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1.
Hua Xi Kou Qiang Yi Xue Za Zhi ; 39(1): 74-80, 2021 Feb 01.
Artigo em Inglês, Chinês | MEDLINE | ID: mdl-33723940

RESUMO

OBJECTIVES: This study aimed to explore the effect of sex determining region Y-box 9 (SOX9) on the microtubule formation and epithelial-mesenchymal transition (EMT) of human oral squamous cell carcinoma (OSCC) CAL27 and the underlying mechanism. METHODS: SOX9-shRNA1 and SOX9-shRNA2 were designed and synthesized and then transfected into CAL27 cells. The expression of SOX9 was detected by quantitative real-time polymerase chain reaction. Microtubule formation assay was used to detect the change in the number of microtubule nodules after interfering with SOX9. Immunofluorescence was used to detect the Vimentin content. Western blot was used to detect the protein expression of EMT marker molecules and Wnt/ß-catenin pathway-related proteins, such as E-cadherin, N-cadherin, Fibronectin, Wnt, ß-catenin, T-cell factor-4 (TCF-4). RESULTS: The expression level of SOX9 significantly decreased after transfection with SOX9-shRNA1 and SOX9-shRNA2 in CAL27 cells (F=578.000, P=0.000; F=96.850, P=0.000). Interference with SOX9 inhibited the EMT of OSCC. After interference with SOX9, the number of tubules and Vimentin positive cells decreased significantly (F=169.700, P=0.000). The expression level of E-cadherin significantly increased (F=181.400, P=0.000). The expression levels of N-cadherin, Fibronectin, Wnt, ß-catenin, and TCF-4 proteins significantly decreased (N-cadherin: F=101.400, P=0.000; Fibronectin: F=122.300, P=0.000; Wnt: F=70.290, P=0.000; ß-catenin: F=81.740, P=0.000; TCF-4: F=37.020, P=0.000). CONCLUSIONS: Interference with SOX9 decreased Vimentin content and inhibited the microtubule formation and protein expression of EMT marker molecules, as well as the expression of proteins related to the Wnt/ß-catenin pathway. Thus, SOX9 can induce microtubule formation and EMT in CAL27, which was related to the inhibition of the Wnt/ß-catenin pathway activation.


Assuntos
Carcinoma de Células Escamosas , Neoplasias de Cabeça e Pescoço , Neoplasias Bucais , Fatores de Transcrição SOX9 , Linhagem Celular Tumoral , Transição Epitelial-Mesenquimal , Humanos , Microtúbulos/metabolismo , Fatores de Transcrição SOX9/metabolismo , Carcinoma de Células Escamosas de Cabeça e Pescoço , Via de Sinalização Wnt , beta Catenina/metabolismo
2.
Rev Sci Instrum ; 90(9): 095103, 2019 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-31575227

RESUMO

Sliding electrical contact exists in various electrical equipment. However, its performance is significantly affected by the sliding condition such as the load, electricity, and the surface state of friction pairs. In this study, a novel instrument is designed and constructed for high-frequency microforce electrical sliding friction testing. The new instrument provides a unique experimental platform that enables high-frequency reciprocating friction and microforce loading, and it has an innovative data collection system that includes a cantilever beam structure to measure the microforce. In this instrument, parameters (positive force, friction, displacement, and voltage of frictional pair) are obtained and monitored in real time. The steel sheet and nickel-plated steel wire were used as materials to conduct an experiment, and the steel sheet morphology after the experiment was observed using a light microscope. Results show that the voltage and positive load significantly influence the friction coefficient and friction wear, which is crucial in understanding friction and wear behaviors.

3.
Artigo em Inglês | MEDLINE | ID: mdl-26161127

RESUMO

There were applications of eye acupuncture for stroke patients. Unfortunately, similar to many other Traditional Chinese Medicine (TCM) treatments, it lacks comprehensive evaluation and system review for its effect and safety. Objective. This study is a systematic review to appraise the safety and effectiveness of eye acupuncture for stroke. Methods. "Eye acupuncture therapy" in eleven databases was searched by randomized controlled trials and quasi-randomized controlled trials. The search activity was ended in April 2014. The data were extracted and assessed by three independent authors. Rev Man 5.0 software was used for data analysis with effect estimate presented as relative risk (RR) and mean difference (MD) with a 95% confidence interval. Results. Sixteen trials (1120 patients) were involved with generally poor methodological quality. The study indicated that when eye acupuncture was combined with western medicine compared to western medicine, there was a significant difference in the areas of mental state, swallow function, and NDS. When eye acupuncture was combined with western medicine and rehabilitation compared to western medicine and rehabilitation, there was significant difference in the changes of SSS, FMA, and constipation symptoms evaluation. No adverse events or side effects have been reported. Conclusions. The current evidence is insufficient and the rigorously designed trials are warranted.

