Effectiveness of composite cure associated with different light-curing regimes

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Biomaterials Engineering

Background:

• Visible light-activated resin composites are widely used in restorative dentistry.
• Optimizing light-curing regimens is crucial for achieving adequate polymerization and material longevity.
• Understanding the impact of different curing modes on cure effectiveness is essential for clinical success.

Purpose of the Study:

• To investigate the effectiveness of various light-curing regimens on the cure of a specific resin composite.
• To compare the Knoop hardness of composite specimens under different light-curing modes.
• To evaluate the influence of curing modes on immediate and one-day post-polymerization hardness.

Main Methods:

• Utilized a Variable Intensity Polymerizer (VIP) for controlled light energy density.
• Tested five light-curing modes: Pulse Delay (PD), Pulse Cure (PC), Soft-start (SS), Turbo (T), and Control (C).
• Measured top and bottom Knoop hardness (KHN) of 2-mm composite specimens immediately and one day post-polymerization.

Main Results:

• Control (C) mode showed significantly lower top KHN immediately and at one day compared to Pulse Delay (PD), Soft-start (SS), and Turbo (T).
• No significant difference in bottom KHN was observed immediately after curing across modes.
• At one day, Control (C) had significantly lower bottom KHN than Soft-start (SS) and Turbo (T).

Conclusions:

• Soft-start and Turbo polymerization regimens can enhance the effectiveness of cure at the bottom surfaces of resin composites.
• Curing mode significantly influences the depth of cure and overall material properties.
• Further research into optimized light-curing protocols is warranted for improved clinical outcomes.