Effects of a new desensitizing paste containing 8% arginine and calcium carbonate on the shear bond strength of orthodontic brackets

Effects of a new desensitizing paste containing 8% arginine and calcium carbonate on the shear bond strength of orthodontic brackets

Objective: The purpose of this study was to evaluate shear bond strength (SBS) and failure site location of brackets bonded to enamel with or without desensitizer application. Methods: Sixty-six freshly extracted human premolar teeth were randomly divided into 3 groups of 22. Group 1 served as the control. Desensitizer was applied to the remaining teeth at two time intervals (Group 2, bonded immediately after Pro-Relief<SUP>TM</SUP> (Colgate-Palmolive Co., New York, NY, USA) application and Group 3, bonded 30 days after Pro-Relief<SUP>TM</SUP> application with the teeth stored in artificial saliva during the 30 days). Orthodontic brackets were bonded with a light cure composite resin and cured with a halogen light. After bonding, the SBS of the brackets was tested using a universal testing device. Adhesive remnant index (ARI) scores were determined after the brackets failed. Data were analyzed with analysis of variance, Tukey s HSD, and G tests. Results: The SBS was significantly lower in Group 2 than in Groups 1 (<I>p </I>= 0.024) and 3 (<I>p</I> = 0.017). Groups 1 and Group 3 did not differ (<I>p</I> = 0.991). ARI scores did not differ significantly among groups. Conclusions: The Pro-Relief<SUP>TM</SUP> desensitizer agent applied immediately before bonding significantly reduces bond strength, but the SBS values still exceed the minimum 5.9 - 7.8 MPa required for adequate clinical performance. Immersing the teeth in artificial saliva for 30 days after applying the Pro-Relief<SUP>TM </SUP>desensitizer agent and before bonding increased the SBS to control levels. (Korean J Orthod 2011;41(2):121-126)