THE SHEAR BOND STRENGTHS OF STAINLESS-STEEL ORTHODONTIC BRACKETS BONDED TO TEETH WITH ORTHODONTIC COMPOSITE RESIN AND VARIOUS FISSURE SEALANTS

Enamel decalcification (whitened areas) around orthodontic brackets during therapy is a well-recognized problem. If a fissure sealant could be used to isolate the enamel and yet withstand debonding of the bracket during therapy, this problem might be overcome. The objective of this in vitro study was to determine (1) the shear bond strengths of stainless steel orthodontic brackets bonded to teeth with an orthodontic bonding resin together with a primary coating of various fissure sealants and (2) the fracture sites of these debonded samples. Forty noncarious human canine teeth were divided into four groups of 10 teeth each. In group A, the brackets were bonded to the buccal surfaces of the prepared teeth with a macrofilled orthodontic composite resin only. In groups B, C, and D, the brackets were similarly bonded, except that the teeth were first treated with a fissure sealant-group B having a light-cured unfilled clear fissure sealant, group C having a light-cured microfilled fissure sealant, and group D having a chemically cured opaque fissure sealant. After storage at 37° C for 24 hours, the brackets were subjected to a shear force in an Instron machine, and the fracture strengths were recorded, together with the sites of fracture. This study demonstrated that (1) a fissure sealant resin can be applied to seal the buccal surface of a tooth and have a bracket bonded to it, which exhibits shear bond strengths that are equal to, if not higher than, the standard method of bonding, and (2) the fracture sites of the fissure-sealed teeth are located more at the resin/enamel interface than those of teeth without sealant, thus leaving less cleaning of the tooth surface after debonding. © 1990 Mosby-Year Book, Inc.