4.
Chin J Integr Med ; 2014 Jun 13.
Artigo em Inglês | MEDLINE | ID: mdl-24928377

RESUMO

OBJECTIVE: To study whether acupuncture affects the tissue distribution of Paclitaxel in mouse lung carcinoma. METHODS: Totally 90 mice were divided into Paclitaxel group, Paclitaxel + Feishu (BL13) group, and Paclitaxel + Lingtai (DU10) group. Each group was consisted of 30 mice. After Paclitaxel injection, the mice received electro-acupuncture at Feishu or Lingtai acupoints once a day for 8 days. The effect of acupuncture on the tissue distribution of Paclitaxel was evaluated using high-performance liquid chromatography at 1, 2, and 3 h, respectively. The lung, liver, spleen, and kidney were examined for the concentration of Paclitaxel seperately. RESULTS: Paclitaxel was widely distributed in various organs, particularly in the lung, liver, and kidney. Acupuncture at Lingtai or Feishu acupoints resulted in an obvious decrease of Paclitaxel distribution in kidney and delayed Paclitaxel distribution in liver. Meanwhile, it increased the time of metabolism. Acupuncture at Feishu acupoint facilitated the delivery of Paclitaxel to lung more effectively than did acupuncture at Lingtai acupoint. CONCLUSIONS: Applying acupuncture at particular acupoints can influence tissue distribution of Paclitaxel. Tissue distribution change might be one of the mechanisms of acupuncture treatment during chemotherapy.

5.
J Huazhong Univ Sci Technolog Med Sci ; 34(3): 425-430, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24939311

RESUMO

The purpose of this study was to develop a new way to localize the impacted canines from three dimensions and to investigate the root resorption of the adjacent teeth by using cone beam computed tomography (CBCT). Forty-six patients undergoing orthodontic treatments and having impacted canines in Tongji Hospital were examined. The images of CBCT scans were obtained from KaVo 3D exam vision. Angular and linear measurements of the cusp tip and root apex according to the three planes (mid-sagittal, occlusal and frontal) have been taken using the cephalometric tool of the InVivo Dental Anatomage Version 5.1.10. The measurements of the angular and linear coordinates of the maxillary and mandibular canines were obtained. Using this technique the operators could envision the location of the impacted canine according to the three clinical planes. Adjacent teeth root resorption of 28.26 % was in the upper lateral incisors while 17.39% in upper central incisors, but no lower root resorption was found in our samples. Accurate and reliable localization of the impacted canines could be obtained from the novel analysis system, which offers a better surgical and orthodontic treatment for the patients with impacted canines.


Assuntos
Tomografia Computadorizada de Feixe Cônico/métodos , Dente Canino/diagnóstico por imagem , Imageamento Tridimensional/métodos , Reabsorção da Raiz/diagnóstico por imagem , Dente Impactado/diagnóstico por imagem , Adolescente , Adulto , Cefalometria/métodos , Criança , Feminino , Humanos , Incisivo/diagnóstico por imagem , Masculino , Maxila/diagnóstico por imagem , Reprodutibilidade dos Testes , Adulto Jovem
6.
Zhongguo Zhen Jiu ; 34(12): 1208-13, 2014 Dec.
Artigo em Chinês | MEDLINE | ID: mdl-25876355

