Avaliação de fontes de luz utilizadas em serviço público de saúde bucal no Brasil: potência radiante, irradiância, espectros de emissão e perfil do feixe

Abstract

Objective: Evaluate the radiant power (mW), emission spectra (mW/cm²/nm), irradiance (mW/cm²), and the tip integrity of 40 light-curing units (LCUs) used in 16 public oral health service units in the city of Uberlândia, Brazil. Methods: Radiant power and emission spectrum were measured using a spectrometer attached to an integrating sphere. Irradiance profiles were obtained using Beam Profile. The tips of the LCUs were photographed to evaluate damage and contamination. Data was analyzed by one-way ANOVA (α = 0.05), the emission spectra and beam profiles were analyzed descriptively. Results: The LCUs tested were all single-peak: 8 LED 6, 17 Prime Led 3, 4 Optilight Max, 1 LuxCler LED, 3 DB686, 6 Emitter A fit and 1 LD Max. The radiant power values were significantly different between LCUs (P < 0.001). Radiant power ranged between 94.2 to 588.2 mW, and irradiance 255.8 to 1597.8 mW/cm². The tip diameter ranged between 6.1 to 8.3 mm. Two-dimensional beam profiles show that light distribution is not homogeneously distributed on tips, and peak irradiance concentrated in small tip central area for the most of the LCUs. Conclusions: LCUs tips showed damaged and contaminated with residues and reduced diameter determining reduced irradiance and heterogeneous light distribution. Clinical relevance: LCUs evaluated showed damaged and contamination by residues, resulting in reduction in emitted power. The limited diameter LCU tips determine multiple light exposition to cover large restorations. This condition can compromise the effectiveness of light curing and, consequently, the longevity of resin composite restorations.