1
|
Yao Q, Zhuang Y, Aji Y, Zhang Q, Luo Y, Li S. Biomechanical impact of different isthmus positions in mandibular first molar root canals: a finite element analysis. Clin Oral Investig 2024; 28:311. [PMID: 38743171 DOI: 10.1007/s00784-024-05715-1] [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: 02/02/2024] [Accepted: 05/07/2024] [Indexed: 05/16/2024]
Abstract
OBJECTIVE This study used image-based finite element analysis (FEA) to assess the biomechanical changes in mandibular first molars resulting from alterations in the position of the root canal isthmus. METHODS A healthy mandibular first molar, characterized by two intact root canals and a cavity-free surface, was selected as the subject. A three-dimensional model for the molar was established using scanned images of the patient's mandibular teeth. Subsequently, four distinct finite element models were created, each representing varied root canal morphologies: non-isthmus (Group A), isthmus located at the upper 1/3 of the root (Group B), middle 1/3 of the root (Group C), and lower 1/3 of the root (Group D). A static load of 200 N was applied along the tooth's longitudinal axis on the occlusal surface to simulate regular chewing forces. The biomechanical assessment was conducted regarding the mechanical stress profile within the root dentin. The equivalent stress (Von Mises stress) was used to assess the biomechanical features of mandibular teeth under mechanical loading. RESULTS In Group A (without an isthmus), the maximum stress was 22.2 MPa, while experimental groups with an isthmus exhibited higher stresses, reaching up to 29.4 MPa. All maximum stresses were concentrated near the apical foramen. The presence of the isthmus modified the stress distribution in the dentin wall of the tooth canal. Notably, dentin stresses at specific locations demonstrated differences: at 8 mm from the root tip, Group B: 13.6 MPa vs. Group A: 11.4 MPa; at 3 mm from the root tip, Group C: 14.2 MPa vs. Group A: 4.5 MPa; at 1 mm from the root tip, Group D: 25.1 MPa vs. Group A: 10.3 MPa. The maximum stress in the root canal dentin within the isthmus region was located either at the top or bottom of the isthmus. CONCLUSION A root canal isthmus modifies the stress profile within the dentin. The maximum stress occurs near the apical foramen and significantly increases when the isthmus is located closer to the apical foramina.
Collapse
Affiliation(s)
- Qingting Yao
- Department of Stomatology, Xuchang Central Hospital, Xuchang, 461000, China
| | - Youmei Zhuang
- Department of Endodontics, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, 830001, China
| | - Yaerken Aji
- Department of Dentoalveolar Surgery, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, 830001, China
| | - Qilin Zhang
- Postgraduate College of Xinjiang Medical University, Urumqi, 830054, China
| | - Yixiang Luo
- Postgraduate College of Xinjiang Medical University, Urumqi, 830054, China
| | - Shuhui Li
- Department of Endodontics, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, 830001, China.
| |
Collapse
|
2
|
Liu Y, Huang X, Ke H, Song X, Huang X, Sun S. Influence of Access Cavities on Maxillary Central Incisor Fracture Resistance: Finite Element Study. Int Dent J 2024:S0020-6539(24)00121-7. [PMID: 38692963 DOI: 10.1016/j.identj.2024.04.017] [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: 01/18/2024] [Revised: 03/26/2024] [Accepted: 04/08/2024] [Indexed: 05/03/2024] Open
Abstract
INTRODUCTION AND AIMS Altering the position and orientation of the root canal access cavity passway, or modifying the reduction of dentin volume, can influence the strength of dentition. This study aimed to compare the effects of different access cavities on the biomechanical performances of maxillary central incisors with a finite element analysis. METHODS Based on the micro-computed tomography (CT) scan of a maxillary central incisor, the finite element models of the intact tooth and teeth with 4 access cavity designs: conservative incisal access cavity, incisal access cavity, conservative access cavity, and traditional access cavity were generated. Simulated occlusal forces were applied at the incisal edge of the incisor in the finite element analysis procedure. RESULTS The maximum von Mises stress and maximum principal stress in the cervical area are highest in the traditional access cavity group, followed by the conservative access cavity group, incisal access cavity group, and conservative incisal access cavity group. CONCLUSION The conservative access cavities minimise the extent of dentin removal from the cervical region, protecting the mechanical behaviour of the incisor. Moving the access cavity entry point to the incisal edge also improves the fracture resistance of the incisor. CLINICAL RELEVANCE This study's findings would help clinicians select the most appropriate endodontics access cavity method when performing the root canal on maxillary central incisors.
Collapse
Affiliation(s)
- Yujiang Liu
- Hospital of Stomatology, Jilin University, Changchun, PR China
| | - Xinyao Huang
- Hospital of Stomatology, Jilin University, Changchun, PR China
| | - Haoyu Ke
- Hospital of Stomatology, Jilin University, Changchun, PR China
| | - Xinyi Song
- Hospital of Stomatology, Jilin University, Changchun, PR China
| | - Xinmeng Huang
- Hospital of Stomatology, Jilin University, Changchun, PR China
| | - Shufen Sun
- Hospital of Stomatology, Jilin University, Changchun, PR China.
