Avaliação, in vitro, da irradiância de fotopolimerizadores na parede gengival de preparos cavitários classe II em dentes humanos

Abstract

Introduction: The appropriate composite resin polymerization is a determinant factor for restorations success since the light intensity affects the material mechanic properties. Class II cavities can physically delimit the light passage of the led curing-unit in the cavity cervical wall. Objective: To measure the light intensity of light curing unit in the depth of the proximal boxes in class II cavities in different occluso-gingival extensions. Methods: The light intensity of three light curing unites (Radii, Emmiter C and Woodpecker) was measured with digital radiometer. Values were obtained with the tip positioned directly on the radiometer reading cell (G1 – control) and on three specimens (extracted human teeth) with preparations on the distal faces at the vestibule-lingual dimensions of 3.7mm and mesio-distal of 2,5 mm and occluso-gingival extensions of 2 mm (G2), 4 mm (G3) and 6 mm (G4). To avoid light lateral infiltration the specimens were involved with condensation silicone. Each specimen underwent 10 exposures of 20 seconds each intercalating the groups (n=10). The data were submitted to the variance analysis and the multiple comparisons to the Tukey test (α = 0,05%). Results: The increase of the cavity occluso-gingival extension caused a decrease in light intensity on all studied devices in absolute values (mW/cm²): 638, 504 and 605 to G2; 750, 634 and 738 to G3; 777, 766 and 966 to G4. Conclusion: The increase of dental cavity deepness on class II restorations leads to significant light intensity decrease in the cavity base.