Stress distribution in a tooth treated through minimally invasive access compared to one treated through traditional access: A finite element analysis study

Abstract

Introduction:The purpose of this study was to compare the stress distributions in the teeth treated through minimally invasive access (MIA) designs to those of the teeth treated through traditional straight-line access and their relationship to the final restoration using three-dimensional finite element analysis (FEA).Materials and Methods:Four FEA models of an extracted mandibular first molar were constructed. An intact model served as the control, whereas the other three were prepared with either an MIA or traditional straight-line access. Simulated composite access fillings with or without a simulated gold crown were applied to the models, followed by application of an occlusal load of 100 N. Von Mises stresses in the teeth were then calculated and analyzed.Results:Stress values within the dentin for baseline, MIA with composite filling, MIA with composite filling and crown, and traditional access with composite filling and crown were 10.14 MPa, 6.98 MPa, 11.79 MPa, and 16.81 MPa, respectively. Higher stress values indicate that the tooth is more prone to fracture.Conclusions:A traditional endodontic access cavity may render a tooth more susceptible to fracture compared with an MIA design.

Effect of Alternative Palatal Root Access Technique on Fracture Resistance of Root Canal Treated Maxillary Fourth Premolar Teeth in Dogs

“…As endodontic treatment in veterinary patients is generally only indicated in teeth that have undergone previous trauma, it would also be important to consider whether changes in fracture resistance are primarily due to previous trauma sustained by the tooth or due to the biomechanical changes that are directly related to endodontic therapy. Specific areas of interest would be evaluation of the effect of cyclic loading and tooth abfraction (28-30) on fracture resistance compared to the direct effects of root canal therapy, such as dentin desiccation and specific access design (14)(15)(16)(17)(18)(19)(20).…”

“…In humans, where the effect of endodontic treatment on tooth strength has been clearly defined, the access method has been identified as one of the most important variables affecting fracture resistance post therapy (14)(15)(16)(17)(18)(19). This is directly related to the fact that more conservative access methods preserve coronal hard tissue, namely dentin, resulting in a higher ultimate strength of the tooth (14)(15)(16)(17)(18)(19). Surprisingly, the present study did not confirm this finding to be the same in dogs, and no significant difference was found between the fracture resistance of the control group with a small mesiobuccal endodontic access and a treatment group with a mesiobuccal access twice as large in diameter nor between the control group and the treatment group with an additional access site.…”

“…Previous studies in human dentistry have shown that endodontically treated teeth have lower fracture resistance than vital teeth (7)(8)(9)(10)(11)(12)(13). Many factors may contribute to this decreased strength including increased brittleness of dentin secondary to desiccation, removal of hard tissue during access and instrumentation, and lack of sensory feedback from the tooth (3,(14)(15)(16)(17)(18)(19)(20). However, it has been shown that the largest contributor to fracture resistance post endodontic therapy is access method, with more conservative access design conferring increased tooth strength (14)(15)(16)(17)(18)(19)(20).…”

“…Many factors may contribute to this decreased strength including increased brittleness of dentin secondary to desiccation, removal of hard tissue during access and instrumentation, and lack of sensory feedback from the tooth (3,(14)(15)(16)(17)(18)(19)(20). However, it has been shown that the largest contributor to fracture resistance post endodontic therapy is access method, with more conservative access design conferring increased tooth strength (14)(15)(16)(17)(18)(19)(20). To the authors' knowledge, there are currently no studies in veterinary medicine evaluating the effects of endodontic therapy or specific access design on the fracture resistance of root canal treated teeth.…”

A comparative evaluation of the effect of different access cavity designs on root canal instrumentation efficacy and resistance to fracture assessed on maxillary central incisors: An in vitro study

“…Interference by the lingual shoulder lead to failure in achieving a straight-line access and directing the file to cut more on the buccal surface of the root canal wall could be the possible reason for the increased DVR. [ 24 25 26 ]…”