Effect of curing depth of polymerization units by light type in Bulk Fill resins
Description
Polymerization units are devices with advanced light-emitting technology in a wide range of nanometer spectra and varying light intensities. These units effectively promote the activation of the photoinitiator found in composite resins, which greatly enhances the conversion of individual monomers into a complex polymer structure. Composite resins are heterogeneous materials composed of two different elements, which exhibit superior optical and mechanical properties when in a single structure. The study sought to analyze the effect of the type of light on the depth of cure of bulk fill resins, materials designed to be applied in thicker layers without compromising their polymerization.
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It was investigated whether polywave lamps, which emit over a wide range of wavelengths, achieve more effective polymerization than single emission monowave lamps. Through a systematic review of literature published between 2014 and 2024, data were collected from in vitro studies that evaluated the degree of conversion (DC), microhardness, and light transmission in Bulk Fill resins. Measurements obtained with Raman spectroscopy, microhardness testers and spectrophotometers were analyzed under controlled conditions. The results show that polywave lamps achieve higher depth of cure, especially in resins with alternative photoinitiators such as Lucerin (TPO). It was evidenced that light transmission decreases with increasing resin thickness, affecting polymerization in deep layers. In addition, prolonged exposure times were found to improve monomer-to-polymer conversion, although they may increase the shrinkage stress of the material. These findings highlight the importance of properly selecting the light source according to the type of resin used. The use of polywave lamps is recommended to enhance polymerization in deep restorations and ensure optimal conversion. In addition, compatibility between the photoinitiator and the wavelength emitted by the lamp is key to optimizing the longevity and clinical performance of dental restorations.
Institutions
- Universidad Nacional Pedro Henriquez Urena