Shear Bond Strength of Repair Materials by Different Polymerization Methods on 3D-Printed Denture Bases

Area of Science:

• Dental Materials Science
• Biomaterials Engineering
• Additive Manufacturing in Dentistry

Background:

• 3D-printed denture bases offer potential advantages over conventional polymethyl methacrylate (PMMA) dentures.
• Assessing the repairability of 3D-printed materials is crucial for their clinical adoption.
• Denture repair strength is a critical factor for long-term prosthesis function.

Purpose of the Study:

• To compare the shear bond strengths (SBSs) of different denture repair materials on 3D-printed denture bases (DLP) versus conventional PMMA.
• To evaluate the influence of polymerization methods (auto-polymerized vs. light-polymerized) on repair bond strength.
• To analyze failure modes and the effect of thermocycling on bond integrity.

Main Methods:

• Fabrication of DLP and PMMA disks, followed by surface roughening and primer application.
• Application and polymerization of auto-polymerized repair (PER) and light-polymerized relining (MRB) materials.
• Specimen storage, thermocycling (5,000 cycles, 5-55 °C), and SBS testing with fracture analysis.

Main Results:

• Light-polymerized (MRB) materials exhibited significantly higher SBS and characteristic strength than auto-polymerized (PER) materials on both DLP and PMMA bases.
• No significant differences in Weibull modulus were found, except for PMMA-MRB showing the highest values.
• Thermocycling generally decreased bond strengths, but without significant differences between aged and non-aged groups. Adhesive failures dominated, except for DLP-MRB, which showed cohesive failures.

Conclusions:

• The repairability of 3D-printed denture bases is comparable to conventional PMMA.
• Light-polymerized denture repair materials provide superior bond strength to 3D-printed bases.
• Denture repair procedures for 3D-printed bases can follow established protocols for conventional PMMA dentures.