Bond Strength of Thermally Fused Vascular Tissue Varies With Apposition Force

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Nicholas S. Anderson ◽  
Eric A. Kramer ◽  
James D. Cezo ◽  
Virginia L. Ferguson ◽  
Mark E. Rentschler
Keyword(s):  
Bond Strength ◽  
Blood Vessels ◽  
Thermal Energy ◽  
Molecular Mechanisms ◽  
Vascular Tissue ◽  
Tissue Temperature ◽  
Tissue Fusion ◽  
Tunica Media ◽  
Adhesive Mechanics ◽  
Bond Strengths

Surgical tissue fusion devices ligate blood vessels using thermal energy and coaptation pressure, while the molecular mechanisms underlying tissue fusion remain unclear. This study characterizes the influence of apposition force during fusion on bond strength, tissue temperature, and seal morphology. Porcine splenic arteries were thermally fused at varying apposition forces (10–500 N). Maximum bond strengths were attained at 40 N of apposition force. Bonds formed between 10 and 50 N contained laminated medial layers; those formed above 50 N contained only adventitia. These findings suggest that commercial fusion devices operate at greater than optimal apposition forces, and that constituents of the tunica media may alter the adhesive mechanics of the fusion mechanism.

scholarly journals Physical Activity and Redox Balance in the Elderly: Signal Transduction Mechanisms

2021 ◽  
Vol 11 (5) ◽  
pp. 2228
Author(s):  
Daniela Galli ◽  
Cecilia Carubbi ◽  
Elena Masselli ◽  
Mauro Vaccarezza ◽  
Valentina Presta ◽  
...  
Keyword(s):  
Physical Activity ◽  
Molecular Mechanisms ◽  
Vascular Tissue ◽  
The Elderly ◽  
Redox Balance ◽  
Antioxidant Systems ◽  
Targeted Prevention ◽  
Individual Subject ◽  
Aged People ◽  
The Individual

Reactive Oxygen Species (ROS) are molecules naturally produced by cells. If their levels are too high, the cellular antioxidant machinery intervenes to bring back their quantity to physiological conditions. Since aging often induces malfunctioning in this machinery, ROS are considered an effective cause of age-associated diseases. Exercise stimulates ROS production on one side, and the antioxidant systems on the other side. The effects of exercise on oxidative stress markers have been shown in blood, vascular tissue, brain, cardiac and skeletal muscle, both in young and aged people. However, the intensity and volume of exercise and the individual subject characteristics are important to envisage future strategies to adequately personalize the balance of the oxidant/antioxidant environment. Here, we reviewed the literature that deals with the effects of physical activity on redox balance in young and aged people, with insights into the molecular mechanisms involved. Although many molecular pathways are involved, we are still far from a comprehensive view of the mechanisms that stand behind the effects of physical activity during aging. Although we believe that future precision medicine will be able to transform exercise administration from wellness to targeted prevention, as yet we admit that the topic is still in its infancy.

scholarly journals An in vivo model allowing continuous observation of human vascular formation in the same animal over time

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Yohei Tsukada ◽  
Fumitaka Muramatsu ◽  
Yumiko Hayashi ◽  
Chiaki Inagaki ◽  
Hang Su ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Blood Vessels ◽  
Human Blood ◽  
Molecular Mechanisms ◽  
Human Tumor ◽  
Continuous Observation ◽  
In Vivo Models ◽  
Cranial Window ◽  
Pathological Conditions

AbstractAngiogenesis contributes to numerous pathological conditions. Understanding the molecular mechanisms of angiogenesis will offer new therapeutic opportunities. Several experimental in vivo models that better represent the pathological conditions have been generated for this purpose in mice, but it is difficult to translate results from mouse to human blood vessels. To understand human vascular biology and translate findings into human research, we need human blood vessel models to replicate human vascular physiology. Here, we show that human tumor tissue transplantation into a cranial window enables engraftment of human blood vessels in mice. An in vivo imaging technique using two-photon microscopy allows continuous observation of human blood vessels until at least 49 days after tumor transplantation. These human blood vessels make connections with mouse blood vessels as shown by the finding that lectin injected into the mouse tail vein reaches the human blood vessels. Finally, this model revealed that formation and/or maintenance of human blood vessels depends on VEGFR2 signaling. This approach represents a useful tool to study molecular mechanisms of human blood vessel formation and to test effects of drugs that target human blood vessels in vivo to show proof of concept in a preclinical model.

scholarly journals Shear bond strength of orthodontic brackets to enamel after application of a caries infiltrant

