Effect Of Self-etching Primer Research Articles

Effect of self-etching primer and adhesive formulations on the shear bond strength of orthodontic brackets

Despite many published articles on the bond strength of self-etching primers and adhesives in the restorative dentistry literature, there have been relatively few laboratory studies of the bond strength of new orthodontic materials, and, in most of these published studies, investigators used various methodologic approaches during different stages of the in vitro testing procedures. The aim of this study was to compare the shear bond strength of 4 self-etching primer and adhesive formulations, a nonrinse conditioner and acetone adhesive system, and a conventional system. The self-etching products tested were Prompt L-Pop (3M ESPE, Seefeld, Germany), Clearfil SE Bond (Kuraray Dental, Osaka, Japan), FL Bond (Shofu Dental, Kyoto, Japan), and One-Up Bond F (Tokuyama, Tokyo, Japan); the nonrinse conditioner and acetone-based adhesive system was NRC and Prime&Bond NT (Dentsply International, Konstanz, Germany); the conventional acid-etch and bond system was Transbond XT (3M Unitek, Monrovia, Calif). Brackets were bonded to intact bovine mandibular incisors (n = 7 per group) according to each manufacturer's recommendations. The specimens were first stored in deionized water at 37 degrees C for 24 hours and then subjected to thermal cycling in deionized water at 5 degrees C +/- 2 degrees C to 55 degrees C +/- 2 degrees C for 1000 cycles. To facilitate degradation of bonds, the specimens were further stored in distilled water for 6 weeks before debonding procedures. The shear bond strengths of the 5 experimental groups were all significantly lower (P < .05) than that of the control group (Prompt L-Pop, 1.72 +/- 0.13 MPa; Clearfil SE Bond, 1.75 +/- 0.19 MPa; FL Bond, 1.71 +/- 0.22 MPa; One-Up Bond F, 1.77 +/- 0.14 MPa; control, 10.5 +/- 0.86 MPa) but not different from one another (P > .05). The tested self-etching primer and adhesive systems produced bond strength values much lower than that of the control product. Clinically, these products might not be suitable for orthodontic bracket bonding in terms of the shear bond strength achieved after thermal cycling and water storage.

Effects of self-etching primers on vascular responses in rat carotid artery.

To investigate the effect of self-etching bonding systems on the control of pulpal haemorrhage in direct pulp exposures by observing the contraction of pulp blood vessels using the rat carotid artery model. Six dentine-bonding agents (Mac Bond, One-Up Bond F, Clearfil SE Bond, FL Bond, Prompt L-Pop and Prime and Bond NT) were used. The efficacy of bonding agents were compared with that of epinephrine for dose and the contraction forces (vasoconstriction) induced on the smooth muscle and the results recorded using a force displacement transducer. Dose-dependent relaxations caused by the test materials were recorded in the same manner in comparison with papaverine. FL Bond, SE Bond, One Up Bond, Mac Bond produced dose-dependent relaxations, while Prompt L-Pop and Prime&Bond NT produced epinephrine-like contractions on the rat carotid artery. For self-etching primers, which produce vascular relaxation, haemorrhage control with additional chemicals should be considered if direct pulp capping is to be performed using such adhesive systems.

Effect of self-etching primer containing N-acryloyl aspartic acid on enamel adhesion

Objectives: A previous study demonstrated that N-acryloyl aspartic acid ( N-AAsp) aqueous solution is useful as a self-etching primer for dentin adhesion. The purpose of this study was to evaluate whether N-AAsp solution can be used for enamel etching, when compared with phosphoric acid. Methods: N-AAsp was synthesized by the reaction of DL-aspartic acid and acryloyl chloride. The experimental self-etching primers were prepared by dissolving N-AAsp in water at various concentrations up to 20 wt%. The tensile bond strength of resin to bovine enamel was measured after the enamel was treated with the N-AAsp primers. The 40 wt% H 3PO 4 was used for comparison. The treated enamel surfaces and the resin–enamel interfaces were also observed with a scanning electron microscope. Results: The tensile bond strength to enamel increased linearly with the increasing N-AAsp concentration and reached the same value as that to enamel etched with 40 wt% H 3PO 4 when N-AAsp concentration was 20 wt%, even though the etching ability of 20 wt% N-AAsp was inferior to 40 wt% H 3PO 4. Regardless of the concentration of N-AAsp, the bond strength to enamel was the same as that to dentin reported in our previous study. Significance: The 20 wt% N-AAsp aqueous solution showed enamel bonding equivalent to 40 wt% H 3PO 4 in addition to the advantage of eliminating the rinse step with water. Based on the results obtained in this study along with those obtained in a previous study, it was concluded that 20 wt% N-AAsp aqueous solution is a promising self-etching primer to simultaneously treat enamel and dentin.

Effects of self-etching primers on dentin

The effects of self-etching dentin primers on the hardness of dentin was evaluated by determination of the Vickers Hardness of both untreated dentin and dentin treated with different primers. Several experimental primers were prepared by dilution of dicarbonates or their esterified salts with different ratios of HEMA to obtain ratios of 5% and 35% by weight. Methacryloxyethyl succinate (MES) and Methacryloxyethyl phthalate (MEP) experimental primers caused less softening of dentin than did maleic acid diluted with HEMA or a commercial dentin primer (Scothchprep, 3M). A high correlation was observed between the pH of a primer and the hardness of dentin treated with the primer. A correlation was also observed between the hardness of treated dentin and the wall-to-wall polymerization contraction of a light-curing microfilled resin (Silux, 3M).