RESUMO

OBJECTIVE: To observe the effects of acupuncture at "Feishu" (BL 13) and "Lingtai" (GV 10) on distribution taxis of paclitaxel in mice with lung cancer to discuss targeted relationship between acupoints and corresponding viscera. METHODS: According to randomized digital table, 315 SPF-grade BALB/C female mice were divided into 7 groups: blank group (group A), model group (group B), medication group (group C), acupuncture at non-acupoint group (group D), acupuncture at Feishu group (group E), acupuncture at Lingtai group (group F) and acupuncture at Feishu and Lingtai group (group G), 45 mice in each one. Except the blank group, the remaining groups were treated with N-nitroso-tris-chloroethyl urea (NTCU) to establish the model of squamous-cell carcinoma. After model establishment, group A, group B and group C were not treated with acupuncture; group A and group B were treated with intraperitoneal injection of 0.9% sodium chlorvde solution by 6 mL/kg while group C was treated with intraperitoneal injection of paclitaxel by 6 mL/kg. The group D, group E, group F and group G were treated with acupuncture at non-acupoint, "Feishu" (BL 13), "Lingtai" (GV 10) and "Feishu" (BL 13) plus "Lingtai" (GV 10), respectively, then were intraperitoneally injected with paclitaxel by 6 mL/kg. The treatment was all given once a day for continuous 10 days. 15 min, 30 min, 1 h, 2 h, 8 h, 12 h and 24 h after the treatments, 6 mice in each group were randomly selected and sacrificed to collect samples of lung, liver, spleen, kidney and heart, etc. High performance liquid chromatography was applied to measure the concentration of paclitaxel in each organ (lung, liver, spleen, kidney and heart) at different time points. RESULTS: (1) The content of paclitaxel in lung, kidney and heart reached the peak at 2 h, then decreased significantly in group C, group D, group E, group F and group G; the content of paclitaxel in spleen showed downtrend at each time point. The content of paclitaxel in liver reached the peak at 2 h in group C and group D; the content of paclitaxel reached the peak at 8 h in group E, group F and group G. (2) The content of paclitaxel in lung in group E and group G was higher than that in group C and group D at each time point (all P < 0.01); the content of paclitaxel in lung in group F was higher than that in group C (P < 0.01) and group D (P < 0.01) only at time point of 2 h. The content of paclitaxel in lung in group G was higher than that in group F at each time point (all P < 0.05). There was no statistical difference between group G and group E (all P > 0.05). CONCLUSION: Acupuncture at "Feishu" (BL 13) and "Lingtai" (GV 10) could influ- ence the metabolism of paclitaxel in lung-cancer mice, leading to distribution change in each organ. As a result, it could cause targeting effects, which is more significant at "Feishu" (BL 13) and "Lingtai" (GV 10).


Assuntos
Terapia por Acupuntura , Antineoplásicos Fitogênicos/farmacocinética , Medicamentos de Ervas Chinesas/farmacocinética , Neoplasias Pulmonares/terapia , Paclitaxel/farmacocinética , Pontos de Acupuntura , Animais , Feminino , Humanos , Neoplasias Pulmonares/tratamento farmacológico , Camundongos , Camundongos Endogâmicos BALB C , Taxus/química
7.
Artigo em Inglês | MEDLINE | ID: mdl-24078820

RESUMO

This study investigated the propagated sensation along meridians (PSM) produced respectively by acupuncture at a specific acupoint of right-side Quchi (LI11), a nonacupoint on meridian (control meridian point), and neither meridian nor acupoint (control point). All the stimulated points were on the right brachioradialis along the large intestine meridian of hand Yangming. Surface electromyography (sEMG) was used to reflect the activity of the brachioradialis along the large intestine meridian of hand Yangming. The PSM rate of LI11 (59.21%) and the control meridian point (53.95%) were significantly higher than the control point (38.16%) (P < 0.05). After acupuncture, the brachioradialis sEMG amplitude was 5.08 ± 2.93 uV at LI11, 3.08 ± 1.18 uV at the control point, and 2.77 ± 1.36 uV at the control meridian point. The amplitude of LI11 was significantly higher than both the control meridian point and the control point (P < 0.05). When the sEMG activity of brachioradialis returned to the stable base line, brachioradialis sEMG duration at LI11 (265 ± 87.87 s) was significantly longer than that at the control meridian point (91.69 ± 42.98 s) and the control point (83.31 ± 32.76 s) (P < 0.05). In conclusion, acupuncture activated PSM at all points but showed an acupoint specificity at LI11 and a meridian specificity at the control meridian point.

8.
Zhongguo Zhen Jiu ; 33(7): 658-60, 2013 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-24032208

RESUMO

Based on traditional acupuncture-moxibustion treatment ideas, with differentiation of channels and collaterals as main part and feature, the important role of associated symptom and sign-based acupoint selection in acupuncture-moxibustion treatment is explained from angles of philosophy and medicine. Combined with clinical experience of acupuncture and moxibustion, the category of associated symptom and sign-based acupoint selection is explained in detail to make sure the accuracy of acupuncture-moxibustion differentiation. It could show uniqueness and advantage of theory and clinic in acupuncture-moxibustion and provide theoretical references in making acupuncture-moxibustion prescription to improve effectiveness of clinical treatment.


