title: An in vitro spectrophotometric analysis of the penetration of bleaching agent into the pulp chamber of intact and restored teeth.
abstract: OBJECTIVE
  To investigate the pulp chamber penetration of bleaching agent in intact teeth and teeth following restorative procedure.
  
  
  METHODS
  Sixty extracted human incisors were selected and divided into 6 Groups. Four Groups were restored with hybrid composite resin and resin modified glass ionomer cement respectively, while 2 Groups were left intact. The Groups were then immersed in the treatment agents for 60 mins at 37°C. The optical density of the resultant blue solution obtained by adding leucocrystal violet and horseradish peroxidise to the acetate buffer solution present in the pulp chamber was measured spectrophotometrically and the data thus obtained was statistically analysed using ANOVA and paired t-test.
  
  
  RESULTS
  The amount of pulpal peroxide penetration in restored teeth was significantly higher than intact teeth (p< 0.001). the control Group showed no peroxide penetration. Groups restored with resin modified glass ionomer cement showed higher pulpal peroxide levels than Groups restored with hybrid composites, though the difference was not statistically significant (p = 0.52).
  
  
  CONCLUSIONS
  Peroxide readily penetrates into the pulp through intact and restored teeth, with restored teeth showing higher pulpal peroxide levels than intact teeth. Teeth restored with resin modified glass ionomer cement showed higher pulpal peroxide level than teeth restored with composite resins.
authors.affiliation: Reader, Department of Conservative Dentistry and Endodontics, Kalinga Institute of Dental Sciences , Bhubaneswar, Odisha, India .
authors.forename: Gaurav
authors.initials: G
authors.lastname: Patri
authors.affiliation: Senior Lecturer, Department of Conservative Dentistry and Endodontics, Hi Tech Dental College and Hospital , Bhubaneswar, Odisha, India .
authors.forename: Yoshaskam
authors.initials: Y
authors.lastname: Agnihotri
authors.affiliation: Professor, Department of Conservative Dentistry and Endodontics, Hi Tech Dental College and Hospital , Bhubaneswar, Odisha, India .
authors.forename: Saketh Rama
authors.initials: SR
authors.lastname: Rao
authors.affiliation: Senior Lecturer, Department of Prosthodontia, Hi Tech Dental College and Hospital , Bhubaneswar, Odisha, India .
authors.forename: Namratha
authors.initials: N
authors.lastname: Lakshmi
authors.affiliation: Senior Lecturer, Department of Conservative Dentistry and Endodontics, Hi Tech Dental College and Hospital , Bhubaneswar, Odisha, India .
authors.forename: Sambarta
authors.initials: S
authors.lastname: Das
keywords: Bleaching; Carbamide peroxide; Hybrid Composite Resin; Pulp; Resin modified glass ionomer cement