Ultra-violet absorption by two ultra-violet activated sealants

Area of Science:

• Dental Materials Science
• Polymer Chemistry
• Photopolymerization

Background:

• The efficacy of ultraviolet (UV) light-cured dental pit and fissure sealants relies on adequate UV radiation penetration.
• Understanding the optical properties, specifically absorption coefficients, of sealant materials is critical for predicting their setting depth.

Purpose of the Study:

• To determine and compare the UV absorption coefficients of Nuva-seal and Alphaseal at 365 nm.
• To evaluate the potential setting depth of these sealants based on their UV absorption characteristics.

Main Methods:

• Measurement of absorption coefficients for Nuva-seal and Alphaseal at 365 nm, the wavelength used for polymerization.
• Analysis of the contribution of UV fluorescent dye and catalyst concentration to the overall absorption of Alphaseal.

Main Results:

• Nuva-seal exhibited a low absorption coefficient (0.165 mm-1).
• Alphaseal demonstrated a significantly higher absorption coefficient (6.25 mm-1), with the UV fluorescent dye contributing substantially (2.5 mm-1).
• The catalyst concentration in Alphaseal also contributed to its high absorption.

Conclusions:

• Nuva-seal likely achieves adequate setting depth for fissure sealants due to its lower UV absorption.
• Alphaseal's high UV absorption may limit its setting depth, potentially requiring high-intensity UV sources for effective polymerization.
• Modifications to Alphaseal, such as reducing catalyst concentration and removing the UV fluorescent dye, could enhance its setting characteristics.