| |
Collapse
|
3
|
Morales MDLNP, Sánchez JAG, Elmsmari F, Duran-Sindreu F, Salmon P, Jaramillo DE, Olivieri JG. Microcomputed tomographic evaluation of 6 NiTi files on the pericervical dentin and the smallest dentin thickness zones in mesial root canals of mandibular molars: an in vitro study. Clin Oral Investig 2024; 28:166. [PMID: 38388725 DOI: 10.1007/s00784-024-05493-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 01/06/2024] [Indexed: 02/24/2024]
Abstract
OBJECTIVE The aim of this study was to evaluate six files on the pericervical dentin (PCD) and the smallest dentin thickness zones (SDTZ) in mesial root canals of mandibular molars. MATERIALS AND METHODS Sixty mandibular molars with two mesial canals and Vertucci configuration were aleatory allocated in 6 experimental groups of 10 molars and 20 root canals. Specimens were scanned before instrumentation using the SkyScan 1275 (Bruker microCT, Kontich, Belgium). Group 1 was treated with WaveOne Gold (WG), group 2 with Reciproc Blue (RB), group 3 with TRUShape (TS), group 4 with XP-endo Shaper (XP), group 5 with iRace (IR), and group 6 with TruNatomy (TN). After instrumentation, the molars were scanned again and the images recorded were reconstructed with the NRecon v.1.7 (Bruker micro-CT) and analyzed with CTAn v.1.20.8 software (Bruker micro-CT) quantifying the changes produced in the surface, volume, structure thickness, SMI, and centroids at the Pericervical Dentin area of the root canals (PCD) located from the root canal orifices at the floor of the pulp chamber to 4 mm in the apical direction, and the changes in the Smallest Dentin Thickness Zones (SDTZ) located (from the furcation to 4 mm and 7 mm in the apical direction. The data obtained were compared using Wilcoxon and ANOVA with a 5% significance level. RESULTS XP and TN were similar in all the parameters (P >.05) at the PCD, but TN showed significant differences from WG, RB, TS, and IR (P <.05), while XP showed significant differences from WG (P <.05) in volume, surface, and structure thickness. Regarding the changes in the SDTZ, the amount of dentin removed was similar between the groups in both canals at the middle 1/3, at the cervical 1/3 for MB canals, and in ML canals for RB, TS, XP, IR, and TN (P>.05). The action of WG was significantly different from that of XP and TN in the cervical 1/3 of the ML canal (P <.05). CONCLUSIONS XP and TN rotatory files with small taper and volume maintained better with minor changes at the PCD and SDTZ, while WG reciprocation file produced the largest change. All the files were maintained centered at the PCD, and their performances were safe with a minimal thickness higher 0.5 mm at the SDTZ, and without risk of perforation. TRIAL REGISTRATION No clinical trials were indicated in this study. CLINICAL RELEVANCE The choice of endodontic files is a relevant factor in the conservative performance of root canal treatments.
Collapse
Affiliation(s)
| | - José Antonio González Sánchez
- Departments of Endodontics, School of Dentistry, International University of Catalunya, Sant Cugat del Valles, Barcelona, Spain.
| | - Firas Elmsmari
- Department of Clinical Sciences, College of Dentistry, Ajman University, Ajman, United Arab Emirates
- Centre of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman, United Arab Emirates
| | - Fernando Duran-Sindreu
- Departments of Endodontics, School of Dentistry, International University of Catalunya, Sant Cugat del Valles, Barcelona, Spain
| | - Phil Salmon
- Department of Scientific Applications, Bruker micro-CT, Kontich, Belgium
| | - David E Jaramillo
- Department of Endodontics, University of Texas Health Science Center at Houston, Houston, TX, USA
| | - Juan Gonzalo Olivieri
- Departments of Endodontics, School of Dentistry, International University of Catalunya, Sant Cugat del Valles, Barcelona, Spain
| |
Collapse
|
4
|
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.
Collapse
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.
| |
Collapse
|
5
|
Wang M, Gao Y, Deng Q, Gao Y, Song D, Huang D. Assessment of the coronal root canal morphology of permanent maxillary first molars using digital 3D-reconstruction technology based on micro-computed tomography data. J Dent Sci 2022; 18:586-593. [PMID: 37021262 PMCID: PMC10068546 DOI: 10.1016/j.jds.2022.08.011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 08/13/2022] [Indexed: 11/17/2022] Open
Abstract
Background The design of minimally invasive access has become a hotspot. This study aimed to evaluate the coronal root canal morphology of permanent maxillary first molars to facilitate the design of endodontic access cavities for minimally invasive linear access. Materials and methods A selection of 91 permanent maxillary first molars was evaluated. Three-dimensional tooth models were reconstructed using micro-computed tomography data. Root canal prevalence and coronal root canal landmarks were recorded. The positional coordinates of landmarks in the horizontal plane and the angles and directions of coronal root canal curvature in the horizontal and axial planes were also assessed. Results The detection rates of the mesiobuccal (MB), distobuccal (DB), and palatal (P) canals were 100%, whereas that of the second mesiobuccal (MB2) canals was 68.1%. All landmarks were located near the central fossa. In the axial plane, the average angles of coronal root canal curvature were DB (27.05°) > MB (25.43°) > P (20.71°) in teeth with three canals, and MB2 (33.20°) > MB (29.61°) > DB (28.40°) > P (23.69°) in teeth with four canals. In the horizontal plane, the average angles were P (78.15°) > DB (42.34°) > MB (32.41°) in teeth with three canals, and P (81.26°) > DB (43.44°) > MB (41.22°) > MB2 (9.41°) in teeth with four canals. Conclusion In maxillary first molars, coronal root canals tend to converge towards the occlusal surface. The results of this study could be applied to improve the precision of endodontic access cavity designs of minimally invasive access.
Collapse
Affiliation(s)
- Mudan Wang
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuxuan Gao
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Qi Deng
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Yuan Gao
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
| | - Dongzhe Song
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Corresponding author.
| | - Dingming Huang
- State Key Laboratory of Oral Diseases and National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Department of Conservative Dentistry and Endodontics, West China Hospital of Stomatology, Sichuan University, Chengdu, China
- Corresponding author.
| |
Collapse
|
6
|
Insights into the March 2022 Issue of the JOE. J Endod 2022; 48:295-297. [DOI: 10.1016/j.joen.2022.01.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|