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Sönmez S, Koç C. Effect of several nickel-titanium rotary systems on stress distribution in mandibular molars under occlusal forces: a finite element analysis. Odontology 2024:10.1007/s10266-024-01002-3. [PMID: 39242406 DOI: 10.1007/s10266-024-01002-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2024] [Accepted: 08/29/2024] [Indexed: 09/09/2024]
Abstract
This study assessed the stress distribution under occlusal forces in mandibular molars after utilizing several nickel-titanium rotary systems and identified potential root fracture patterns through finite element analysis (FEA). Five three-dimensionally printed mandibular molars were used, with one tooth left unshaped and the remaining four shaped using ProTaper Gold (Dentsply, Tulsa Dental Specialties, Tulsa, OK), Reciproc Blue (VDW, Munich, Germany), XP-endo Shaper (FKG Dentaire, La Chaux-de-Fonds, Switzerland), and Hyflex EDM (Coltene/Whaledent, Altst€atten, Switzerland) rotary systems. Subsequently, micro-CT scans were performed on the teeth, and representative FEA models were generated. Two distinct loadings, vertical and oblique, were applied, and stress parameters including von Mises stress, maximum principal stress, and minimum principal stress were recorded and compared across groups. Although stress values in both loading conditions correlated with volume increases post-shaping, the stress distribution patterns indicative of potential fractures were comparable across groups. Stresses under oblique loads were observed to be higher than those under vertical loads. Several rotary systems, based on the volumetric changes they induce in dental hard tissues, may elevate stress values throughout the tooth, leading to root fractures in regions where stress concentration occurs. Conservative root canal shaping leads to a lower overall stress concentration. In mandibular molars, oblique forces have a more destructive effect compared to vertical forces.
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Affiliation(s)
- Sinem Sönmez
- Dept. of Endodontics, Faculty of Dentistry, Aydın Adnan Menderes University, 09100, Aydın, Turkey
| | - Cemre Koç
- Dept. of Endodontics, Faculty of Dentistry, Aydın Adnan Menderes University, 09100, Aydın, Turkey.
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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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Puleio F, Lo Giudice G, Militi A, Bellezza U, Lo Giudice R. Does Low-Taper Root Canal Shaping Decrease the Risk of Root Fracture? A Systematic Review. Dent J (Basel) 2022; 10:94. [PMID: 35735636 PMCID: PMC9222076 DOI: 10.3390/dj10060094] [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: 04/22/2022] [Revised: 05/23/2022] [Accepted: 05/27/2022] [Indexed: 11/16/2022] Open
Abstract
Minimal root-canal preparation has been suggested to reduce the risk of root fracture, but as a result, satisfactory cleaning and shaping do not take place. Large-scale taper instrumentation can contribute to removing infected tissue; however, it may weaken the tooth structure. The aim of this systematic review is to evaluate whether root-canal shaping with low-taper instruments decreases the risk of root fracture, compared to high-conicity shaping. A search was performed on Ovid MEDLINE, PubMed, and the Web of Science. The inclusion criteria were: studies comparing the root fracture resistance of endodontically treated teeth, shaped with low- and high-conicity taper instruments, in human trials, and via in vitro study. The review includes all types of endodontically treated teeth, with various instrument tapers. The scientific search engines produced 328 results. Only 20 of the results were evaluated after screening. Based on the articles analyzed, it is not clear whether a taper difference can determine differences in root fracture resistance. No randomized controlled trial (RCTs) with long follow-ups have been published to date. It must also be taken into account that the in vitro studies do not consider the numerous differences that there are between in vitro and clinical evaluation. The review was registered on the PROSPERO website, with the protocol number CRD42020151451.
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Affiliation(s)
- Francesco Puleio
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Messina University, 98100 Messina, Italy; (F.P.); (A.M.)
| | - Giuseppe Lo Giudice
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Messina University, 98100 Messina, Italy; (F.P.); (A.M.)
| | - Angela Militi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Messina University, 98100 Messina, Italy; (F.P.); (A.M.)
