A 3d Analysis of Influence of Canal Preparations on the Fracture Resistance of Molars- An Original Research
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Abstract
Introduction: The success of the root canal therapy depends on many factors. Loss of the tooth structure during the canal preperation leads to the fracture of the tooth. The rotary instruments were invented to put less force on the tooth during the preparation.
Hence in the present study we aim to compare the effect of three rotary file systems (Vortex Blue, VTaper, ProTaper,) with dissimilar tapers on fracture resistance of root canal treated teeth by various static and dynamic forces applied to different parts of the coronal part of teeth.
Materials and Methods: 3D printed acrylic maxillary first molar was used. The original geometry was changed and primed for using Spaceclaim software for ANSYS modeling and analysis. The three experimental groups and one control group were created. Group one was ProTaper, group two was Vortex Blue and group three was V-Taper. Young modulus and Poisson ratio of all the materials (Enamel, Dentin, Gutta-Percha, Composite) were used for ANSYS software to recognize these volumes and the constituents that are contained within these individual spaces. In this study seven total contact points were considered on the occlusal surface of the models during the chewing cycle. The Von Mises stress and maximum principal stress on the cervical region were calculated and investigated in four different cross sections of pre cervical dentin.
Results: The highest Von Mises stress was observed in the ProTaper group although V-Taper and Vortex Blue groups showed homogeneous stress distributions in the cervical regions as well. Tensile stress was concentrated on the palatal side of the palatal root and the distal portion of the distobuccal (DB) root in all the experimental groups. However, the control group had the least amount of stressed area followed by V-Taper group, Vortex Blue and ProTaper.
Conclusions: Taper size of endodontic files seems to affect the distribution of forces along the root structure. Preserving dental hard tissue in precervical dentin significantly reduces the stress concentration in the cervical region and increases the eventual fracture resistance of the tooth.