Bond strength of aged composites found in brackets placed by an indirect technique
The “Thomas” indirect technique for bracket attachment produces an interface not present in direct techniques, that is, an aged composite-sealant interface. Our primary goal was to determine if a weakened interface was produced by a modified (sealant was mixed prior to placement of brackets) Thomas indirect technique when the composite was aged for 7 days. The enamel-bracket system was investigated in vitro by comparison of shear bond strengths for metal and ceramic brackets bonded to bovine teeth by a direct and indirect method. Nearly all specimens failed at the bracket-composite interface and, subsequently, no difference was found between specimens placed by direct or indirect methods. No evidence was found to suggest that an aged composite would predispose the enamel-bracket system to fail at the sealant-composite interface. The ceramic brackets used in this investigation had lower bond strengths then metal ones, but the breaking loads were similar.Abstract
Contributor Notes
J.Y. Shiau is a graduate of the orthodontic program at Case Western Reserve Uniuersity and is now in private practice in San Diego, California
S.T. Rasmussen is a Senior Fellow at the Department of Biologic and Materials Sciences at the School of Dentistry, The University of Michigan
A.E. Phelps is a Clinical Professor of Orthodontics at Case Western Reserve University
D.H. Enlow is an Emeritus Professor of Orthodontics at Case Western Reserve University
G.R. Wolf is a Clinical Instructor of Orthodontics at Case Western Reserve University