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Bond strength of orthodontic adhesives to dry and saliva-moistened enamel a comparative in vitro study

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Stefański T. , Kloc-Ptaszna A. , Postek-Stefańska L.

Archives of Materials Science and Engineering

2019

tom Vol. 96, nr 2

79--84

Purpose: To compare the bond strengths of six different dental adhesives to dry and salivamoistened enamel. Design/methodology/approach: One hundred twenty stainless steel brackets were bonded to human mandibular third molars with six materials: Enlight LC® (Ormco Corp), Grengloo® (Ormco Corp), Light Bond® (Reliance Orthodontic Products), Charisma® (Heraeus Kulzer), SmartBond® (Gestenco), and Transbond XT® with MIP® primer (3M Unitek). One half of the specimens in each group (n=10) was bonded to dry enamel, while the other half to saliva-moistened enamel. Bond strength testing was performed with a wire loop loading technique after 30-min incubation in artificial saliva. Failure mode was evaluated using adhesive remaining index (ARI). Findings: No significant differences in bond strength to dry enamel were noted for all composite materials (p>0.05). SmartBond exhibited significantly greater bond strength to moistened enamel (7.10 ± 1.47 MPa) and comparable with other composite materials to dry enamel. Composite materials demonstrated significantly reduced bond strength to saliva-moistened enamel (p<0.001), except for Transbond MIP, whose bond strength was not significantly decreased by saliva contamination (p=0.089). There was not statistically significant difference between bond strength of SmartBond and Transbond to saliva contaminated enamel. A higher incidence of cohesive failures was noted for all materials. Research limitations/implications: Composite light-cured materials provide adequate bond strength to dry enamel. Cyanoacrylate adhesive provides sufficient bond strength only under moist conditions. Transbond XT+MIP has sufficient bond strength to either dry or saliva-moistened enamel. Practical implications: The study evaluated the bonding strength of orthodontic brackets, which is a critical parameter in orthodontics, especially in situations that do not allow for proper isolation from saliva, such as bonding to impacted teeth following surgical exposure. Originality/value: Bond strengths evaluated with loop loading technique in different study environments would help the orthodontist to choose the most effective adhesive for the specific clinical situation.

Erosive potential of calcium-supplemented citric acid on bovine enamel

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Stefański T. , Malara P. , Kloc-Ptaszna A. , Postek-Stefańska L. , Tyrpień-Golder K. , Dobrzański L. A.

Archives of Materials Science and Engineering

2013

tom Vol. 64, nr 2

175--181

Purpose: of this paper is to present results of wear resistance investigations of epoxy-hard coal composites produced by gravity casting Design/methodology/approach: In short introduction wear resistance of polymers is presented, methods used to prepare composites together with short characterization of physical properties of applied fillers are described. Wear resistance of the specimens was determined using Schopper-Schlobach method and APGi device. During the test, the rigidly fixed specimen moves with constant velocity along a rotating cylinder with abrasive paper type corundum P60 on its surface. Wear resistance of specimens was determined after 20 meters distance of abrasion under pressing load of10Nand expressed as the weight loss of the specimen after abrasion. Findings: Addition of the hard coal particles into the epoxy resin matrix caused a decrease of the wear resistance. Wear resistance decreased in a little extend with increasing filler content. Statistical analysis of achieved results showed that the influence of hard coal on wear resistance is significant comparing neat resin and filled resin but is not significant comparing composites with different solid particles content. Practical implications: Tested composite materials can be applied among others in electrical or chemical industry where electrical properties are important but wear resistance is not so important. Originality/value: New types of epoxy-hard coal graded composites were tested. It was demonstrated that by proper gravity casting technology control it is possible to produce graded composites for which hard coal particles do not deteriorate the wear resistance in significant extend.