title: An in vitro study to evaluate the effects of addition of zinc oxide to an orthodontic bonding agent.
abstract: OBJECTIVE
  The objective of this study is to test the antimicrobial effect of zinc oxide when incorporated into an orthodontic bonding material and to check the effect of addition of zinc oxide on the shear bond strength of the bonding material.
  
  
  METHODS
  Zinc oxide was added to a resin modified light cure glass ionomer cement (GIC) (Fuji Ortho LC GC America, Alsip, Ill) to make modified bonding agent containing 13% and 23.1% ZnO and the antimicrobial assay was done using agar disc diffusion method. Discs of the modified bonding agent were prepared and a culture of Streptococcus mutans mixed with soft agar was poured over it and incubated at 38°C for 48 h and zones of inhibition were measured. The test was repeated after a month to check the antimicrobial effect. In addition shear bond strength of the brackets bonded with the modified bonding agent was tested.
  
  
  RESULTS
  The agar disc showed zones of inhibition around the modified bonding agent and the antimicrobial activity was more when the concentration of ZnO was increased. The antimicrobial effect was present even after a month. The shear bond strength decreased as the concentration of ZnO increased.
  
  
  CONCLUSIONS
  The incorporation of ZnO into a resin modified light cure GIC (Fuji Ortho LC GC America, Alsip, Ill) added antimicrobial property to the original compound.
authors: Department of Orthodontics, Saraswati Dhanwantri Dental College, Parbhani, Maharashtra, India.
authors: Archana
authors: A
authors: Jatania
authors: Department of Orthodontics, JSS Dental College and Hospital, Mysore, Karnataka, India.
authors: B M
authors: BM
authors: Shivalinga
keywords: Antimicrobial effect; bond strength; decalcification; white spot lesion; zinc oxide; zone of inhibition