The effect of retreatment procedure on the pH changes at the surface of root dentin using two different calcium hydroxide pastes.

Aim: To compare pH changes at the cervical, middle and apical surfaces of root dentin in retreated and non- retreated teeth, after canal obturation with two different calcium hydroxide pastes.

Materials And Methods: After instrumentation of 55 extracted teeth, three cavities with 0.75 mm depth and 1.