We have modified Merrifield’s resin to provide polymers containing secondary amine groups. Lithiation of the solids gives strongly basic yet poorly nucleophilic resins useful for rearrangement of epoxides to their corresponding allylic alcohols. The resins are easy to handle, non-volatile, non-toxic, and are easily recovered and reused, providing environmental and economic benefits that might h...

objectives: color change of composite restorations is well known to dentists. however, the effect of commonly consumed drinks on discoloration of composite resins has yet to be determined. this study sought to assess the color change of a nanofilled (premise) and a flowable composite resin (premise flowable) following simulated consumption of tea, cola, iron drops and multivitamin syrup. materi...

Some higher plants, both angiosperms and gymnosperms, can produce resins and some of these resins can polymerize and fossilize to form ambers. Various physical and chemical techniques have been used to identify and profile different plant resins and have then been applied to fossilized resins (ambers), to try to detect their parent plant affinities and understand the process of polymerization, ...

     To evaluate the ultimate compressive strength of five composite resins after 1 hour, 24 hours, 7 days and 1 month. Twenty four cylindric...

background and purpose: in people wearing dentures, the growth of various candida species under the prosthesis leads to the formation of biofilm, which can play the role of a reservoir for candida and other kinds of microbes. since nano-chitosan particles can cause lasting antimicrobial activity, a more recent approach that utilizes acrylic resins with nano-chitosan particles is proposed. there...

phenolic resins are synthetic low molecular weight thermoset resins which are polymerized and cured to higher molecular weights by condensation method. these resins have high weathering resistance, high oxidative thermal properties and good chemical resistance. phenolic resins can be cured thermally or by acid curing. the most common method of curing phenolic resin is by thermal curing that tak...

tooth fracture is a common dental problem. by extension of cavity dimensions, the remaining tooth structure weakens and occlusal forces may cause tooth fracture. the aim of this study was to evaluate and compare the fracture resistance of teeth restored with direct and indirect composite restorations.sixty-five sound maxillary premolar teeth were chosen and randomly divided into five groups eac...

objectives: this study sought to compare the push-out bond strength of two bulk-fill and one conventional composite to intracanal dentin in primary anterior teeth. materials and methods: this in vitro, experimental study was conducted on 39 primary anterior teeth, which were randomly divided into three groups. after cleaning and shaping, the root canals were filled with metapex in such a way th...

this study aimed to evaluate the cellular toxicity of two newly-released acrylic resins (futura gen and gc reline hard) in comparison with the conventional heat-cure resin (meliodent).sample discs from each acrylic resin were placed in 24-well culture plates along with l929 mouse fibroblast cell line. a mixture of the rpmi 1640 medium, antibiotics and 10% fbs was added to the plates and the spe...

statement of the problem addition of metallic nano-particles to composite resins can change their water contact angle purpose the aim of this study was to evaluate the effect of addition of nano-particles of silver and zinc oxide to composite resins on their water contact angle materials and methods this in vitro study was performed on 60 composite resin samples. nano-silver and nano-zinc oxide...