Laser microspectral analysis for validation of en-face OCT imagistic evaluation of microleakage between the metallic framework and veneer materials in fixed partial prostheses

Optical tomographic techniques are of particular importance in the medical imaging field, because these techniques can provide non-invasive diagnostic images. Using an en-face version of OCT, we have recently demonstrated real time thorough evaluation of quality of dental restorations. The microleakage at the interface between the metal infrastructure and the veneering part of the fixed partial prostheses (FPP's) are a common problem of aesthetic dentistry. The purpose of this study is to evaluate the capability of en-face optical coherence tomography (efOCT) to detect and analyze the possible defects at the interface of several FPP's. For validation, we used the method of laser microspectral analysis. The laser microspectral analysis is a punctual method of analysis, which allows to investigate small quantities of materials of around 0.1 ng. This method allows to establish the content of atoms and molecules and to perform semi-quantitative and quantitative analysis. By this method it is possible to establish trace elements, i. e. with concentration of ppm (parts per million). The advantages of the OCT method consist in non-invasiveness and high resolution. En-face OCT investigations permit to visualize a more complex stratificated structure at the interface metallic framework /veneering material