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Elraggal A, Abdelraheem IM, Watts DC, Roy S, Dommeti VK, Alshabib A, Althaqafi KA, Afifi RR. Biomechanical reinforcement by CAD-CAM materials affects stress distributions of posterior composite bridges: 3D finite element analysis. Dent Mater 2024; 40:869-877. [PMID: 38609774 DOI: 10.1016/j.dental.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/28/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024]
Abstract
OBJECTIVES This 3D finite element analysis study aimed to investigate the effect of reinforcing CAD-CAM bars on stress distribution in various components of a posterior composite bridge. METHODS A virtual model mimicking the absence of an upper second premolar was created, featuring class II cavity preparations on the proximal surfaces of the adjacent abutment teeth surrounding the edentulous space. Five distinct finite element analysis (FEA) models were generated, each representing a CAD-CAM reinforcing bar material: 3-YTZP (IPS. emax ZirCAD MO; Zr), lithium disilicate (IPS e.max CAD; EX), nano-hybrid resin composite (Grandio Blocs; GB), Fibre-reinforced composite (Trilor; Tri), and polyetheretherketone (PEEK). A veneering resin composite was employed to simulate the replacement of the missing premolar (pontic). In the FEA, an axial force of 600 N and a transverse load of 20 N were applied at the center of the pontic. Subsequently, maximum von Mises (mvM) and maximum principal stresses (σmax) were computed across various components of the generated models. Additionally, shear stresses at the interface between the CAD-CAM bars and the veneering resin composite were determined. RESULTS CAD-CAM materials with high modulus of elasticity, such as Zr and EX, exhibited the highest mvM stresses and shear stresses while transferring the lowest stress to the veneering resin composite in comparison to other materials. Conversely, PEEK demonstrated the lowest mvM stresses but produced the highest stresses within the veneering resin composite. There was a uniform distribution of mvM stresses in the remaining tooth structure among all groups, except for a noticeable elevation in the molar region of Zr and EX groups. SIGNIFICANCE Reinforcing CAD-CAM bar materials with a high modulus of elasticity, such as Zr and EX, may result in debonding failures at the connector sites of posterior composite bridges. Conversely, GB, PEEK, and Tri have the potential to cause fracture failures at the connectors rather than debonding.
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Affiliation(s)
- Alaaeldin Elraggal
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
| | - Islam M Abdelraheem
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - David C Watts
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Sandipan Roy
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Vamsi Krishna Dommeti
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Abdulrahman Alshabib
- Restorative Dentistry Department, Faculty of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Khaled Abid Althaqafi
- Restorative Dentistry Department, Faculty of Dentistry, College of Dental Medicine, University of Umm Al Qura, Makkah, Saudi Arabia
| | - Rania R Afifi
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
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Neri H, Aripin D, Muryani A, Dharsono HDA, Yolanda Y, Mahyuddin AI. Stress Analysis on Mesiolingual Cavity of Endodontically Treated Molar Restored Using Bidirectional Fiber-Reinforced Composite (Wallpapering Technique). Clin Cosmet Investig Dent 2024; 16:75-89. [PMID: 38632981 PMCID: PMC11022878 DOI: 10.2147/ccide.s450325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2023] [Accepted: 03/27/2024] [Indexed: 04/19/2024] Open
Abstract
Introduction Endodontically treated teeth (ETT) undergo extensive structure change and experience high stress during biomechanical function. Stress distribution is influenced by the restoration material and the type of bond between material and tooth structure. The selection of materials that can distribute stress will affect the resistance and retention of ETT to mastication forces, thus biomechanical functions were achieved. Composite has mechanical properties similar to dentin, it can transmit and distribute stresses throughout the tooth surface. The disadvantage of composites in large cavities is their lack of toughness. The addition of fiber to composites can increase their toughness. Purpose This research is to determine the stress distribution of a fiber-reinforced composite made of polyethylene and e-glass on the mesiolingual cavity of ETT. Materials and Methods A three-dimensional model of the mandibular molar was prepared for cavity preparation and the formation of restorations using SolidWorks 2021. The models were analyzed with Abaqus 2020 to determine stress concentrations after given vertical and oblique loading. Results The maximum and minimum principal stress data were obtained to assess material resistance and interfacial damage criterion. Polyethylene fiber shows a more homogeneous stress distribution because the modulus of elasticity is close to the dentin and has a thickness that can reduce the volume of the composite. The E-glass shows the stress concentration on the circumferential fiber and cavity floor. Conclusion The stress distribution of fiber-reinforced composite on the buccolingual cavity of ETT using the finite element method did not show structural failure in the polyethylene group because the maximum and minimum principal stresses were lower than the strength of the material. Interfacial bond failure occurs at the enamel portion. The maximum and minimum principal values of e-glass indicate structural failure in the circumferential fiber and the base fiber because the stress exceeds the strength of the material. Interfacial bond failure occurred on the circumferential and the cavity floor.
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Affiliation(s)
- Harnia Neri
- Department of Conservative Dentistry, Faculty of Dentistry, Universitas Padjadjaran, Bandung, Indonesia
| | - Dudi Aripin
- Department of Conservative Dentistry, Faculty of Dentistry, Universitas Padjadjaran, Bandung, Indonesia
| | - Anna Muryani
- Department of Conservative Dentistry, Faculty of Dentistry, Universitas Padjadjaran, Bandung, Indonesia
| | | | - Yolanda Yolanda
- Department of Conservative Dentistry, Faculty of Dentistry, Universitas Padjadjaran, Bandung, Indonesia
| | - Andi Isra Mahyuddin
- Faculty of Mechanical and Aerospace Engineering, Bandung Institute of Technology, Bandung, Indonesia
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Abdelhady WA, Metwally MF, Haggag KM. Effect of thermomechanical loading on fracture resistance and failure mode of new pressable zirconia-reinforced lithium disilicate onlay restoration. J Dent Res Dent Clin Dent Prospects 2024; 18:29-36. [PMID: 38881646 PMCID: PMC11179138 DOI: 10.34172/joddd.40843] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Accepted: 01/29/2024] [Indexed: 06/18/2024] Open
Abstract
Background Insufficient information exists regarding the fracture resistance and failure pattern of newly developed zirconia-reinforced lithium disilicate (ZL, Vita Ambria) onlays. This in vitro study compared the fracture resistance of two types of onlays: monolithic lithium disilicate (LD) and monolithic ZL. Methods Forty-eight ceramic onlay restorations were fabricated on epoxy dies using a maxillary first premolar model. The samples were divided into two main groups: LD and ZL. Half of each group was subjected to thermomechanical fatigue loading (TML) using a chewing simulator. All the samples were cemented with self-adhesive resin cement. Subsequently, they were loaded until failure in a universal testing machine, and the fracture patterns and resistance were recorded. Results Before TML, ZL demonstrated the highest statistically significant mean fracture resistance (499.76±34.14N) compared to LD (470.40±27.38N). After TML, ZL showed the highest non-statistically significant mean fracture resistance (429.27±131.42N), while LD's mean fracture resistance decreased (377.31±62.18N). Conclusion Monolithic zirconia-reinforced onlays demonstrated higher fracture resistance and a more favorable failure mode compared to LD. However, the impact of thermomechanical aging resulted in reduced fracture resistance for both materials, with a notable preference observed for ZL.
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Affiliation(s)
- Walid A Abdelhady
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
| | - Mohamed F Metwally
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
| | - Khaled M Haggag
- Crown and Bridge Department, Faculty of Dental Medicine, Al Azhar University, Cairo, Egypt
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Guler MS. Low and high viscosity bulk-fill composite resins stress distribution in primary molar tooth inlay cavity. Comput Methods Biomech Biomed Engin 2024; 27:411-418. [PMID: 37216569 DOI: 10.1080/10255842.2023.2215370] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/08/2023] [Accepted: 05/12/2023] [Indexed: 05/24/2023]
Abstract
The aim of this study is to evaluate the stress distributions of low and high viscosity bulk-fill composite resins at class II MOD inlay cavity in primary molar tooth using Finite Element Analysis (FEA). Original DICOM data of a primary molar tooth from a research archive was used to create a 3D model. Two models were prepared as Model 1: the tooth model without restoration (control group) and Model 2: the tooth model with class II MOD inlay restoration. Two different bulk-fill composite resins were tested in study: Model 2 A (class II MOD inlay cavity model restored with low viscosity bulk-fill composite resin) and Model 2B (class II MOD inlay cavity model restored with high viscosity bulk-fill composite resin). Occlusal vertical loading of 232 N was applied to the teeth in occlusal contact areas. Maximum Von Mises stress values in the models for enamel, dentin, and restorative material were evaluated as MPa. More intense stress accumulation is observed in enamel than in dentin. In addition, more stress values were determined in Model 2B (206.15 MPa, 32.76 MPa, 128.95 MPa) than in Model 2 A (203.39 MPa, 29.77 MPa, 120.61 MPa) for enamel, dentin and restorative material, respectively.
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Affiliation(s)
- Mehmet Sami Guler
- Department of Machinery and Metal Technologies, Vocational School of Technical Sciences, Ordu University, Ordu, Turkey
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Kirmali Ö, Icen G, Kursat Celik H, Rennie AE. Evaluation of stress distribution on an endodontically treated maxillary central tooth with lesion restored with different crown materials: A finite element analysis. Heliyon 2024; 10:e25829. [PMID: 38356502 PMCID: PMC10865034 DOI: 10.1016/j.heliyon.2024.e25829] [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: 06/01/2023] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 02/16/2024] Open
Abstract
Objectives The biomechanical response of teeth with periapical lesions that have been restored using various substructure materials, as well as the stress mapping in the alveolar bone, has not been thoroughly described. In this context, the objective of this study is to investigate the structural stress distributions on root canal-treated maxillary right central incisors with lesions restored using different crown materials under linear static loading conditions through finite element analysis (FEA). Methods In the study, five FEA models were utilised to represent healthy teeth and teeth restored with different substructure materials: (A) a healthy tooth, (B) a lesioned, root canal-treated, composite-filled tooth, (C) a lesioned, fiber-posted, zirconia-based crown, (D) a tooth with lesions, a fiber post, and Ni-Cr infrastructure crown, (E) a tooth with a lesion, a fiber post, and an IPS E-max infrastructure crown. A force of 100 N was applied at an angle of 45° to the long axis of the tooth from 2 mm cervical to the incisal line on the palatal surface. Deformation behaviour and maximum equivalent stress distributions on the tooth sub-components, including the bony structure for each model, were simulated. Results Differences were observed in the stress distributions of the models. The maximum stress values of the models representing the restorations with different infrastructures varied, and the highest value was obtained in the model of the E-max crown (Model E: 136.050 MPa). The minimum stress magnitudes were obtained from Model B the composite-filled tooth (80.39 MPa); however, it was observed that the equivalent stresses in all the models showed a similar distribution for all components with varying magnitudes. In periapical lesion areas, low stresses were observed. In all models, the cervicobuccal collar region of the teeth had dense equivalent stresses. Conclusion Different restorative treatment methods applied to root canal-treated teeth with periapical lesions can impact the stress in the alveolar bone and the biomechanical response of the tooth. Relatively high stress values in the cortical bone at the cervical line of the tooth have been observed to decrease towards the apical region. This observation may suggest a potential healing effect by reducing pressure in the periapical lesion area. Clinical significance Composite resin restorations can be considered the first-choice treatment option for the restoration of root canal-treated teeth with lesions. In crown restorations, it would be advantageous to prefer zirconia or metal-supported prostheses in terms of biomechanics.
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Affiliation(s)
- Ömer Kirmali
- Department of Prosthodontics, Faculty of Dentistry, Akdeniz University, Antalya, Turkey
| | - Gülsah Icen
- Department of Prosthodontics, Faculty of Dentistry, Akdeniz University, Antalya, Turkey
| | - H. Kursat Celik
- Dept. of Agr. Machinery and Technology Engineering, Akdeniz University, Antalya, Turkey
| | - Allan E.W. Rennie
- School of Engineering, Lancaster University, Lancaster, United Kingdom
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AboElhassan RG, Watts DC, Alamoush RA, Elraggal A. Biomechanical behavior and Weibull survival of CAD-CAM endocrowns with different marginal designs: A 3D finite element analysis. Dent Mater 2024; 40:227-235. [PMID: 37977990 DOI: 10.1016/j.dental.2023.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/04/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023]
Abstract
OBJECTIVES To evaluate and compare the effect of tooth preparation designs and different CADCAM. materials on stress distribution and Weibull survival probability of endocrowns. applied to root canal-treated lower first permanent molar using the 3D finite element. analysis method. METHODS A root canal-treated lower first permanent molar was prepared for endocrowns with a. butt joint or with a ferrule design by placing, circumferentially, a 1-mm wide shoulder. finish line. The prepared molar was scanned for the two designs and modeled on a 3D. Finite element model. Monolithic zirconia (IPS e.max ZirCAD MT, FCZ), lithium. disilicate (IPS e.max CAD, EX), and nano-ceramic resin composite (Lava Ultimate, LU). CAD-CAM materials were used for each preparation to design the virtual endocrown. A. total of six models were built according to the different tooth preparation designs and. endocrown materials. An occlusal load of 600 N and a transverse load of 20 N in. magnitude that simulates the average occlusal load was directed toward the occlusal. surfaces. von Mises and maximum principle values were evaluated Weibull risk-ofrupture. analysis was used to analyze the survival probability of the restorations and. tooth in the different models. RESULTS The highest von Mises were found in the butt joint design for FCZ, EX, and LU (45.3. MPa, 35.2 MPa, and 24.2 MPa, respectively) compared to the ferrule design for the. same materials (42.6 MPa, 31.2 MPa, and 23.6 MPa, respectively). For von Mises. stress distribution in the remaining part of tooth structure (dentin), the highest stresses. were found in LUFerrule which was closely similar to LUButt joint (135.4 MPa and. 134.7 MPa, respectively), followed by EXFerrule and FCZFerrule (132.2 MPa and. 131.7 MPa, respectively), while the lowest stresses were found in EXButt joint and. FCZButt joint (129.0 MPa and 128.4 MPa, respectively). Shear stresses within the. resin cement were the highest in FCZ and EX compared to LU. EX was found to be the. most reliable material with the highest survival probability, while FCZ showed the. lowest survival probability according to the Weibull risk-of-fracture results. SIGNIFICANCE Materials with high elastic modulus transfer more stresses to the endocrown and less. to the remaining tooth structure. Endocrown tooth preparation with ferrule design has. better stress distribution and magnitude compared to the butt joint design.
