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Lin F, Feng X, Ordinola-Zapata R, VanHeel B, Fok ASL. Load capacity and fracture modes of instrumented tooth roots under axial compression. Dent Mater 2023; 39:938-945. [PMID: 37648562 DOI: 10.1016/j.dental.2023.08.177] [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: 08/19/2023] [Accepted: 08/23/2023] [Indexed: 09/01/2023]
Abstract
OBJECTIVE To investigate the influences of root canal instrumentation on the load capacity and fracture modes of tooth roots under axial compression by performing mechanical tests and finite element analysis (FEA). METHODS Thirty bovine incisor roots were trimmed into cylinders of 5.0 mm diameter. They were randomly divided into two groups, one with root canals instrumented to ∼2.0 mm in diameter, and one without instrumentation. The specimens were fractured under uniaxial compression at a crosshead speed of 0.2 mm/min, and then micro-CT was used to reveal the fracture patterns in three dimensions. FEA was further performed, using the extended finite element method (XFEM), to compare the compression-induced stress distributions and the initiation and propagation of root fractures in both groups. RESULTS The mean fracture load of the non-instrumented group (2334 ± 436 N) was statistically significantly higher than that of the instrumented group (1857 ± 377 N) (p < 0.01). Three types of root fractures were identified according to the path and length of the cracks: end-face crack, partial-length crack, and full-length crack. As to the fracture modes, the incidence of partial-length root fracture was the highest in both groups (60% for the non-instrumented group and 53.3% for the instrumented group), followed by that of full-length fracture (26.7% and 40%, respectively) and then end-face fracture (13.3% and 6.7%, respectively). The percentage of full-length fracture was slightly higher in the instrumented group. FEA showed that the compression induced higher Tresca stresses but lower maximum principal stresses in the canal walls of the instrumented group. The XFEM simulations predicted that the fracture of both groups initiated from the outer root surface near an end face and propagated axially to the middle third of the root and radially towards the root canal. These numerical results agreed well with our experimental findings. SIGNIFICANCE Within the limitation of this study, it was found that root canal instrumentation could significantly decrease the load capacity of tooth roots and potentially increase their susceptibility to full-length root fracture under uniaxial compression.
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Affiliation(s)
- Fei Lin
- Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China
| | - Xiqiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Ronald Ordinola-Zapata
- Division of Endodontics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Bonita VanHeel
- Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alex S L Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA.
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Wang X, Wang D, Wang YR, Cheng XG, Ni LX, Wang W, Tian Y. Effect of access cavities on the biomechanics of mandibular molars: a finite element analysis. BMC Oral Health 2023; 23:196. [PMID: 37009868 PMCID: PMC10069102 DOI: 10.1186/s12903-023-02878-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/13/2023] [Indexed: 04/04/2023] Open
Abstract
INTRODUCTION This study aimed to predict the fracture resistance of a mandibular first molar (MFM) with diverse endodontic cavities using finite element analysis (FEA). METHODS Five experimental finite element models representing a natural tooth (NT) and 4 endodontically treated MFMs were generated. Treated MFM models were with a traditional endodontic cavity (TEC) and minimally invasive endodontic (MIE) cavities, including guided endodontic cavity (GEC), contracted endodontic cavity (CEC) and truss endodontic cavity (TREC). Three loads were applied, simulating a maximum bite force of 600 N (N) vertically and a normal masticatory force of 225 N vertically and laterally. The distributions of von Mises (VM) stress and maximum VM stress were calculated. RESULTS The maximum VM stresses of the NT model were the lowest under normal masticatory forces. In endodontically treated models, the distribution of VM stress in GEC model was the most similar to NT model. The maximum VM stresses of the GEC and CEC models under different forces were lower than those of TREC and TEC models. Under vertical loads, the maximum VM stresses of the TREC model were the highest, while under the lateral load, the maximum VM stress of the TEC model was the highest. CONCLUSION The stress distribution of tooth with GEC was most like NT. Compared with TECs, GECs and CECs may better maintain fracture resistance, TRECs, however, may have a limited effect on maintenance of the tooth resistance.
