scholarly journals The effect of tooth morphology and vertical bracket positioning on resultant stress in periodontal ligament- a three dimensional finite element study

Author(s):  
Rohit Kumar Maheshwari ◽  
Ashish Garg ◽  
Bhavna Virang ◽  
Upendra Singh Bhadauria

Introduction. The purpose of this study is to evaluate the effect of change in vertical placement of bracket and effect of tooth morphology on stress developed on periodontal ligament with the help of three dimensional finite element modeling. Methods. A three-dimensional model of the maxillary bone, maxillary right central incisor, lateral incisor and canine was designed based on the average dimensions of the anatomy and morphology given by Wheeler’s and standard edgewise bracket with Slot of 0.022″ X 0.028″ inch was designed using the finite element method. Brackets were placed on each tooth, on the mentioned labial surface at variable distances from the cusp tip, and a full size archwire was virtually engaged into the bracket, then optimum orthodontic load of 2N is applied and PDL stress were calculated. Results. The lowest stress values were measured as bracket position changes from crest of teeth to the apical direction. By displacing the bracket gingivally from 1.5 to 6 mm, a 16.2% decrease in stress level for central incisor, for lateral incisor the stress level decrease by 25.8% and for canine the stress level decrease by 21.6% thus our study confirms that variation in vertical bracket position results in change in resultant stress in PDL. Conclusion.It can be concluded that the variation in the vertical position of the bracket on different tooth can have an important effect on the stresses developed in the PDL.

2021 ◽  
pp. 030157422097434
Author(s):  
V Sandhya ◽  
AV Arun ◽  
Vinay P Reddy ◽  
S Mahendra ◽  
BS Chandrashekar ◽  
...  

Background and Objectives: This study was conducted to determine the effective method to torque the incisor with thermoplastic aligner using a three-dimensional (3D) finite element method. Materials and Methods: Three finite element models of maxilla and maxillary dentition were developed. In the first model, thermoplastic aligner without any auxiliaries was used. In the second and third models, thermoplastic aligner with horizontal ellipsoid composite attachment and power ridge were used, respectively. The software used for the study was ANSYS 14.5 FE. A force of 100 g was applied to torque the upper right central incisor. The resultant force transfer, stress distribution, and tooth displacement were evaluated. Results: The overall tooth displacement and stress distribution appeared high in the model with power ridge, whereas the root movement was more in the horizontal ellipsoid composite attachment model. The model without any auxillaries produced least root movement and stress distribution. Conclusion: Horizontal ellipsoid composite attachment achieved better torque of central incisor than the model with power ridge and model without any auxillaries.


2020 ◽  
Vol 2020 ◽  
pp. 1-9 ◽  
Author(s):  
Xiaoning Kang ◽  
Yiming Li ◽  
Yixi Wang ◽  
Yao Zhang ◽  
Dongsheng Yu ◽  
...  

Occlusal trauma caused by improper bite forces owing to the lack of periodontal membrane may lead to bone resorption, which is still a problem for the success of dental implant. In our study, to avoid occlusal trauma, we put forward a hypothesis that a microelectromechanical system (MEMS) pressure sensor is settled on an implant abutment to track stress on the abutment and predict the stress on alveolar bone for controlling bite forces in real time. Loading forces of different magnitudes (0 N–100 N) and angles (0–90°) were applied to the crown of the dental implant of the left central incisor in a maxillary model. The stress distribution on the abutment and alveolar bone were analyzed using a three-dimensional finite element analysis (3D FEA). Then, the quantitative relation between them was derived using Origin 2017 software. The results show that the relation between the loading forces and the stresses on the alveolar bone and abutment could be described as 3D surface equations associated with the sine function. The appropriate range of stress on the implant abutment is 1.5 MPa–8.66 MPa, and the acceptable loading force range on the dental implant of the left maxillary central incisor is approximately 6 N–86 N. These results could be used as a reference for the layout of MEMS pressure sensors to maintain alveolar bone dynamic remodeling balance.


2019 ◽  
pp. 0000-0000 ◽  
Author(s):  
Karina Albino Lencioni ◽  
Pedro Yoshito Noritomi ◽  
Ana Paula Macedo ◽  
Ricardo Faria Ribeiro ◽  
Rossana Pereira Almeida

This study analyzed the biomechanical behavior of rigid and non-rigid tooth-implant supported fixed partial dentures. Different implants were used in order to observe the load distribution over teeth, implants, and adjacent bone using three-dimensional finite element analysis. A simulation of tooth loss of the first and second right molars was created with an implant placed in the second right molar and a prepared tooth with simulated periodontal ligament (PDL) in the second right premolar. Configurations of two types of implants and their respective abutments, i.e., external hexagon (EX) and Morse taper (MT), were transformed into a 3D format. Metal-ceramic fixed partial dentures were constructed with rigid and non-rigid connections. Mesh generation and data processing were performed on the 3D FEA results. Static loading of 50 N (premolar) and 100 N (implant) were applied. When an EX implant was used, with a rigid or non-rigid connection, there was intrusion of the tooth in the distal direction with flexion of the periodontal ligament. Tooth intrusion did not occur when the MT implant was used independent of a rigid or non-rigid connection. The rigid or non-rigid connection resulted in a higher incidence of compressive forces at the cortical bone and stress in the abutment/pontic area, regardless of whether EX or MT implants were used. MT implants have a superior biomechanical performance in tooth-implant supported fixed partial dentures. This prevents the intrusion of the tooth independent of the connection. Both types of implants that were studied caused a greater tendency of compressive forces at the crestal area.


2016 ◽  
Vol 36 (2) ◽  
pp. 385-390 ◽  
Author(s):  
Wojciech Ryniewicz ◽  
Anna M. Ryniewicz ◽  
Łukasz Bojko ◽  
Piotr Pełka ◽  
Jolanta Filipek ◽  
...  

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