Evaluation of a quadwave curing light compared to a dual-peak LED curing light

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Photochemistry

Background:

• Resin-based composites (RBCs) are widely used in restorative dentistry.
• Effective light-curing is crucial for achieving optimal physical properties and longevity of RBC restorations.
• Traditional light-curing units (LCUs) primarily emit blue light, which can limit penetration depth and conversion efficiency.

Purpose of the Study:

• To evaluate the impact of the PinkWave (PW) light-curing unit (LCU), which emits red and infrared (IR) light alongside violet and blue light, on the depth of cure and degree of conversion (DC) of RBCs.
• To assess the influence of different wavelengths and LCU design on the temperature rise during photocuring.

Main Methods:

• Degree of conversion (DC) was measured using attenuated total reflectance Fourier-transform infrared spectroscopy at various distances.
• Optical filters were employed to isolate the effects of different wavelengths emitted by the PW.
• Depth of cure was assessed by measuring the length of cured resin in metal and plastic molds.
• Temperature changes during photocuring were monitored in both mold types.

Main Results:

• The PW generally produced a greater depth of cure compared to controls, although metal molds reduced this effect due to lower temperature increases.
• Increasing the distance from the light tip up to 4 mm significantly improved DC for RBCs cured with the PW.
• The longer blue peak wavelength (473 nm) of the PW compared to a control LCU (448 nm) negatively impacted photocuring efficiency in some resins.
• The PW's internal optics and additional red/IR wavelengths significantly increased RBC temperature, depth of cure, and DC.

Conclusions:

• The PinkWave LCU, with its broader spectrum including red and IR light, demonstrates potential for enhanced depth of cure and degree of conversion in RBCs.
• The increased temperature generated by the PW's advanced optics and wavelengths plays a significant role in improving photocuring outcomes.
• Further research is warranted to optimize PW usage with different RBC formulations, considering the impact of wavelength differences and mold materials.