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Affiliation(s)
- Xiao Wang
- Department of Endodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, The Fourth Military Medical University, 710032, Xi'an, China
| | - Dan Wang
- Department of Endodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, The Fourth Military Medical University, 710032, Xi'an, China
| | - Yi-Rong Wang
- Department of Endodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, The Fourth Military Medical University, 710032, Xi'an, China
| | - Xiao-Gang Cheng
- Department of Endodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, The Fourth Military Medical University, 710032, Xi'an, China
| | - Long-Xing Ni
- Department of Endodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, The Fourth Military Medical University, 710032, Xi'an, China
| | - Wei Wang
- Department of Endodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, The Fourth Military Medical University, 710032, Xi'an, China.
| | - Yu Tian
- Department of Endodontics, School of Stomatology, State Key Laboratory of Military Stomatology & National Clinical Research Center for Oral Diseases & Shaanxi Clinical Research Center for Oral Diseases, The Fourth Military Medical University, 710032, Xi'an, China.
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García-Guerrero C, Mendoza-Beltrán W, Roldan-Roldan M, Villa-Machado P, Restrepo-Restrepo F. Vertical root fractures: A time-dependent clinical condition. A case-control study in two colombian populations. J Clin Exp Dent 2021; 13:e1104-e1111. [PMID: 34824696 PMCID: PMC8601699 DOI: 10.4317/jced.58701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/20/2021] [Indexed: 12/02/2022] Open
Abstract
Background This nested case-control study can be viewed as an efficient way to sample subjects from a large cohort study case-control study aimed to analyze the effect of different clinical factors on the appearance of vertical root fractures in endodontically-treated teeth (ETT) over time.
Material and Methods By matching 90 cases and 270 controls nested in a cohort of 450 patients. Incident “cases” included those ETT in which a confirmed VRF. The “controls” were ETT with clinical and radiographic evidence of normality. When an “incident case” was detected, three random “controls” according to the evaluation time registered in years were selected. Time interval corresponded to the exposure time from the end of the endodontic treatment until the tooth was included in the study. Demographic and clinical parameters included: age, gender, type, and location of the tooth, type of endodontic treatment, number of appointments necessary to complete the endodontic treatment, use of intra-canal medication, the apical extension of the filling, type of coronal restoration, the role of the tooth in the rehabilitation treatment, presence of intra-radicular posts, and presence of an adjacent implant, were analyzed over time. Statistical analysis: univariate descriptive analysis, Pearson’s χ2 test, and a logistic regression model adjusted for the most significant variables with a 95% confidence interval.
Results The prevalence of vertical root fractures was 16.42%. The multivariate analysis confirmed that re-treatment (OR:12.19; OR:4.28;P<0.05) lasting five to ten years and intra-canal medication (OR:6.16;P=0.004) for more than eleven years significantly more associated with the risk of vertical root fracture. For teeth with intra-canal post or direct coronal restorations, the risk of vertical root fracture was three times lower.
Conclusions Endodontic re-treatment and the use of intracanal medication such as calcium hydroxide should be considered primary and secondary risk factors, respectively, according to the appearance of VRF over time. Key words:Apical surgery, endodontic re-treatment, endodontically-treated teeth, risk factors, vertical root fracture.
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Affiliation(s)
- Claudia García-Guerrero
- DDS, MSc. Universidad Nacional de Colombia, Sede Bogotá, Facultad de Odontología, Departamento de Ciencias Básicas y Medicina Oral, Grupo de investigación INVENDO, Bogotá D.C., Colombia
| | - William Mendoza-Beltrán
- DDS. Universidad Nacional de Colombia, Sede Bogotá, Facultad de Odontología, Departamento de Ciencias Básicas y Medicina Oral, Grupo de investigación INVENDO, Bogotá D.C., Colombia
| | - Mateo Roldan-Roldan
- DDS. Endodontist, Universidad de Antioquia. Medellín, Colombia, Laboratory of Immunodetection and Bioanalysis. Medellín, ColombiaDDS. Endodontist, Universidad de Antioquia. Medellín, Colombia, Laboratory of Immunodetection and Bioanalysis. Medellín, Colombia
| | - Paula Villa-Machado
- DDS. Endodontist, Universidad de Antioquia. Medellín, Colombia, Faculty of Dentistry, Laboratory of Immunodetection and Bioanalysis. Medellín, Colombia
| | - Felipe Restrepo-Restrepo
- DDS. Endodontist, Universidad de Antioquia. Medellín, Colombia, Faculty of Dentistry, Laboratory of Immunodetection and Bioanalysis. Medellín, Colombia
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Houg KP, Adanty K, MacGillivray SR, McAllister L, Levin L, Alexiou M, Graf D, Romanyk DL, Dennison CR. On the ability of experimental impact measures to predict tooth injuries in an ex vivo swine model. Dent Traumatol 2021; 37:464-473. [PMID: 33550707 DOI: 10.1111/edt.12645] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Revised: 11/26/2020] [Accepted: 11/28/2020] [Indexed: 12/01/2022]
