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VOLUME 12 , ISSUE 3 ( May-June, 2011 ) > List of Articles


Effect of Calcium Hydroxide on pH Changes of the External Medium after Intracoronal Bleaching

Carlos Rocha Gomes Torres, Patrícia Marra de Sá, Raffaela Di Iorio Jeronymo, Karen Cristina Kazue Yui, Eduardo Galera da Silva, Maria Filomena Rocha Lima Huhtala, Ana Paula Martins Gomes

Citation Information : Torres CR, de Sá PM, Jeronymo RD, Yui KC, da Silva EG, Huhtala MF, Gomes AP. Effect of Calcium Hydroxide on pH Changes of the External Medium after Intracoronal Bleaching. J Contemp Dent Pract 2011; 12 (3):158-163.

DOI: 10.5005/jp-journals-10024-1027

Published Online: 01-02-2012

Copyright Statement:  Copyright © 2011; The Author(s).



This in vitro study evaluated the effect of calcium hydroxide on pH changes of the external medium after intracoronal bleaching.

Materials and methods

A total of 50 extracted human premolars were prepared and filled with gutta-percha and endodontic sealer. The teeth were randomly divided into five groups according to the bleaching agents employed: (a) Sterile cotton pellet with distilled water (control group); (b) sodium perborate and distilled water; (c) sodium perborate and 10% carbamide peroxide; (d) sodium perborate and 35% hydrogen peroxide; (e) 35% hydrogen peroxide. The teeth were stored in vials containing distilled water and the pH values of the medium surrounding the teeth were analyzed. After 7-day storage, the bleaching agent was removed and replaced by calcium hydroxide, and the distilled water was changed, in which the teeth were kept stored for further 14 days. Measurement of pH of the external medium (distilled water) was performed 7 days after insertion of the bleaching agents, immediately, 7 and 14 days after insertion of the calcium hydroxide. Data were submitted to statistical analysis by the two-way ANOVA and Tukey, s test.


There were pH changes of the external medium at 7- day period after bleaching procedures. These results confirmed the diffusion of bleaching agents to the external medium.


Calcium hydroxide increased the external medium pH and was effective for pH alkalinization after intracoronal bleaching.

Clinical significance

Intracoronal bleaching of endodontically treated teeth may cause cervical root resorption. A possible explanation for this process is the passage of bleaching agents to the periodontal tissues yielding an inflammatory process. In an attempt to keep the neutrality of the periodontal pH, the calcium hydroxide has been recommended. Results of this study showed that this material should be always used after intracoronal bleaching.

How to cite this article

de Sá PM, Jeronymo RDI, Yui KCK, de Silva EG, Huhtala MFRL, Torres CRG, Gomes APM. Effect of Calcium Hydroxide on pH Changes of the External Medium after Intracoronal Bleaching. J Contemp Dent Pract 2011;12(3): 158-163.

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