The Effect of Access Cavity Designs and Sizes of Root Canal Preparations on the Biomechanical Behavior of an Endodontically Treated Mandibular First Molar: A Finite Element Analysis

2020 ◽  
Vol 46 (11) ◽  
pp. 1675-1681
Author(s):  
Shehabeldin Mohamed Saber ◽  
Dennis Mohamed Hayaty ◽  
Nawar Naguib Nawar ◽  
Hyeon-Cheol Kim
2021 ◽  
Vol 11 (6) ◽  
pp. 2547 ◽  
Author(s):  
Carlo Prati ◽  
João Paulo Mendes Tribst ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Alexandre Luiz Souto Borges ◽  
Maurizio Ventre ◽  
...  

The aim of the present investigation was to calculate the stress distribution generated in the root dentine canal during mechanical rotation of five different NiTi endodontic instruments by means of a finite element analysis (FEA). Two conventional alloy NiTi instruments F360 25/04 and F6 Skytaper 25/06, in comparison to three heat treated alloys NiTI Hyflex CM 25/04, Protaper Next 25/06 and One Curve 25/06 were considered and analyzed. The instruments’ flexibility (reaction force) and geometrical features (cross section, conicity) were previously investigated. For each instrument, dentine root canals with two different elastic moduli(18 and 42 GPa) were simulated with defined apical ratios. Ten different CAD instrument models were created and their mechanical behaviors were analyzed by a 3D-FEA. Static structural analyses were performed with a non-failure condition, since a linear elastic behavior was assumed for all components. All the instruments generated a stress area concentration in correspondence to the root canal curvature at approx. 7 mm from the apex. The maximum values were found when instruments were analyzed in the highest elastic modulus dentine canal. Strain and von Mises stress patterns showed a higher concentration in the first part of curved radius of all the instruments. Conventional Ni-Ti endodontic instruments demonstrated higher stress magnitudes, regardless of the conicity of 4% and 6%, and they showed the highest von Mises stress values in sound, as well as in mineralized dentine canals. Heat-treated endodontic instruments with higher flexibility values showed a reduced stress concentration map. Hyflex CM 25/04 displayed the lowest von Mises stress values of, respectively, 35.73 and 44.30 GPa for sound and mineralized dentine. The mechanical behavior of all rotary endodontic instruments was influenced by the different elastic moduli and by the dentine canal rigidity.


Author(s):  
Cédric P Laurent ◽  
Béatrice Böhme ◽  
Jolanthe Verwaerde ◽  
Luc Papeleux ◽  
Jean-Philippe Ponthot ◽  
...  

Osteosynthesis for canine long bones is a complex process requiring knowledge of biology, surgical techniques and (bio)mechanical principles. Subject-specific finite element analysis constitutes a promising tool to evaluate the effect of surgical intervention on the global properties of a bone–implant construct, but suffers from a lack of validation. In this study, the biomechanical behavior of 10 canine humeri was compared before and after creation of a 10 mm bone defect stabilized with an eight-hole locking compression plate (Synthes®) and two locking screws on each fragment. The response under compression of both intact and plated samples was measured experimentally and reproduced with a finite element model. The experimental stiffness ratio between plated and intact bone was equal to 0.39 ± 0.06. A subject-specific finite element analysis including density-dependent elasto-plastic material properties for canine bone and automatic generation of orthopedic implants was then conducted to recover these experimental results. The stiffness of intact and plated samples could be predicted, with no significant differences with experimental data. The simulated stiffness ratio between plated and intact canine bone was equal to 0.43 ± 0.03. This study constitutes a first step toward the building of a virtual database of pre-computed cases, aiming at helping the veterinary surgeons to make decisions regarding the most suited orthopedic solution for a given dog and a given fracture.


2014 ◽  
Vol 658 ◽  
pp. 441-446
Author(s):  
Ruxandra Margarit ◽  
Stefan Sorohan ◽  
Alice Tanasescu ◽  
Constantin Dăguci ◽  
Oana Cella Andrei

Abstract. The problem of root fracture in case of prosthetically restored non-vital teeth is a common concern among clinicians. These fractures are caused by increasing the diameter of the root canal during the endodontic retreatment and occure on the dental arches in both the anterior and posterior area. Such treatment failures lead to extraction, therefore the physician’s goal is to limit as much as possible their occurrence. We used finite element analysis method to find out what type of corono-radicular restoration is more appropriate in order to avoid fractures. We selected two of the most commun posts used in our country: metallic NiCr casted RCR (corono-radicular reconstruction) and prefabricated fiberglass endodontic posts of various diameters and we analyzed the existing tensions in the dental structures that would predispose the root to fracture.


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