title: An in vitro evaluation of radicular penetration of hydrogen peroxide from bleaching agents during intra-coronal tooth bleaching with an insight of biologic response.
abstract: OBJECTIVE
  External root resorption is the complication of intra-coronal bleaching done with 30% H2O2 alone or mixed with sodium perborate but not with sodium perborate mixed with water. The study was done to comparatively evaluate the H2O2 leakage from three H2O2 liberating bleaching agents.
  
  
  METHODS
  Fifty one single rooted human teeth were used. After root canal therapy gutta percha was removed below cemento-enamel junction. Three bleaching agents: sodium perborate mixed with water, sodium perborate mixed with 30% H2O2 and 30% H2O2 alone were used. Teeth without defect, with cervical root defect and with mid root defect constituted group A, group B and group C. According to various bleaching agents groups were subdivided into subgroup 1, 2 and 3. H2O2 leakage was measured with the help of spectrophotometer
  
  
  RESULTS
  Almost all teeth showed H2O2 leakage. It was maximum in B1 followed by C1, B2, A1, A2, C2, B3, A3 and C3.
  
  
  CONCLUSIONS
  Sodium perborate mixed with water was found to be the best bleaching agent.
authors.affiliation: Department of Pediatric and Preventive Dentistry, Modern Dental College and Research Centre, Gandhi Nagar, Airport Road, Indore (MP), India. drdivyaagra@yahoo.co.in
authors.forename: Divya S
authors.initials: DS
authors.lastname: Sharma
authors.forename: Sanjay
authors.initials: S
authors.lastname: Sharma
authors.forename: S M
authors.initials: SM
authors.lastname: Natu
authors.forename: Satish
authors.initials: S
authors.lastname: Chandra
mesh_terms: D001881:Borates / Q000008:administration & dosage / Q000009:adverse effects; D003763:Dental Leakage / Q000139:chemically induced*; D003786:Dental Pulp Cavity / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D006861:Hydrogen Peroxide / Q000008:administration & dosage* / Q000009:adverse effects; D012391:Root Resorption / Q000139:chemically induced / Q000517:prevention & control; D014073:Tooth Bleaching / Q000379:methods*; D058205:Tooth Bleaching Agents / Q000008:administration & dosage* / Q000009:adverse effects; D019237:Tooth Cervix / Q000187:drug effects; D019228:Tooth Crown / Q000187:drug effects; D014075:Tooth Discoloration / Q000628:therapy; D014092:Tooth Root / Q000187:drug effects*
chemical_list: D001881:Borates; D058205:Tooth Bleaching Agents; D006861:Hydrogen Peroxide; C027707:sodium perborate