The Effect of Varying Occlusal Loading Conditions on Stress Distribution in Roots of Sound and Instrumented Molar Teeth: A Finite Element Analysis

Wan, Boyang; Chung, Bonnie Han; Zhang, Michelle Ruijia; Kim, Su A; Swain, Michael V.; Peters, Ove A.; Krishnan, Unni; Moule, Alex J.

doi:10.1016/j.joen.2022.03.009

Cited by 10 publications

(4 citation statements)

References 34 publications

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“…It is worth mentioning that the value of tensile stresses in the tooth with a MOD cavity (≈ 4.5 MPa) was approximately 50% more than that found in the intact tooth (3.1 MPa). This may be a concern given that dental tissues are more vulnerable to stresses with tensile character [ 33 , 34 ] and justify adopting full coverage restorations in cases where both proximal sides of a maxillary premolar are compromised.…”

Section: Discussionmentioning

confidence: 99%

“…This finding contrasts with Smoljan et al [ 35 ] who found that wider progressive taper preparations have less fracture resistance than narrow progressive taper canal preparations. This can be attributed to the difference in loading conditions as they utilized 200N in static loading and the numerical values of total deformation as an indicator of fracture [ 33 ].…”

Section: Discussionmentioning

confidence: 99%

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How loss of tooth structure impacts the biomechanical behavior of a single-rooted maxillary premolar: FEA

et al. 2023

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To evaluate the influence of the loss of coronal and radicular tooth structure on the biomechanical behavior and fatigue life of an endodontically treated maxillary premolar with confluent root canals using finite element analysis (FEA). An extracted maxillary second premolar was scanned to produce intact (IT) 3D model. Models were designed with an occlusal conservative access cavity (CAC) with different coronal defects; mesial defect (MO CAC), occlusal, mesial and distal defect (MOD CAC), and 2 different root canal preparations (30/.04, and 40/.04) producing 6 experimental models. FEA was used to study each model. A simulation of cycling loading of 50N was applied occlusally to stimulate the normal masticatory force. Number of cycles till failure (NCF) was used to compare strength of different models and stress distribution patterns via von Mises (vM) and maximum principal stress (MPS). The IT model survived 1.5 × 1010 cycles before failure, the CAC-30.04 had the longest survival of 1.59 × 109, while the MOD CAC-40.04 had the shortest survival of 8.35 × 107 cycles till failure. vM stress analysis showed that stress magnitudes were impacted by the progressive loss of coronal tooth structure rather than the radicular structure. MPS analysis showed that significant loss of coronal tooth structure translates into more tensile stresses. Given the limited size of maxillary premolars, marginal ridges have a critical role in the biomechanical behavior of the tooth. Access cavity preparation has a much bigger impact than radicular preparation on their strength and life span.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

How loss of tooth structure impacts the biomechanical behavior of a single-rooted maxillary premolar: FEA

et al. 2023

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“…It has been noted, however, that once the occlusal force is applied to a tooth, a range of forces and magnitudes are created at various root locations. Under all loading situations, the largest root biomechanical stress occurred in the cervical third of the root surface and not in the apical one [ 39 ]. It is possible that variations in the laminin expression pattern are associated with the shear force-dominant location at the level of the root surface.…”

Section: Discussionmentioning

confidence: 99%

Alteration of extracellular matrix proteins in atrophic periodontal ligament of hypofunctional rat molars

et al. 2023

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Objectives The aim of this study was to investigate the effect of mechanical force on possible dynamic changes of the matrix proteins deposition in the PDL upon in vitro mechanical and in vivo occlusal forces in a rat model with hypofunctional conditions. Materials and methods Intermittent compressive force (ICF) and shear force (SF) were applied to human periodontal ligament stem cells (PDLSCs). Protein expression of collagen I and POSTN was analyzed by western blot technique. To establish an in vivo model, rat maxillary molars were extracted to facilitate hypofunction of the periodontal ligament (PDL) tissue of the opposing mandibular molar. The mandibles were collected after 4-, 8-, and 12-weeks post-extraction and used for micro-CT and immunohistochemical analysis. Results ICF and SF increased the synthesis of POSTN by human PDLSCs. Histological changes in the hypofunctional teeth revealed a narrowing of the PDL space, along with a decreased amount of collagen I, POSTN, and laminin in perivascular structures compared to the functional contralateral molars. Conclusion Our results revealed that loss of occlusal force disrupts deposition of some major matrix proteins in the PDL, underscoring the relevance of mechanical forces in maintaining periodontal tissue homeostasis by modulating ECM composition.

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“…The stress concentration on the dentin walls, associated with the risk of cracks at this level, is exacerbated by endodontic instruments with active tips and aggressive cutting contours (which tend to have a screwing effect in the root dentin), those with increased tapering, and those that can cause the accumulation of debris [7]. The removal of root-filling materials can cause additional stress during endodontic retreatment [8], and the type of occlusion and the occlusal load are other variables that can influence the level of dentinal stress [9]. A rotary system consisting of a single engine-driven endodontic file has a higher taper, and although the instrument has periodic clearance at the root canal walls, it can also cause dentin microcracks.…”

Section: Introductionmentioning

confidence: 99%

Endodontic Dentistry: Analysis of Dentinal Stress and Strain Development during Shaping of Curved Root Canals

Iosif,

Dimitriu,

Niţoi

et al. 2023

Healthcare

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Background: Endodontic shaping causes stress and strain in the root canal dentin. Dentin microcracks have the potential to be later followed by root fractures occurring under the occlusal load. The aim of our research was to theoretically determine the values of such dentinal states of stress and strain during the endodontic shaping of curved root canals using finite element analysis (FEA). Methods: To highlight the stress concentrations in dentin, two geometric models were created considering the volume of the curved dental root and the contact between the endodontic file and the root canal walls. The application of forces with different values was simulated both on a uniform curved root canal and on a root canal with an apical third curvature of 25° as they would be applied during the preparation of a root canal. Results: In the case of the first model, which was acted upon with a force of 5 N, the deformations of the root canal appeared along the entire working length, reaching the highest values in the apical third of the root, although there were no geometric changes in the shape of the root canal. Regarding the second root model, with an apical third curvature of 25°, although the applied force was 2 N, the deformations were accompanied by geometric changes in the shape of the root, especially in the upper part of the apical third. At a higher force of 7 N exerted on the endodontic file, the geometric shape changed, and the deformation reached extreme critical values. The resulting tensile stresses appearing in the experimental structure varied similarly to the deformations. Conclusions: Significant stress and strain can develop, especially in the apical third of curved root canals during their shaping, and the risk of cracks is higher for endodontically treated teeth presenting severe curvatures in the apical third of the root.

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The Effect of Varying Occlusal Loading Conditions on Stress Distribution in Roots of Sound and Instrumented Molar Teeth: A Finite Element Analysis

Cited by 10 publications

References 34 publications

How loss of tooth structure impacts the biomechanical behavior of a single-rooted maxillary premolar: FEA

How loss of tooth structure impacts the biomechanical behavior of a single-rooted maxillary premolar: FEA

Alteration of extracellular matrix proteins in atrophic periodontal ligament of hypofunctional rat molars

Endodontic Dentistry: Analysis of Dentinal Stress and Strain Development during Shaping of Curved Root Canals

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