Assuntos
Pontos de Acupuntura , Terapia por Acupuntura , Moxibustão , Humanos
9.
Ying Yong Sheng Tai Xue Bao ; 24(8): 2301-9, 2013 Aug.
Artigo em Chinês | MEDLINE | ID: mdl-24380352

RESUMO

By using Biolog Ecoplate system, this paper studied the structure and functional diversity of soil microbial community under different vegetation types in Wuyishan National Nature Reserve, aimed to probe into the effects of vegetation type on the diversity of soil microbial community. The results showed that the soil chemical properties, soil enzyme activities, and average well color development (AWCD) were higher in natural forest than in planted forest, and were the lowest in abandoned field. The AWCD reflecting soil microbial activity and functional diversity was increased with increasing incubation time, but there existed significant differences among different vegetation types. The carbon sources mostly used by soil microbes were carbohydrates and carboxylic acids, followed by amino acids, phenolic acids and polymers, and amines had the lowest utilization rate. The Simpson index, Shannon index, Richness index and McIntosh index in natural forest were holistically higher than those in planted forest. Principal component analysis (PCA) identified 2 principal component factors in relation to carbon sources, explaining 56.3% and 30.2% of the variation, respectively. The carbon sources used by soil microbial community differed with vegetation types. Amino acids and amides were the two main carbon sources separating the 2 principal component factors. The results of this study could provide basis for further approaching the relationships between vegetation diversity and soil microbial community diversity.


Assuntos
Florestas , Microbiologia do Solo , Árvores/classificação , Biodiversidade , China , Conservação dos Recursos Naturais , Consórcios Microbianos , Árvores/crescimento & desenvolvimento
10.
Am J Chin Med ; 39(4): 687-92, 2011.
Artigo em Inglês | MEDLINE | ID: mdl-21721149

RESUMO

This research explored and identified the protein composition of rat kidneys after acupuncture at the Taixi acupoint (KI3). Twelve adult male Wistar rats were randomly divided into a control group (n = 6) and an acupuncture group (n = 6). Rats in the acupuncture group received electroacupuncture on the bilateral KI3 for seven days. The kidneys were perfused with ice-cold saline and all kidney proteins were isolated. After protein sample preparation, two-dimensional gel electrophoresis (2-DE) was performed. The interesting spots were analyzed using matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS). There were nine protein spots with three-fold up-regulation in the kidney after the acupuncture. NAD-dependent isocitrate dehydrogenase and quinone reductase, the proteins involved in energy metabolism, the reduction of endogenous quinones, chemoprotection, and electrophilic stress, were identified. The data indicated that acupuncture at the KI3 of the kidney meridian of the foot shaoyin was able to increase NAD-dependent isocitrate dehydrogenase and quinone reductase expression in the kidney, and supported the relationship between the kidney and KI3.


Assuntos
Pontos de Acupuntura , Acupuntura/métodos , Estimulação Elétrica/métodos , Rim/metabolismo , Proteínas/metabolismo , Animais , Eletroacupuntura , Eletroforese em Gel Bidimensional , , Isocitrato Desidrogenase/metabolismo , Masculino , NAD/metabolismo , NAD(P)H Desidrogenase (Quinona)/metabolismo , Proteoma , Ratos , Ratos Wistar , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Regulação para Cima
11.
J Proteome Res ; 10(3): 932-40, 2011 Mar 04.
Artigo em Inglês | MEDLINE | ID: mdl-21142081

RESUMO

Soil rhizospheric metaproteomics is a powerful scientific tool to uncover the interactions between plants and microorganisms in the soil ecosystem. The present study established an extraction method suitable for different soils that could increase the extracted protein content. Close to 1000 separate spots with high reproducibility could be identified in the stained 2-DE gels. Among the spots, 189 spots representing 122 proteins on a 2-DE gel of rice soil samples were successfully identified by MALDI-TOF/TOF-MS. These proteins mainly originated from rice and microorganisms. They were involved in protein, energy, nucleotide, and secondary metabolisms, as well as signal transduction and resistance. Three characteristics of the crop rhizospheric metaproteomics seemed apparent: (1) approximately one-third of the protein spots could not be identified by MALDI-TOF/TOF/MS, (2) the conservative proteins from plants formed a feature distribution of crop rhizospheric metaproteome, and (3) there were very complex interactions between plants and microorganisms existing in a crop rhizospheric soil. Further functional analysis on the identified proteins unveiled various metabolic pathways and signal transductions involved in the soil biotic community. This study provides a paradigm for metaproteomic research on soil biology.


