Abstract
Sufficient bond strength of the brackets to the tooth surfaces in the course of active treatment and the adhesion characteristics which facilitate the removal of the brackets from the tooth surfaces in the last treatment phase have been one of the essential requirements in orthodontics.The purpose of this study is to develop such adhesion system.In the present study, thermal property a sa adhesion factor was adopted in order to investigate the effects on the adhesion between brackets and tooth surfaces.Orthodontic metal brackets were directly bonded to extracted human teeth with three orthodontic adhesives(Super-Bond, Concise and System 1).The bond strength were measured at 30℃, 70℃, 90℃ and 150℃ in a simple small electric furnace.All the adhesives had a tendency that their tensile and shearing strength decreased with the increase of temperature.The tensile strength of Super-Bond and Concise showed their maximum values at 30℃.Super-Bond lost almost its bond strength at 90℃.Concise decreased gradually its bond strength and even at 150℃ it maintained still low value.Similar tendency was observed for System 1 at higher temperature when compared with Concise.The pattern of the shearing strength in each adhesive with the increasing temperature was also analogous to that of its tensile strength.