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Affiliation(s)
- Rewaa G AboElhassan
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - David C Watts
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Rasha A Alamoush
- Department of Fixed and Removable Prosthodontics, School of Dentistry, the University of Jordan, Amman, Jordan
| | - Alaaeldin Elraggal
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt; Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
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Çoban Öksüzer M, Şanal Çıkman A. Evaluation of Fracture Strength after Repair of Cervical External Resorption Cavities with Different Materials. J Endod 2024; 50:85-95. [PMID: 37879603 DOI: 10.1016/j.joen.2023.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Revised: 10/07/2023] [Accepted: 10/16/2023] [Indexed: 10/27/2023]
Abstract
INTRODUCTION The aim was to evaluate the stress distributions on dentin and repair materials caused by static force applied to teeth, with cervical external root resorption (CER) after repair with different materials using finite element analysis. METHODS This study was performed with the 3-dimensional finite element analysis method. Access cavity, root canal cavity dimensions, and supporting tissues other than cementum were modeled in the maxillary central tooth. The CER cavity was created on the labial side of the tooth model. The coronal side of the resorption cavity was restored with composite, and the radicular side with different materials (MTA, Biodentine, BioAggregate, calcium-enriched cement [CEM], glass ionomer cement [GIC], and resin-modified glass ionomer cement [RMGIC]). A static force of 300 N was applied to the palatal surface of the crown at an angle of 135° to the long axis of the tooth. The stress distributions in dentin and repair materials were analyzed. RESULTS The highest stress in dentin was seen in the fFigmodel with unrepaired CER. In the models repaired with MTA, GIC, and RMGIC, von Mises stress values in dentin were greater than for repairs with Biodentine, BioAggregate, and CEM materials. The von Mises stress on the repair materials applied to the root were highest for the BioAggregate material. This was followed by CEM, Biodentine, MTA, RMGIC, and GIC materials, respectively. CONCLUSION The repair of CER in the tooth significantly decreased the stress values in dentin. Biodentine, BioAggregate, and CEM absorbed more force and caused less stress to be transmitted to dentin compared to MTA, GIC, and RMGIC.
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Affiliation(s)
- Merve Çoban Öksüzer
- Department of Endodontics, Faculty of Dentistry, Recep Tayyip Erdoğan University, Rize, Türkiye.
| | - Ahter Şanal Çıkman
- Department of Endodontics, Faculty of Dentistry, Recep Tayyip Erdoğan University, Rize, Türkiye
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Lempel E, Gyulai S, Lovász BV, Jeges S, Szalma J. Clinical evaluation of lithium disilicate versus indirect resin composite partial posterior restorations - A 7.8-year retrospective study. Dent Mater 2023; 39:1095-1104. [PMID: 37821330 DOI: 10.1016/j.dental.2023.10.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2023] [Revised: 09/26/2023] [Accepted: 10/07/2023] [Indexed: 10/13/2023]
Abstract
OBJECTIVE To evaluate retrospectively the longevity of lithium disilicate ceramic (LidiSi) vs. laboratory-processed resin-based composite (RBC) inlay/onlay/overlay restorations and risk factors associated with restoration deficiencies and failures. METHODS Patients (n = 91) receiving LidiSi (73.1%) and RBC (36.9%) inlays/onlays/overlays between 2007 and 2017 were selected. The restorations were evaluated using the modified U.S. Public Health Service criteria. The survival of the restorations was analyzed using the Kaplan-Meier method and log rank test. Factors affecting the occurrence of deficiencies were examined by logistic regression analysis. This was performed with the use of the Generalized Estimating Equation model including Repeated measurements (GEER), with the consideration that the same patient had several teeth in the sample. Risk estimation was conducted for each evaluated criterion (p < 0.05). RESULTS The survival of LidiSi and RBC restorations were 96.8% and 84.9%, respectively after a mean observation period of 7.8 ± 3.3 years. The annual failure rate was 0.2% for LidiSi and 1.0% for RBC. The probability of survival was above 98% for both restorations in the first 6 years, however, it dropped to 60% for RBC by the end of the 15th year. For both materials the reasons for failure included secondary caries, restoration fracture, and endodontic complication. In addition, LidiSi also failed due to tooth fracture, while RBC due to marginal gap formation and loss of retention. Among the evaluated risk factors, material of restoration (OR=6.8, CI95%:3.1-14.9), oral hygiene (OR=8.0, CI95%: 2.9-22.1], and bruxism (OR=1.9, CI95%: 1.1-3.3) showed a significant impact on the evaluated criteria. SIGNIFICANCE LidiSi and RBC restorations showed similarly excellent 6-year survival, however, in the long term significantly more failures should be expected for RBCs.
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Affiliation(s)
- Edina Lempel
- Department of Restorative Dentistry and Periodontology, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary.
| | - Sarolta Gyulai
- Department of Restorative Dentistry and Periodontology, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary; Department of Oral and Maxillofacial Surgery, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary
| | - Bálint Viktor Lovász
- Oral and Maxillofacial Department, Manchester University Foundation Trust, Manchester Royal Infirmary Hospital, Oxford Rd, Manchester M13 9WL, United Kingdom
| | - Sára Jeges
- Faculty of Health Sciences, University of Pécs, Vörösmarty M. Street 4, Pécs 7621, Hungary
| | - József Szalma
- Department of Oral and Maxillofacial Surgery, University of Pécs Medical School, Tüzér Street 1, Pécs 7623, Hungary
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Soares PM, da Rosa LS, Pereira GKR, Valandro LF, Rippe MP, Dal Piva AMDO, Feilzer AJ, Kleverlaan CJ, Tribst JPM. Mechanical Behavior of Repaired Monolithic Crowns: A 3D Finite Element Analysis. Dent J (Basel) 2023; 11:254. [PMID: 37999018 PMCID: PMC10670502 DOI: 10.3390/dj11110254] [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: 09/20/2023] [Revised: 10/20/2023] [Accepted: 10/26/2023] [Indexed: 11/25/2023] Open
Abstract
This study evaluated the mechanical behavior and risk of failure of three CAD-CAM crowns repaired with different resin composites through a three-dimensional (3D) finite element analysis. Three-dimensional models of different cusp-repaired (conventional nanohybrid, bulk-fill, and flowable resin composites) crowns made of zirconia, lithium disilicate, and CAD-CAM resin composite were designed, fixed at the cervical level, and loaded in 100 N at the working cusps, including the repaired one. The models were analyzed to determine the Maximum Principal and Maximum Shear stresses (MPa). Complementary, an in vitro shear bond strength test (n = 10) was performed to calculate the risk of failure for each experimental group. The stress distribution among the models was similar when considering the same restorative material. The crown material affected the stress concentration, which was higher for the ceramic models (±9 MPa for shear stress; ±3 MPa for tensile stress) than for the CAD-CAM composite (±7 MPa for shear stress; ±2 MPa for tensile stress). The shear bond strength was higher for the repaired CAD-CAM resin composite (±17 MPa) when compared to the ceramics (below 12 MPa for all groups), while the repair materials showed similar behavior for each substrate. The stress distribution is more homogenous for repaired resin composite crowns, and a flowable direct resin composite seems suitable to repair ceramic crowns with less risk of failure.
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Affiliation(s)
- Pablo Machado Soares
- Post-Graduate Program in Oral Sciences, Center for Development of Advanced Materials, Division of Prosthodontics-Biomaterials, Federal University of Santa Maria (UFSM), Santa Maria 97105-900, Brazil (L.S.d.R.); (G.K.R.P.)
| | - Lucas Saldanha da Rosa
- Post-Graduate Program in Oral Sciences, Center for Development of Advanced Materials, Division of Prosthodontics-Biomaterials, Federal University of Santa Maria (UFSM), Santa Maria 97105-900, Brazil (L.S.d.R.); (G.K.R.P.)
| | - Gabriel Kalil Rocha Pereira
- Post-Graduate Program in Oral Sciences, Center for Development of Advanced Materials, Division of Prosthodontics-Biomaterials, Federal University of Santa Maria (UFSM), Santa Maria 97105-900, Brazil (L.S.d.R.); (G.K.R.P.)
| | - Luiz Felipe Valandro
- Post-Graduate Program in Oral Sciences, Center for Development of Advanced Materials, Division of Prosthodontics-Biomaterials, Federal University of Santa Maria (UFSM), Santa Maria 97105-900, Brazil (L.S.d.R.); (G.K.R.P.)
| | - Marilia Pivetta Rippe
- Post-Graduate Program in Oral Sciences, Center for Development of Advanced Materials, Division of Prosthodontics-Biomaterials, Federal University of Santa Maria (UFSM), Santa Maria 97105-900, Brazil (L.S.d.R.); (G.K.R.P.)
| | - Amanda Maria de Oliveira Dal Piva
- Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit Amsterdam, 1081 LA Amsterdam, The Netherlands; (A.M.d.O.D.P.)
| | - Albert J. Feilzer
- Department of Reconstructive Oral Care, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit Amsterdam, 1081 LA Amsterdam, The Netherlands;
| | - Cornelis J. Kleverlaan
- Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit Amsterdam, 1081 LA Amsterdam, The Netherlands; (A.M.d.O.D.P.)
| | - João Paulo Mendes Tribst
- Department of Reconstructive Oral Care, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit Amsterdam, 1081 LA Amsterdam, The Netherlands;
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Hofsteenge JW, Carvalho MA, Borghans PM, Cune MS, Özcan M, Magne P, Gresnigt MMM. Effect of preparation design on fracture strength of compromised molars restored with lithium disilicate inlay and overlay restorations: An in vitro and in silico study. J Mech Behav Biomed Mater 2023; 146:106096. [PMID: 37659167 DOI: 10.1016/j.jmbbm.2023.106096] [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: 06/08/2023] [Revised: 08/24/2023] [Accepted: 08/28/2023] [Indexed: 09/04/2023]
Abstract
PURPOSE The objective of this study was to determine the influence of different preparation designs on the fracture strength, failure type, repairability, formation of polymerization-induced cracks, and tooth deformation of structurally compromised molars restored with lithium disilicate inlays and overlays in combination with Immediate Dentin Sealing (IDS). MATERIAL AND METHODS Human molars (N = 64) were randomly assigned to four different preparation designs: Undermined Inlay (UI), Extended Inlay (EI), Restricted Overlay (RO), and Extended Overlay (EO). The teeth were restored using lithium disilicate partial restorations and subjected to thermomechanical fatigue in a chewing simulator (1,2 × 10 (Mondelli et al., 2007) cycles on 50 N, 8000x 5-55 °C), followed by load to failure testing. In silico finite element analysis was conducted to assess tooth deformation. Polymerization-induced cracks were evaluated using optical microscopy and transillumination. Fracture strengths were statistically analyzed using a Kruskal-Wallis test, while the failure mode, repairability, and polymerization cracks were analyzed using Fisher exact test. RESULTS The propagation of polymerization-induced cracks did not significantly differ among preparation designs. All specimens withstood chewing simulator fatigue, with no visible cracks in teeth or restorations. Fracture strength was significantly influenced by preparation design, with restricted overlay (RO) showing higher fracture strength compared to extended inlay (EI) (p = .042). Tooth deformation and fracture resistance correlated between in vitro and in silico analyses). UI exhibited a statistically less destructive failure pattern than EO (p < .01) and RO (p = .036). No statistically significant influence of the preparation design on repairability was observed. Groups with higher repairability rates experienced increased tooth deformation, leading to less catastrophic failures. CONCLUSIONS The preparation design affected the fracture strength of compromised molars restored with lithium disilicate inlays and overlays, with significantly lower fracture strength for an extended inlay. The failure pattern of lithium disilicate overlays is significantly more destructive than that of undermined and extended inlays. The finite element analysis showed more tooth deformation in the inlay restorations, with lower forces in the roots, leading to less destructive fractures. Since cusp coverage restorations fracture in a more destructive manner, this study suggests the undermined inlay preparation design as a viable option for restoring weakened cusps.