Assuntos
Proteoma/análise , Proteômica/métodos , Rizoma/química , Microbiologia do Solo , Solo/análise , Produtos Agrícolas/microbiologia , Ecossistema , Eletroforese em Gel Bidimensional/instrumentação , Eletroforese em Gel Bidimensional/métodos , Proteínas de Plantas/análise , Plantas/química , Plantas/microbiologia , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz
12.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 41(6): 323-6, 2006 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-16836896

RESUMO

OBJECTIVE: To evaluate the microtensile bond strength and bond interface of total-etch or self-etch adhesives to normal dentin and caries-affected dentin. METHODS: A total of 20 molars with occlusal caries lesion were used. The caries-affected dentin was obtained by removing the caries-infected dentin under the guidance of the caries detector. Beyond the level of caries-affected dentin all the enamel and partial dentin were removed. The adhesive systems, two total-etch adhesives (All-Bond 2, Prime&Bond NT) and two self-etch adhesives (Clearfil SE Bond, Xeno III) were applied respectively under the instructions of manufacturers. A block of composite resin was build up superficially. All the teeth were sectioned to obtain bar-shaped specimens with bonded surface area about 0.9 mm x 0.9 mm. The specimens were divided into normal dentin group and caries-affected dentin group via stereomicroscope. The bond strength was tested in a microtensile tester with a crosshead speed of 1 mm/min. The mean values of bond strength were compared using two-way ANOVA. The bonding interface between the dentin and adhesives was qualitatively evaluated under the observation of scanning electron microscope (SEM). RESULTS: Two-way ANOVA revealed a significant influence of both the type of dentin and the adhesive systems tested on microtensile bond strength values. All the adhesives attained higher strength in normal dentin. In normal dentin, there was no significant difference between total-etch and self-etch adhesives. In caries-affected dentin, bond strength of Xeno III was significantly lower than the others. For SEM, the hybrid layer in caries-affected dentin was thicker but more porous than that in normal dentin. Compared with normal dentin, there was fewer resin tag exhibited in caries-affected dentin and no lateral branches were observed. CONCLUSIONS: The total-etch adhesive had higher bond strength than self-etch adhesive systems in caries-affected dentin.


Assuntos
Condicionamento Ácido do Dente , Adesivos Dentinários , Dentina/ultraestrutura , Resistência à Tração , Adulto , Cárie Dentária/terapia , Adesivos Dentinários/classificação , Humanos , Pessoa de Meia-Idade , Desmineralização do Dente/terapia
13.
Chin Med J (Engl) ; 118(19): 1623-8, 2005 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-16232347

RESUMO

BACKGROUND: The wet-bonding technique is recommended for the one-bottle dentin adhesive systems, but the moisture concept varies widely among the instructions of manufacturers as well as among investigators. The aim of this study was to evaluate the effects of different dentin surface moisture on the microtensile bond strength(s) of an ethanol/water-based adhesive system and an acetone-based system to dentin. METHODS: Forty intact human premolars extracted for orthodontic reasons were used. Superficial occlusal flat dentin surfaces of these premolars were exposed, finished with wet 600-grit silicon carbide paper. Under four wet and dry conditions (overwet, blot dry, one-second dry and desiccated), resin composite was bonded to dentin by using Single Bond (SB) or Prime & Bond NT (PB) according to the manufacturers' instructions. The teeth were longitudinally sectioned in the "x" and "y" directions to obtain bonded beams with a cross-sectional area of 0.81 mm(2) with a slow-speed diamond saw. The bonded specimens were tested in tension at a crosshead speed of 1 mm/min until failure of the bonds. Failure modes were observed with a scanning electron microscope. The mean bond strengths were analyzed by one-way ANOVA and Turkey's test. RESULTS: The bond strength of the overwet/SB, blot dry/SB, one-second dry/SB and desiccated/SB groups was 10.87 MPa, 22.47 MPa, 24.91 MPa and 12.99 MPa, respectively. The bond strength of the overwet/PB, blot dry/PB, one-second dry/PB and desiccated/PB groups was 10.02 MPa, 20.67 MPa, 21.82 MPa and 10.09 MPa, respectively. For both SB and PB, the blot dry group and one-second dry group revealed significantly higher bond strengths than the overwet and desiccated groups (P < 0.05). CONCLUSIONS: In order to achieve the highest bond strength to dentin, keeping the dentin surface in an appropriately moist condition is critical for the one-bottle dentin adhesive systems with ethanol/water or acetone solvent.


