Journal Article

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American Journal of Orthodontics and Dentofacial Orthopedics : Official Publication of the American Association of Orthodontists, its Constituent Societies, and the American Board of Orthodontics

Am.J.Orthod.Dentofacial Orthop.

Dec

96

6

485

492

LR: 20121115; JID: 8610224; 0 (Composite Resins); 0 (Dental Cements); 0 (Phosphoric Acids); E4GA8884NN (phosphoric acid); ppublish

UNITED STATES

0889-5406; 0889-5406

PMID: 2686399

eng

Comparative Study; Journal Article; D; IM

0889-5406(89)90115-7 [pii]

Unknown(0)

2686399

The purpose of this in vitro study was to determine the effects of phosphoric acid (H3PO4) concentration and duration of etching on the shear bond strength of an orthodontic bonding resin to enamel. Nine bonding procedures, each involving 18 extracted human maxillary permanent canines, were used. Ground enamel surfaces were etched with a 37% H3PO4 solution, a 15% H3PO4 gel, or a 5% H3PO4 solution for 60, 30, and 15 seconds, respectively. Cylinders of an orthodontic bonding resin, Concise, were prepared in a special device. The test specimens were disassembled 15 minutes after preparation and stored in distilled water at 37 degrees C for 24 hours. A shear load was applied to the bonded cylinders at a crosshead speed of 0.02 in.min-1 in an Instron testing machine, and the shear bond strengths were calculated and expressed in MN.m-2. A two-factor analysis of the data showed that the H3PO4 concentration had no significant effect on the shear bond strength, but the duration of etching affected shear bond strength significantly. The enamel aspects of the fractured test specimens were examined microscopically and the percent failure within the bonding resin at the bonding sites estimated. The correlation between shear bond strength and percentage failure within the bonding resin was not significant. The effects of the nine etching procedures on ground and unground enamel surfaces were studied by scanning electron microscopy. The etching procedures produced well-defined etching patterns on both ground and unground enamel surfaces.

Acid Etching, Dental/methods, Composite Resins, Dental Bonding, Dental Cements, Dental Enamel/ultrastructure, Dental Stress Analysis, Humans, Microscopy, Electron, Scanning, Phosphoric Acids/administration & dosage, Time Factors

Legler,L. R., Retief,D. H., Bradley,E. L., Denys,F. R., Sadowsky,P. L.

University of Alabama, Birmingham.

http://vp9py7xf3h.search.serialssolutions.com/?charset=utf-8&pmid=2686399

1989