Automatic method of analysis of OCT images in the assessment of the tooth enamel surface after orthodontic treatment with fixed braces

Introduction: Fixed orthodontic appliances, despite years of research and development, still raise a lot of controversy because of its potentially destructive influence on enamel. Therefore, it is necessary to quantitatively assess the condition and therein the thickness of tooth enamel in order to select the appropriate orthodontic bonding and debonding methodology as well as to assess the quality of enamel after treatment and clean-up procedure in order to choose the most advantageous course of treatment. One of the assessment methods is computed tomography where the measurement of enamel thickness and the 3D reconstruction of image sequences can be performed fully automatically. Material and method: OCT images of 180 teeth were obtained from the Topcon 3D OCT-2000 camera. The images were obtained in vitro by performing sequentially 7 stages of treatment on all the teeth: before any interference into enamel, polishing with orthodontic paste, etching and application of a bonding system, orthodontic bracket bonding, orthodontic bracket removal, cleaning off adhesive residue. A dedicated method for the analysis and processing of images involving median filtering, mathematical morphology, binarization, polynomial approximation and the active contour method has been proposed. Results: The obtained results enable automatic measurement of tooth enamel thickness in 5 seconds using the Core i5 CPU M460 @ 2.5GHz 4GB RAM. For one patient, the proposed method of analysis confirms enamel thickness loss of 80 μm (from 730 ± 165 μm to 650 ± 129 μm) after polishing with paste, enamel thickness loss of 435 μm (from 730 ± 165 μm to 295±55 μm) after etching and bonding resin application, growth of a layer having a thickness of 265 μm (from 295 ± 55 μm to 560 ± 98 μm after etching) which is the adhesive system. After removing an orthodontic bracket, the adhesive residue was 105 μm and after cleaning it off, the enamel thickness was 605 μm. The enamel thickness before and after the whole treatment decreased by about 125 μm. Conclusions: This paper presents an automatic quantitative method for the assessment of tooth enamel thickness. This method has proven to be an effective diagnostic tool that allows evaluation of the surface and cross section of tooth enamel after orthodontic treatment with fixed thin-arched braces and proper selection of the methodology and course of treatment

Możliwe interakcje fluorków, wapnia i kwasów tłuszczowych w blaszkach miażdżycowych izolowanych z tętnic szyjnych

Background. Quantitative and qualitative changes in the mineral composition of the arterial wall seem to be engaged in the formation of the atherosclerotic plaque. The aim of this study was to determine the content of fluoride and calcium in atherosclerotic plaques and to understand the process of fluorine ions binding into the plaque. Material and methods. Plaques were obtained from patients operated for atherosclerosis of carotid arteries. Median content of fluoride and calcium in the atherosclerotic plaques were 0.75 and 207 μmol/g, respectively. Results. No correlation between the content of fluoride and calcium (R = 0.11, p = 0.60) was disclosed. Conclusions. We are of the opinion that fluoride reacts with fatty acids of the plaque, disrupting carbon bonds of the fatty acid molecule. Fluoride is a component of the atherosclerotic plaque but apparently is not deposited together with calcium ions. Fluoride is capable of interacting with fatty acids of the atherosclerotic plaque.Wstęp. Zmiany ilościowe oraz jakościowe składników mineralnych w ścianie tętniczej mogą być jednym z czynników stymulujących rozwój blaszki miażdżycowej. Celem niniejszej pracy było oznaczenie zawartości fluorku oraz wapnia w blaszce oraz zbadanie sposobu wiązania jonu fluorkowego w złogu miażdżycowym. Materiał i metody. Pomiary zawartości fluorku i wapnia prowadzono w blaszkach miażdżycowych uzyskanych od chorych operowanych z powodu zaawansowanej miażdżycy tętnic szyjnych. Zmierzona mediana zawartości fluorku w blaszce osiągnęła 0,75 μmola/gram. Wyniki. Nie odnotowano istotnej statystycznie korelacji pomiędzy zawartością fluorku oraz wapnia w blaszce miażdżycowej (R = 0,11, p = 0,60). Wnioski. Fluorek może reagować z zawartymi w blaszce miażdżycowej kwasami tłuszczowymi, prawdopodobnie przyczyniając się do degradacji wiązania pomiędzy atomami węgla w cząsteczce kwasu tłuszczowego. Fluorek jest składnikiem blaszki miażdżycowej, ale nie odkłada się w niej w połączeniu z jonami wapnia i może on oddziaływać w blaszce z zawartymi w niej kwasami tłuszczowymi