Evaluation of the effect of calcium hydroxide paste on sealer penetration into dentinal tubules by confocal laser scanning microscopy.

The study evaluated sealer penetration after calcium hydroxide (Ca(OH) ) removal from the root canals. Sixty single-rooted mandibular premolars were divided into six groups. Ca(OH) paste placed into the root canals except for the control group (CG) was removed using the following irrigation techniques: conventional needle irrigation (CNI), EndoActivator (EA), EndoVac (EV), passive ultrasonic irrigation (PUI) and photon-induced photoacoustic streaming (PIPS) technique. After canal filling, the penetration depth, penetration area and penetration percentage of the sealer were determined using confocal microscopy. The CG and EA had a greater penetration depth than CNI in the middle section. The CG exhibited a higher dentinal tubule penetration area than CNI, EV and PUI in the middle section. EA was significantly more effective than PUI in the coronal section for the percentage of sealer penetration. EA and PIPS removed Ca(OH) from root canals effectively because they presented similar penetration to the CG in all sections.