In vitro analysis of the pH alteration of the dentine after using different calcium hydroxidebased pastes

Resumo

To analyze the pH increase at the
external root surface after the use of different calcium hydroxide
pastes (Calen, calcium hydroxide associated with 2% chlorhexidine
gel, calcium hydroxide associated with saline) with and without EDTA
as chelating agent before the topical application of the intracanal
medication. Material and methods: One-hundred single-rooted
extracted teeth were cleaned and shaped. They were randomly divided
into six experimental groups (n = 15) and one control group (n =
10), according to the medication to be used. The teeth were kept
immersed in saline solution and the pH measurements were weekly
verified with the aid of a pH meter. Results: It was verified the pH
increasing at the first week in almost all groups. Only the groups in
which Ca(OH)2 was associated with 2% chlorhexidine gel exhibited
a significant evolution in the pH increasing over time (p = 0.0116).
The use of EDTA did not result in higher pH values (p = 0.2278).
Conclusion: i) the pH increased in all associations used; ii) 2%
chlorhexidine gel allowed the gradual pH increasing over time; iii)
the smear layer removal did not influence on the pH increasing.