نتایج جستجو برای: acid strength
تعداد نتایج: 942704 فیلتر نتایج به سال:
cement is an essential ingredient in the concrete buildings. for production of cement considerable amount of fossil fuel and electrical energy is consumed. on the other hand for generating one tone of portland cement, nearly one ton of carbon dioxide is released. it shows that 7 percent of the total released carbon dioxide in the world relates to the cement industry. considering ecological issu...
background: repair bond strength of different composite resins has been assessed in few studies. in addition, reports on the effi cacy of surface treatments are debated. therefore, this in vitro study was conducted to evaluate the effect of three surface treatments on two nanocomposites versus a microhybrid composite. materials and methods: in this experimental study, 135 composite blocks (45 s...
OBJECTIVE To evaluate the effect of optional phosphoric acid etching on the shear bond strength (SBS) of two self-etch adhesives to enamel and dentin. MATERIAL AND METHODS Ninety-six bovine mandibular incisors were ground flat to obtain enamel and dentin substrates. A two-step self-etch adhesive (FL-Bond II) and a one-step self-etch adhesive (BeautiBond) were applied with and without a prelim...
BACKGROUND Over the years, it has been known that 34% phosphoric acid is the benchmark in etchants with the best shear bond strength shown with composites in primary teeth. However, with latest technological advancements and innovations, in order to reduce the number of steps and less damage to the tooth structure, non-rinse conditioner (NRC) & Single-Etch and various other etchants have been t...
The purpose of this study was to examine the feasibility of a conditioner for treating enamel and dentin simultaneously for MMA-TBB resin bonding. Various phosphoric acid solutions containing copper salts were prepared and used as conditioners before bonding MMA-TBB resin to bovine teeth. Their effects on the surface morphology and bonding were studied by scanning electron microscopy and tensil...
objective: different ceramic repair systems have been reported for fractured ceramics. however, limited information is available concerning the bond strength of these systems especially after thermocycling. the aim of this in-vitro study was to determine the effect of thermocycling on the shear bond strength of composite-resin to feldspathic porcelain with and without silane pretreatment. mater...
the wheat straw as abundant lignocellulosic resource was successfully undergone in a benzylation reaction and plasticized with different contents (2.5, 3, 5 and 7 wt. %) of glycerol and stearic acid.the effect of type and concentration of plasticizers on the mechanical, thermomechanical, morphological and water absorption properties of benzylated wheat straw (bws) was investigated by tensile, d...
background dentin sensitivity is one of the most important problems in dentistry. enamel loss due to root exposure is serious issue and common exposure is one of the reasons for dentin hypersensitivity. there are different methods for solving this problem. one of the most conservative and least expensive methods is use of casein phosphopeptide-amorphous calcium phosphate (cpp-acp) paste. object...
This study assessed bonding of orthodontic brackets to porcelain teeth using two different surface preparation techniques and comparing two bonding systems, Fuji Ortho L.C. and Transbond. Four groups of 20 porcelain premolar teeth were bonded with metal orthodontic brackets (0.022 inch Minitwin, 3M Unitek) according to the following protocol: Transbond with a phosphoric acid etch (group 1), Tra...
خواص فیزیکی و مکانیکی چوب مورد مطالعه قرار گرفته است . برای اینکار چوب درخت چنار انتخاب شده است . آزمایشات انجام شده هم بصورت استاتیک و هم بصورت دینامیک بوده است . نمونه هائی با رطوبت و دانسیته های مختلف آزمایش شده اند. همه موارد آزمایشات در دمای آزمایشگاه انجام شده است . خواص مکانیکی چون ضریب ارتجاعی (modulus of elasticity) حد تناسب (proportional limit) حد کشش (tensile strength) تاب خرد شدگی (...
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