Fracture Resistance and Stress Distribution Pattern of Different Posts-Core Systems in Immature Teeth: An In Vitro Study and 3D Finite Element Analysis

Abstract

Introduction. Restoration of immature teeth with open apices and thin dentinal walls with conventional post systems remains a challenge. The purpose of this study was to evaluate the fracture resistance of simulated immature teeth restored with different intraradicular posts and assess their stress distribution pattern using 3D Finite Element Analysis (FEA). Methods. Fracture strength testing using universal testing machine was carried out in simulated immature teeth restored with different intraradicular posts grouped as follows: Group A: teeth not restored with posts served as control group; Group B: Cast metal post (CMP); Group C: Customized Composite Post (CCP); Group D: Fiber post (FP). Four 3D FEA models of the above groups were created using CATIATM software and analyzed for stress distribution using ANSYSTM. The results of fracture strength testing and FEA were correlated. Multiple group comparisons were analyzed by one-way ANOVA followed by Tukey HSD post hoc test. Results. The CMP exhibited highest fracture resistance (336.43 N) but resulted in root fractures. The CCP exhibited lower fracture resistance (240.90 N) and favorable stress distribution as compared to CMP. The FP and control group exhibited lower fracture resistance values of 182.69 N and 130.46 N, respectively. The results of 3D FEA demonstrated higher stress concentration in model comprising metallic post and core. Conclusions. Teeth restored with cast metal posts and cores exhibited maximum fracture resistance followed by the customized composite posts, the fiber posts, and the control group. The cast metal posts indicated higher von Mises stresses concentrated in the radicular region; however, the customized composite posts, the fiber posts, and the control group demonstrated stress concentration in the coronal region.

Restorative Modalities for Structurally Compromised Teeth with Thin-walled Roots: A Literature Review

“…Also, Li et al 15 reported that groups with fiber posts showed more resistance compared with metal posts. Considering stress values, Khadar et al 5 observed higher stress concentration for teeth restored with cast metal posts, whereas it is more even for fiber post and composite posts. This may be due to the possible monoblock unit formation in the tooth structure.…”

“…In some of them, optimal treatments with suitable techniques have been proposed; however, the long-term success of those treatments is not determined yet. 5 6 In ETT, posts are placed to improve fracture resistance and the maintenance of coronal restorative treatments. 7 In current restorative approaches, post and core systems are gradually developing toward being more corrosion resistant and stronger, and less invasive techniques that do not weaken the remaining root structure are recommended due to the likeliness of flared canals to fracture.…”

Understanding the Complexities of Cast Post Retention: A Comprehensive Review of Influential Factors

“…This preemptive risk assessment allows for adjustments in the post design, mitigating potential challenges before they manifest clinically. CAE/FEA is a robust risk management tool, contributing to the overall reliability of the restoration [ 37 ].…”

Biomechanical Analysis of Mandibular Premolar Restored with Different Custom Post Core

“…18 19 Some authors presented those materials with a lower modulus of elasticity, such as fiber-reinforced composite posts (FRC posts), which lead to lower stress on the root structures and reduce the risk of root fracture, but have limited application in case of greater tooth destruction and lower resistance to fracture than custom cast post core. 5 20 21 If there is not enough coronary tooth structure or the ferrule effect is insufficient, the use of FRC posts is not indicated. In that case, they present quite high stresses in the cervical region due to their flexibility and the presence of a less stiff core material.…”