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. MATERIALS AND 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. CONCLUSION: 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.
ABSTRACT
Root resorption that occurs in permanent teeth is an unwanted process and is considered pathologic. Although apical root resorption occurs in individuals who have never experienced orthodontic tooth movement, the incidence among treated individuals is seen to be significantly higher. Some resorption occurs in most orthodontic patients, but because of repair the changes are difficult to detect with radiographic examination and therefore are clinically insignificant. This article gives a review of the various types of root resorption, the etiological factors, the biology and the identification of root resorption.