Assuntos
Colagem Dentária , Adesivos Dentinários/farmacologia , Adolescente , Adulto , Humanos , Solventes , Resistência à Tração , Água
14.
Shanghai Kou Qiang Yi Xue ; 14(2): 147-50, 2005 Apr.
Artigo em Chinês | MEDLINE | ID: mdl-15886839

RESUMO

PURPOSE: To compare the effects of teeth stored with different methods and different durations of storage on the microtensile bond strength of the dentin adhesive system Single Bond. METHODS: 30 human first premolars were stored immediately after extraction in one of five commonly used methods respectively: 0.02% distilled water and thymol, 10% formalin, 1% chloramine, distilled water at 4 degrees C and were refrigerated at -20 degrees C. After 10 days, 90 days, the dentin adhesive system Single Bond and composite Z250 were applied to superficial occlusal flat dentin according to the manufacturers' instructions and microtensile bond strength measurements were evaluated, freshly extracted teeth being used as control. Stero-microscope and scanning electronic microscope were used to evaluate the fracture modes of the microtensile bond strength specimens. Two-way ANOVA was used for analysis of the microtensile bond strengths among different groups. RESULTS: The results showed that there was significant difference among five tooth storage methods on the microtensile bond strength of dentin bonding agent (P=0.01). Compared with freshly extracted teeth, two of five storage methods/media, 0.02% distilled water and thymol at 4 degrees C (P=0.008) and distilled water at 4 degrees C (P=0.024), resulted in significantly lower microtensile bond strengths. The duration of teeth storage had no effect on the microtensile bond strength of dentin bonding agent (P=0.279). The interaction of two factors was significant (P=0.000). Stero-microscope and SEM examination indicated that all fracture modes were adhesive failures. CONCLUSIONS: From this study, it can be concluded that the teeth storage methods/media can influence the microtensile bond strength of Single Bond adhesive system. If sufficient numbers of freshly extracted teeth are not available for bond strength test, the freezing teeth at -20 degrees C and teeth stored in 1% chloramine at 4 degrees C are preferred .


Assuntos
Colagem Dentária/métodos , Adesivos Dentinários/química , Armazenamento de Medicamentos/métodos , Resistência à Tração , Teste de Materiais , Cimentos de Resina
15.
Zhonghua Kou Qiang Yi Xue Za Zhi ; 39(6): 496-500, 2004 Nov.
Artigo em Chinês | MEDLINE | ID: mdl-15854324

RESUMO

OBJECTIVE: To evaluate in vitro the microtensile bond strengths of three dentin adhesive systems and their respective fracture modes. METHODS: A total of 15 intact young human premolars extracted for orthodontic reasons were used. The enamel of occlusal surfaces of these premolar teeth was removed and superficial dentine was exposed, finished with wet 600-grit silicon carbide paper. And then these teeth were randomly divided into three groups. A block of composite resin was bonded respectively with three dentin adhesive systems: All-bond 2 (Group AB(2)), Fluoro-Bond (Group FB) and Xeno III (Group Xeno) according to manufacturers' instructions. The bonded teeth were kept in distilled water for 24 h at 37 degrees C. The roots were removed from the remaining crown approximately 1 - 2 mm below the cemento-enamel junction with a slow-speed diamond saw. The teeth were sectioned to obtain bar-shaped specimens, whose bonded surface areas were about 0.8 mm(2). The specimens were stressed at a crosshead speed of 1 mm/min until rupture of the bond. SEM was used to observe the fracture modes. The mean bond strengths were compared using one-way ANOVA and LSD tests. The frequency of fracture modes was compared using Krukal-Wallis and Mann-Whitney U-test. RESULTS: Mean microtensile bond strengths were (29.56 +/- 5.47) MPa for Group AB(2), (15.81 +/- 7.67) MPa for Group Xeno, and (14.61 +/- 4.50) MPa for Group FB. The bond strength of Group AB(2) was greater than those of the other two groups (P < 0.01). The bond strengths of Group Xeno and Group FB were not significantly different. SEM examination indicated that the adhesive failure was the most mode of fracture. CONCLUSIONS: The microtensil bond strengths of three dentin adhesive systems to normal human dentine were different and the total-etching adhesive All-Bond 2 exhibited the greatest bond strength. It was recommended that dentin adhesive agent should be used according to clinical situation.


Assuntos
Adesivos Dentinários/química , Dentina/ultraestrutura , Adolescente , Colagem Dentária , Humanos , Técnicas In Vitro , Teste de Materiais , Microscopia Eletrônica de Varredura , Resistência à Tração , Adulto Jovem
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