2014 ◽  
Vol 85 (4) ◽  
pp. 645-650 ◽  
Author(s):  
Laura Mews ◽  
Matthias Kern ◽  
Robert Ciesielski ◽  
Helge Fischer-Brandies ◽  
Bernd Koos
Keyword(s):  
Statistical Analysis ◽  
Bond Strength ◽  
Shear Force ◽  
Shear Bond Strength ◽  
Orthodontic Brackets ◽  
Enamel Defects ◽  
Adhesive Remnant Index ◽  
Demineralized Enamel ◽  
Kolmogorov Smirnov ◽  
Bond Strengths

ABSTRACT Objective:  To examine differences in the shear bond strength of orthodontic brackets on differently mineralized enamel surfaces after applying a caries infiltrant or conventional adhesive. Materials and Methods:  A total of 320 bovine incisors were assigned to eight pretreated groups, and the shear force required for debonding was recorded. Residual adhesive was evaluated by light microscopy using the adhesive remnant index. Statistical analysis included Kolmogorov-Smirnov, analysis of variance (ANOVA), and Scheffé tests. Results:  The highest bond strength (18.8 ± 4.4 MPa) was obtained after use of the caries infiltrant. More residual adhesive and fewer enamel defects were observed on infiltrated enamel surfaces. Brackets on demineralized enamel produced multiple enamel defects. Conclusions:  Acceptable bond strengths were obtained with all material combinations. A caries-infiltrant applied before bracket fixation has a protective effect, especially on demineralized enamel.

scholarly journals Effect of Using Nano and Micro Airborne Abrasive Particles on Bond Strength of Implant Abutment to Prosthesis

2015 ◽  
Vol 26 (1) ◽  
pp. 50-55 ◽  
Author(s):  
Mansour Rismanchian ◽  
Amin Davoudi ◽  
Elham Shadmehr
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
Control Group ◽  
Abrasive Particles ◽  
Significant Difference ◽  
Implant Abutments ◽  
Implant Abutment ◽  
Roughened Surface ◽  
Bond Strengths ◽  
Spss Software

Connecting prostheses to the implant abutments has become a concern and achieving a satisfactory retention has been focused in cement-retention prostheses recently. Sandblasting is a method to make a roughened surface for providing more retention. The aim of this study was to compare effects of nano and micro airborne abrasive particles (ABAP) in roughening surface of implant abutments and further retention of cemented copings. Thirty Xive abutments and analogues (4.5 D GH1) were mounted vertically in self-cured acrylic blocks. Full metal Ni-Cr copings with a loop on the top were fabricated with appropriate marginal adaptation for each abutment. All samples were divided into 3 groups: first group (MPS) was sandblasted with 50 µm Al2O3 micro ABAP, second group (NSP) was sandblasted with 80 nm Al2O3 nano ABAP, and the third group (C) was assumed as control. The samples were cemented with provisional cement (Temp Bond) and tensile bond strength of cemented copings was evaluated by a universal testing machine after thermic cycling. The t test for independent samples was used for statistical analysis by SPSS software (version 15) at the significant level of 0.05. Final result showed significant difference among all groups (p<0.001) and MPS manifested the highest mean retention (207.88±45.61 N) with significant difference among other groups (p<0.001). The control group showed the lowest bond strength as predicted (48.95±10.44 N). Using nano or micro ABAP is an efficient way for increasing bond strengths significantly, but it seems that micro ABAP was more effective.

scholarly journals Effects of Fluorosis and Self Etching Primers on Shear Bond Strengths of Orthodontic Brackets

2009 ◽  
Vol 03 (03) ◽  
pp. 173-177 ◽  
Author(s):  
Ahmet Yalcin Gungor ◽  
Hakan Turkkahraman ◽  
Necdet Adanir ◽  
Huseyin Alkis
Keyword(s):  
Bond Strength ◽  
Testing Machine ◽  
Orthodontic Brackets ◽  
Universal Testing ◽  
Adhesive Remnant Index ◽  
Halogen Light ◽  
Significant Difference ◽  
Bond Strengths ◽  
Group Ii ◽  
Clinical Changes