| | - Ugo Bellezza
- Department of Dentistry, Sapienza University of Rome, Piazzale Aldo Moro 5, 00185 Rome, Italy;
| | - Roberto Lo Giudice
- Department of Clinical and Experimental Medicine, Messina University, 98100 Messina, Italy;
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Evaluation of Palatal Furcation Groove and Root Canal Anatomy of Maxillary First Premolar: A CBCT and Micro-CT Study. BIOMED RESEARCH INTERNATIONAL 2021; 2021:8862956. [PMID: 33506045 PMCID: PMC7814948 DOI: 10.1155/2021/8862956] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 12/10/2020] [Accepted: 12/15/2020] [Indexed: 12/17/2022]
Abstract
Objectives This study is aimed at investigating the root and root canal morphology by cone beam computed tomography (CBCT) and palatal furcation groove of the buccal root by microcomputed tomography (micro-CT) of maxillary first premolars in a Chinese subpopulation. Methods This study assessed CBCT images of 440 patients aged 14-80 years. Based on Vertucci's classification, the number of roots and the canal configuration were determined. Forty-eight maxillary first premolars with furcation grooves were analyzed by micro-CT in patients aged 18-25 years. Results Based on the CBCT assay, 70.22% and 29.32% of maxillary first premolars were 1 root and 2 roots, respectively. The configuration indicated statistical difference (P < 0.05) between male and female patients. The most common canal type was type IV and was found in 44.32% of cases, followed by type I in 27.84%, and then type II in 20.57%. Root bifurcations had 40.13% prevalence which was distributed more in the middle third than in the cervical and the apical third. For the micro-CT study, 95.83% of the furcation groove configuration was found in the bifurcated maxillary first premolars. The length varied from 1.02 to 7.63 mm. The mean depth of this groove was 0.57 mm in the root coronal, 0.47 mm in the root middle, and 0.22 mm in the root apical level. Palatal dentin width was smaller than 1 mm. Conclusion The anatomy of the root and root canal system and the irregular wall width of maxillary first premolars with furcation grooves may help dentists to understand the anatomical morphology and improve the outcomes of endodontic treatment.
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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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Kfir A, Mostinsky O, Elyzur O, Hertzeanu M, Metzger Z, Pawar AM. Root canal configuration and root wall thickness of first maxillary premolars in an Israeli population. A Cone-beam computed tomography study. Sci Rep 2020; 10:434. [PMID: 31949190 PMCID: PMC6965655 DOI: 10.1038/s41598-019-56957-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Accepted: 12/09/2019] [Indexed: 11/09/2022] Open
Abstract
Anatomical features of first maxillary premolars may greatly affect endodontic and following restorative treatments. The aim of this study was to evaluate root canal configuration and root wall thickness of first maxillary premolars using a preexisting CBCT database. A CBCT database of 400 first maxillary premolar was used to study canal configuration, presence of furcation-facing groove on the buccal root and root wall thickness. Root wall thickness was measured from axial CBCT slices at three critical points of the root: The most coronal part of the furcation-facing groove in the buccal root, when present, the CEJ level of the palatal root and 5 mm apically to the CEJ level of the palatal root. Vertucci Type IV configuration was the most common among all teeth, but in single-rooted teeth, Vertucci Type II was predominant. The mean thickness of the buccal root in the area of a furcation-facing groove was 1.1 (±0.2) mm, but in 39% of the cases, it was thinner than 1 mm. The mean thickness of the palatal root at 5 mm from the CEJ was 1.1 (±0.2), but in 28% of the cases, it was thinner than 1 mm. Thickness of root dentin walls of first maxillary premolars varies and may be limited at critical points in both buccal and palatal roots. In case the patient has a previous CBCT scan it may be useful for planning treatment of first maxillary premolars, in order to recognize and avoid potential risks such as furcation-facing groove, thin dentin walls in critical areas and presence of Type II Verucci canal, all of which may dictate less invasive procedures, using smaller files.
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Affiliation(s)
- Anda Kfir
- Department of Endodontology, Tel Aviv University, Tel Aviv, Israel
| | - Olga Mostinsky
- Department of Endodontology, Tel Aviv University, Tel Aviv, Israel
| | - Orly Elyzur
- Department of Endodontology, Tel Aviv University, Tel Aviv, Israel
| | - Moran Hertzeanu
- Department of Endodontology, Tel Aviv University, Tel Aviv, Israel
| | - Zvi Metzger
- Department of Endodontology, Tel Aviv University, Tel Aviv, Israel.
| | - Ajinkya M Pawar
- Department of Conservative Dentistry and Endodontics, Nair Hospital Dental College and Hospital, Mumbai, Maharashtra, India
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