LED and Halogen Light Transmission through a CAD/CAM Lithium Disilicate Glass-Ceramic

• Autor(a) principal: Pereira,Carolina Nemesio de Barros
• Data de Publicação: 2015
• Outros Autores: Magalhães,Cláudia Silami de, Daleprane,Bruno, Peixoto,Rogéli Tibúrcio Ribeiro da Cunha, Ferreira,Raquel da Conceição, Cury,Luiz Alberto, Moreira,Allyson Nogueira
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Brazilian Dental Journal
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-64402015000600648
• topic: halogen dental curing lights; LED dental curing lights; lithium disilicate; dental porcelain; glass ceramics

The effect of thickness, shade and translucency of CAD/CAM lithium disilicate glass-ceramic on light transmission of light-emitting diode (LED) and quartz-tungsten-halogen units (QTH) were evaluated. Ceramic IPS e.max CAD shades A1, A2, A3, A3.5, high (HT) and low (LT) translucency were cut (1, 2, 3, 4 and 5 mm). Light sources emission spectra were determined. Light intensity incident and transmitted through each ceramic sample was measured to determine light transmission percentage (TP). Statistical analysis used a linear regression model. There was significant interaction between light source and ceramic translucency (p=0.008) and strong negative correlation (R=-0.845, p<0.001) between ceramic thickness and TP. Increasing one unit in thickness led to 3.17 reduction in TP. There was no significant difference in TP (p=0.124) between shades A1 (ß1=0) and A2 (ß1=-0.45) but significant reduction occurred for A3 (ß1=-0.83) and A3.5 (ß1=-2.18). The interaction QTH/HT provided higher TP (ß1=0) than LED/HT (ß1=-2.92), QTH/LT (ß1=-3.75) and LED/LT (ß1=-5.58). Light transmission was more effective using halogen source and high-translucency ceramics, decreased as the ceramic thickness increased and was higher for the lighter shades, A1 and A2. From the regression model (R2=0.85), an equation was obtained to estimate TP value using each variable ß1 found. A maximum TP of 25% for QTH and 20% for LED was found, suggesting that ceramic light attenuation could compromise light cured and dual cure resin cements polymerization.