After-polymerization of visible light activated resins: surface hardness vs. light source

Area of Science:

• Dental Materials Science
• Polymer Chemistry

Background:

• Visible light-activated dental resins are widely used in restorative dentistry.
• Understanding the kinetics of resin hardening is crucial for clinical success.

Purpose of the Study:

• To investigate the Wallace hardness development over time for four visible light-activated dental resins.
• To compare the hardening patterns of different resin brands.

Main Methods:

• Wallace hardness testing was performed on four resins (Durafill, Heliosit, Silux, Visio-Dispers).
• Measurements were taken at various time points post-irradiation, starting from 1 minute and 35 seconds up to 60 minutes.

Main Results:

• A significant increase in surface hardness was observed within the first few minutes after irradiation for all tested resins.
• The rate of hardness increase slowed down considerably after the initial rapid phase.
• The hardening pattern was similar across all investigated resin materials, irrespective of the light source used.

Conclusions:

• Visible light-activated dental resins achieve most of their surface hardness rapidly after irradiation.
• Clinicians can expect a quick development of surface hardness, which is a critical factor for immediate post-operative function.