Abstract
Introduction
This study aimed to investigate the fracture behavior of a mandibular first premolar
with a severely curved h-shaped canal using the extended finite element method.
Methods
Following the micro–computed tomographic data, models of the intact tooth, the conservative
endodontic cavity (CEC), the modified conservative endodontic cavity (MCEC), and the
traditional endodontic cavity (TEC) were created. All models were subjected with a
total load of 600 N perpendicularly to the contact areas. The distributions of maximum
principal stress were recorded. The evolution of cracks in the enamel and dentin was
simulated with the extended finite element method.
Results
The intact tooth showed the highest crack initiation load and the smallest stress
concentration area. The CEC and MCEC showed higher crack initiation loads and smaller
stress concentration areas compared with the TEC. On the occlusal surface, tensile
stress was centralized around the distal fossa and the distal margins of cavities.
In the root, the stress was concentrated at the mesiolingual side for all models and
at the internal surface on the bifurcation section for the CEC. Cracks originated
at buccal side of the distal fossa and microcracks were formed confined to the enamel,
and then cracks occurred in the dentin below the bone level.
Conclusions
For the mandibular first premolar with a severely curved h-shaped canal, the MCEC
preserved the fracture resistance equally as well as the CEC and reduced the stress
concentration on the bifurcation section. The fracture initiated in the enamel, forming
microcracks on the buccal side of the distal fossa and then occurred as an irreparable
fracture in the dentin.
Key Words
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Article info
Publication history
Published online: March 24, 2021
Identification
Copyright
© 2021 American Association of Endodontists.
