Peroxide penetration from the pulp chamber to the external root surface after internal bleaching
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Published on: October 27, 2023
Renato Miotto Palo1, Marcia Carneiro Valera, Samira Esteves Afonso Camargo
1Department of Endodontics, São Paulo State University, Araraquara, SP, Brazil.
Purpose:
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.