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Affiliation(s)
- Jelte W Hofsteenge
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands.
| | | | - Pauline M Borghans
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands
| | - Marco S Cune
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands; St. Antonius Hospital Nieuwegein, Department of Oral-Maxillofacial Surgery, Prosthodontics and Special Dental Care, Nieuwegein, the Netherlands
| | - Mutlu Özcan
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands; University of Zurich, Center of Dental Medicine, Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, Zurich, Switzerland
| | - Pascal Magne
- Center for Education and Research in Biomimetic Restorative Dentistry (CER BRD), Beverly Hills, CA, USA
| | - Marco M M Gresnigt
- University of Groningen, University Medical Center Groningen, Center for Dentistry and Oral Hygiene, Department of Restorative Dentistry, Groningen, the Netherlands; Martini Hospital, Department of Special Dental Care, Groningen, the Netherlands
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Gönder HY, Mohammadi R, Harmankaya A, Yüksel İB, Fidancıoğlu YD, Karabekiroğlu S. Teeth Restored with Bulk–Fill Composites and Conventional Resin Composites; Investigation of Stress Distribution and Fracture Lifespan on Enamel, Dentin, and Restorative Materials via Three-Dimensional Finite Element Analysis. Polymers (Basel) 2023; 15:polym15071637. [PMID: 37050251 PMCID: PMC10096709 DOI: 10.3390/polym15071637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 03/21/2023] [Accepted: 03/24/2023] [Indexed: 03/29/2023] Open
Abstract
Objectives: the aim of this study was to examine the stress distribution of enamel, dentin, and restorative materials in sound first molar teeth with restored cavities with conventional resin composites and bulk–fill composites, as well as to determine their fracture lifetimes by using the three-dimensional finite element stress analysis method. Materials and Methods: an extracted sound number 26 tooth was scanned with a dental tomography device and recorded. Images were obtained as dicom files, and these files were transferred to the Mimics 12.00 program. In this program, different masks were created for each tooth tissue, and the density thresholds were adjusted manually to create a three-dimensional image of the tooth, and these were converted to a STL file. The obtained STL files were transferred to the Geomagic Design X program, and some necessary adjustments, such as smoothing, were made, and STP files were created. Cavity preparation and adhesive material layers were created by transferring STP files to the Solidworks program. Finally, a FE model was created in the ABAQUS program, and stress distributions were analyzed. Results: when the bulk–fill composite and conventional resin composite materials were used in the restoration of the cavity, the structures that were exposed to the most stress as a result of occlusal forces on the tooth were enamel, dentin, restorative material, and adhesive material. When the bulk–fill composite material was used in restoration, while the restorative material had the longest fracture life as a result of stresses, the enamel tissue had the shortest fracture life. When the conventional resin composite material was used as the restorative material, it had the longest fracture life, followed by dentin and enamel. Conclusion: when the bulk–fill composite material was used instead of the conventional resin composite material in the cavity, the stress values on enamel, dentin, and adhesive material increased as a result of occlusal forces, while the amount of stress on the restorative material decreased. In the fracture analysis, when the bulk–fill composite material was used instead of the conventional resin composite material, a decrease in the number of cycles required for the fracture of enamel, dentin, and restorative materials was observed as a result of the forces generated in the oral cavity.
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Kincses D, Jordáki D, Szebeni D, Kunsági-Máté S, Szalma J, Lempel E. Effect of Ceramic and Dentin Thicknesses and Type of Resin-Based Luting Agents on Intrapulpal Temperature Changes during Luting of Ceramic Inlays. Int J Mol Sci 2023; 24:ijms24065466. [PMID: 36982546 PMCID: PMC10057599 DOI: 10.3390/ijms24065466] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/06/2023] [Accepted: 03/10/2023] [Indexed: 03/16/2023] Open
Abstract
The adhesive cementation of ceramic inlays may increase pulpal temperature (PT) and induce pulpal damage due to heat generated by the curing unit and the exothermic reaction of the luting agent (LA). The aim was to measure the PT rise during ceramic inlay cementation by testing different combinations of dentin and ceramic thicknesses and LAs. The PT changes were detected using a thermocouple sensor positioned in the pulp chamber of a mandibular molar. Gradual occlusal reduction obtained dentin thicknesses of 2.5, 2.0, 1.5, and 1.0 mm. Light-cured (LC) and dual-cured (DC) adhesive cements and preheated restorative resin-based composite (RBC) were applied to luting of 2.0, 2.5, 3.0, and 3.5 mm lithium disilicate ceramic blocks. Differential scanning calorimetry was used to compare the thermal conductivity of dentin and ceramic slices. Although ceramic reduced heat delivered by the curing unit, the exothermic reaction of the LAs significantly increased it in each investigated combination (5.4–7.9 °C). Temperature changes were predominantly influenced by dentin thickness followed by LA and ceramic thickness. Thermal conductivity of dentin was 24% lower than that of ceramic, and its thermal capacity was 86% higher. Regardless of the ceramic thickness, adhesive inlay cementation can significantly increase the PT, especially when the remaining dentin thickness is <2 mm.
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Affiliation(s)
- Dóra Kincses
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
| | - Dóra Jordáki
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
| | - Donát Szebeni
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
| | - Sándor Kunsági-Máté
- Department of Organic and Medicinal Chemistry, Faculty of Pharmacy, University of Pécs, Honvéd Street 1, 7624 Pécs, Hungary
- János Szentágothai Research Center, Ifjúság Street 20, 7624 Pécs, Hungary
| | - József Szalma
- Department of Oral and Maxillofacial Surgery, Faculty of Dentistry, University of Pécs Medical School, Tüzér Street 1, 7623 Pécs, Hungary
| | - Edina Lempel
- Department of Restorative Dentistry and Periodontology, Faculty of Dentistry, University of Pécs Medical School, PTüzér Street 1, 7623 Pécs, Hungary
- Correspondence: ; Tel.: +36-(72)-536402
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Arya A, Grewal MS, Arya V, Choudhary E, Duhan J. Stress distribution of endodontically treated mandibular molars with varying amounts of tooth structure restored with direct composite resin with or without cuspal coverage: A 3D finite element analysis. J Conserv Dent 2023; 26:20-25. [PMID: 36908730 PMCID: PMC10003291 DOI: 10.4103/jcd.jcd_333_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Revised: 08/11/2022] [Accepted: 08/19/2022] [Indexed: 12/12/2022] Open
Abstract
Background Decision-making regarding whether cuspal coverage is required or not for the restoration of root canal-treated posterior teeth is still a matter of challenge for the dentist. Methodology Four models of endodontically treated mandibular molars with mesio-occlusal (MO) cavity were designed and simulated with direct composite resin restorations. Group 1A - cavity width <½ the intercuspal distance restored without cuspal coverage, Group 1B - same as Group 1A but with cuspal coverage, Group 2A - MO cavity width >½ but <2/3rd the intercuspal distance restored without cuspal coverage, and Group 2B - same as Group 2A but with cuspal coverage. The models received occlusal load to simulate a mastication load. Static finite element analysis (FEA) was adopted for predicting the stress distribution generated in the restored tooth by the loading condition. Results FEA of the models have shown that the variations in stress values were significant in bulk-fill material compared to enamel and other structures. Comparing the maximum and minimum principal stress values in the overall region demonstrated that 2A was safer, whereas 2B was found to be the worst case. Conclusions The results indicate that restoration of endodontically treated mandibular molar with loss of one marginal ridge with composite resin without cuspal coverage revealed minimal internal stress values and showed the best performance overall.
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Affiliation(s)
- Ashtha Arya
- Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| | - Mandeep S. Grewal
- Department of Conservative Dentistry and Endodontics, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| | - Vishal Arya
- Department of Preventive and Paediatric Dentistry, Faculty of Dental Sciences, SGT University, Gurgaon, Haryana, India
| | - Ekta Choudhary
- Department of Conservative Dentistry and Endodontics, School of Dental Sciences, Sharda University, Greater Noida, Uttar Pradesh, India
| | - Jigyasa Duhan
- Department of Conservative Dentistry and Endodontics, PGIDS, Rohtak, Haryana, India
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Yazdani N, Ashrafi H, Özcan M, Nekoueimehr N, Kholdi M, Farzad A. Mechanical and Thermal Stress Analysis of Cervical Resin Composite Restorations Containing Different Ratios of Zinc Oxide Nanoparticles: A 3D Finite Element Study. MATERIALS (BASEL, SWITZERLAND) 2022; 15:5504. [PMID: 36013640 PMCID: PMC9412397 DOI: 10.3390/ma15165504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 08/05/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
Due to an increase in prevalence of cervical lesions, it is important to use appropriate restorative materials to reduce the incidence of secondary lesions. Owing to having antibacterial properties, cervical composite restorations containing different ratios of Zinc Oxide nanoparticles (ZnO NPs) have been analyzed using the Finite Element method to determine the optimal incorporation ratio from mechanical and thermal perspectives. A numerical simulation is conducted for a mandibular first premolar with a cervical lesion (1.5 × 2 × 3 mm3) restored with composites containing 0 to 5% wt. ZnO NPs. Subsequently, the samples are exposed to different thermo-mechanical boundary conditions, and stress distributions at different margins are examined. The accumulated stress in the restoration part increases for the 1% wt. sample, whereas the higher percentage of ZnO NPs leads to the reduction of stress values. In terms of different loading conditions, the least and most stress values in the restoration part are observed in central loading and lingually oblique force, respectively. The change in the surface temperature is inversely correlated with the ratio of ZnO NPs. In conclusion, the composite containing 5% wt. ZnO NPs showed the most proper thermo-mechanical behavior among all samples.
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Affiliation(s)
- Negar Yazdani
- Faculty of Dentistry, Kashan University of Medical Sciences, Kashan 8715988141, Iran
| | - Hossein Ashrafi
- Department of Applied Design, Faculty of Mechanical Engineering, University of Kashan, Kashan 8731753153, Iran
| | - Mutlu Özcan
- Division of Dental Biomaterials, Clinic for Reconstructive Dentistry, University of Zürich, CH-8032 Zürich, Switzerland
| | - Negin Nekoueimehr
- Faculty of Dentistry, Kashan University of Medical Sciences, Kashan 8715988141, Iran
| | - Mohsen Kholdi
- Department of Solid Mechanic, Faculty of Mechanical Engineering, University of Kashan, Kashan 8731753153, Iran
| | - Azin Farzad
- Faculty of Dentistry, Kashan University of Medical Sciences, Kashan 8715988141, Iran
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Influence of Artificial Aging on Mechanical Properties of Six Resin Composite Blocks for CAD/CAM Application. COATINGS 2022. [DOI: 10.3390/coatings12060837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
(1) The interactions in the oral cavity between resin composite blocks for CAD/CAM application and saliva, biofilm, and chemicals and their influence on mechanical properties are still mostly unknown. The purpose of this study is to examine the impact of artificial aging on the flexural strength, flexural modulus, hardness, Weibull modulus, and probability of failure of six resin composite CAD/CAM materials. (2) The aging was conducted by storing the specimens in water at 37 °C for 3 months, then a 3-point bending test was applied and measured. The microhardness was measured with a Vickers microhardness tester. Weibull analysis (according to ISO) was also performed. The shape and scale parameters were calculated. (3) After aging, the flexural strength values ranged from 95.51 (SD 9.07) MPa for the aged Shofu Block HC (HC) to 160.28 (SD 10.37) MPa for non-aged Gandio blocks (GR), and the flexural modulus values ranged from 7.75 (SD 0.19) GPa for HC to 16.77 (SD 0.60) GPa for GR. The microhardness (HV01) ranged from 72.71 (SD 1.43) for the Katana Avencia Block (AV) to 140.50 (SD 5.51) for GR. After aging, the Weibull characteristic strength ranged from 99.47 MPa for HC to 169.25 MPA for Brilliant Crios (CR). (4) Water storage led to a decrease in flexural strength and characteristic strength and slightly affected the flexural modulus. Gandio Blocks, Tetric CAD, and Brilliant Crios presented higher flexural strength than others.
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16
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Yildirim G, Demir C, Güven MÇ, Koç O, Dalkiliç EE. Influence of fiber insertion and different material type on stress distribution in endocrown restorations: a 3D-FEA study. Comput Methods Biomech Biomed Engin 2021; 25:1509-1519. [PMID: 34964689 DOI: 10.1080/10255842.2021.2019228] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
The study aimed to evaluate the effects of fibers insertion and restorative material type on the stress distribution in endocrowns with finite element analysis. Five 3D models of first mandibular molars were created and restored as follows: (1) IN: intact tooth, (2) IPS-E: tooth restored with lithium disilicat ceramic endocrowns, (3) C-E: tooth restored with composite endocrowns, (4) IPS-E + F: lithium disilicate ceramic endocrowns + fiber, (5) C-E + F: composite endocrowns + fiber. Vertical masticatory load was imitated with finite element analysis. The equivalent stress of von Mises failure criterion (mvM) was calculated. The maximum mvM stress, enamel/crown, dentin and cement were compared among models and strength of the materials. Endocrowns presented a lower mvM stress level than intact tooth. In IPS-E, the mvM stress values in the crown and dentin were higher than C-E, while the mvM stress values in cement were higher in C-E group. Fibers insertion did not affect the stress level of IPS-E and C-E groups. In IPS model, fiber showed more stress absorption than C-E. The restorative material type changed the stress distribution of endocrown restorations. The fiber application did not affect the stress distribution in either endocrown group. But, more stress absorption was observed in fiber under IPS-E than C-E.
