Affiliation:
1. Department of Periodontology, Operative and Preventive Dentistry, Bonn University, 53111 Bonn, Germany
2. Center of Applied Medical Laser Research and Biomedical Optics (AMLaReBO), Bonn University, 53111 Bonn, Germany
3. Laser Application in Medical Sciences Research Center, Shahid Beheshti University of Medical Sciences, Tehran 19839 69411, Iran
4. Oral Technology, Bonn University, 53111 Bonn, Germany
5. Independent Researcher, 53111 Bonn, Germany
Abstract
The use of dental ceramics as restorative materials requires corresponding luting materials (cements) that, in turn, influence the visual appearance of the restoration. Due to the high light transmission through the ceramics, the cements can affect the color perception of the dental restoration. This study aims to investigate the optical effects of various cements on the visual appearance of full-ceramic restorations. Three fixing polymer resins (Bifix SE (VOCO GmbH, Cuxhafen, Germany), BreezeTM (Pentron Clinical, West Collins Orange, CA, USA), and PanaviaTM F. 2.0 (Kuraray, Noritake, Osaka, Japan)), with layer thicknesses of 50, 100, 200, and 250 µm, were applied onto a ceramic base model (0.4 mm thick), and irradiated with laser light of wavelengths 532, 632.8, and 1064 nm. Light intensities and scattering effects of light of various wavelengths were angle-dependent, analyzed using a goniophotometer with perpendicular light incidence on the sample specimen (base model plus luting material). In addition, the transmitted power of the light through the sample specimen was determined as a function of the layer thickness. With increasing layer thickness, power losses of respectively 30% for Bifix SE and BreezeTM in the visible spectral range were comparable, whereas PanaviaTM F. 2.0 showed a power loss of ca. 44% here. For the near-infrared range, the power losses for all cements were 25%. This could be confirmed by the interpretation of the line widths. Moreover, the line widths for thin cement layer thicknesses (50 and 100 µm) in the visible spectral range displayed only a redistribution of light by scattering, which does not affect color perception at all. In addition, at 200 and 250 µm, absorption occurred which causes a change in color perception. Within the scope of this study, it could be shown that for thin-layer thicknesses of the cement applied here, there is no adverse optical effect on the aesthetic visual appearance of the restoration.
Subject
General Materials Science
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