EVALUATION OF SCOTCHBOND MULTIPURPOSE AND MALEIC-ACID AS ALTERNATIVE METHODS OF BONDING ORTHODONTIC BRACKETS

Damage to the enamel surface during bonding and debonding of orthodont ic brackets is a clinical concern. Alternative bonding methods that mi nimize enamel surface damage while maintaining a clinically useful bon d strength is an aim of current research. The purpose of this study wa s to compare the effects on bond strength and bracket failure location of two adhesives (System 1 + and Scotchbond Multipurpose, 3M Dental P roducts Division) and two enamel conditioners (37% phosphoric acid and 10% maleic acid). Forty-eight freshly extracted human premolars were pumiced and divided into four groups of 12 teeth, and metal orthodonti c brackets were attached to the enamel surface by one of four protocol s: (1) System 1+ and phosphoric acid, (2) Scotchbond and phosphoric ac id, (3) System 1+ and maleic acid, and (4) Scotchbond and maleic acid. After bracket attachment, the teeth were mounted in phenolic rings an d stored in deionized water at 37 degrees C for 72 hours. A Zwick univ ersal testing machine (Zwick GmbH & Co.) was used to determine shear b ond strengths. The residual adhesive on the enamel surface was evaluat ed with the Adhesive Remnant Index. The analysis of variance was used to compare the four groups. Significance was predetermined at p less t han or equal to 0.05. The results indicated that there were no signifi cant differences in bond strength among the four groups (p = 0.386). T he results of the Chi square test, evaluating the residual adhesives o n the enamel surfaces, revealed significant differences among the four groups (X-2 = 0.005). A Duncan multiple range test revealed the diffe rence occurred between the phosphoric acid and maleic acid groups, wit h maleic acid having bond failures at the enamel-adhesive interface. I n conclusion, the use of Scotchbond Multipurpose and/or maleic acid do es not significantly effect bond strength, however, the use of maleic acid resulted in an unfavorable bond failure location.