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Affiliation(s)
- Gulhan Yildirim
- Department of Prosthodontics, Beykent University, Istanbul, Turkey
| | - Cihan Demir
- Faculty of Mechanical Engineering, Yildiz Technical University, Istanbul, Turkey
| | | | - Osman Koç
- Faculty of Mechanical Engineering, Yildiz Technical University, Istanbul, Turkey
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Yu P, Xiong Y, Zhao P, Yu H, Arola D, Gao S. Ceramic Inlay Bonded Interfaces in Minimally Invasive Preparations: Damage and Contributing Mechanisms in Sliding Contact. Oper Dent 2021; 47:E1-E11. [PMID: 34843621 DOI: 10.2341/20-144-l] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/24/2021] [Indexed: 11/23/2022]
Abstract
BACKGROUND In the preparation of inlay cavities, a choice must be made between conventional standard and minimally invasive preparation designs; in the long run, this choice can affect the integrity of the bonded interface. PURPOSE To evaluate the effect of minimally invasive cavity preparation designs on the extent and contributing mechanisms of damage to ceramic inlay bonded interfaces. METHODS AND MATERIALS Tooth blocks with 90°, 120° and 75° marginal angles were prepared, representing tooth cavities with conventional standard and minimally invasive preparations with large divergence and convergence angles and bonded to monolithic ceramic (IPS e.max CAD). Vickers indentations were placed at various distances from the bonded interface. The indentation morphology and crack length were observed. Reciprocating wear tests were performed on the bonded interface with a 20-newton (N) vertical load. The wear depth and wear-scar morphology were characterized after increments of cyclic sliding contact. RESULTS The 120° group exhibited longer indentation cracks in the ceramic, whereas the 75° group showed larger indentations in the enamel when compared to the 90° group (p<0.001). Consistent with the weaker edge crack resistance, the 120° group experienced the greatest wear (p=0.008), and the wear depth in the enamel of the 75° group exceeded that of the 90° group (p<0.001) in the early stage (5×102 cycles). However, no significant difference in the wear depth (p>0.147) and morphology were found at the later wear stage among the three groups. CONCLUSION Within the limitations of this study, minimally invasive preparations with 120° and 75° marginal angles can result in early sever damage at the ceramic inlay bonded interface but show comparable wear behaviors to the conventional 90° group at the later stage.
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Affiliation(s)
- P Yu
- Ping Yu, PhD, DDS, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Y Xiong
- Yuhuan Xiong, MD, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - P Zhao
- Peng Zhao, MD, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - H Yu
- Haiyang Yu, PhD, DDS, professor, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - D Arola
- Dwayne Arola, PhD, professor, Department of Materials Science and Engineering, Department of Oral Health Sciences, Department of Restorative Dentistry, University of Washington, Seattle, WA, USA
| | - S Gao
- *Shanshan Gao, PhD, DDS, associate professor, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
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Meng Q, Zhang Y, Chi D, Gong Q, Tong Z. Resistance fracture of minimally prepared endocrowns made by three types of restorative materials: a 3D finite element analysis. JOURNAL OF MATERIALS SCIENCE. MATERIALS IN MEDICINE 2021; 32:137. [PMID: 34716807 PMCID: PMC8557147 DOI: 10.1007/s10856-021-06610-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Accepted: 09/28/2021] [Indexed: 06/13/2023]
Abstract
A thin endocrown restoration was often applied in endodontically treated teeth with vertical bite height loss or inadequate clinical crown length. A model of mandibular molars made by endocrown restoration with 1 mm thickness and 2 mm depth of pulp chamber was constructed and imported into FEA ANSYS v18.0 software. The three CAD/CAM materials, feldspathic (Mark2), lithium disilicate (EMAX), and lava ultimate (LU), were assigned, and the five load indenters were loaded on the full occlusal (FO), occlusal center (OC), central fossa (CF), buccal groove (BG), and mesiobuccal cusp (MC) of restoration in the model. The MinPS and MaxPS of the thin endocrown were significantly higher than those of tooth tissue in five types of loads except for the LU endocrown loaded in the FO group. The smaller the contact surface of the load was, the higher MaxPS and MinPS were. MaxPS and MinPS of the MC were the highest, followed by the BG and CF in the restoration. In the stress distribution of tooth tissue, MaxPS in the LU endocrown accumulated at the external edge of enamel and was significantly higher than MaxPS in Mark2 and EMAX endocrown concentrated on the chamber wall of dentin under OC, CF and BG loads. Within the limitations of this FEA study, the LU endocrown transferred more stress to tooth tissue than Mark2 and EMAX, and the maximum principal stress on endocrown restoration and tooth tissue at the mesiobuccal cusp load was higher than that at the central fossa and buccal groove load.
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Affiliation(s)
- Qingzhen Meng
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Yuejiao Zhang
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Danlu Chi
- The First Affiliated Hospital, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Qimei Gong
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China
| | - Zhongchun Tong
- Department of Operative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China.
- Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China.
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Grassi EDA, de Andrade GS, Tribst JPM, Machry RV, Valandro LF, Ramos NDC, Bresciani E, Saavedra GDSFA. Fatigue behavior and stress distribution of molars restored with MOD inlays with and without deep margin elevation. Clin Oral Investig 2021; 26:2513-2526. [PMID: 34643807 DOI: 10.1007/s00784-021-04219-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2021] [Accepted: 10/04/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVES This study evaluated the effect of deep margin elevation (DME) and restorative materials (leucite-reinforced glass-ceramics [C] vs. indirect resin composite [R]) on the fatigue behavior and stress distribution of maxillary molars with 2-mm deep proximal margins restored with MOD inlay. METHODS Fifty-two extracted human third molars were randomly assigned into four groups (n = 13): C; DME + C; R; and DME + R. Inlays were fabricated in CAD-CAM and bonded to all teeth. The fatigue behavior was assessed with the stepwise stress test (10,000 cycles/step; step = 50 N; 20 Hz; initial load = 200 N). Fatigue failure loads and the number of cycles were analyzed with 2-way ANOVA and Tukey's test (p < 0.05) and Kaplan-Meier survival plots. The stress distribution was assessed with finite element analysis. The models were considered isotropic, linear, and homogeneous, and presented bonded contacts. A tripod axial load (400 N) was applied to the occlusal surface. The stress distribution was analyzed with the maximum principal stress criterion. RESULTS For fatigue, there was no difference for DME factor (p > 0.05). For the material factor, the load and number of cycles for failure were statistically higher in the R groups (p < 0.05). The finite element analysis showed that resin composite inlays concentrated more stress in the tooth structure, while ceramic inlays concentrated more stress in the restoration. Non-reparable failures were more frequent in the resin composite inlays groups. CONCLUSIONS DME was not negative for fatigue and biomechanical behaviors. Resin composite inlays were more resistant to the fatigue test, although the failure mode was more aggressive. CLINICAL SIGNIFICANCE DME does not impair mechanical behavior. Resin composite inlays failed at higher loads but with a more aggressive failure mode.
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Affiliation(s)
- Elisa Donaria Aboucauch Grassi
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil
| | - Guilherme Schmitt de Andrade
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil
| | - João Paulo Mendes Tribst
- Post-Graduate Program in Dentistry, University of Taubaté (UNITAU), 09th Rua Dos Operários St., Taubaté, SP, 12020-340, Brazil
| | - Renan Vaz Machry
- Graduate Program of Oral Science, Prosthodontics Unit, School of Dentistry, Federal University of Santa Maria (UFSM), Roraima Av, Santa Maria, RS, 100097105-340, Brazil
| | - Luiz Felipe Valandro
- Graduate Program of Oral Science, Prosthodontics Unit, School of Dentistry, Federal University of Santa Maria (UFSM), Roraima Av, Santa Maria, RS, 100097105-340, Brazil
| | - Nathalia de Carvalho Ramos
- School of Dentistry, São Francisco University (USF), 218th São Francisco de Assis Av., Bragança Paulista, SP, 12916-900, Brazil
| | - Eduardo Bresciani
- Department of Restorative Dentistry, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil
| | - Guilherme de Siqueira Ferreira Anzaloni Saavedra
- Department of Dental Materials and Prosthodontics, Institute of Science and Technology, São Paulo State University (Unesp), 777th Eng. Francisco José Longo Av., São José dos Campos, SP, 12245-000, Brazil.
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Grzebieluch W, Kowalewski P, Grygier D, Rutkowska-Gorczyca M, Kozakiewicz M, Jurczyszyn K. Printable and Machinable Dental Restorative Composites for CAD/CAM Application-Comparison of Mechanical Properties, Fractographic, Texture and Fractal Dimension Analysis. MATERIALS 2021; 14:ma14174919. [PMID: 34501009 PMCID: PMC8434230 DOI: 10.3390/ma14174919] [Citation(s) in RCA: 48] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Revised: 08/20/2021] [Accepted: 08/26/2021] [Indexed: 12/12/2022]
Abstract
Thanks to the continuous development of light-curing resin composites it is now possible to print permanent single-tooth restorations. The purpose of this study was to compare resin composites for milling -Gandio Blocks (GR), Brilliant Crios (CR) and Enamic (EN) with resin composite for 3D printing-Varseo Smile Crown plus (VSC). Three-point bending was used to measure flexural strength (σf) and flexural modulus (Ef). The microhardness was measured using a Vickers method, while fractographic, microstructural, texture and fractal dimension (FD) analyses were performed using SEM, optical microscope and picture analysis methods. The values of σf ranged from 118.96 (±2.81) MPa for EN to 186.02 (±10.49) MPa for GR, and the values of Ef ranged from 4.37 (±0.8) GPa for VSC to 28.55 (±0.34) GPa for EN. HV01 ranged from 25.8 (±0.7) for VSC to 273.42 (±27.11) for EN. The filler content ranged from 19-24 vol. % for VSC to 70-80 vol. % for GR and EN. The observed fractures are typical for brittle materials. The correlation between FD of materials microstructure and Ef was observed. σf of the printed resin depends on layers orientation and is significantly lower than σf of GR and CR. Ef of the printed material is significantly lower than Ef of blocks for milling.
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Affiliation(s)
- Wojciech Grzebieluch
- Laboratory for Digital Dentistry, Department of Conservative Dentistry Witch Endodontics, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland
- Correspondence: ; Tel.: +48-71-784-03-61
| | - Piotr Kowalewski
- Department of Fundamentals of Machine Design and Mechatronic Systems, Wroclaw University of Science and Technology, Lukasiewicza 7/9, 50-371 Wroclaw, Poland;
| | - Dominika Grygier
- Department of Vehicle Engineering, Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, Lukasiewicza 5, 50-371 Wroclaw, Poland; (D.G.); (M.R.-G.)
| | - Małgorzata Rutkowska-Gorczyca
- Department of Vehicle Engineering, Faculty of Mechanical Engineering, Wroclaw University of Science and Technology, Lukasiewicza 5, 50-371 Wroclaw, Poland; (D.G.); (M.R.-G.)
| | - Marcin Kozakiewicz
- Department of Maxillofacial Surgery, Medical University of Lodz, 113 S. Zeromski Street, 90-549 Lodz, Poland;
| | - Kamil Jurczyszyn
- Department of Oral Surgery, Wroclaw Medical University, Krakowska 26, 50-425 Wroclaw, Poland;
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Effect of Direct and Indirect Materials on Stress Distribution in Class II MOD Restorations: A 3D-Finite Element Analysis Study. BIOMED RESEARCH INTERNATIONAL 2021; 2020:7435054. [PMID: 33381580 PMCID: PMC7755472 DOI: 10.1155/2020/7435054] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 12/02/2020] [Accepted: 12/05/2020] [Indexed: 11/18/2022]
Abstract
The aim of this study is to investigate the stress distributions of different restoration options for class II mesio-occluso-distal (MOD) cavities. A class II MOD cavity with proximal box gingival floor 1 mm below cementoenamel junction was designed in a mandibular first molar tooth model. 3D finite-element analysis (FEA) and 3D-CAD modelling were used to examine the occlusal stresses distributed to the remaining buccal enamel (RBE), remaining lingual enamel (RLE), adhesive surfaces, and restorative materials by direct and indirect materials resulting from a 600 N of static occlusal load stimulating foodstuff. von Mises (VM) and maximum principal (Pmax) stresses were evaluated for two CAD/CAM materials and three direct materials. CAD/CAM materials exerted less stress than the direct restorative materials. Significant von Mises and Pmax stress value differences were seen among all restoration models on RBE. Reducing RLE and including it into the cavity would be a more effective option for this model in this scenario. As VM and Pmax stresses of PIHC CAD/CAM material for RBE and dentin were significantly lower than other tested materials, it may be the choice of material for indirect MOD restorations.
