The effects of crystal growth on shear bond strength of orthodontic bracket adhesives to enamel surface

Lee, Young Jun; Park, Young Guk

Abstract

It has been submitted that different ion solutions containing sulfate induce crystal growth and might substitute conventional acid etching for pretreatment of enamel in orthodontic bonding(Artun et al., Am. J. Orthod. 85, 333, 1984). This investigation was designed to evaluate the relevance of crystal growth on the enamel surface as an alternative to conventional acid etching in direct bonding of orthodontic brackets. Annexing Li2SO4, MgSO4, KeSO4 respectively in the solution with 25% polyacrylic and 0.3M sulfuric acids were employed to enhance the crystal growth. Human bicuspids were treated with various parameters as combinations of crystal growth and glass ionomer cement, crystal growth and orthodontic resin, acid etching and orthodontic resin for an inveatigative purpose. Crystal growth solution cintaining MgSO4 showed the highest shear bond strength(15.6MPa) wuthin the groups of bonding brackets with glass ionomer cement(P<0.01). Bonding with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 was not different shear bond strength statistically from bonding with orthodontic resin on the acid-etched surface. It suggests that bonding brackets with glass ionomer cement on the surface treated with crystal growth solution containing MgSO4 or K2SO4 is a potential altermative to bonding with resin on the acid etched sufrace.