1. The correlation between pain perception among patients with six different orthodontic archwires and the degree of dental crowdingEvgenija Marković, Janko Ferčec, Ivana Ščepan, Branislav Glišić, Nenad Nedeljković, Jovana Juloski, Rebeka Rudolf, 2015, original scientific article Abstract: Introduction: Forces generated in orthodontic treatment with fixed appliances create tension and compression zones in the periodontal ligament resulting in a painful experience for patients. In the first phase of orthodontic treatment, when leveling of teeth is needed, nickel-titanium (NiTi) archwires can be completely engaged in brackets, even in the cases of extreme crowding, exerting small forces. There is a great individual variation in the pain perception related to the application of orthodontic forces.
Objective: The aim of this study was to investigate the pain perception among patients with dental crowding after insertion of six different NiTi orthodontic archwires as a part of fixed appliances in the first stage of orthodontic treatment.
Methods: The study was conducted on a sample of 189 orthodontic patients receiving one of six different either superelastic or heat activated NiTi archwires, in the first phase of orthodontic treatment. Pain perception was evaluated in groups of patients with different degree of crowding. The modified McGill Pain Questionnaire with Visual Analogue Scale was used to evaluate the quality and intensity of pain. Statistical analysis was performed using simple descriptive statistics, and Pearson`s chi-square test with statistical significance of p<0.05.
Results: Majority of patients reported pain as discomfort or pressure of moderate intensity caused by chewing or biting, started within 12 hours, carried on for 3-4 days, and decreased over time without self-medication.
Conclusion: No correlation was found between pain perception among patients with different types of NiTi archwires and the degree of crowding.
Keywords: nickel-titanium archwires, pain, dental crowding, orthodontics
Published in DKUM: 04.08.2017; Views: 1293; Downloads: 348
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2. Comparison of NiTi orthodontic archwires and a determination of the charasteristic propertiesJanko Ferčec, Matija Kos, Mihael Brunčko, Ivan Anžel, Branislav Glišić, Evgenija Marković, Rebeka Rudolf, 2014, original scientific article Abstract: The aim of this paper was to analyse the characteristic properties of six different, commercially available nickel-titaniumorthodontic wires with a diameter of 0.305 mm (0.014"). The characteristic properties were determined by usingsemi-quantitative EDX analyses, DSC analyses for a determination of the phase temperatures, and a tensile test to obtain themechanical properties of the wires. The investigation of the chemical composition showed an equiatomic NiTi alloy. Analysesof phase temperatures showed that the nickel-titanium orthodontic wires were, in an austenitic microstructure, exhibiting asuperelastic effect in the oral environment. The uniaxial tensile stressstrain curves showed different values for the beginningand the end of the transformation range during the loading.
Keywords: shape-memory alloy, phase transformation, thermal analysis, tensile test
Published in DKUM: 21.12.2015; Views: 1548; Downloads: 113
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3. Determination of stresses and forces on the orthodontic system by using numerical simulation of the finite elements methodJanko Ferčec, Branislav Glišić, I. Šćepan, Evgenija Marković, Dragoslav Stamenković, Ivan Anžel, Jože Flašker, Rebeka Rudolf, 2012, original scientific article Abstract: This study was addressed to use knowledge about the orthodontic system with numerical simulation of the nite elements method. For the rst time we simulated the stresses on the orthodontic system and, in this manner, calculated the orthodontic force on the tooth. A 3D orthodontic model or orthodontic system was designed resembling moderate crowding in the dental arch with all supporting structures. CATIA V5 computer software was used to set up a model for the orthodontic system and ABAQUS was used for simulation of the stresses on the orthodontic system. Our attention was focused on the stresses on the tooth lateral incisor and its periodontal ligament. The results of the numerical simulation showed complex stresses on the tooth lateral incisor and its periodontal ligament. In this paper is presented a calculation of the orthodontic force acting on the tooth lateral incisor due to the orthodontic wire. This orthodontic force was calculated from the stresses on the bracket. The calculated orthodontic force was in the area which is considered as the optimal orthodontic force for movement of the tooth.
Keywords: okluzija, ortodontski sistem, metoda končnih elementov, ortodonske sile, zobje, malocclusion, orthodontic system, finite elements method, orthodontic force, tooth
Published in DKUM: 10.07.2015; Views: 1361; Downloads: 106
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4. Gold in the past, today and futureRebeka Rudolf, Maša Anžel, Evgenija Marković, Miodrag Čolić, Dragoslav Stamenković, 2012, review article Abstract: This paper deals with gold, which is described as a chemical element. Special attention is paid to its physical-chemical properties and, furthermore, where or in what form it can be found in nature. We discuss the role it has played through history and we inform how gold has been developed to the level it has reached today's value. Still more, when gold is broken into nanoparticles, this form could be highly useful for a wide range of processes, including general nanotechnology, electronics manufacturing and the synthesizing of different functional materials. It is important that we know that gold is also used in industry in many engineering applications (contacts in micro-electronics) and medicine (dental alloys, implants).
Keywords: gold, physical-chemical properties, nano-particles, applications
Published in DKUM: 01.06.2012; Views: 3469; Downloads: 120
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