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Chen Y, Chen D, Ding H, Chen Q, Meng X. Fatigue behavior of endodontically treated maxillary premolars with MOD defects under different minimally invasive restorations. Clin Oral Investig 2021; 26:197-206. [PMID: 34031731 DOI: 10.1007/s00784-021-03991-9] [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: 10/23/2020] [Accepted: 05/14/2021] [Indexed: 11/29/2022]
Abstract
OBJECTIVES To analyze the stress distribution and subsequent fracture resistance of human maxillary premolars with mesial-occlusal-distal (MOD) defects restored with different minimally invasive restorations. MATERIALS AND METHODS Seventy non-carious human maxillary premolars were selected and divided into seven groups (n = 10). Ten teeth without further preparation served as control. The remaining teeth were endodontically treated and received three restorative patterns: inlays without cusp coverage (I), onlays with palatal coverage (O), overlays with both buccal and palatal coverage (Ov). Lithium disilicate glass ceramics (EM) and machinable composite resin (LU) were used for restoration. Specimens were tested under cycling loading with tongue direction of 45° for 1.2 × 106 cycles at a 50-N load and 2.0-Hz frequency. The survival time and two fracture mode classifications were assessed. Three-dimensional models of each group were designed. The magnitude and pattern of stresses were analyzed under the same condition of the in vitro test using finite element stress analysis. RESULTS Although the overlay model pattern produced more favorable stress distribution, three restorative patterns restored with the same material had no difference in survival curves (P > 0.05). Only the survival curve of the EM-Ov group had no statistical difference with that of the control group (P > 0.05). EM groups presented mainly interface adhesive failure, while LU groups were mainly material cohesive failure. CONCLUSION For the endodontically treated maxillary premolars with MOD defect, the lithium disilicate glass ceramic overlay pattern can reach the best restorative effect. CLINICAL RELEVANCE Comparing with restorative pattern, restorative material had a greater influence on the minimally invasive restoration of posterior teeth.
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Affiliation(s)
- Yani Chen
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Du Chen
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Hong Ding
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China
| | - Qiang Chen
- Biomechanics Laboratory, School of Biological Science & Medical Engineering, Southeast University, Nanjing, Jiangsu, China
| | - Xiangfeng Meng
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, China.
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Chen YC, Lin CL, Hou CH. Investigating inlay designs of class II cavity with deep margin elevation using finite element method. BMC Oral Health 2021; 21:264. [PMID: 33993877 PMCID: PMC8127254 DOI: 10.1186/s12903-021-01630-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2021] [Accepted: 05/06/2021] [Indexed: 11/25/2022] Open
Abstract
Background This study evaluates the mechanical performance of deep margin elevation technique for carious cavities by considering the shape designs and material selections of inlay using a computational approach combined with the design of experiments method. The goal is to understand the effects of the design parameters on the deep margin elevation technique and provide design guidelines from the biomechanics perspective. Methods Seven geometric design parameters for defining an inlay’s shape of a premolar were specified, and the influence of cavity shape and material selection on the overall stress distribution was investigated via automated modelling. Material selection included composite resin, ceramic, and lithium disilicate. Finite element analysis was performed to evaluate the mechanical behavior of the tooth and inlay under a compressive load. Next, the analysis of variance was conducted to identify the parameters with a significant effect on the stress occurred in the materials. Finally, the response surface method was used to analyze the stress responses of the restored tooth with different design parameters. Results The restored tooth with a larger isthmus width demonstrated superior mechanical performance in all three types of inlay materials, while the influence of other design parameters varied with the inlay material selection. The height of the deep margin elevation layer insignificantly affected the mechanical performance of the restored tooth. Conclusions A proper geometric design of inlay enhances the mechanical performance of the restored tooth and could require less volume of the natural dentin to be excavated. Furthermore, under the loading conditions evaluated in this study, the deep margin elevation layer did not extensively affect the strength of the tooth structure. Supplementary Information The online version contains supplementary material available at 10.1186/s12903-021-01630-z.
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Affiliation(s)
- Yung-Chung Chen
- School of Dentistry and Institute of Oral Medicine, Medical College, National Cheng Kung University, Tainan, Taiwan, Republic of China.,Division of Prosthodontics, Department of Stomatology, National Cheng Kung University Hospital, National Cheng Kung University, Tainan, Taiwan, Republic of China
| | - Chi-Lun Lin
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan, Republic of China.
| | - Chun-Hsien Hou
- Department of Mechanical Engineering, National Cheng Kung University, Tainan, Taiwan, Republic of China
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Influence of Cavity Geometry on the Fracture Strength of Dental Restorations: Finite Element Study. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11094218] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The main purpose of this work was to analyze the stress distribution in premolars restored with indirect IPS Empress® CAD onlays or inlays. The three-dimensional geometry of a human first premolar was created using modeling software. The tooth fixation system was simulated through box geometry, comprising a cortical bone layer with 2 mm of thickness over a layer of trabecular bone with 15 mm of thickness. The tooth had the following approximated crown dimensions: 10.35 mm buccolingual length; 7.1 mm mesiodistal width; and 7.0 mm cervico-occlusal height. The mesio-occluso-distal (MOD) cavity preparations followed the suggestions available in the literature. The cement geometry was modified to include cohesive zone models (CZM) to perform the adhesive joint’s strength prediction. The loading body was created assuming contact between the food bolus and the tooth surface. Numerical solutions were obtained by performing static analysis and damage analysis using the finite element method. Von Mises stress values generated in the ceramic inlay restoration ranged from 1.39–181.47 MPa, which were on average 4.4% higher than those of the onlay ceramic restoration. The fracture strength of the onlay restoration was about 18% higher than that of the inlay restoration. The onlay design seems to contribute to higher homogenization of the adhesive resin cement strain and higher tooth structure protection.
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Resin Composite Materials for Chairside CAD/CAM Restorations: A Comparison of Selected Mechanical Properties. JOURNAL OF HEALTHCARE ENGINEERING 2021; 2021:8828954. [PMID: 34007429 PMCID: PMC8099508 DOI: 10.1155/2021/8828954] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/02/2020] [Accepted: 04/16/2021] [Indexed: 11/18/2022]
Abstract
Objective The aim was to evaluate the flexural strength, flexural modulus, microhardness, Weibull modulus, and characteristic strength of six resin composite blocks (Grandio Blocs-GR, Tetric CAD-TE, Brilliant Crios-CR, Katana Avencia-AV, Cerasmart-CS, and Shofu Block HC-HC). Methods Flexural strength and flexural modulus were measured using a three-point bending test and microhardness using the Vickers method. Weibull analysis was also performed. Results The materials showed flexural strength ranging from 120.38 (HC) to 186.02 MPa (GR), flexural modulus from 8.26 (HC) to 16.95 GPa (GR), and microhardness from 70.85 (AV) to 140.43 (GR). Weibull modulus and characteristic strength ranged from 16.35 (CS) to 34.98 (TE) and from 123.45 MPa (HC) to 190.3 MPa (GR), respectively. Conclusions GR, TE, and CR presented significantly higher flexural strength, modulus, Weibull modulus, and characteristic strength than the others.
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Evaluation of two CAD/CAM materials for Nayyar core and post-retained restorations: Three dimensional stress analysis. J Mech Behav Biomed Mater 2021; 117:104381. [PMID: 33582503 DOI: 10.1016/j.jmbbm.2021.104381] [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: 12/11/2020] [Revised: 01/27/2021] [Accepted: 01/31/2021] [Indexed: 11/21/2022]
Abstract
OBJECTIVES The aim of this study is to assess the stress distribution of a nanoceramic resin CAD/CAM material, Lava Ultimate (LU) and a polymer-infiltrated hybrid ceramic CAD/CAM material, Vita Enamic (VE) for enamel replacement for Nayyar core (corono-radicular dowel and core) or post-retained restoration designs of a maxillary first premolar tooth with missing palatal cusp. MATERIALS AND METHODS A three dimensional finite element (FE) modelof maxillary first premolar with two roots was modeled. A mesial-occlusal-distal-palatal (MODP) cavity was designed with cavity floor above cemento-enamel junction and including buccal cuspal reduction. Restoration designs consisted of Nayyar core restoration (NCR) and post-retained restoration (PRR) with a glass fiber post. Vita Enamic (VE), Lava Ultimate (LU) were used for enamel and everX Posterior was used for dentin replacement. Vertical occlusal load (100 N) was applied on a spherical solid rigid material simulating the food stuff. Von Mises (VM) and maximum principle stress values were evaluated separately for the remaining enamel, remaining dentin and restorative material in megapascal (MPa). RESULTS The analysis of both VM and maximum principle stress values revealed that the most intense stress accumulation was in the cervical region of enamel for both designs. For VM, similar stress values were observed only in dentin. Stress analysis of restorative materials showed that everX Posterior had the highest stress accumulation. CONCLUSIONS The comparison of the two techniques showed that PRR had better stress distribution than NCR. NCR or PRR with LU or VE exhibited similar VM stress accumulation in dentin. Maximum principle stress analyses showed that PRR with LU transmitted the least stress to enamel and dentin indicating that when LU is the material of choice, post-retained restoration would be a satisfactory design. VM stress values of enamel revealed that VE absorbed the stress in itself and transferred less stress to dentin. This could point out that for the restoration of maxillary first premolar tooth with missing palatal cusp, VE may be a suitable material for NCR and PRR restoration techniques. HIGHLIGHTS When fiber reinforced composite is used as dentin replacement in combination with VE as enamel replacement; any technique; PRR or NCR, may be preferred in the restoration of MODP cavities of endodontically treated maxillary premolars. The clinical relevance has to be further studied in-vivo.
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Koshida S, Maeno M, Nara Y. Effect of differences in the type of restoration and adhesive resin cement system on the bonding of CAD/CAM ceramic restorations. Dent Mater J 2020; 39:1022-1032. [PMID: 32727963 DOI: 10.4012/dmj.2019-308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The effect of differences in the type of restoration and adhesive resin cement system on the bonding of CAD/CAM ceramic restoration after cyclic loading was examined quantitatively and qualitatively. Seventy-two human maxillary first molars were divided into three restoration groups: MOD-inlay, MODP-onlay, and crown. Immediate dentin sealing was applied to the exposed dentin of all prepared specimens. The 24 specimens of each restoration group were further divided into another three groups, and a different adhesive resin cement system was applied to each group for cementation. All restoratives were fabricated from feldspathic-ceramic-blocks and cemented with each adhesive resin cement system according to the manufacturer's instructions. The microtensile bond-strength was measured after cyclic loading and was not significantly affected by differences in the type of restoration or adhesive resin cement system. However, the type of restorations and adhesive resin cement systems did show significant differences in terms of the bonding reliability.
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Affiliation(s)
- Seisuke Koshida
- Department of Adhesive Dentistry, School of Life Dentistry at Tokyo, The Nippon Dental University
| | - Masahiko Maeno
- Department of Adhesive Dentistry, School of Life Dentistry at Tokyo, The Nippon Dental University
| | - Yoichiro Nara
- Department of Adhesive Dentistry, School of Life Dentistry at Tokyo, The Nippon Dental University
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Yu P, Zhi Li, Tan X, Yu H. Effect of sealing gel on the microleakage resistance and mechanical behavior during dynamic loading of 3 implant systems. J Prosthet Dent 2020; 127:308-317. [PMID: 33246561 DOI: 10.1016/j.prosdent.2020.05.030] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/20/2020] [Accepted: 05/20/2020] [Indexed: 02/05/2023]
Abstract
STATEMENT OF PROBLEM Sealing products have been produced to reduce microleakage at the implant abutment interface. However, little is known about their effectiveness and any alterations in mechanical behavior of implant systems with their application. PURPOSE The purpose of this in vitro study was to evaluate the effect of a silicone sealing gel on implant abutment interface microleakage, abutment screw torque loss, and thread wear of implant systems in a simulated oral environment. MATERIAL AND METHODS Five specimens each of 3 implants systems (Nobel, Straumann, and WEGO) that included sealed and unsealed groups were analyzed (N=30). Before assembling the components, toluidine blue solution was injected to the implant intaglio cavity to evaluate implant abutment interface microleakage. After tightening to the recommended torque, 20 to 200 N of 30-degree off-axis dynamic force was applied at 2 Hz for 48 hours. The toluidine blue solution was extracted to test optical density values at 1, 3, 9, 24, 33, and 48 hours. Detorque values were measured before and after cycling loading, and torque loss rates were calculated. The abutment screw morphologies were observed by using scanning electron microscopy. The coefficient of friction tendency of applying sealing gel was explored with a ball-on-flat configuration. One-way ANOVA and Student t test were used for statistical analysis (α=.05). RESULTS The optical density value increased with the loading time, especially for Straumann group. The sealing gel decreased the implant abutment interface microleakage of Straumann assemblies after cyclic loading of 9 hours (P=.044), whereas no statistical difference was found for Nobel (P=.140) or WEGO groups (P=.402) at 6 time points. Torque loss occurred during tightening and further increased after dynamic cyclic load in each group. Among the 3 implant systems, Straumann implants reported the best antiloosening property (P<.001). The application of sealing gel reduced the initial (P=.048) and final (P=.032) torque loss rate in all the 3 systems. Scanning electron microscopy observations revealed the bottom thread tended to have more abrasion than the first thread. After applying sealing gel, less thread abrasion was found in Nobel and WEGO assemblies, whereas the protective effect was not evident for the Straumann group. The coefficient of friction of sealed group (0.17 ±0.026) was significantly (P=.012) lower than that of unsealed group (0.24 ±0.044). CONCLUSIONS The silicone sealing gel improved the immediate fastening and long-term antiloosening performances of 3 implant systems, decreased the implant abutment interface microleakage of Straumann system, and reduced abutment screw thread abrasion of the Nobel and WEGO systems.
