Response of Differently Structured Dental Polymer-Based Composites to Increasingly Aggressive Aging Conditions

Area of Science:

• Materials Science
• Biomaterials Engineering
• Dental Materials

Background:

• Dental composites are susceptible to degradation from various aging factors.
• Understanding the influence of material structure and curing methods on composite aging is crucial for long-term clinical performance.

Purpose of the Study:

• To investigate the impact of different structuring and curing methods on the aging response of nano- and micro-hybrid polymer-based dental composites.
• To evaluate the effectiveness of various artificial aging protocols on composite properties.

Main Methods:

• Three distinct dental composites were selected: Vita Enamic (VE), Brillinat CriosST (BC), and Admira Fusion5 (AF5).
• Specimens underwent four aging conditions: water storage, thermal cycling (TC), TC with ethanol-water solution, and TC with demineralization/remineralization cycling.
• Mechanical properties (flexural strength, elastic modulus, hardness) and reliability were assessed using three-point bending, instrumented indentation, fractography, and Weibull analysis.

Main Results:

• Material type significantly affected composite properties, with VE showing higher elastic moduli and hardness than BC and AF5.
• BC exhibited the highest strength but also greater deformation.
• Aging effects were more pronounced in instrumented indentation test parameters than in flexural properties.
• Reliability remained high for VE and BC post-aging, but significantly decreased for AF5 after specific aging protocols.

Conclusions:

• Thermal cycling was the most impactful artificial aging method, while demineralization/remineralization cycling had minimal effect.
• Composite degradation occurred regardless of structuring and curing, with only slight deterioration in measured properties observed.