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1.
J Contemp Dent Pract ; 22(6): 605-609, 2021 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-34393114

RESUMO

AIM AND OBJECTIVE: The present study compared the frictional forces of three types of self-ligating lingual appliances. MATERIALS AND METHODS: The lingual appliances (2D, Forestadent; Alias, Ormco; and Clippy L, Tomy International) consisted of a self-ligating bracket (second premolar) and two self-ligating tubes (first and second molars) bonded to a stainless steel jig and attached to a "drawing-friction tester." Full-size and non-full-size stainless steel archwires were tested, and the static and kinetic friction acting on six lingual appliance/wire combinations was estimated (n = 5). Three-dimensional micro-computed tomography (micro-CT) analysis of each premolar bracket was performed. The frictional forces were compared between the bracket/wire combinations using the Kruskal-Wallis and Mann-Whitney U tests. RESULTS: The Alias and Clippy L bracket/wire combinations had greater contact between the wire surfaces and bracket slots compared to the 2D bracket/wire combination. For all lingual appliances, the static and kinetic frictional forces were significantly higher for the full-size than non-full-size archwire. The 2D bracket, which had a wider outer wing, had less frictional force than the other appliances. The Alias, which had a narrower outer wing, had a significantly lower frictional force than the Clippy L. CONCLUSIONS: Frictional force was significantly higher for heavier full-size bracket/archwire combinations than for non-full-size archwires. The 2D bracket had lower frictional force due to its archwire-holding mechanism. The outer wing width may influence the frictional resistance. CLINICAL SIGNIFICANCE: The frictional forces of self-ligating lingual appliances vary, and bracket design and archwire size may influence the frictional performance.


Assuntos
Braquetes Ortodônticos , Fios Ortodônticos , Ligas Dentárias , Análise do Estresse Dentário , Fricção , Humanos , Teste de Materiais , Desenho de Aparelho Ortodôntico , Aço Inoxidável , Titânio , Microtomografia por Raio-X
2.
Materials (Basel) ; 13(2)2020 Jan 19.
Artigo em Inglês | MEDLINE | ID: mdl-31963840

RESUMO

In current orthodontic practice, miniscrew implants (MSIs) for anchorage and bone fixation plates (BFPs) for surgical orthodontic treatment are commonly used. MSIs and BFPs that are made of bioabsorbable material would avoid the need for removal surgery. We investigated the mechanical, degradation and osseointegration properties and the bone-implant interface strength of the AZ31 bioabsorbable magnesium alloy to assess its suitability for MSIs and BFPs. The mechanical properties of a Ti alloy (TiA), AZ31 Mg alloy (MgA), pure Mg and poly-L-lactic acid (PLA) were investigated using a nanoindentation test. Also, pH changes in the solution and degradation rates were determined using immersion tests. Three-dimensional, high-resolution, micro-computed tomography (CT) of implants in the rat femur was performed. Biomechanical push-out testing was conducted to calculate the maximum shear strength of the bone-implant interface. Scanning electron microscopy (SEM), histological analysis and an evaluation of systemic inflammation were performed. MgA has mechanical properties similar to those of bone, and is suitable for implants. The degradation rate of MgA was significantly lower than that of Mg. MgA achieved a significantly higher bone-implant bond strength than TiA. Micro-CT revealed no significant differences in bone density or bone-implant contact between TiA and MgA. In conclusion, the AZ31 Mg alloy is suitable for both MSIs and BFPs.

3.
Dent Mater J ; 36(4): 461-468, 2017 Jul 26.
Artigo em Inglês | MEDLINE | ID: mdl-28367912

RESUMO

We investigated single application of pastes containing a surface reaction-type pre-reacted glass-ionomer (S-PRG) filler on enamel demineralization. Human enamel blocks were polished using pastes containing S-PRG filler (0, 5, and 30%) and immersed in demineralizing solution for 5 days with daily change of solutions. The pH measurement and nanoindentation testing was carried out during the immersion period, and the enamel surfaces were examined using scanning electron microscopy and atomic force microscopy. A non-fluoride paste and a hydroxyapatite-containing paste were used for comparison. The specimens polished with the S-PRG filler-containing paste exhibited acid-neutralizing properties, which became stronger with an increasing S-PRG filler content. Following immersion in the demineralizing solution, specimens polished with the S-PRG filler-containing paste exhibited significantly greater hardness and elastic modulus values than those polished with the other pastes and exhibited a smoother surface than did the other specimens. Pastes containing S-PRG filler inhibits the demineralization of enamel.


