Effects of Lutting Cements on Optical Properties of Temporary Restorations

Objectives: The aim of this study was to evaluate the effects of lutting cements on the optical properties of temporary restorations.
Methods: Twenty dentin disks (6mm of diameter and 1mm thick) were obtained from the labial surface of bovine incisors. Twenty disks of acrylic resin (color A2) with the same dimentions were prepared. The acrylic disks were cemented over the dentin ones using one of the following cements: BT–Bifix Temp (resin based - Voco), CT-ClearTemp LC (resin based - Ultradent), P-Provicol (Voco), TC-TempCem NE (Coltene). The same dentin and acrilic disks were used for all cements. After the cementation, the color, Translucency Parameter (TP) and fluorescence of the samples (sets dentin/cement/acrylic) were compared among them and with a control group (C), in which a drop of propileneglicol (transparent liquid) was applied between the the disks, as an optical contact. The color difference in relation to the control (Delta E) and the tranlucency of the samples were evaluated using a reflectance spectrophotometer (CM-2600, Konica Minolta) and the fluorescence using a spectrofluorophotometer (RF-5301PC, Shimadzu). After each cementation and optical properties analysis, the sets were separated, cleaned and cemented with another material. The results were evaluated using one-way ANOVA and Tukey test.
Results: ANOVA showed significante differences for all analysis (p=0.0001). The results of Tukey test for COLOR were: BT-1.28(±0.73)a, CT-2.06(±1.05)b, P-2.74(±0.87)b, TC-3.55(±1.02)c. The results for TRANSLUCENCY were: TC-2.15(±0.61)a, P-5.71(±1.17)b, CT-7.52(±1.77)c, BT-9.17(±1.90)c, C-12.88(±2.93)c. The results for FLUORESCENCE were: C-73.29(±15.29)a, P-73.80(±12.03)a, TC-80.82(±15.33)ab, BT-109.87(±16.96)b, CT-548.09(±79.25)c.
Conclusions: The cement Bifix Temp produced the smaller color difference of all cements tested. The groups cemented with resin based cements Bifix Temp and ClearTemp LC were more translucent than all the other cements tested and similar to the control group. Only the cements Bifix Temp and ClearTemp LC groups showed more fluorescence than the control group.