Abstract
BACKGROUND/AIM Impact to the orofacial region, in particular teeth, is a frequent incident leading to injury in many sports and can result in health and economic costs for the injured individual. The majority of previous work has applied synthetic models such as plaster or stone, to form analogs of relevant structures to study the potential for impact-induced injury. Biomechanical studies that have applied tissue models (animal or human) for the purpose of determining the biomechanical measures associated with dental injury are rare. The aim of this study was to apply a simple ex vivo model based on swine dentition to ascertain which of a select list of measurable quantities associated with impact mechanics could predict luxation and fracture of teeth due to impact. METHODS Mandibular central incisors of ex vivo swine dentitions were impacted using a linear drop tower with heights ranging from 1.20 m to 2.42 m. Seven mechanical predictors were assessed at impact and were then subjected to binary logistic regression techniques to determine which was the best predictor of luxations or fractures of the teeth. RESULTS Of the seven mechanical predictors, (1) the velocity of the impacting body (R2 = 0.477), (2) a proxy measure for the change in kinetic energy of the impacting body (R2 = 0.586), and (3) the approximate energy absorbed by the tissue (R2 = 0.722) were found to be statistically significantly different (p < .05), offering the greatest specificity as indicated by receiver operator characteristics. Other measures that are frequently used in impact mechanics, including peak linear acceleration and velocity change, were not statistically significant predictors of tooth injury. CONCLUSION Identifying mechanical predictors for dental injury of unprotected teeth provides a first step in understanding which aspects of an impact event attribute to dental injury and can lay the foundation for future studies that examine alteration in injury mechanics associated with protection devices.
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Affiliation(s)
- Kathryn P Houg
- Biomedical Instrumentation Lab, University of Alberta, Edmonton, Alberta, Canada.,Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Kevin Adanty
- Biomedical Instrumentation Lab, University of Alberta, Edmonton, Alberta, Canada.,Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Samantha R MacGillivray
- Biomedical Instrumentation Lab, University of Alberta, Edmonton, Alberta, Canada.,Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Lowell McAllister
- Biomedical Instrumentation Lab, University of Alberta, Edmonton, Alberta, Canada.,Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
| | - Liran Levin
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Maria Alexiou
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Daniel Graf
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Dan L Romanyk
- Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada.,Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Christopher R Dennison
- Biomedical Instrumentation Lab, University of Alberta, Edmonton, Alberta, Canada.,Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta, Canada
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Loroño G, Zaldívar JMR, Jimenez-Octavio JR, Dorado S, Arias A, Cisneros R. CFD analysis on the effect of combining positive and negative pressure during the irrigation of artificial isthmuses. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2020; 36:e3385. [PMID: 32639658 DOI: 10.1002/cnm.3385] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2019] [Revised: 06/16/2020] [Accepted: 07/05/2020] [Indexed: 06/11/2023]
Abstract
Fluid dynamics generated by irrigation needles have not been deeply analyzed in root canal irregularities such as apical ramifications or isthmus where the cleaning capacity of irrigants might be compromised and hence the treatment outcome. The goal of this study was to compare the key irrigation parameters (flow pattern, irrigant velocity, apical pressure, and shear stress) between two irrigation needles and the additional effect of aspiration cannulas through computational fluid dynamics. A 3D-model consisting of two canals linked by an isthmus was modeled. The abovementioned needles irrigated the primary canal, whereas an aspiration cannula was located inside the secondary canal. Both the geometry definition and spatial discretization were carried out with ANSYS 16.2, through which six different simulations were performed: lateral exit (LE) needle, frontal exit (FE) needle, LE and cannula in crown (LEC), FE and cannula in crown (FEC), LE and cannula in middle third (LEM), FE and cannula in middle third (FEM). FE and FEM showed that the irrigation flow only passes through the isthmus in the most apical section (maximum irrigant velocity / shear stress = 8.44 m/s / 1628.44 Pa and 8.63 m/s / 1185.69 Pa, respectively). However, the remaining simulations showed the irrigation flow passing through the isthmus twice, through the most apical section first and through the upper part of the isthmus later (maximum irrigant velocity / shear stress = 8.48 m/s / 1298.24 Pa (LE), 8.61 m/s / 1261.36 Pa (LEM), 8.61 m/s / 1355.24 Pa (LEC), 8.59 m/s / 1256.87 Pa (FEC)). Furthermore, the highest velocity values were detected when aspiration cannulas were added.
