Search results for "In vitro study"

In vitro study of human alveolar macrophage and peripheral blood mononuclear cell reactive oxygen-intermediates release induced by sulfur dioxide at …

1994

Sulfur dioxide (SO2) is a major air pollutant in urban areas. Alveolar macrophages (AM) located on the alveolar surface are in direct contact with this inhaled gas. We evaluated the dose-dependent effect of SO2 exposure on the oxidative metabolism of AM and peripheral blood mononuclear cells (PBMNC) by measuring the spontaneous and stimulated reactive oxygen intermediates (ROI) release. AM or PBMNC were placed on a polycarbonate membrane, which was in direct contact with the surface of a nutrient reservoir. For exposure of the cells to SO2 a special chamber was employed, in which humidified standard air with 5% CO2 at 37 degrees C was mixed with SO2 at the desired concentration. Periods of …

Potential Use of a Diluted High-relaxivity Gadolinium-based Intra-articular Contrast Agent for Magnetic Resonance Arthrography: An In-vitro Study

2019

Abstract Background Magnetic resonance arthrography (MRA) requires intra-articular injection of gadolinium-based diluted paramagnetic contrast material. To our knowledge, gadobenate dimeglumine (Gd-BOPTA) has never been used for intra-articular applications. Our aim was to test in vitro different concentrations of Gd-BOPTA to be potentially used to perform MRA. Methods Gd-BOPTA was diluted in saline (NaCl 0.9%) to achieve different concentrations (4 mmol/l; 2 mmol/l; 1 mmol/l; 0.67 mmol/l; 0.5 mmol/l). Six sets of five sterile pipes were prepared with 5 ml of each solution, five sets added with 0.5 ml of fresh synovial fluid. Two separate pipes were prepared with 5 ml of gadopentetate dimeg…

Effects of endodontic treatment on apparent Young’s modulus of human teeth: in vitro study using speckle interferometry

2012

The introduction of new techniques for endodontic procedures requires the analysis of the biomechanical behavior of dental structures. Digital speckle shearing pattern interferometry (DSSPI) is a nondestructive optical measuring technique that allows one to directly quantify deformations in teeth that are subjected to stress. DSSPI technique was applied to measure small deformations caused by flexion in different types of teeth. The test was carried out both before and after endodontic treatment with the ProTaper method in order to evaluate the variation of dental elasticity, taking into the account the type of tooth and the endodontic treatment. The results obtained show that dental elasti…

Effect of water-jet flossing on surface roughness and color stability of dental resin-based composites.

2019

Background The purpose of this in vitro study was to investigate the effects of water-jet flossing on the color stability and surface roughness of five resin-based composites. Material and methods Five commercially available composite resins were studied. Nine disc-shaped specimens (6x2mm) were fabricated from each composite. The specimens were randomly allocated into three groups and three different treatments were performed on each group: storage in water (control group), water-jet flossing using 50 Psi water pressure, and water-jet flossing using 100 Psi water pressure. The water-jet flossing was performed in a standardized manner using a Waterpik® Aquarius® water flosser. Color and roug…

The effect of preheating of composite resin on its color stability after immersion in tea and coffee solutions: An in-vitro study

2019

Background One of the concerns in using composite resins is color change. The aim of this study was to investigate the effect of preheating on color stability of composite resins when immersed in coffee and tea. Material and Methods This experimental study included 60 composite disks. The samples were divided into 2 groups, one group prepared at room temperature and the other prepared at 68 °C. After curing, the samples were placed in 37 °C distilled water for 24 hours. The color of the samples was measured (t0) using spectrophotometer according to CIE-L*a*b* system. The samples of each group were then divided into 3 subgroups and respectively immersed in distillated water, coffee and tea f…

Effect of framework type on survival probability of implant-supported temporary crowns : an in vitro study

2020

Made available in DSpace on 2020-12-12T01:29:18Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-01-01 Background: This in vitro study evaluated the effect of framework type on the survival probability of temporary implant-supported crowns and on the implant platform structure after dynamic fatigue. Material and Methods: Thirty (30) external hexagon implants (3.75 x 10 mm) were embedded in acrylic resin following the ISO-14801. Standardized temporary crowns (n=10, N=30) were manufactured in acrylic resin and divided according to the framework type: Total plastic, Plastic with CoCr base and Titanium. The crowns were installed onto the implants (20N. cm) and fatigued (100N, 2 Hz) to det…

Evaluation of surface roughness of enamel after various bonding and clean-up procedures on enamel bonded with three different bonding agents : an in-…

2016

Background The purpose of this study was to analyze and compare the enamel surface roughness before bonding and after debonding, to find correlation between the adhesive remnant index and its effect on enamel surface roughness and to evaluate which clean-up method is most efficient to provide a smoother enamel surface. Material and methods 135 premolars were divided into 3 groups containing 45 premolars in each group. Group I was bonded by using moisture insensitive primer, Group II by using conventional orthodontic adhesive and Group III by using self-etching primer. Each group was divided into 3 sub-groups on the basis of type of clean-up method applied i,e scaling followed by polishing, …

OR 62 Are electronic apex locators reliable? An in vitro study

1999

Inclusion of the periodontal ligament in studies on the biomechanical behavior of fiber post-retained restorations: An in vitro study and three-dimen…

2016

Endodontically treated teeth are known to have reduced structural strength. Periodontal ligament may influence fracture resistance. The purpose of this study was to assess the influence of including the periodontal ligament in biomechanical studies about endodontically treated and restored teeth. Forty human maxillary central incisors were treated endodontically and randomly divided into four groups: non-crowned (with and without an artificial ligament) and crowned (with and without an artificial ligament) with glass-ceramic crowns. All groups received prefabricated glass-fiber posts and a composite resin core. Specimens were tested, under a flexural–compressive load, until failure occurre…

Fracture resistance of tooth restored with four glass fiber post systems of varying surface geometries-An in vitro study

2016

Background The purpose of this study was to relate the fracture resistance of endodontically treated teeth in relation to post geometry. Material and methods Forty single rooted mandibular premolars were instrumented by step - back technique and obturated by lateral condensation. Forty teeth were randomly divided into four groups: Reforpost glass fiber X-ray®, RelyX®, Exacto conical® and Parapost Fiber Lux®. The post spaces were prepared using respective drills and luted. The core build up was done and metal crowns were luted. Fracture resistance was determined in universal testing machine. The statistical analysis was done using one way ANOVA and post hoc Tukey Kramer test. Results The tee…