Effect of chitosan nanoparticles on microtensile bond strength of resin composite to dentin: an in vitro study / Efeito de nanopartículas de quitosana na resistência a união por microtração da resina composta à dentina: um estudo in vitro

Objective: The purpose of this study was to evaluate the effect of chitosan nanoparticles on microtensile bond strength of resin composite to dentin using self etch adhesive after aging. Material and Methods: A total number of 90 freshly extracted, sound human molar teeth. Flat tooth surface was gained after cut of the occlusal surface. Three main groups according to pretreatment of dentin before adhesive application; 0.2 % chitosan, 2.5 % chitosan and no treatment control group. Universal self etch adhesive were applied according to manufacture instruction and 4 mm of Feltik Z250 xt composite. Storage of specimens for 1 day, 3 months and 6 months in 37O C distilled water. After that, the tooth was sectioned to beams of 1 mm x8 mm sticks for microtensile bond strength test using universal testing machine. Scanning electron microscope (SEM) was used to evalute the effect of chitosan nanoparticles on dentin and smear layer. Kruskal-Wallis test was used to compare between the three groups as well as the three aging periods. Dunn's test was used for pair-wise comparisons. The significance level was set at P ≤ 0.05. Results: chitosan 0.2% is statistically significant increase in bond strength than chitosan 2.5% and control in one day group. Three months chitosan 0.2 % groups have statistically significant increase in bond strength than chitosan 2.5%. It was found in 6 months that control and chitosan 0.2 % have statistically significant increase in bond strength than chitosan 2.5%. There was statistically significant difference found between the three studied groups regarding bond strength at different storage times . Conclusion: Microtensile bond strength was influenced by different chitosan concentration. Different aging periods had no effect on the microtensile bond strength without application of chitosan and with application of 2.5% chitosan concentration. (AU)

Introdução: O objetivo deste estudo foi avaliar o efeito das nanopartículas de quitosana na resistência da microtração de união do compósito de resina à dentina usando adesivo autocondicionante após o envelhecimento. Material e Métodos: Foram utilizados um total de 90 dentes molares humanos extraídos e sadios. A superfície plana do dente foi obtida após o corte da superfície oclusal. Os dentes foram divididos em três grupos principais de acordo com o pré-tratamento da dentina e antes da aplicação do adesivo: 0,2% de quitosana, 2,5% de quitosana e nenhum tratamento foi utilizado no grupo controle. O adesivo autocondicionante universal foi aplicado de acordo com as instruções do fabricante e 4 mm de composito Feltik Z250 xt foi inserido. O armazenamento de amostras foi realizado por 1 dia, 3 meses e 6 meses em água destilada a 37 °C. Depois disso, o dente foi seccionado em peças de 1 mm x 8 mm para teste de resistência de união por microtração, utilizando máquina de teste universal. Microscópio eletrônico de varredura (MEV) foi usado para avaliar o efeito das nanopartículas de quitosana na dentina e na camada de smear layer. O teste de Kruskal-Wallis foi utilizado para comparar os três grupos e os três períodos de envelhecimento. O teste de Dunn foi usado para comparação pareada dos grupos. O nível de significância foi estabelecido em P ≤ 0,05. (AU)

Orthopaedic surgeons as clinical leaders in the national health service, United Kingdom [NHS UK]: can the world learn from us?

This article outlines some of the key concepts in leadership [both styles and theories] to provide a platform for further learning and to help the modern day orthopaedic surgeons to apply these concepts to their current practice. It is focused on two major aspects: management of medical organizations and effective twenty-first century care by surgeons through proper leadership guide and aimed in improving patient care outcomes. Practicing proper leadership skills based on evidence resulted in effective management of organization. Thus achieving patient's satisfaction

Primary carcinoid tumors at atypical sites: report of 3 cases with vague clinical presentations

Carcinold tumors at atypical sites are rare and mostly asymptomatic. In the majority they show normal levels of serotonin and its metabolites in plasma and urine, resulting in a relatively late diagnosis and hence poor prognosis. Relatively large sizes and local recurrences are features of carcinoids at atypical locations and may direct the surgeons' attention to their possible existence. A report of three cases of Carcinoid tumors in the breast, abdominal paravertebral region and the duodenum is given. The symptoms and clinical findings in the three cases were vague and did not raise any suspicion of Carcinoid. Repeated local recurrence in the three cases after excision was the clue for the diagnosis that was confirmed by appropriate diagnostic tools. Carcinoid tumors at atypical sites are either benign or low grade malignant neoplasms with a good long-term prognosis after surgical treatment. Routine resection, which may be aggressive, is the treatment of choice whenever possible, even in recurrent cases. The survival of patients depends basically on the tumor size and the presence of distant metastases. When resection is not feasible, reduction of tumor size may be possible by treatment with Somatostatin analogs

Early effects of vertical banded gastroplasty on pulmonary function tests

The aim of this study was to obtain a numerical assessment of the effect of vertical banded gastroplasty [VBG] on different pulmonary function tests [PFTs]. The study included 21 morbidly obese patients who had PFTs measured preoperatively and six months following VBG. Changes in the mean body mass index [BMI] and PFTs were analyzed using paired t test. Six months following VBG there was a significant BMI reduction from a mean of 49.64 +/- 8.44 kg/m2 to 38.01 +/- 6.46 kg/m2. There was a highly significant improvement in restrictive pulmonary dysfunction represented by changes of mean SVC from 3.13 +/- 10.47 L to 3.33 +/- 0.53 L and mean FVC from 3.07 +/- 0.5 L to 3.33 +/- 0.5 L. There was also a significant improvement in obstructive pulmonary dysfunction represented by changes of mean PEFR from 5.58 +/- 0.85 L/S to 6.12 +/- 0.94 L/S and mean FEVl from 2.54 +/- 0.42 L to 2.81 +/- 0.41 L. The FEF75% was significantly improved from 0.81 +/- 0.13 L/S to 0.94 +/- 0.18 L/S. Also, the peak inspiratory flow rate [PIFR] showed a significant improvement from 5.1 +/- 1.32 L/S to 6.01 +/- 1.03 L/S. The overall lung performance significantly improved as evidenced by elevation of ERV from 0.63 +/- 0.2 L to 0.93 +/- 0.24 L. MVV, which reflects work of breathing, also revealed significant improvement from 88.9 +/- 15.41 L/min. to 98.35 +/- 17.01 L/min. It was concluded that VBG produced highly significant improvement in both restrictive and obstructive PFTs as well as overall lung performance in a period of six months. Also it produced a significant improvement in the work of breathing