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1.
J Clin Med ; 13(10)2024 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-38792296

RESUMO

Background: This study aimed to investigate the relationship between the Curve of Spee (COS) depth and malocclusion characteristics in a population from Sibiu County, Romania. The research sought to understand how the COS's anatomical dimensions correlate with different classes of malocclusion and the position of the frontal teeth. Methods: A total of 265 participants from the Dentistry Ambulatory of the Military Hospital of Sibiu were included in this study. It employed digital intraoral scanning technology to measure the COS, overjet, and overbite, with malocclusion classification. Statistical analyses, including correlation and regression, were conducted to examine the relationships between COS depth, frontal teeth position, and malocclusion characteristics. Results: The average COS depth measured was 1.0564 mm, presenting variability when compared to existing literature. Most of the study participants had Class I malocclusion. A significant positive correlation between COS depth and overjet was identified, with no notable gender-based differences in these occlusal parameters. Conclusions: The findings affirm the integral role of COS in occlusal dynamics and malocclusion diagnosis. The COS measurement of a mean of 1.0564 mm, when compared to other results emphasizes the differences in occlusal curvature among various populations. The results contribute to a refined understanding of occlusal relationships, supporting the need for personalized orthodontic and prosthetic treatments based on precise anatomical measurements.

4.
Materials (Basel) ; 16(5)2023 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-36903057

RESUMO

In the present study, the microstructure and mechanical properties of Ti-xTa (x = 5%, 15%, and 25% wt. Ta) alloys produced by using an induced furnace by the cold crucible levitation fusion technique were investigated and compared. The microstructure was examined by scanning electron microscopy and X-ray diffraction. The alloys present a microstructure characterized by the α' lamellar structure in a matrix of the transformed ß phase. From the bulk materials, the samples for the tensile tests were prepared and based on the results and the elastic modulus was calculated by deducting the lowest values for the Ti-25Ta alloy. Moreover, a surface alkali treatment functionalization was performed using 10 M NaOH. The microstructure of the new developed films on the surface of the Ti-xTa alloys was investigated by scanning electron microscopy and the chemical analysis revealed the formation of sodium titanate and sodium tantanate along with titanium and tantalum oxides. Using low loads, the Vickers hardness test revealed increased hardness values for the alkali-treated samples. After exposure to simulated body fluid, phosphorus and calcium were identified on the surface of the new developed film, indicating the development of apatite. The corrosion resistance was evaluated by open cell potential measurements in simulated body fluid before and after NaOH treatment. The tests were performed at 22 °C as well as at 40 °C, simulating fever. The results show that the Ta content has a detrimental effect on the investigated alloys' microstructure, hardness, elastic modulus, and corrosion behavior.

5.
Materials (Basel) ; 15(11)2022 May 27.
Artigo em Inglês | MEDLINE | ID: mdl-35683112

RESUMO

Ti and its alloys have the most satisfactory properties for biomedical applications due to their specific strength, high corrosion resistance, and high biocompatibility. Ti-6Al-7Nb has been approved for clinical use, proving to be a viable replacement for the Ti-6Al-4V alloy that has been used for many decades in medical applications. In our study, the Ti-6Al-7Nb alloy underwent heat treatment, was cooled in various cooling media such as mineral oil and water, and was then quenched in the oven. The microstructure was investigated, and the mechanical characterization was carried out by Vickers microhardness test. Young's modulus measurements and tensile tests were performed in order to study the effect of cooling media on the material. To study the corrosion behavior, in vitro studies were performed on the Ti-6Al-7Nb samples in simulated body conditions by using artificial saliva. It was observed that the martensitic phase changed as a function of cooling media, and a less intensive cooling medium decreases strength properties' indicators as well as hardness values. The results emphasize that the use of heat treatment improves the passive layer's resistance in the presence of artificial saliva.

6.
Materials (Basel) ; 15(2)2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-35057284

RESUMO

Fluoride conversion coatings on Mg present many advantages, among which one can find the reduction of the corrosion rate under "in vivo" or "in vitro" conditions and the promotion of the calcium phosphate deposition. Moreover, the fluoride ions released from MgF2 do not present cytotoxic effects and inhibit the biofilm formation, and thus these treated alloys are very suitable for cardiovascular stents and biodegradable orthopedic implants. In this paper, the biodegradation behavior of four new magnesium biodegradable alloys that have been developed in the laboratory conditions, before and after surface modifications by fluoride conversion (and sandblasting) coatings, are analyzed. We performed structural and surface analysis (XRD, SEM, contact angle) before and after applying different surface treatments. Furthermore, we studied the electrochemical behavior and biodegradation of all experimental samples after immersion test performed in NaCl solution. For a better evaluation, we also used LM and SEM for evaluation of the corroded samples after immersion test. The results showed an improved corrosion resistance for HF treated alloy in the NaCl solution. The chemical composition, uniformity, thickness and stability of the layers generated on the surface of the alloys significantly influence their corrosion behavior. Our study reveals that HF treatment is a beneficial way to improve the biofunctional properties required for the studied magnesium alloys to be used as biomaterials for manufacturing the orthopedic implants.

7.
Brain Sci ; 11(12)2021 Dec 02.
Artigo em Inglês | MEDLINE | ID: mdl-34942906

RESUMO

A 23-year-old woman was presented to the Emergency Unit with intracranial hypertension syndrome and blindness in her left eye which had started recently. A cranial native computed tomography scan and a magnetic resonance imaging (MRI) with contrast examinations revealed a giant intracranial cystic lesion, extending into the left frontal lobe, which was compressing the optic chiasm and eroding the internal plate of the left frontal bone. Surgical craniotomy was performed for evacuation and decompression, but during the craniotomy the cyst ruptured. After assessing the degree of erosion of the internal bone plate, we concluded that the primary origin of the cyst was intraosseous. With the dura mater being intact, abundant lavage with H2O2 was applied and the bone flap was replaced after rigorous bone scraping. Imaging control at six and twelve months identified no recurrence of the cyst. In the literature, hydatid cysts located in the skull bone are very rare and most of them rupture intraoperatively. Given their extremely low incidence in developed countries, any neurosurgeons' experience with such pathology is limited and in some cases surgery cannot be delayed. In the case of intracerebral hydatid cysts, a neurosurgeon usually has only one shot at surgery, so simple and quick-to-access therapeutic guidelines must be developed in order to inform the choice of surgical technique. We conclude that the most successful surgical approach could be double concentric craniotomy. This surgical technique is used in intracerebral tumors, which also have an important bone invasion.

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