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Affiliation(s)
- Gaizka Loroño
- Departamento de Endodoncia, Universidad Europea de Madrid, Madrid, Spain
| | - J M R Zaldívar
- Departamento de Endodoncia, Universidad Europea de Madrid, Madrid, Spain
| | - J R Jimenez-Octavio
- Universidad Pontificia Comillas, Escuela Técnica Superior de Ingeniería ICAI, Instituto de Investigación Tecnológica, Madrid, Spain
| | - Saul Dorado
- Universidad Pontificia Comillas, Escuela Técnica Superior de Ingeniería ICAI, Instituto de Investigación Tecnológica, Madrid, Spain
| | - Ana Arias
- Departamento de Odontología Conservadora, Facultad (Estomatologia II) de Odontología, Universidad Complutense de Madrid, Madrid, Spain
| | - Rafael Cisneros
- Departamento de Endodoncia, Universidad Europea de Madrid, Madrid, Spain
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Aydın U, Aksoy F, Tosun S. Fracture resistance of root-filled teeth after cavity preparation with conventional burs, Er: YAG and Er,Cr: YSGG lasers. Eur Oral Res 2019; 52:59-63. [PMID: 30775703 DOI: 10.26650/eor.2018.442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2017] [Revised: 02/03/2017] [Accepted: 02/21/2017] [Indexed: 11/20/2022] Open
Abstract
Purpose The aim of the present study is to compare the fracture resistance of teeth after access cavity preparation with conventional rotary burs, Erbium-doped yttrium aluminum garnet laser (Er:YAG) and Erbium, cromium: yttrium scandium gallium garnet laser (Er,Cr:YSGG) lasers. Materials and methods Fifty five intact mandibular molars were divided into 3 negative groups (groups 1, 2, 3; n=5 for each), 3 study groups (groups 4, 5, 6; n=10 for each) and 1 positive control group (intact teeth; n=10). Access cavities of groups 1, 2 and 3 were prepared with conventional burs, Er:YAG laser and Er,Cr:YSGG laser respectively. After root canal obturation, their coronal portions were left non-restored. Access cavities of groups 4, 5 and 6 were prepared by using the same equipment but their coronal portions were restored with composite resinafter root canal obturation. Following thermocycling, fracture strength was evaluated with a Universal Testing Machine. Mean force at which each sample is fractured was recorded in Newton unit and statistically analyzed. Results Fracture resistance of group 7 (intact teeth) was significantly higher than all other groups (p<0.001). Differences among the fracture resistance values of groups 4, 5 and 6 were not significantly different but they were significantly higher than those of groups 1, 2 and 3 (p<0.001). No significant difference was found between Groups 1, 2 and 3. Conclusion Preparing access cavities with either laser or bur has no effect on the fracture resistance of teeth with root canal treatment.
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Affiliation(s)
- Uğur Aydın
- Department of Endodontics, Gaziantep University Faculty of Dentistry, Gaziantep, Turkey
| | - Fatih Aksoy
- Department of Endodontics, Adıyaman University Faculty of Dentistry, Adıyaman, Turkey
| | - Samet Tosun
- Higher School of Health Services Gaziantep University, Gaziantep, Turkey
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Brosh T, Metzger Z, Pilo R. Circumferential root strains generated during lateral compaction with stainless steel vs. nickel-titanium finger spreaders. Eur J Oral Sci 2018; 126:518-525. [DOI: 10.1111/eos.12569] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/07/2018] [Indexed: 11/28/2022]
Affiliation(s)
- Tamar Brosh
- Department of Oral Biology; The Goldschleger School of Dental Medicine; Tel Aviv University; Tel Aviv Israel
| | - Zvi Metzger
- Department of Endodontology; The Goldschleger School of Dental Medicine; Tel Aviv University; Tel Aviv Israel
| | - Raphael Pilo
- Department of Oral Rehabilitation; The Goldschleger School of Dental Medicine; Tel Aviv University; Tel Aviv Israel
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Chai H, Tamse A. Vertical Root Fracture in Buccal Roots of Bifurcated Maxillary Premolars from Condensation of Gutta-percha. J Endod 2018; 44:1159-1163. [DOI: 10.1016/j.joen.2018.03.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2017] [Revised: 03/25/2018] [Accepted: 03/28/2018] [Indexed: 11/16/2022]
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