Laser-induced autofluorescence spectra of teeth irradiated by a 337 nm nitrogen laser were measured during in vitro caries formation through initial enamel demineralization and introducing of carious bacterial flora in the lesions developed. Spectra obtained from sound teeth consist of an intensive maximum at 480-500 nm and secondary maximum at 430-450 nm. In the process of caries formation, we observed an increase in the intensity at 430-450 nm and the appearance of two maxima in the red spectral region-at 590-650 nm. The intensity increase at 430-450 nm was related to the tooth demineralization. Bacteria presence and their metabolism products induced an increase in the absorption in the UV-blue spectral region at 350-420 nm and the appearance of a fluorescence signal in the long-wave spectral region at 590-650 nm. From the point of view of tissue optics, these results allow caries to be considered as consisting of two different phenomena-tissue destruction and bacterial flora and its metabolism products increase. The results could be used to obtain a more complete picture of caries formation on the base of its fluorescent properties.

Abstract. The pulp hyperaemia is associated with increased blood

A differentiation between initial tooth demineralization and early stages of caries could be made by the laser-induced fluorescence spectroscopy method.

Occlusal splints are the most common devices for preventing bruxism and its consequences. Their application significantly reduces the pathologies of the dental and periodontal structures. Apart from the well-known technologies of manufacturing occlusal splints – thermo-vacuum forming, wax elimination and CAD/CAM machining, three-dimensional (3D) printing is a novel promising technique. It makes use of stereolithography, whereby the splint is built layer-by-layer through consecutive polymerization of a liquid photo-polymer by ultraviolet laser light. A very important stage in stereolithography following the 3D-printing is the post polymerization processing. It is a key moment in achieving biocompatibility and the final mechanical parameters – hardness, elasticity modulus, and strength. The process comprises two steps – washing with isopropyl alcohol (IPA) followed by post-curing in a polymerization device with an ultraviolet light source. The aim of the present study is determining the influence of the polymerization device’s light source on the mechanical characteristics of the occlusal splint.

No abstract