Researchers found that the 135° shoulder design in endocrowns results in a more uniform stress distribution, minimizing stress-related complications.
A recent study published in BMC Oral Health investigated the effects of different margin designs and loading conditions on the stress distribution of endocrowns using finite element analysis (FEA). The research aimed to inform clinical applications by evaluating stress patterns in endocrowns.
The researchers established three FEA models based on margin designs: butt-joint (E0), 90° shoulder (E90), and 135° shoulder (E135). Each model was subjected to nine static loads totaling 225 N to measure maximum von Mises stresses and stress distribution.
The results revealed that stress distribution in endocrowns was similar across all margin designs under identical loading conditions. The E135 design exhibited reduced stress concentration compared to the E0 and E90 models. When loading was applied to the lingual side, the E135 and E90 models had lower stresses compared to the E0 model. In enamel, stress concentration was higher in the E0 model.
In dentin, stress patterns were consistent among the models, except for specific loading scenarios where E90 showed higher stress concentrations at the cementoenamel junction. The researchers noted that the sharp margin contact at the shoulder may lead to cervical stress concentration.
The findings indicate that shoulder-type margin designs, especially the 135° shoulder, may provide better stress distribution for the longevity of endocrowns. Tooth morphology and axial wall thickness are important factors in selecting margin designs to minimize stress-related complications.
The authors reported no potential conflicts of interest.