Luminic Intensity for the Photopolimerization of Cement in Lithium Disilicate-ceramics

Objectives: Determine the necessary light intensity of light-curing lamps for cementation of lithium disilicate ceramic restorations.
Methods: 2 photopolymerizable Bluephase lamps (Ivoclar Vivadent) with an intensity of 1080 and 2205 mW / cm2 were evaluated and calibrated using a LED radiometer (SDI, Australia). Wax patterns (0.3, 0.5 and 0.7mm) were made with the active form of the radiometer, pressed with IPS e.max Press (Ivoclar Vivadent). The ceramics were placed in the active part of the radiometer and the intensity was measured again. 20 disks were made and cemented in dental organs (0.5mm). The sample was divided into two: n = 10 and cemented with 2 types of lamps. Shear strength tests were performed with Instron 3365. The data obtained were analyzed by SPSS Statics v20 and subjected to the Shapiro-Wilk test to determine normality, later t student test test to determine the difference between the groups.
Results: With the lamp of 1080 mW / cm2: 0.3 mm: 417; 0.5 mm: 216 and to 0.7mm - did not register. The lamp of 2205 mW / cm2: 0.3 mm: 706; 0.5 mm: 509 and to 0.7mm: 396. In the shear strength test, a resistance of 43.3 N was obtained using a lamp of 1080 mW / cm2 and of 60.2 N with that of 2205 mW / cm2, showing a statistically significant difference (p <0.005).
Conclusions: There are important differences in the shear test when polymerizing with the two lamps, which suggests that the higher the light intensity, the higher the tensile strength, denoting a complete polymerization that prevents breakage of the tooth-restoration interface.