Nowadays in dentistry a correct diagnosis is given only after a clinical and radiological evaluation. Radiographs are also required for treatment assessments. The aim of this study is to present results obtained on evaluating dental cavities in a dental clinic in Western Romania, using both X-ray radiography and Optical Coherence Tomography (OCT). The most common methods for daily-basis clinical imaging are utilized, i.e. panoramic radiography and three-dimensional (3D) cone beam computed tomography (CBCT). Advantages of OCT as an imaging method in dentistry are discussed: it avoids exposing the patient to X-ray radiation, and image resolution of OCT is superior. This led us to test this technique for dental assessments and see how it can work in conjunction with radiography. The study also provides upsides and downsides of both medical imaging techniques. Panoramic radiographs and 3D CBCT to several extracted teeth are performed. Dedicated toolbars from Romexis software (Planmeca, Helsinki, Finland) are analyzed with regard to their capability to make precise measurements. Processing of images are made to obtain a high-quality; measurements are done and data are collected. The same teeth are scanned with an in-house developed SS-OCT system. Images from both investigations are presented, and clinical conclusions are drawn. For dental issues (i.e., cavities) that appear on the surface of the teeth, OCT proves to be more suitable than radiographs; it is also more accurate and radiation-free.
Metals can break either in a ductile or brittle manner if a static or dynamic load is applied to the same material. This depends on a variety of factors, such as the manner in which the load is applied, the shape of the mechanical part, the operating conditions, the nature and structure of the metallic material, and the working temperature. If subjected to variable loads, metallic materials break due to what is called fatigue. The microscopic analysis of fracture surfaces is currently carried out by using scanning electron microscopy (SEM). We have proposed, for the first time to our knowledge, a new method to analyze fracture surfaces, using a low coherence interferometry technique, Optical Coherence Tomography (OCT) [Gh. Hutiu, V.-F. Duma, et al., Surface imaging of metallic material fractures using optical coherence tomography, Appl. Opt. 53, 5912-5916 (2014); Gh. Hutiu, V.-F. Duma, et al., Assessment of ductile, brittle, and fatigue fractures of metals using optical coherence tomography, Metals 8, 117 (2018)]. The present paper presents the way we have demonstrated that OCT can replace the gold standard in such assessments, i.e. SEM, despite the fact that OCT has a resolution of 20 to 4 μm (in our investigations), while the SEM we employed has a 4 to 2 nm resolution. A few examples are given in this respect–for different types of fractures. The advantages of OCT versus SEM are discussed. This development opens the way for in situ investigations, for example in forensic sciences, where OCT can be applied (including with handheld scanning probes. as we have developed). In contrast, SEM, TEM, and AFM are lab-based techniques, more expensive, and they require trained operators.