Assuntos
Esmalte Dentário , Desmineralização do Dente , Dureza , Humanos , Microscopia Eletrônica de Varredura , Pomadas , Cremes Dentais
4.
Eur J Oral Sci ; 125(2): 160-167, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28145593

RESUMO

In this study, wear and inhibition of enamel demineralization by resin-based coating materials were investigated. Seven commercially available coating materials, with and without fillers, were used. A mechanical wear test was performed, and the specimens were then examined with a scanning electron microscope. Hardness and elastic modulus measurements for each material were obtained by nanoindentation testing. Thin layers of each material were applied on human enamel surfaces, which were subjected to alternating immersion in demineralizing and remineralizing solutions. The inhibition ability of enamel demineralization adjacent to the coating was estimated with depth-dependent mechanical properties using the nanoindentation test. The non-filled coating material showed significantly lower hardness, lower elastic modulus, and higher weight loss. There were no significant differences in weight loss among the six filled coating materials. After the alternating immersion protocol, the enamel specimens having application of coating materials with ion-releasing ability were harder than those in the other groups in some locations 1-11 µm from the enamel surface and within 300 µm from the edge of the coating materials. In conclusion, clinical use of the resin-based coating materials with ion-releasing ability may prevent demineralization of exposed enamel adjacent to the coating during treatment.


Assuntos
Esmalte Dentário/efeitos dos fármacos , Adesivos Dentinários/química , Cimentos de Resina/química , Desmineralização do Dente/prevenção & controle , Dente Pré-Molar , Módulo de Elasticidade , Dureza , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura
5.
BMC Res Notes ; 6: 455, 2013 Nov 12.
Artigo em Inglês | MEDLINE | ID: mdl-24215903

RESUMO

BACKGROUND: Long-term administration of low-dose aspirin (LDA) is associated with a greater risk of adverse events, including gastroduodenal ulcers. The purpose of this study was to identify the risk factors for and assess the role of medication use in the development of peptic ulcer disease in Japanese patients with no history of peptic ulcers. METHODS: Consecutive outpatients receiving LDA (75 mg/day) who underwent esophagogastroduodenoscopy between January and December 2010 were enrolled. Clinical parameters, peptic ulcer history, concomitant drugs, the presence of Helicobacter pylori infection, reason for endoscopy, and endoscopic findings were analysed. RESULTS: Of 226 total patients, 14 (6.2%) were endoscopically diagnosed with peptic ulcer. Age, sex, current smoking status, current alcohol consumption, endoscopic gastric mucosal atrophy, and abdominal symptoms were not significantly associated with peptic ulcers. Diabetes mellitus was more frequent (42.9% vs. 16.5%; P = 0.024) in patients with peptic ulcers than in those without peptic ulcers. Using multiple logistic regression analysis, co-treatment with anticoagulants or proton pump inhibitors (PPIs) was significantly associated with increased and decreased risk for peptic ulcer, respectively (odds ratio [OR], 5.88; 95% confidence interval [CI], 1.19 - 28.99; P = 0.03 and OR, 0.13; 95% CI, 0.02 - 0.73; P = 0.02, respectively). Co-treatment with additional antiplatelet agents, H2-receptor antagonists, angiotensin II Type 1 receptor blockers, angiotensin-converting enzyme inhibitor, 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor, or nonsteroidal anti-inflammatory drugs was not associated with peptic ulcer development. CONCLUSION: The use of PPIs reduces the risk of developing gastric or duodenal ulcers in Japanese patients taking LDA without pre-existing gastroduodenal ulcers. However, this risk is significantly increased in both patients ingesting anticoagulants and patients with diabetes. These results may help identify patients who require intensive prophylaxis against aspirin-induced peptic ulcers.


Assuntos
Antiulcerosos/uso terapêutico , Aspirina/efeitos adversos , Úlcera Duodenal/induzido quimicamente , Fibrinolíticos/efeitos adversos , Inibidores da Bomba de Prótons/uso terapêutico , Úlcera Gástrica/induzido quimicamente , Idoso , Idoso de 80 Anos ou mais , Grupo com Ancestrais do Continente Asiático , Complicações do Diabetes , Diabetes Mellitus/etnologia , Diabetes Mellitus/patologia , Úlcera Duodenal/complicações , Úlcera Duodenal/patologia , Úlcera Duodenal/prevenção & controle , Duodenoscopia , Feminino , Gastroscopia , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Úlcera Gástrica/complicações , Úlcera Gástrica/patologia , Úlcera Gástrica/prevenção & controle
6.
Case Rep Gastroenterol ; 6(2): 232-7, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22679410