ABSTRACTObjectives: To evaluate the effects fluorosis and self etching primers (SEP) on shear bond strengths (SBS) of orthodontic brackets.Methods: A total of 48 (24 fluorosed and 24 non-fluorosed) non-carious freshly extracted human permanent premolar teeth were used in this study. Fluorosed teeth were selected according to the modified Thylstrup and Fejerskov index (TFI), which is based on the clinical changes in fluorosed teeth. Fluorosed and non-fluorosed teeth were randomly assigned to 4 groups of 12 each. In groups I (non-fluorosed teeth) and II (fluorosed teeth), standard etching protocol was used and brackets were bonded with Light Bond. In groups III (non-fluorosed teeth) and IV (fluorosed teeth), Transbond Plus SEP was used and brackets were bonded with Transbond XT Light Cure Adhesive. All specimens were cured with a halogen light. After bonding, SBS of the brackets were tested with Universal testing machine. After debonding, all teeth and brackets in the test groups were examined under 10x magnifications. Any adhesive remained after debonding was assessed and scored according to the modified Adhesive Remnant Index (ARI).Results: ANOVA indicated a significant difference between groups (P<.001). SBS in group II (Light Bond+Fluorosis) were significantly lower than other groups. ARI scores of the groups were also significantly different (P<.001). There was a greater frequency of ARI scores of 1,2 and 3 in group II (Light Bond+Fluorosis).Conclusions: When standard etching protocol was used enamel fluorosis significantly decreased the bond strength of orthodontic brackets. Satisfactory bond strengths were obtained when SEP was used for bonding brackets to the fluorosed teeth. (Eur J Dent 2009;3:173-177)

Scaffolds in tissue engineering of blood vessels

2010 ◽  
Vol 88 (9) ◽  
pp. 855-873 ◽  
Author(s):  
Divya Pankajakshan ◽  
Devendra K. Agrawal
Keyword(s):  
Tissue Engineering ◽  
Extracellular Matrix ◽  
Blood Vessels ◽  
Vascular Tissue ◽  
Small Diameter ◽  
Biological Scaffolds ◽  
Hemodynamic Forces ◽  
Biodegradable Scaffolds

Tissue engineering of small diameter (<5 mm) blood vessels is a promising approach for developing viable alternatives to autologous vascular grafts. It involves in vitro seeding of cells onto a scaffold on which the cells attach, proliferate, and differentiate while secreting the components of extracellular matrix that are required for creating the tissue. The scaffold should provide the initial requisite mechanical strength to withstand in vivo hemodynamic forces until vascular smooth muscle cells and fibroblasts reinforce the extracellular matrix of the vessel wall. Hence, the choice of scaffold is crucial for providing guidance cues to the cells to behave in the required manner to produce tissues and organs of the desired shape and size. Several types of scaffolds have been used for the reconstruction of blood vessels. They can be broadly classified as biological scaffolds, decellularized matrices, and polymeric biodegradable scaffolds. This review focuses on the different types of scaffolds that have been designed, developed, and tested for tissue engineering of blood vessels, including use of stem cells in vascular tissue engineering.

scholarly journals The Impact of Chlorhexidine Mouth Rinse on the Bond Strength of Polycarbonate Orthodontic Brackets

2014 ◽  
Vol 15 (6) ◽  
pp. 688-692 ◽  
Author(s):  
Sukumaran Anil ◽  
Farouk Ahmed Hussein ◽  
Mohammed Ibrahim Hashem ◽  
Elna P Chalisserry
Keyword(s):  
Bond Strength ◽  
Shear Bond Strength ◽  
Testing Machine ◽  
Test Group ◽  
Orthodontic Brackets ◽  
Control Group ◽  
Mouth Rinse ◽  
Significant Difference ◽  
Bond Strengths ◽  
The Impact

ABSTRACT Objective The purpose of the current in-vivo study was to assess the effect of using 0.12% chlorhexidine (CHX) mouth rinse, before bonding, on shear bond strength of polycarbonate brackets bonded with composite adhesive. Subjects and methods Eighteen orthodontic patients with a mean age 21.41 ± 1.2 years, who were scheduled to have 2 or more first premolars extracted, were included in this study. Patients were referred for an oral prophylaxis program which included, in part, the use of a mouth rinse. Patients were divided into 2 groups, a test group of 9 patients who used 0.12% CHX gluconate mouth rinse twice daily and a control group of 9 patients who used a mouth rinse without CHX, but with same color. After 1 week, polycarbonate brackets were bonded to first premolars with Transbond XT composite adhesive. Premolars were extracted after 28 days and tested for shear bond strength on a universal testing machine. Student's t-test was used to compare shear bond strengths of both groups. Results No statistically significant difference was found in bond strengths’ values between both groups. The test group (with CHX) has mean shear bond strength of 14.21 ± 2.42 MPa whereas the control group (without CHX) revealed a mean strength of 14.52 ± 2.31 MPa. Conclusion The use of 0.12% CHX mouth rinse, for one week before bonding, did not affect the shear bond strength of polycarbonate brackets bonded with Transbond composite. Furthermore, these brackets showed clinically acceptable bond strength. How to cite this article Hussein FA, Hashem MI, Chalisserry EP, Anil S. The Impact of Chlorhexidine Mouth Rinse on the Bond Strength of Polycarbonate Orthodontic Brackets. J Contemp Dent Pract 2014;15(6):688-692.

