title: Effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate using electron microscopy and energy dispersive X-ray microanalysis.
abstract: OBJECTIVE
  To investigate the effect of bleaching agents having a neutral pH on the surface of mineral trioxide aggregate (MTA) used as a coronal seal material for nonvital bleaching, beneath the bleaching agent, with the help of energy dispersive X-ray microanalysis and scanning electron microscopy (SEM).
  
  
  METHODS
  Six samples of plastic tubes filled with white MTA (Angelus white) were kept in 100% humidity for 21 days. Each sample was divided into 2 and made into 12 samples. These were then divided into three groups. Group A was exposed to Opalescence Boost 40% hydrogen peroxide (HP) (Ultradent). Group B to Opalescence 10% carbamide peroxide (Ultradent) and Group C (control group) not exposed to any bleaching agent. After recommended period of exposure to bleaching agents according to manufacturers' instructions, the samples were observed under SEM with an energy dispersive X-ray microanalysis system (JSM-6380 LA).
  
  
  RESULTS
  There were no relevant changes in color and no statistically significant surface structure changes of the MTA in both the experimental groups.
  
  
  CONCLUSIONS
  The present findings suggest that even high concentration HP containing bleaching agents with neutral pH can be used on the surface of MTA without causing structural changes. The superior sealing ability of MTA and the high alkalinity would prevent cervical resorption postbleaching.
authors.affiliation: Department of Conservative Dentistry and Endodontics, Yenepoya Dental College, Mangalore, Karnataka, India.
authors.forename: Nooh
authors.initials: N
authors.lastname: Kazia
authors.affiliation: Department of Conservative Dentistry and Endodontics, Yenepoya Dental College, Mangalore, Karnataka, India.
authors.forename: Nithin
authors.initials: N
authors.lastname: Suvarna
authors.affiliation: Department of Conservative Dentistry and Endodontics, Yenepoya Dental College, Mangalore, Karnataka, India.
authors.forename: Harish Kumar
authors.initials: HK
authors.lastname: Shetty
authors.affiliation: Department of Conservative Dentistry and Endodontics, Yenepoya Dental College, Mangalore, Karnataka, India.
authors.forename: Pradeep
authors.initials: P
authors.lastname: Kumar
keywords: Carbamide peroxide; energy-dispersive X-ray; mineral trioxide aggregate; opalescence boost; scanning electron microscopy