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Affiliation(s)
- Ping Yu
- Doctoral candidate, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, and Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Zhi Li
- Resident Doctor, Aerospace Center Hospital, Beijing, PR China
| | - Xin Tan
- Doctoral candidate, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, and Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China
| | - Haiyang Yu
- Professor, State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, and Department of Prosthodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, PR China.
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Fracture strength of non-invasively reinforced MOD cavities on endodontically treated teeth. Odontology 2020; 109:368-375. [PMID: 32886263 PMCID: PMC7954736 DOI: 10.1007/s10266-020-00552-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 08/23/2020] [Indexed: 11/24/2022]
Abstract
The purpose of this in-vitro study was to evaluate the fracture resistance and failure mode of non-invasively reinforced endodontically treated mandibular molars. Sixty freshly extracted defect-free mandibular molars were divided into four experimental groups with extensive MOD cavities on endodontically treated teeth with different restoration types and one control group with intact teeth (n = 12). The groups were as follows: “Normal”: direct resin composite; “Ring”: glass fiber-reinforced strip (Dentapreg) wrapped around buccal and lingual walls followed by direct resin composite; “Inlay”: indirect CAD/CAM resin composite inlay; “Onlay”: indirect CAD/CAM resin composite onlay; “Intact”: Intact teeth (Control). Tetric EvoCeram and Adhese Universal (Ivoclar Vivadent) were used for direct restorations and Tetric CAD (Ivoclar Vivadent) adhesively luted with Adhese Universal and Variolink Esthetic LC (Ivoclar Vivadent) were used for indirect restorations. All teeth were submitted to thermo-mechanical cyclic loading. All samples were then submitted to a compressive load until fracture. Fracture load was noted and teeth were analyzed to classify the failure mode as either catastrophic (C) or non-catastrophic (NC). No statistically significant difference was found between fracture strength of the five groups when all specimens were considered (p = 0.1461). Intact group showed the lowest percentage of catastrophic failures (41.67%). Ring group presents less catastrophic failures (75%) than Normal group (83.34%), and failures of indirect restorations—Inlay and Onlay—were almost all catastrophic (91.67% and 100%, respectively).
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Influence of Occlusal Thickness and Radicular Extension on the Fracture Resistance of Premolar Endocrowns from Different All-Ceramic Materials. APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10082696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Endocrowns are primarily recommended in a molar region with a standardized preparation design. The aim of the study was to evaluate the effect of different occlusal preparation depths, pulp chamber-radicular extension, and all-ceramic materials on the fracture resistance of premolar endocrowns. Ninety human premolar teeth were root canal treated, randomly divided into three main groups according to all-ceramic material used for fabrication as Lithium Disilicate (LD) ceramic, Polymer infiltrated ceramic (PIC) and High translucency zirconia (HTZ). They were further subdivided into three subgroups (n = 10) according to preparation design of 2 mm occlusal reduction, 4.5 mm occlusal reduction and 4.5 mm occlusal reduction with 2 mm radicular extension. The endocrowns from respective restorative materials were fabricated, surface conditioned, and cemented with self-adhesive resin cement. All samples were thermocycled for 5000 cycles and subjected to compressive static load at 45° angluation with the cross-head speed of 0.5 mm/minute until the fracture. The mean fracture resistance of LD ceramic at 2 mm, 4.5 mm thickness and radicular extension was 62.55 MPa, 45.80 MPa, 74.27 MPa respectively. The corresponding values for the PIC and HTZ ceramics were 26.30 MPa, 21.65 MPa, 25.66 Mpa and 23.47 MPa, 27.30 MPa, 37.29 MPa respectively. The LD ceramic and greater extension inside the pulp chamber had higher fracture resistance.
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Falakaloğlu S, Adıgüzel Ö, Özdemir G. Root canal reconstruction using biological dentin posts: A 3D finite element analysis. J Dent Res Dent Clin Dent Prospects 2020; 13:274-280. [PMID: 32190211 PMCID: PMC7072088 DOI: 10.15171/joddd.2019.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Background. Several types of post have been developed for clinical use. A biological dentin post obtained from an extracted tooth eliminates the problems arising from material differences and reduces the fracture rate in teeth undergoing root canal treatment. This study used finite element analysis to compare a biological dentin post with posts made of two different materials. Methods. Three 3D models of the upper central incisor were created, and stainless-steel, glass fiber and biological dentin posts were applied to these models. The restoration of the models was completed by applying a composite as the core structure and a ceramic crown as the superstructure. Using finite element stress analysis in the restoration models, a 100-N force was applied in the vertical and horizontal directions and at a 45º angle, and the suitability of the biological dentin post was evaluated by comparing the data. Results. Under the applied forces, the greatest stress accumulation was seen in the models with the stainless steel post. Because the stainless steel post was more rigid, stress forces accumulated on the surface instead of being transmitted to the tooth tissue. In the models with the glass fiber and biological dentin posts, the post material responded to the stratification in tandem with the dental tissue and did not cause excessive stress accumulation on the tooth or post surfaces. Conclusion. The results showed that biological dentin posts prevent the accumulation of stresses that might cause fractures in teeth undergoing root canal treatment. In addition, the physical compatibility and biocompatibility of a biological dentin post with the tooth imply that it is a good alternative to the types of post currently used.
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Affiliation(s)
- Seda Falakaloğlu
- Department of Endodontics, Faculty of Dentistry, Afyonkarahisar Health Sciences University, Afyonkarahisar, Turkey
| | - Özkan Adıgüzel
- Department of Endodontics, Faculty of Dentistry, Dicle University, Diyarbakır, Turkey
| | - Gökhan Özdemir
- Dental Prosthetics Technology, Vocational School of Health Services, Bahçeşehir University, Istanbul, Turkey
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Yu P, Xiong Y, Zhao P, Xu Z, Yu H, Arola D, Gao S. On the wear behavior and damage mechanism of bonded interface: Ceramic vs resin composite inlays. J Mech Behav Biomed Mater 2019; 101:103430. [PMID: 31557660 DOI: 10.1016/j.jmbbm.2019.103430] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2019] [Revised: 09/09/2019] [Accepted: 09/12/2019] [Indexed: 02/05/2023]
Abstract
Advances in adhesive technologies have increased indications for the use of inlays. Decrease in the bonded interface integrity due to wear has been cited as the main cause of its failure. However, this process of interface degradation and the influence of inlay material on damage mechanism appear to be poorly understood. Thus, we aimed to compare the wear behavior and interface damage between ceramic and resin composite inlays bonded to enamel under sliding contact and use the experimental findings to support recommendation of the appropriate inlay material. Bonded interface specimens involving tooth enamel and either ceramic or resin composite inlays were prepared and subjected to reciprocating wear tests up to 5×104 cycles. The wear track profiles and morphologies were characterized after increments of cyclic sliding contact using white light interferometry and scanning electron microscopy, respectively. Optical microscopy was used to evaluate sub-surface cracks and their propagation within the samples. A finite element analysis was used to analyze the stress distributions of the bonded interfaces. Composite inlays showed higher wear depth than the ceramic in the early stage (N ≤ 5×102 cycles), while no significant difference was found at the later stage. For ceramic inlay a greater portion of the contact load was concentrated in the ceramic structure, which facilitated cracks and chipping of the ceramic inlay, with rather minimal damage in the adjacent interface and enamel. In contrast, for the resin composite inlay there was larger stress concentrated in the adjacent enamel, which caused the development of cracks and their propagation to the inner enamel. The restoration material could contribute to the stress distribution and extent of damage within enamel-inlay bonded interfaces. A tough ceramic appears to be more effective at protecting the residual dental tissue.
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Affiliation(s)
- Ping Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuhuan Xiong
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Peng Zhao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Zhou Xu
- Shanghai Putuo District Eye & Tooth Disease Control and Prevention Hospital, Shanghai, China
| | - Haiyang Yu
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Dwayne Arola
- Department of Materials Science and Engineering, University of Washington, Seattle, WA, USA; Departments of Oral Health Sciences, School of Dentistry, University of Washington, Seattle, WA, USA; Departments of Restorative Dentistry, School of Dentistry, University of Washington, Seattle, WA, USA
| | - Shanshan Gao
- State Key Laboratory of Oral Diseases, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China.
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Fasbinder DJ, Neiva GF, Heys D, Heys R. Clinical evaluation of chairside Computer Assisted Design/Computer Assisted Machining nano-ceramic restorations: Five-year status. J ESTHET RESTOR DENT 2019; 32:193-203. [PMID: 31393651 DOI: 10.1111/jerd.12516] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2019] [Accepted: 07/22/2019] [Indexed: 11/30/2022]
Abstract
OBJECTIVES This investigation was a longitudinal, randomized clinical trial to measure the clinical performance of a nano-ceramic material (Lava Ultimate/3M) for chairside Computer Assisted Design/Computer Assisted Machining (CAD/CAM) fabricated restorations. MATERIALS AND METHODS One hundred and twenty chairside CAD/CAM onlays were restored with a CEREC system randomly assigned to 60 leucite-reinforced ceramic (IPS EmpressCAD/Ivoclar Vivadent AGBendererstrasse 2FL-9494 SchaanLiechtenstein) onlays and 60 nano-ceramic (Lava Ultimate/3M) onlays. Equal groups of onlays were cemented using a self-etch and a total etch adhesive resin cement. The onlays were recalled for a period of 5 years. RESULTS At 1 week postoperatively, 10% of the onlays cemented with both the self-etch and total etch adhesive resin cements were reported as slightly sensitive. However, all patients were asymptomatic by the 4th week without treatment. Four leucite-reinforced onlays and one nano-ceramic onlay fractured and required replacement. CONCLUSIONS Adhesive retention with a self-etch or total etch cementation technique resulted in a similar clinical outcome with no reported debonds. The nano-ceramic onlays had a lower incidence of fracture compared to the leucite-reinforced ceramic onlays with both having a very low risk of fracture. Nano-ceramic onlays performed equally as well as glass ceramic onlays over 5 years of clinical service. CLINICAL SIGNIFICANCE Ceramic materials have been a mainstay for chairside CAD/CAM restorations for the past 30 years and a new category of resilient ceramics with a resin matrix has been introduced reported to offer ceramic-like durability and esthetics with resin-like efficiency in handling. There are no long-term clinical studies on the performance of these materials. This is a 5-year randomized clinical trial on the performance of nano-ceramic onlays.
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Affiliation(s)
- Dennis J Fasbinder
- Department of Cariology, Restorative Sciences, and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan
| | - Gisele F Neiva
- Department of Cariology, Restorative Sciences, and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan
| | - Donald Heys
- Department of Cariology, Restorative Sciences, and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan
| | - Ronald Heys
- Department of Cariology, Restorative Sciences, and Endodontics, School of Dentistry, University of Michigan, Ann Arbor, Michigan
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Sun J, Ruan W, He J, Lin X, Ci B, Yin S, Yan W. Clinical efficacy of different marginal forms of endocrowns: study protocol for a randomized controlled trial. Trials 2019; 20:454. [PMID: 31340845 PMCID: PMC6657076 DOI: 10.1186/s13063-019-3530-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Accepted: 06/17/2019] [Indexed: 11/23/2022] Open
Abstract
Background After root canal treatment, most tooth defects need to be restored. Onlay restoration is widely used to restore dental defects. Endocrown is a new type of onlay; however, dentists have yet to obtain a full understanding of the clinical effects of marginal forms of endocrowns. Here, we present a multicenter protocol to compare the clinical efficacy of two marginal forms (flat and 90-degree shoulder) for tooth restoration. The efficacy will be evaluated by marginal fit, marginal discoloration, and integrity of restoration. Methods The proposed flat and 90-degree shoulder marginal endocrown assessment trial is an open-label, parallel-group, multicenter randomized controlled trial involving two hospitals. A total of 200 patients will be included in this trial, and the following patient inclusion criteria will be applied: good oral hygiene habits, no periodontal diseases, receipt of standard root canal treatment, and need for endocrown restoration. Patients will be enrolled after providing signed informed consent and will be divided into two groups (flat and 90-degree shoulder endocrown) in accordance with a random number table. Treatment allocation will be balanced (1:1). Endocrowns will be cemented by dual-cured luting composite. Clinical evaluations will be performed at baseline and at 24 months after treatment in accordance with modified US Public Health Service criteria by two independent evaluators. The primary outcome will be marginal fit; secondary outcome measures will include debonding, marginal discoloration, and integrity of restoration. All acquired data will be analyzed by an independent statistician. Wilcoxon one-sample tests will be used for intra-group comparisons, and Wilcoxon two-sample tests will be used for inter-group comparisons. The Bonferroni method will be used to correct for multiple comparisons, and hierarchical logistic regression will be applied to determine central effects. Discussion The results of this trial will provide a clinical basis for clinicians to restore teeth by endocrowns and to improve long-term restoration for patients. Trial registration ClinicalTrials.gov identifier: NCT03398395. Registered on 12 January 2018. Electronic supplementary material The online version of this article (10.1186/s13063-019-3530-1) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Jieli Sun
- Department of Conservative and Endodontic Dentistry, Nanfang Hospital, Southern Medical University, 1838 N Guangzhou Rd, Guangzhou, 510515, China
| | - Wenhao Ruan
- Department of Conservative and Endodontic Dentistry, Nanfang Hospital, Southern Medical University, 1838 N Guangzhou Rd, Guangzhou, 510515, China
| | - Jiahui He
- Department of Conservative and Endodontic Dentistry, Nanfang Hospital, Southern Medical University, 1838 N Guangzhou Rd, Guangzhou, 510515, China
| | - Xiaoyu Lin
- Department of Conservative and Endodontic Dentistry, Nanfang Hospital, Southern Medical University, 1838 N Guangzhou Rd, Guangzhou, 510515, China
| | - Bowen Ci
- Department of Conservative and Endodontic Dentistry, Nanfang Hospital, Southern Medical University, 1838 N Guangzhou Rd, Guangzhou, 510515, China
| | - Siye Yin
- Department of Conservative and Endodontic Dentistry, Nanfang Hospital, Southern Medical University, 1838 N Guangzhou Rd, Guangzhou, 510515, China
| | - Wenjuan Yan
- Department of Conservative and Endodontic Dentistry, Nanfang Hospital, Southern Medical University, 1838 N Guangzhou Rd, Guangzhou, 510515, China.
