Search results for "Universal testing machine"
showing 10 items of 69 documents
Influence of different veneering techniques and thermal tempering on flexural strength of ceramic veneered yttria partially stabilized tetragonal zir…
2019
Background Different technique for ceramic veneering and thermal tempering process are expected to be a reason for alteration in strength of ceramic veneered zirconia. This study evaluates the effect of different veneering technique and varied thermal tempering process on flexural strength of ceramic veneered zirconia. Material and Methods Ceramic veneered zirconia bars (25 mm length, 4 mm width, 0.7&1.0mm of zirconia & ceramic thickness) were prepared from zirconia block (e.max® ZirCAD), sintered at 1500°C for 4 hours, and veneered with ceramics with different techniques including CAD-fused using e.max CAD® (C), Pressed-on using e.max® Zirpress (P), and layering using e.max® ceram (L), wit…
An in vitro evaluation of the effect of sandblasting and laser surface treatment on the shear bond strength of a composite resin to the facial surfac…
2015
Objectives: The present study was conducted to evaluate the optimal method of enhancing the bond strength of a composite resin to the facial surface of the primary anterior stainless steel crowns using various surface treatments namely Nd: YAG laser surface treatment, sandblasting , alloy primer application and no surface treatment. Study Design: The study sample consisted of 60 primary anterior stainless steel crowns (UnitekTM size R 4), with 15 samples randomly divided into the 4 study groups, embedded in acrylic blocks. The facial surface of these surface treated crowns was utilized as the bonding surface to which 2.5mm diameter composite resin cylinders were bonded for the evaluation of…
Effect of sodium ascorbate on the bond strength of all-in-one adhesive systems to NaOCl-treated dentin
2015
Background: Ascorbic acid and its salts are low-toxicity products, which are routinely used in food industries as antioxidants. The aim of the present study was to evaluate the effect of 10% sodium ascorbate on the bond strength of two all-in-one adhesive systems to NaOCl-treated dentin. Material and Methods: After exposing the dentin on the facial surface of 90 sound human premolars and mounting in an acrylic resin mold, the exposed dentin surfaces were polished with 600-grit SiC paper under running water. Then the samples were randomly divided into 6 groups of 15. Groups 1 and 4 were the controls, in which no surface preparation was carried out. In groups 2 and 5 the dentin surfaces were …
Effect of antioxidants on the shear bond strength of composite resin to enamel following extra-coronal bleaching
2019
Background Recently patients need faster treatments, and delaying restoration is not possible following bleaching treatment. The purpose of this study was to determine the effect of antioxidants, namely 10% sodium ascorbate, 10% alpha-tocopherol, 10% green tea and 10% Aloe vera extract on the shear bond strength of composite resin to enamel following extra-coronal bleaching using 40% hydrogen peroxide. Material and Methods Seventy premolars were randomly assigned into 7 groups of 10 each. Group 1: bleaching treatment and no antioxidants application. Group 2: composite was built-up immediately after bleaching. Group 3: bleached specimens received composite build-up delayed by 2 weeks. Group …
Biomechanical comparison between the modified rolling-hitch and the modified finger-trap suture techniques
2016
Purpose: The purpose of this study was to characterize the biomechanical effect of two grasping suture techniques used during ligament reconstruction: the modified rolling-hitch (MRH) and the modified finger-trap (MFT). Methods: Flexor profundus tendons were harvested from fresh pig hind-leg trotters. Each specimen was mounted on an electro-mechanic universal testing machine (Instron 3367). In half of all tendons (15 specimens), the suture was passed around the tendon following the MRH knot (Group 1). In the remaining half of all tendons (15 specimens), the suture was passed over a distance of 30 mm according to the MFT suture technique (Group 2). As per standard intra-operative technique, …
Evaluation of the force generated by gradual deflection of 0.016-inch NiTi and stainless steel orthodontic wires in self-ligating metallic and esthet…
2019
Background The purpose of this study was to evaluate the deflection forces of 0.016-inch Nitinol and stainless steel orthodontic wires, in association to different self-ligating brackets. Material and Methods Specimens were mounted in a clinical simulation model and evaluated in a Universal Testing Machine (INSTRON 3342), using a 10N load cell and ISO 15,841, as a protocol. Eight of these models were prepared, each one for the bonding of each set of self-ligating accessories to be tested: Damon Q, Damon Clear (Ormco), In-Ovation R, In-Ovation C (GAC), BioQuick, QuickClear (Forestadent), SmartClip and Clarity SL (3M). Data were subjected to One-way ANOVA, followed by Tukey tests (P<0.05). Re…
Mechanical evaluation for three-dimensional printed orthodontic springs with different heights-in vitro study
2021
Background The orthodontic spring materials in use have a significant influence on the applied forces. The prerequisite to identify the in vitro< force deflection of the CAD/CAM fabricated springs is considered mandatory to identify the material characteristics. The purpose of the present investigation was to evaluate the mechanical load on 3D printed springs using different coil heights. Material and Methods The springs were digitally designed with different coil heights using Autodesk Netfabb CAD software (San Rafael, CA, USA). Test specimens were manufactured using 3D printable experimental flexible material (Code: BM2008, GC, Tokyo, Japan). The specimens were divided according to the co…
Shear force comparative evaluation for surface treated and non- treated 3D interim printed materials with different types of glass-ionomer cements
2020
Background The purpose of this investigation was to compare shear force of different glass-ionomer cements on 3D printed interim material in combination with and without surface pretreatment. Material and Methods 120 rectangular specimens made of printable provisional material (Bego, Bremen, Germany) were used. After post-processing the specimens were blasted with aluminum oxide 110µm (Bego, Bremen, Germany). Extra 120 non-surface treated specimens were used as an experimental negative test group. All 240 specimens were divided randomly into 6 groups. All were cemented with a compressive load of 20 N using universal testing machine Z010 (Zwick/Roell, Ulm, Germany) to ensure a comparable cem…
Evaluation of bond strength of orthodontic brackets without enamel etching
2015
Background: to compare the shear bond strength of brackets with and without enamel etching. Material and Methods: In this study, 60 sound premolars were randomly divided into four different groups: 1- TXE group: Enamel etching + Transbond XT adhesive + Transbond XT composite. 2- TXS group: Transbond plus self-etch adhesive + Transbond XT composite. 3- PQ1E group: Enamel etching + PQ1 adhesive + Transbond XT composite. 4- PQ1 group: PQ1 adhesive + Transbond XT composite. The shear bond strengths of brackets were evaluated using universal testing machine at cross head speed of 0.5 mm/ min. The Adhesive Remnant Index (ARI) was also measured. One-way ANOVA, Tukey’s post hoc, Kruskal-wallis and …
Evaluation of micro shear bonding strength of two universal dentin bondings to superficial dentin by self etch and etch-and-rinse strategies
2018
Background Universal bondings can be used either with the etch-and-rinse or self-etch technique. Thus, the present study was done to evaluate the micro-shear bonding strength of two types of Universal Bondings to superficial dentin i.e self-etch and etch and rinse. Material and Methods The samples included 70 tooth blocks taken from 35 extracted sound premolar teeth. The superficial dentin was exposed to grinding by 800 grit silicon carbide Disk. The samples were randomly divided into 5 equal groups (14 samples in each group). Scotch bond universal (3M/USA) and All bond universal (BISCO/USA) were applied by self-etch and etch and rinse technique in group 1-4 and Adper Single bond 2 (3M/USA)…