Peroxide penetration from the pulp chamber to the external root surface after internal bleaching.
OBJECTIVE
To quantify the amount of peroxide penetration from the pulp chamber to the external surface of teeth during the walking bleaching technique.


METHODS
Seventy-two bovine lateral incisors were randomly divided over five experimental groups and one control (n = 12 per group): (1) 35% hydrogen peroxide (HP); (2) 35% carbamide peroxide (CP); (3) sodium perborate (SP); (4) (HP+SP); (5) (CP+SP) and (6) Control (CG), deionized water. All groups were treated according to the walking bleach technique. After 7 days at 37 degrees C in an acetate buffer solution, 100 microl violet leukocrystal coloring and 50 microl peroxidase was added, producing a blue stain that could be measured in a spectrophotometer and then converted into peroxide microg/ml.


RESULTS
G5 exhibited the greatest penetration, while G2 and G3 produced the lowest values. All bleaching agents penetrated from the pulp chamber to the external root surface. There was a direct correlation between the presence of oxidative agents and penetration potential. Sodium perborate in distilled water was less oxidative and appeared to be the least aggressive bleaching agent.
Palo
Renato Miotto
RM
Department of Endodontics, São Paulo State University, Araraquara, SP, Brazil.
Valera
Marcia Carneiro
MC
Camargo
Samira Esteves Afonso
SE
Camargo
Carlos Henrique Ribeiro
CH
Cardoso
Paula Elaine
PE
Mancini
Maria Nadir Gasparoto
MN
Pameijer
Cornelis H
CH
D000134:Acid Etching, Dental; D000818:Animals; D001881:Borates / Q000008:administration & dosage / Q000493:pharmacokinetics*; D000077463:Carbamide Peroxide; D002417:Cattle; D003739:Dental Cementum / Q000378:metabolism; D003745:Dental Enamel Permeability; D003806:Dentin Permeability; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D006861:Hydrogen Peroxide / Q000008:administration & dosage / Q000493:pharmacokinetics*; D016877:Oxidants / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010545:Peroxides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011897:Random Allocation; D014073:Tooth Bleaching / Q000379:methods*; D019237:Tooth Cervix / Q000378:metabolism*; D019553:Tooth, Nonvital; D014508:Urea / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000493:pharmacokinetics
D001881:Borates; D004338:Drug Combinations; D016877:Oxidants; D010545:Peroxides; D000077463:Carbamide Peroxide; D014508:Urea; D006861:Hydrogen Peroxide; C027707:sodium perborate