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Halaçoğlu DM, Yamanel K. The Effects of Different Base Materials on the Stress Distribution of the Endodontically Treated Teeth: 3D FEA. CUMHURIYET DENTAL JOURNAL 2019. [DOI: 10.7126/cumudj.453467] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Yin R, Kim YK, Jang YS, Lee JJ, Lee MH, Bae TS. Comparative evaluation of the mechanical properties of CAD/CAM dental blocks. Odontology 2019; 107:360-367. [PMID: 30610399 DOI: 10.1007/s10266-018-0407-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2018] [Accepted: 12/14/2018] [Indexed: 11/28/2022]
Abstract
This study compares the mechanical properties of commercially available CAD/CAM (Computer-Aided Design/Computer-Aided Manufacturing) millable dental blocks including Vita Enamic, Lava Ultimate, and MAZIC Duro. All the discs were cut in dimension of 1.2 mm in thickness and 12 mm in diameter, ground up to #1200 Sic papers and polished. The biaxial flexure strength of the ceramic discs was measured after thermocycling treatment and the broken surfaces were observed using scanning electron microscopy (SEM). The discs were brushed using a toothbrush testing machine under a 150 g load. Surface roughness and morphology were determined after toothbrushing cycles. Finally, the friction and wear behavior of the materials against an opposing tooth were studied using a reciprocating pin-on-plate test configuration. The vertical loss of dental cusp was measured, and the surface image was examined using field emission scanning electron microscopy (FE-SEM). The biaxial flexural strength data were subjected to Weibull analysis. To compare the significance between the groups, all data were analyzed by one-way analysis (ANOVA). The biaxial flexural strength of the Lava Ultimate and MAZIC Duro materials is significantly higher than that of Vita Enamic. In addition, Lava Ultimate and MAZIC Duro exhibited significantly smoother surfaces than that of Vita Enamic after toothbrushing. Lava Ultimate and MAZIC Duro also showed less wear to the opposing tooth than that of Vita Enamic. In addition, Lava Ultimate possesses more suitable mechanical properties than the Vita Enamic and Mazic Duro for use in oral clinical prosthesis.
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Affiliation(s)
- Ruizhi Yin
- Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, 664-14, Duckjin-dong, Jeonju, 561-756, Republic of Korea
| | - Yu-Kyoung Kim
- Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, 664-14, Duckjin-dong, Jeonju, 561-756, Republic of Korea
| | - Yong-Seok Jang
- Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, 664-14, Duckjin-dong, Jeonju, 561-756, Republic of Korea
| | - Jung-Jin Lee
- Department of Prosthodontics, Institute of Oral Bio-Science, School of Dentistry, Chonbuk National University and Research Institute of Clinical Medicine of Chonbuk National University-Biomedical Research Institute of Chonbuk National University, 664-14, Duckjin-dong, Jeonju, 561-756, Republic of Korea
| | - Min-Ho Lee
- Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, 664-14, Duckjin-dong, Jeonju, 561-756, Republic of Korea
| | - Tae-Sung Bae
- Department of Dental Biomaterials, School of Dentistry, Chonbuk National University, 664-14, Duckjin-dong, Jeonju, 561-756, Republic of Korea.
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Arinc H. Effects of Prosthetic Material and Framework Design on Stress Distribution in Dental Implants and Peripheral Bone: A Three-Dimensional Finite Element Analysis. Med Sci Monit 2018; 24:4279-4287. [PMID: 29930240 PMCID: PMC6045918 DOI: 10.12659/msm.908208] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
BACKGROUND The purpose of this study was to evaluate the effects of prosthetic material and framework design on the stress within dental implants and peripheral bone using finite element analysis (FEA). MATERIAL AND METHODS A mandibular implant-supported fixed dental prosthesis with different prosthetic materials [cobalt-chromium-supported ceramic (C), zirconia-supported ceramic (Z), and zirconia-reinforced polymethyl methacrylate (ZRPMMA)-supported resin (ZP)] and different connector widths (2, 3, and 4 mm) within the framework were used to evaluate stress via FEA under oblique loading conditions. Maximum principal (smax), minimum principal (smin), and von Mises (svM) stress values were obtained. RESULTS Minimum stress values were observed in the model with a 2-mm connector width for C and ZP. The models with 3-mm and 4-mm connector widths showed higher stress values than the model with a 2-mm connector width for C (48-50%) and ZP (50-52%). Similar stress values were observed in the 3- and 4-mm models. There was no significant difference in the amount of stress with Z regardless of connector width. The Z and ZP models showed similar stress values in the 3- and 4-mm models and higher stress values than in the C model. Z, ZP, and C showed the highest stress values for the model with a 2-mm connector width. CONCLUSIONS Changes in the material and width of connectors may influence stress on cortical bone, cancellous bone, and implants. C was associated with the lowest stress values. Higher maximum and minimum principal stress values were seen in cortical bone compared to cancellous bone.
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Affiliation(s)
- Hakan Arinc
- Department of Prosthodontics, Faculty of Dentistry, Near East University, Mersin, Turkey
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Yang H, Park C, Shin JH, Yun KD, Lim HP, Park SW, Chung H. Stress distribution in premolars restored with inlays or onlays: 3D finite element analysis. J Adv Prosthodont 2018; 10:184-190. [PMID: 29930787 PMCID: PMC6004358 DOI: 10.4047/jap.2018.10.3.184] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Revised: 12/20/2017] [Accepted: 02/27/2018] [Indexed: 11/08/2022] Open
Abstract
PURPOSE To analyze stress distribution in premolars restored with inlays or onlays using various materials. MATERIALS AND METHODS Three-dimensional maxillary premolar models of abutments were designed to include the following: 1) inlay with O cavity (O group), 2) inlay with MO cavity (MO group), 3) inlay with MOD cavity (MOD group), and 4) onlay (ONLAY group). A restoration of each inlay or onlay cavity was simulated using gold alloy, e.max ceramic, or composite resin for restoration. To simulate masticatory forces, a total of 140 N static axial force was applied onto the tooth at the occlusal contact areas. A finite element analysis was performed to predict the magnitude and pattern of stresses generated by occlusal loading. RESULTS Maximum von Mises stress values generated in the abutment teeth of the ONLAY group were ranged from 26.1 to 26.8 MPa, which were significantly lower than those of inlay groups (O group: 260.3-260.7 MPa; MO group: 252.1-262.4 MPa; MOD group: 281.4-298.8 MPa). Maximum von Mises stresses generated with ceramic, gold, and composite restorations were 280.1, 269.9, and 286.6 MPa, respectively, in the MOD group. They were 252.2, 248.0, 255.1 MPa, respectively, in the ONLAY group. CONCLUSION The onlay design (ONLAY group) protected tooth structures more effectively than inlay designs (O, MO, and MOD groups). However, stress magnitudes in restorations with various dental materials exhibited no significant difference among groups (O, MO, MOD, ONLAY).
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Affiliation(s)
- Hongso Yang
- Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Chan Park
- Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Jin-Ho Shin
- Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Kwi-Dug Yun
- Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Hyun-Pil Lim
- Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Sang-Won Park
- Department of Prosthodontics, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
| | - Hyunju Chung
- Department of Periodontology, School of Dentistry, Chonnam National University, Gwangju, Republic of Korea
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Özkir SE. Effect of restoration material on stress distribution on partial crowns: A 3D finite element analysis. J Dent Sci 2018; 13:311-317. [PMID: 30895139 PMCID: PMC6388833 DOI: 10.1016/j.jds.2017.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2016] [Revised: 02/18/2017] [Accepted: 03/01/2017] [Indexed: 12/04/2022] Open
Abstract
Background/purpose Various restoration materials have been used to restore as onlay materials to restore highly defected molar teeth. Different mechanical and physical properties of these materials may affect the success or survival of the restoration. The purpose of this study was to evaluate the restoration materials effects on stress distribution. Materials and methods Three dimensional finite element analysis (FEA) was used to evaluate the stress concentrations and distributions at the restoration and the tooth. Maxillar first molar tooth constructed to evaluate the stress distribution and concentration levels at the restorations and the tooth structure. Two kinds of restoration materials, bulkfill composite and conventional hybrid composite was evaluated for direct method, while full ceramic and indirect composite was used for indirect method. A load of 200 N was applied on the restorations and stress levels were calculated by von Mises stress values. Results Highest stress concentration was observed at the ceramic restoration (3.77 GPa). Stress levels were 2.90 GPa for bulkfill composite and 2.14 GPa for direct and indirect composite. At the tooth structure the stress levels were 3.33 GPa, 3.18 GPa and 2.48 GPa for bulkfill, direct and indirect composites respectively. The lowest stress values was observed with the porcelain restoration (1.69 GPa). Stress concentrations at the adhesive system were 2.10 MPa for bulkfill composite, 1.35 MPa for direct and indirect composites and 1.25 Mpa for porcelain restoration. Conclusion The restoration material affects the stress levels at the restoration and the tooth while the stress concentration areas remained nearly the same.
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Affiliation(s)
- Serhat Emre Özkir
- Afyon Kocatepe University, Faculty of Dentistry, Department of Restorative Dentistry, Afyonkarahisar, Turkey
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Yoon HI, Sohn PJ, Jin S, Elani H, Lee SJ. Fracture Resistance of CAD/CAM-Fabricated Lithium Disilicate MOD Inlays and Onlays with Various Cavity Preparation Designs. J Prosthodont 2018. [PMID: 29533499 DOI: 10.1111/jopr.12787] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
PURPOSE To examine the fracture resistance of premolars restored with CAD/CAM lithium disilicate mesio-occlusal-distal (MOD) inlays and onlays of different cavity designs. MATERIALS AND METHODS Two widths of occlusal isthmus (75%, 100% of intercuspal distance) and three designs of cuspal coverage (none, palatal, complete) were used for the preparation of MOD inlays and onlays in the extracted maxillary premolars. Sixty lithium disilicate restorations were milled and bonded into the cavities. After 24 hours of water storage, the specimens were loaded until fracture, and the fracture loads (N) were measured. Any evidence of cracks and fractures on the tested specimens were examined to classify failure patterns. RESULTS Mean fracture load values for the tested groups were as follows: 664.4 ± 214.7 N (group A), 659.3 ± 391.2 N (B), 681.9 ± 258.1 N (C), 938.1 ± 862.0 N (D), 841.7 ± 375.4 N (E), and 994.2 ± 486.3 N (F). The width of occlusal isthmus did not significantly affect the fracture loads among all the groups. Within groups with identical isthmus width, the fracture loads showed no significant difference depending on the designs of cuspal coverage. The majority of specimens showed either type III or IV fracture mode. CONCLUSIONS Within limitations of this study, the bonded restorations of premolars with CAD/CAM-generated lithium disilicate were reliable, regardless of cavity preparation design.