Effects of Multipurpose, Universal Adhesives on Resin Bonding to Zirconia Ceramic

2015 ◽  
Vol 40 (1) ◽  
pp. 55-62 ◽  
Author(s):  
J-H Kim ◽  
S-Y Chae ◽  
Y Lee ◽  
G-J Han ◽  
B-H Cho
Keyword(s):  
Bond Strength ◽  
Artificial Aging ◽  
Resin Cement ◽  
Zirconia Ceramic ◽  
Single Bond ◽  
Surface Conditioning ◽  
Universal Adhesives ◽  
Bond Strengths ◽  
Microshear Bond Strength ◽  
Composite Cylinders

SUMMARY This study evaluated the effects of single-bottle, multipurpose, universal adhesives on the bond strength of resin cement to zirconia ceramic. Polished zirconia ceramic (Cercon base) discs were randomly divided into four groups (n=40) according to the applied surface-conditioning agent: Single Bond 2, Single Bond Universal, All-Bond Universal, and Alloy Primer. Cured composite cylinders (Ø 0.8 mm × 1 mm) were cemented to the conditioned zirconia specimens with resin cement (RelyX ARC). The bonded specimens were subjected to a microshear bond-strength test after 24 hours of water storage and after 10,000 cycles of thermocycling. The surface-conditioning agent significantly influenced the bond strength (p&lt;0.05). Single Bond Universal showed the highest initial bond strength (37.7 ± 5.1 MPa), followed by All-Bond Universal (31.3 ± 5.6 MPa), Alloy Primer (26.9 ± 5.1 MPa), and Single Bond 2 (8.5 ± 4.6 MPa). Artificial aging significantly reduced the bond strengths of all the test groups (p&lt;0.05). After 10,000 cycles of thermocycling, All-Bond Universal showed the highest bond-strength value (26.9 ± 6.4 MPa). Regardless of artificial aging, Single Bond Universal and All-Bond Universal showed significantly higher bond strengths than Alloy Primer, a conventional metal primer.

scholarly journals Adhesion of Two Bonding Systems to Air-Abraded or Bur-Abraded Human Enamel Surfaces

2008 ◽  
Vol 02 (03) ◽  
pp. 167-175 ◽  
Author(s):  
Abdulkadir Sengun ◽  
Hasan Orucoglu ◽  
Ilknur Ipekdal ◽  
Fusun Ozer
Keyword(s):  
Bond Strength ◽  
Composite Resin ◽  
In Vitro Study ◽  
Air Abrasion ◽  
Adhesive Resin ◽  
Bonding Performance ◽  
Human Enamel ◽  
Bond Strengths ◽  
Bonding Systems

ABSTRACTObjectives: The purpose of this in vitro study was to evaluate whether mechanical alteration of the enamel surfaces with air abrasion and bur abrasion techniques could enhance the bonding performance of a three step and a self etching adhesive resin systems to enamel.Methods: 126 extracted lower human incisor teeth were used. The teeth were divided into three groups including 40 teeth each. First group; teeth were used as control and no preparation was made on enamel surfaces, 2nd group; outer enamel surfaces were air abraded, 3rd group; outer enamel surfaces were abraded mechanically with a diamond fissure bur. Cylinder composite resin blocks were bonded to the buccal enamel surfaces with two bonding systems (20 specimens in each group). Bond strengths to enamel surfaces were measured at a cross-head speed of 1 mm/min. The data were analyzed by ANOVA and Duncan Tests. To examine interface composite resin/enamel surfaces at scanning electron microscopy, remaining 6 teeth were used. Fracture analysis was performed using an optical stereomicroscope.Results: Bond strengths values of Solid Bond were significantly higher than bond strengths of Clearfil SE Bond for all types of enamel (P<.05). Shear bond strength values obtained with Solid Bond (three step system) to three types of enamel surfaces [air-abraded (30.25±7.00 MPa), bur-abraded (29.07±3.53 MPa), control (31.74±7.35 MPa)] were close to each other (P>.05). The macroscopic mode of failures for bonding systems, SB and SE Bond appeared to be adhesive and cohesive in nature.Conclusions: In order to get better bond strength values with self etching systems, it is advisable to prepare enamel surfaces with bur or air abrasion, but it enamel preparation is not necessary for three step systems. (Eur J Dent 2008;2:167-175)

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