The Biomechanical Behaviour and life span of a Three-Rooted Maxillary First Premolar with Different Access Cavity Designs: A Finite Element Analysis.

Objective: The present study aimed to evaluate the influence of different access cavity designs on the biomechanical behaviour of a three-rooted maxillary first premolar using finite element analysis (FEA).

Methods: Three experimental FEA models were generated: the intact tooth (IT) model, the traditional access cavity (TAC) model, and the conservative access cavity (CAC) model. In both TAC and CAC models, root canals preparation was simulated as follows: the mesiobuccal and distobuccal canals with a final tip size of 30 and taper of 0.04 and the palatal canal with a final tip size of 35 and taper of 0.04. Cyclic loading of 50 N was simulated on the occlusal surface of the three models. The number of cycles until failure (NCF), the location of failure, stress distribution patterns, maximum von Mises (VM), and maximum principal stress (MPS) were all evaluated and compared.

Results: Both types of access cavity preparation caused a reduction in the lifelog of the tooth; when compared to the IT model the TAC model had a lifelog of 94.82% while the CAC model had a lifelog of 95.80%. The maximum VM stresses value was registered on the occlusal surface of the TAC model (7 MPa), while the minimum was on the occlusal surface of the IT (6.2 MPa). MPS analysis showed that the highest stress value was recorded on the occlusal surface of the CAC model (7.71 MPa), while the least was recorded on the occlusal surface of the TAC model (3.77 MPa). Radicular stresses were always of minimal value regardless the model.

Conclusion: The relation between the access cavity margins and the functional load points is a deciding factor that influences the biomechanical behaviour and fatigue life of endodontically treated teeth. (EEJ-2023-01-03).