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Crack propagation directions in unfilled resins
G Baran1, K Sadeghipour, S Jayaraman
1School of Dentistry, Temple University, Philadelphia, Pennsylvania 19140, USA.
Journal of Dental Research
|November 21, 1998
Summary
Developing a predictive wear model for dental composites is crucial. This study found that cracks in resins propagate at an angle, guided by subsurface shear stresses, informing future material development.
Area of Science:
- Dental Materials Science
- Mechanical Engineering
- Biomaterials
Background:
- Posterior composite restorative materials experience significant wear.
- Fatigue is a primary wear mechanism in occlusal contact areas.
- A predictive wear model is needed for developing improved dental materials.
Purpose of the Study:
- To develop a finite element model for predicting crack propagation in dental resin matrices.
- To verify model predictions against experimental wear data.
- To understand crack behavior during sliding wear.
Main Methods:
- Finite element analysis using ABAQUS software.
- Modeling a sliding cylinder on a cracked material surface.
- Pin-on-disc wear testing of BISGMA:TEGDMA and EBPADMA resins.
- Laser confocal scanning microscopy for crack observation.
Main Results:
- Experimental crack propagation deviated from previous observations.
- Most surface cracks initiated orthogonally but turned 20-30 degrees from horizontal.
- Finite element modeling highlighted the role of subsurface shear stresses.
- Cracks were found to propagate in the direction of maximum K(II)(theta), aligning with indenter movement.
Conclusions:
- Finite element modeling accurately predicts crack propagation angles in dental resins.
- Subsurface shear stresses are critical in determining crack direction during sliding wear.
- This research provides a foundation for a predictive sliding wear model for unfilled glassy resins.