title: Spectrophotometric Evaluation of the Pulpal Peroxide Levels in Intact and Restored Teeth - An Invitro Study.
abstract: BACKGROUND
  Hydrogen peroxide (30%) is a commonly used "in office" bleaching agent. Deleterious effects of hydrogen peroxide on the pulp have been observed.
  
  
  OBJECTIVE
  The present study was conducted with the aim to evaluate the penetration of 30% hydrogen peroxide into the pulp chamber through intact teeth and through the surface of teeth, restored with either hybrid composite or Resin Modified Glass Ionomer Cement (RMGIC).
  
  
  METHODS
  Sixty extracted human maxillary central incisors were selected and divided into six groups. Two groups were restored with hybrid composite resin and two with RMGIC, while two groups were left intact. The teeth with acetate buffer solution in their pulp cavity were then immersed in either 30% hydrogen peroxide or distilled water depending upon the group, for 60 minutes at 37°C. Then horseradish peroxidase and leucocrystal violet were added to the acetate buffer solution present in the pulp chamber after it was transferred to a test tube and the optical density of the resultant blue solution obtained was measured spectrophotometrically.
  
  
  METHODS
  The data obtained were analyzed using one way ANOVA and Student's t-test.
  
  
  RESULTS
  The data obtained established that hydrogen peroxide penetrated into the pulp from the bleaching agent used. Hydrogen peroxide (30%) showed the highest pulpal peroxide level in teeth restored with RMGIC followed by teeth restored with hybrid composite resin and the least amount of penetration was observed in intact teeth.
  
  
  CONCLUSIONS
  The amount of peroxide penetration into the tooth is more through restored tooth than intact tooth and is also dependant on the type of restorative materials used.
authors.affiliation: Reader, Department of Conservative Dentistry and Endodontics, Kalinga Institute of Dental Sciences, KIIT University , Bhubaneshwar, Odisha, India .
authors.forename: Gaurav
authors.initials: G
authors.lastname: Patri
authors.affiliation: Senior Lecturer, Department of Conservative Dentistry and Endodontics, Kalinga Institute of Dental Sciences, KIIT University , Bhubaneshwar, Odisha, India .
authors.forename: Gourismita
authors.initials: G
authors.lastname: Acharya
authors.affiliation: Senior Lecturer, Department of Conservative Dentistry and Endodontics, Kalinga Institute of Dental Sciences, KIIT University , Bhubaneshwar, Odisha, India .
authors.forename: Pratik
authors.initials: P
authors.lastname: Agrawal
authors.affiliation: Postgraduate Student, Department of Orthodontics, Kalinga Institute of Dental Sciences, KIIT University , Bhubaneshwar, Odisha, India .
authors.forename: Vijeta
authors.initials: V
authors.lastname: Panda
keywords: Bleaching; Hybrid composite resin; Hydrogen peroxide; Pulp; Resin modified Glass ionomer cement