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Affiliation(s)
- Hyung-In Yoon
- Department of Prosthodontics, School of Dentistry, Seoul National University, Seoul, Korea
| | - Paul J Sohn
- Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA
| | - Sharon Jin
- Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA
| | - Hawazin Elani
- Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA
| | - Sang J Lee
- Department of Restorative Dentistry and Biomaterials Sciences, Harvard School of Dental Medicine, Boston, MA
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Wafaie RA, Ibrahim Ali A, Mahmoud SH. Fracture resistance of prepared premolars restored with bonded new lab composite and all-ceramic inlay/onlay restorations: Laboratory study. J ESTHET RESTOR DENT 2018; 30:229-239. [PMID: 29368375 DOI: 10.1111/jerd.12364] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Affiliation(s)
- Ramy Ahmed Wafaie
- Department of Operative Dentistry, Faculty of Oral and Dental Medicine; Delta University for Science and Technology; Gamasa Egypt
| | - Ashraf Ibrahim Ali
- Department of Operative Dentistry, Faculty of Dentistry; Mansoura University; Mansoura Egypt
| | - Salah Hasab Mahmoud
- Operative Dentistry Department, Faculty of Dentistry; Mansoura University; Mansoura Egypt
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Doğan MS, Demirci F, Eratilla E, Eratilla V, Yavuz Y, Unal M. Evaluation of stress distribution of a new restorative material and composite resin: a finite-element analysis study. BIOTECHNOL BIOTEC EQ 2017. [DOI: 10.1080/13102818.2017.1373600] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
Affiliation(s)
- Mehmet Sinan Doğan
- Department of Pediatric Dentistry, Faculty of Dentistry, Harran University, Şanlıurfa, Turkey
| | - Fatih Demirci
- Nuh Cimento Sanayi Vakfi Oral and Dental Health Center, Kocaeli, Turkey
| | - Elif Eratilla
- Department of Restorative Dentistry, Faculty of Dentistry, Dicle University, Diyarbakır, Turkey
| | - Veysel Eratilla
- Diyarbakır Oral and Dental Health Center, Diyarbakır, Turkey
| | - Yasemin Yavuz
- Department of Restorative Dentistry, Faculty of Dentistry, Dicle University, Diyarbakır, Turkey
| | - Mehmet Unal
- Department of Pediatric Dentistry, Faculty of Dentistry, Afyon Kocatepe University, Afyon, Turkey
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Effect of Endocrown Restorations with Different CAD/CAM Materials: 3D Finite Element and Weibull Analyses. BIOMED RESEARCH INTERNATIONAL 2017; 2017:5638683. [PMID: 29119108 PMCID: PMC5651139 DOI: 10.1155/2017/5638683] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/18/2017] [Accepted: 08/08/2017] [Indexed: 11/23/2022]
Abstract
The aim of this study was to evaluate the effects of two endocrown designs and computer aided design/manufacturing (CAD/CAM) materials on stress distribution and failure probability of restorations applied to severely damaged endodontically treated maxillary first premolar tooth (MFP). Two types of designs without and with 3 mm intraradicular extensions, endocrown (E) and modified endocrown (ME), were modeled on a 3D Finite element (FE) model of the MFP. Vitablocks Mark II (VMII), Vita Enamic (VE), and Lava Ultimate (LU) CAD/CAM materials were used for each type of design. von Mises and maximum principle values were evaluated and the Weibull function was incorporated with FE analysis to calculate the long term failure probability. Regarding the stresses that occurred in enamel, for each group of material, ME restoration design transmitted less stress than endocrown. During normal occlusal function, the overall failure probability was minimum for ME with VMII. ME restoration design with VE was the best restorative option for premolar teeth with extensive loss of coronal structure under high occlusal loads. Therefore, ME design could be a favorable treatment option for MFPs with missing palatal cusp. Among the CAD/CAM materials tested, VMII and VE were found to be more tooth-friendly than LU.
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Çelik Köycü B, Imirzalioğlu P, Özden UA. Three-dimensional finite element analysis of stress distribution in inlay-restored mandibular first molar under simultaneous thermomechanical loads. Dent Mater J 2017; 35:180-6. [PMID: 27041006 DOI: 10.4012/dmj.2014-341] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Functional occlusal loads and intraoral temperature changes create stress in teeth. The purpose of this study was to evaluate the impact of simultaneous thermomechanical loads on stress distribution related to inlay restored teeth by three-dimensional finite element analysis. A mandibular first molar was constructed with tooth structures, surrounding bone and inlays of Type II gold alloy, ceramic, and composite resin. Stress patterns on the restorative materials, adhesive resin, enamel and dentin were analyzed after simulated temperature changes from 36°C to 4 or 60°C for 2 s with 200-N oblique loading. The results showed that the three types of inlays had similar stress distribution in the tooth structures and restorative materials. Concerning the adhesive resin, the composite resin inlay model exhibited lower stresses than ceramic and gold alloy inlays. Simultaneous thermomechanical loads caused high stress patterns in inlay-restored teeth. Composite resin inlays may be the better choice to avoid adhesive failure.
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Affiliation(s)
- Berrak Çelik Köycü
- Department of Prosthetic Dentistry, Faculty of Dentistry, Başkent University
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Trindade FZ, Valandro LF, de Jager N, Bottino MA, Kleverlaan CJ. Elastic Properties of Lithium Disilicate Versus Feldspathic Inlays: Effect on the Bonding by 3D Finite Element Analysis. J Prosthodont 2016; 27:741-747. [DOI: 10.1111/jopr.12550] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/21/2016] [Indexed: 01/06/2023] Open
Affiliation(s)
- Flávia Zardo Trindade
- Department of Dental Materials and Prosthodontics, Araraquara School of Dentistry; Univ. Estadual Paulista; Araraquara Brazil
- Department of Dental Materials and Prosthodontics, Instituto de Ciência e Tecnologia-ICT; Univ Estadual Paulista-UNESP; São José dos Campos Brazil
| | - Luiz Felipe Valandro
- Department of Restorative Dentistry (Prosthodontics), School of Dentistry; Federal University of Santa Maria; Rio Grande do Sul State Santa Maria Brazil
| | - Niek de Jager
- Department of Dental Materials Science at ACTA; Universiteit van Amsterdam and Vrije Universiteit; Amsterdam The Netherlands
| | - Marco Antônio Bottino
- Department of Dental Materials and Prosthodontics, Instituto de Ciência e Tecnologia-ICT; Univ Estadual Paulista-UNESP; São José dos Campos Brazil
| | - Cornelis Johannes Kleverlaan
- Department of Dental Materials Science at ACTA; Universiteit van Amsterdam and Vrije Universiteit; Amsterdam The Netherlands
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Mynampati P, Babu MR, Saraswathi DD, Kumar JR, Gudugunta L, Gaddam D. Comparison of fracture resistance and failure pattern of endodontically treated premolars with different esthetic onlay systems: An in vitro study. J Conserv Dent 2015; 18:140-3. [PMID: 25829694 PMCID: PMC4379655 DOI: 10.4103/0972-0707.153072] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2014] [Revised: 01/13/2015] [Accepted: 01/26/2015] [Indexed: 11/06/2022] Open
Abstract
Aim: To compare the fracture resistance and modes of failures of three different aesthetic MOD onlays on endodontically treated premolars. Materials and Methods: Forty sound maxillary premolars were selected of which 10 untreated teeth were taken as control (Group I). The other thirty premolars were subjected to standardized MOD onlay preparations and root canal treatments and divided into 3 equal groups. Onlays were prepared in Group II- Indirect composite, Group III- Lithium Disilicate ceramic and Group IV- Full Zirconia. All onlays were cemented using Multilink Automix. All the 40 samples were subjected to fracture resistance testing on Universal testing machine. Also fractured specimens were observed under stereo-microscope for modes of failure. Results: Group IV presented the highest fracture resistance. Groups II and III presented no significant difference in fracture resistance from each other (P > 0.05). Group II and Group III showed significantly lower fracture resistance values than Group I. Coming to modes of failure, only Group IV had showed no cracks in any of the restorations. Conclusion: Full Zirconia MOD onlays increased the fracture resistance of endodontically treated premolars to a significantly higher level than the sound teeth.
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Affiliation(s)
- Praffulla Mynampati
- Department of Conservative Dentistry and Endodontics, Drs Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinoutapalli, Andhra Pradesh, India
| | - Mandava Ramesh Babu
- Department of Conservative Dentistry and Endodontics, Drs Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinoutapalli, Andhra Pradesh, India
| | - Devabhaktuni Disha Saraswathi
- Department of Conservative Dentistry and Endodontics, Drs Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinoutapalli, Andhra Pradesh, India
| | - Janga Ravi Kumar
- Department of Conservative Dentistry and Endodontics, Drs Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinoutapalli, Andhra Pradesh, India
| | - Leneena Gudugunta
- Department of Conservative Dentistry and Endodontics, Drs Sudha and Nageswara Rao Siddhartha Institute of Dental Sciences, Chinoutapalli, Andhra Pradesh, India
| | - Divya Gaddam
- Department of Pedodontics and Preventive Dentistry, Mamata Dental College, Khammam, Telangana, India
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Homsy F, Eid R, El Ghoul W, Chidiac JJ. Considerations for Altering Preparation Designs of Porcelain Inlay/Onlay Restorations for Nonvital Teeth. J Prosthodont 2015; 24:457-62. [PMID: 25754648 DOI: 10.1111/jopr.12279] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/23/2014] [Indexed: 11/29/2022] Open
Abstract
PURPOSE The aim of this study was to compare all ceramic inlay/onlay survival rates in vital and nonvital teeth having the same cavity design. Filling the pulp chamber with ceramic materials or not was also discussed. MATERIALS AND METHODS Ceramic class II inlays/onlays were made on 11 premolars and 30 molars: 14 vital, 27 endodontically treated. The same tooth preparation design was performed on vital and nonvital teeth: In nonvital teeth the pulp chambers were covered by a glass ionomer cement until the pulpal floor depths were between 2 and 2.5 mm, more likely similar to the vital teeth preparations. In vital teeth, glass ionomer was used as a liner to achieve pulpal floor depths between 2 and 2.5 mm when needed. The restorations were assessed (at baseline, 6 months, 1 and 2 years) according to three criteria: marginal discoloration, marginal integrity, and fracture of teeth/restorations, consistent with United States Public Health Service (USPHS) criteria. RESULTS Eight teeth (19%) showed minor marginal discolorations, while three molars (7%) had loss of marginal integrity. These margins were adjusted using rubber polishing cups and were then judged clinically acceptable. From these three molars, one was vital and two were endodontically treated. No fracture of teeth or restorations was observed. Chi square and exact probability tests were used. There was no statistical difference between vital and nonvital teeth (p = 0.719 chi-squared and Fisher) or between premolars and molars (p = 0.564 chi-squared; 1.000, Fisher). CONCLUSION Within the limitations of this study there was no difference for the same inlay/onlay cavity design between vital and nonvital teeth. In nonvital teeth, it seems that filling the pulp chamber with a ceramic core material is not important. Long-term observation periods are needed to reinforce the clinical behavior outcome.
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Affiliation(s)
- Foudda Homsy
- Department of Prosthodontics, Lebanese University, Baabda, Lebanon
| | - Rita Eid
- Department of Prosthodontics, Lebanese University, Baabda, Lebanon
| | - Wiam El Ghoul
- Department of Prosthodontics, Lebanese University, Baabda, Lebanon
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Dejak B, Młotkowski A. A comparison of stresses in molar teeth restored with inlays and direct restorations, including polymerization shrinkage of composite resin and tooth loading during mastication. Dent Mater 2014; 31:e77-87. [PMID: 25544104 DOI: 10.1016/j.dental.2014.11.016] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2014] [Revised: 06/11/2014] [Accepted: 11/26/2014] [Indexed: 11/17/2022]
Abstract
UNLABELLED Polymerization shrinkage of composites is one of the main causes of leakage around dental restorations. Despite the large numbers of studies there is no consensus, what kind of teeth reconstruction--direct or indirect composite restorations are the most beneficial and the most durable. OBJECTIVE The aim was to compare equivalent stresses and contact adhesive stresses in molar teeth with class II MOD cavities, which were restored with inlays and direct restorations (taking into account polymerization shrinkage of composite resin) during simulated mastication. METHOD The study was conducted using the finite elements method with the application of contact elements. Three 3D models of first molars were created: model A was an intact tooth; model B--a tooth with a composite inlay, and model C--a tooth with a direct composite restoration. Polymerization linear shrinkage 0.7% of a direct composite restoration and resin luting cement was simulated (load 1). A computer simulation of mastication was performed (load 2). In these 2 situations, equivalent stresses according to the modified von Mises criterion (mvM) in the materials of mandibular first molar models with different restorations were calculated and compared. Contact stresses in the luting cement-tooth tissue adhesive interface around the restorations were also assessed and analyzed. RESULTS Equivalent stresses in a tooth with a direct composite restoration (the entire volume of which was affected by polymerization shrinkage) were many times higher than in the tooth restored with a composite inlay (where shrinkage was present only in a thin layer of the luting cement). In dentin and enamel the stress values were 8-14 times higher, and were 13 times higher in the direct restoration than in the inlay. Likewise, contact stresses in the adhesive bond around the direct restoration were 6.5-7.7 times higher compared to an extraorally cured restoration. In the masticatory simulation, shear contact stresses in the adhesive bond around the direct composite restoration reached the highest values 32.8 MPa and significantly exceeded the shear strength of the connection between the resin luting cement and the tooth structure. SIGNIFICANCE Equivalent stresses in the tooth structures restored with inlays and in the restoration material itself and contact stresses at the tooth-luting cement adhesive interface are many times lower compared to teeth with direct composite restorations. Teeth with indirect restorations are potentially less susceptible to damage compared to those with direct restorations. Composite inlays also ensure a better seal compared to direct restorations. Polymerization shrinkage determines stress levels in teeth with direct restorations, while its impact on adhesion in indirectly restored teeth is insignificant.
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Affiliation(s)
- Beata Dejak
- Department of Prosthetic Dentistry, Medical University of Łódź, Łódź, Poland.
| | - Andrzej Młotkowski
- Department of Strength of Materials and Structures, Technical University of Łódź, Łódź, Poland
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Liu X, Fok A, Li H. Influence of restorative material and proximal cavity design on the fracture resistance of MOD inlay restoration. Dent Mater 2014; 30:327-33. [DOI: 10.1016/j.dental.2013.12.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 09/07/2013] [Accepted: 12/13/2013] [Indexed: 11/17/2022]
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50
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Fron Chabouis H, Smail Faugeron V, Attal JP. Clinical efficacy of composite versus ceramic inlays and onlays: A systematic review. Dent Mater 2013; 29:1209-18. [DOI: 10.1016/j.dental.2013.09.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Revised: 07/06/2013] [Accepted: 09/16/2013] [Indexed: 11/25/2022]
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