RESUMO

A 41-year-old woman was admitted to our hospital with abdominal pain that developed about 1 year after a Cesarean section. Pelvic computed tomography (CT) revealed diffuse dilation of the small intestine with fluid shadows and a pelvic tumor 55 mm in diameter. The density of the tumor, which was not enhanced by intravenous contrast medium, was diffuse and similar to that of muscular tissue, whereas the density of a capsule surrounding the mass was relatively high. T1- and T2-weighted pelvic magnetic resonance imaging (MRI) of the tumor revealed the same diffuse low-intensity signals as muscular tissue, and diffuse high-intensity signals, respectively. The CT and MRI findings were consistent with those of a gastrointestinal stromal tumor (GIST) causing ileus of the small intestine. As inserting an ileus tube did not improve her symptoms, the patient was scheduled for tumor resection. The operative findings revealed a hard, solid tumor adhering to the surrounding small intestine. The macroscopic findings revealed that the tumor consisted of layers of stratified gauze surrounded by a thick granulomatous wall. The gossypiboma was considered to have originated from gauze that had been left behind after the Cesarean section. If a patient has a history of surgery, the possibility of gossypiboma should be considered when CT or MRI findings indicate features of GIST.

7.
Hepatogastroenterology ; 58(110-111): 1588-94, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-22086689

RESUMO

In case 1, endoscopy revealed a submucosal tumor with central ulceration in the esophagus of a 54- year-old man. A biopsy specimen revealed small cell carcinoma without metastasis and the stage of the cancer was stage I (T2N0M0). Two cycles of concurrent cisplatin, etoposide and radiotherapy resulted in an incomplete response/stable disease. The tumor recurred and had metastasized to the brain, lung, liver, lymph nodes of the mediastinum, abdomen and bones after six cycles. Two cycles of irinotecan and cisplatin then elicited a complete response in the primary esophageal lesion. However, progressive disease was identified in the metastatic bone tumors. Despite two further cycles of therapy, he died 447 days after the initial course. In case 2, a biopsy specimen of a tumor with central ulceration in the esophagus of a 77-year old man with swallowing difficulty indicated small cell carcinoma. The stage of the cancer was diagnosed as stage II (T3N0M0). Two cycles of irinotecan, cisplatin and concurrent radiotherapy elicited a complete response. However, the tumor metastasized to the brain and the liver 644 days after starting treatment. Two cycles of carboplastin plus irinotecan elicited a partial response in the metastatic tumors, but he died 988 days after starting chemotherapy.


Assuntos
Neoplasias Esofágicas/tratamento farmacológico , Neoplasias Esofágicas/radioterapia , Qualidade de Vida , Idoso , Antineoplásicos/uso terapêutico , Biópsia , Camptotecina/análogos & derivados , Camptotecina/uso terapêutico , Cisplatino/uso terapêutico , Diagnóstico por Imagem , Neoplasias Esofágicas/patologia , Feminino , Humanos , Irinotecano , Pessoa de Meia-Idade , Estadiamento de Neoplasias
8.
J Clin Biochem Nutr ; 47(1): 53-8, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20664731

RESUMO

A triple therapy based on a proton pump inhibitor (PPI), amoxicillin (AMPC), and clarithromycin (CAM) is recommended as a first-line therapy for Helicobacter pylori (H. pylori) eradication and is widely used in Japan. However, a decline in eradication rate associated with an increase in prevalence of CAM resistance is viewed as a problem. We investigated CAM resistance and eradication rates over time retrospectively in 750 patients who had undergone the triple therapy as first-line eradication therapy at Nagoya City University Hospital from 1995 to 2008, divided into four terms (Term 1: 1997-2000, Term 2: 2001-2003, Term 3: 2004-2006, Term 4: 2007-2008). Primary resistance to CAM rose significantly over time from 8.7% to 23.5%, 26.7% and 34.5% while the eradication rate decreased significantly from 90.6% to 80.2%, 76.0% and 74.8%. Based on the PPI type, significant declines in eradication rates were observed with omeprazole or lansoprazole, but not with rabeprazole. A decrease in the H. pylori eradication rate after triple therapy using a PPI + AMPC + CAM has been acknowledged, and an increase in CAM resistance is considered to be a factor. From now on, a first-line eradication regimen that results in a higher eradication rate ought to be investigated.

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