The effects of various beverages on the shear bond strength of light-cured orthodontic composite (An in vitro comparative study)

Abstract

Background: This study was conducted to assess the effects of various beverages on the shear bond strength of lightcuredorthodontic composite used to bond stainless steel orthodontic brackets on human teeth and to determinethe site of bonding failure of this material.Materials and Methods: Fifty extracted human premolars were selected and randomly divided into five equal groupseach with 10 teeth according to the beverage type (Control, One Tiger, Milk, Green tea and Coffee). After bonding,the teeth were immersed in specific beverages for 5 minutes twice daily with equal intervening intervals then washedand stored in distilled water at 37º C for the reminder of the day. The process was carried out for 30 days. Thesamples were then tested for shear bond strength using Tinius-Olsen testing machine with a crosshead speed of0.5mm/minute. For adhesive remnant index, the enamel surface and bracket base of each tooth were inspectedunder magnifying lens (20X) of a stereomicroscope.Results: Milk, coffee and one Tiger energy drink reduced the shear bond strength of the light-cured compositesignificantly unlike the green tea. The predominant site of bond failure was between the bracket base and theadhesive leaving the composite on the tooth rather on the brackets base.Conclusions: Orthodontic patients should be instructed to reduce the intake of acidic and fatty beverages toprevent debonding of the orthodontic brackets