, and total deformation. The different materials influenced the stress distribution for all structures; the higher the material’s elastic modulus, the lower the stress magnitude on the cement layer. In the present study, all provisional restorative materials showed similar stress patterns in the endocrown and on the cement layer however, with different magnitude. Based on this study limitation, the use of resin composite to manufacture provisional endocrowns is suggested as a promising material to reduce the stresses in the cement layer and in the dental tissue surfaces.
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Affiliation(s)
- João Paulo Mendes Tribst
- School of Dentistry, University of Taubaté, Taubaté, São Paulo 12020-340, Brazil; (J.P.M.T.); (L.R.S.-C.)
| | - Alexandre Luiz Souto Borges
- Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos, São Paulo 12220-690, Brazil; (A.L.S.B.); (M.A.B.)
| | | | - Marco Antonio Bottino
- Institute of Science and Technology, São Paulo State University (Unesp), São José dos Campos, São Paulo 12220-690, Brazil; (A.L.S.B.); (M.A.B.)
| | - Mutlu Özcan
- Division of Dental Biomaterials, Center for Dental and Oral Medicine, Clinic for Reconstructive Dentistry, University of Zurich, 8032 Zurich, Switzerland
- Correspondence:
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Lin J, Lin Z, Zheng Z. Effect of different restorative crown design and materials on stress distribution in endodontically treated molars: a finite element analysis study. BMC Oral Health 2020; 20:226. [PMID: 32811484 PMCID: PMC7437004 DOI: 10.1186/s12903-020-01214-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 08/10/2020] [Indexed: 11/23/2022] Open
Abstract
Background The purposes of this simulation study were to evaluate the stresses in the roots of endodontically treated molars with extensive coronal tissue loss which were restored by endocrowns (all-in-one core and crown) and traditional crowns with post-cores, during masticatory simulation using finite element analysis. Methods A mesio-distal cross-section of a lower right first molar was digitized and used to create 2-dimensional models of the teeth and supporting tissue; different crown designs, viz., endocrown with 2 mm occlusal clearance, endocrown with 4 mm occlusal clearance and post-core crown; different crown materials, viz., zirconia (Zr) and lithia-disilicate reinforced glass ceramic (LDRGC), and different post and core materials, viz., glass fiber (GF), stainless steel (SS) and metal cast (MC). An axial load of 600 N was applied to the central fossa of occlusal surface. Results The stress distributions were similar between Zr and LDRGC for periodontal ligament and alveolar bone. The root canal inner wall maximum principal stresses of SS post (70.8 MPa) and MC post (71.4 MPa) were higher than that of GF post (36.0 MPa) and endocrown (2.4 MPa). Conclusion The endocrowns reduced stress concentration for the root canal inner wall in comparison with the conventional post-core crown. Molars restored with endocrowns are less prone to root fracture than those with posts.
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Affiliation(s)
- Jie Lin
- Fujian Key Laboratory of Oral Diseases, School and Hospital of Stomatology, Fujian Medical University, 246 Yangqiao Zhong Road, Fuzhou, Fujian, 350002, People's Republic of China.,Department of Crown and Bridge, School of Life Dentistry at Tokyo, The Nippon Dental University, 1-9-20 Fujimi, Chiyoda-ku, Tokyo, 102-8159, Japan
| | - Zhenxiang Lin
- Department of Stomatology, Hospital of Fujian Provincial Authorities, 68 Guping Road, Fuzhou, Fujian, 350001, People's Republic of China
| | - Zhiqiang Zheng
- Fujian Key Laboratory of Oral Diseases, School and Hospital of Stomatology, Fujian Medical University, 246 Yangqiao Zhong Road, Fuzhou, Fujian, 350002, People's Republic of China.
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