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Successful root canal treatment is based on diagnosis, treatment planning, knowledge of tooth anatomy, endodontic access cavity design, controlling the infection by thorough cleaning and shaping, methods and materials used in root canal obturation. An endodontic obturation must be a complete, three-dimensional filling of the root canal system, as close as possible to cemento-dentinal junction, without massive overfilling or underfilling. There are several known methods which are used to assess the quality of the endodontic sealing, but most are invasive. These lead to the destruction of the samples and often no conclusion could be drawn in respect to the existence of any microleakage in the investigated areas of interest. Using an time domain en-face OCT system, we have recently demonstrated real time thorough evaluation of quality of root canal fillings. The purpose of this in vitro study was to validate the en face OCT imagistic evaluation of endodontically treated human teeth by using scanning electron microscopy (SEM) and microcomputer tomography (μCT). SEM investigations evidenced the nonlinear aspect of the interface between the endodontic filling material and the root canal walls and materials defects in some samples. The results obtained by μCT revealed also some defects inside the root-canal filling and at the interfaces between the material and the root canal walls. The advantages of the OCT method consist in non-invasiveness and high resolution. In addition, en face OCT investigations permit visualization of the more complex stratified structure at the interface between the filling material and the dental hard tissue.

The purpose of this study is to present a non invasive method for the marginal adaptation evaluation in class V composite restorations. Standardized class V cavities prepared in human extracted teeth were filled with composite resin (Premise, Kerr). The specimens were thermocycled. The interfaces were examined by Optical Coherence Tomography (OCT) combined with confocal microscopy and fluorescence. The optical configuration uses two single mode directional couplers with a superluminiscent diode as the source at 1300 nm. The scanning procedure is similar to that used in any confocal microscope, where the fast scanning is en-face (line rate) and the depth scanning is much slower (at the frame rate). Gaps at the interfaces as well as on the inside of the composite resin were identified. OCT has numerous advantages that justify its in vivo and in vitro use compared to conventional techniques. One of the main concerns was the fact that at the adhesive layer site it was very hard to tell the adhesive apart from material defects. For this reason the adhesive was optimized in order to be more scattering. This way we could make a difference between the adhesive layer and the material defects that could lead to microleakages.