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Published on: January 18, 2022
3D-FE analysis of soft liner-acrylic interfaces under shear loading
Muhanad M Hatamleh1, Flávia Pires Rodrigues, Nick Silikas
1Biomaterials Research Group, School of Dentistry, University of Manchester, Higher Cambridge Street, Manchester M15 6FH, UK. muhanad.hatamleh@manchester.ac.uk
Summary
Applying shear load closer to the bond interface (0.25-0.50mm) ensures uniform stress distribution for Molloplast-B soft-liner bonded to PMMA acrylic. Increased distances amplify tensile stresses and bending moments, especially on rough surfaces, impacting bond strength test reliability.
Area of Science:
- Materials Science and Engineering
- Biomaterials
- Dental Materials
Background:
- Molloplast-B soft-liners are used with polymethyl methacrylate (PMMA) acrylic substrates in dental applications.
- Understanding the stress distribution at the bond interface is crucial for evaluating the mechanical integrity of these materials.
- Shear bond tests are commonly used to assess the bond strength, but factors influencing test accuracy require investigation.
Purpose of the Study:
- To analyze stress distribution at the Molloplast-B/PMMA acrylic interface under varying geometries (smooth and rough) and load-application distances.
- To evaluate the influence of load-application distance and surface roughness on shear and tensile stresses using 3D-FEA.
- To provide insights into optimizing shear bond testing methodologies for soft-liner/acrylic systems.
Main Methods:
- Three-dimensional finite element analysis (3D-FEA) was employed using Patran and Marc software.
- Models simulated Molloplast-B liners bonded to smooth and rough PMMA acrylic surfaces.
- Shear loading was applied at distances of 0.25, 0.5, 1, and 2mm from the interface to analyze stress patterns.
Main Results:
- Shear loading at shorter distances (0.25-0.50mm) resulted in more uniform shear and tensile stress distribution for both smooth and rough surfaces.
- Increased load-application distances led to higher stress magnitudes and a greater influence of bending moments, particularly on rough surfaces.
- Tensile stresses exceeded shear stresses at greater distances from the bond interface.
Conclusions:
- Shear and tensile stresses are inherent in shear bond tests, irrespective of load application distance.
- Shorter load application distances (0.25-0.50mm) promote uniform stress distribution and minimize bending moment effects, regardless of surface geometry.
- In vitro shear bond strength studies should cautiously interpret results, considering load application distance and substrate surface treatment as critical factors.
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