title: LED and Halogen Light Transmission through a CAD/CAM Lithium Disilicate Glass-Ceramic.
abstract: 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.
authors.affiliation: Department of Restorative Dentistry, Dental School, UFMG - Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Carolina Nemesio de Barros
authors.initials: CN
authors.lastname: Pereira
authors.affiliation: Department of Restorative Dentistry, Dental School, UFMG - Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Cláudia Silami
authors.initials: CS
authors.lastname: De Magalhães
authors.affiliation: Department of Restorative Dentistry, Dental School, UFMG - Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Bruno
authors.initials: B
authors.lastname: Daleprane
authors.affiliation: Department of Restorative Dentistry, Dental School, UFMG - Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Rogéli Tibúrcio Ribeiro da Cunha
authors.initials: RT
authors.lastname: Peixoto
authors.affiliation: Department of Social and Preventive Dentistry, Dental School, UFMG - Universidade Federal de Minas Gerais Belo Horizonte, Belo Horizonte, MG, Brazil.
authors.forename: Raquel da Conceição
authors.initials: Rda C
authors.lastname: Ferreira
authors.affiliation: Department of Optical Physics, Institute of Exact Sciences, UFMG - Universidade Federal de Minas Gerais Belo Horizonte, Belo Horizonte, MG, Brazil.
authors.forename: Luiz Alberto
authors.initials: LA
authors.lastname: Cury
authors.affiliation: Department of Restorative Dentistry, Dental School, UFMG - Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
authors.forename: Allyson Nogueira
authors.initials: AN
authors.lastname: Moreira
mesh_terms: D002516:Ceramics; D017076:Computer-Aided Design; D003776:Dental Porcelain / Q000737:chemistry*; D005898:Glass; D006219:Halogens; D008027:Light
chemical_list: D006219:Halogens; C493120:lithia disilicate; D003776:Dental Porcelain