http://www.revmaterialeplastice.ro MATERIALE PLASTICE ♦54♦No.1 ♦2017 122 In vitro Assessment of Calcium Hydroxide Removal from Endo Blocks by Simple Irrigation with NaOCl and the Passive Ultrasonic Irrigation Technique ALEXANDRU VLASA 1 , CARMEN BIRIS 1 *, LUMINITA LAZAR 1 , ANAMARIA BUD 1 , EUGEN BUD 1 , IOAN SEBASTIAN CERNUSCA MITARIU 2 , MARIANA PACURAR 1 1 Faculty of Dental Medicine, UMF Targu Mures, 38 Gh. Marinescu, 540139, Targu Mureº, Romania 2 Faculty of Medicine, Lucian Blaga University of Sibiu, 2A Lucian Blaga Str., 550169, Sibiu, Romania Because endodontic pathology is caused due to bacterial contamination of the root canal system, endodontic treatment should focus on eliminating microorganisms in root canals. For more than 70 years Calcium Hydroxide has an important role in antimicrobial endodontic therapy. The use of calcium hydroxide is limited by the incomplete removal thereof, a residue covering 20% to 45% of the ductal wall, even after irrigation with NaOCl or EDTA. This study aims to evaluate the removal of calcium hydroxide in root canals using two different techniques. Keywords: calcium hydroxide, root canal, NaOCl, endo block Because endodontic pathology is caused due to bacterial contamination of the root canal system, endodontic treatment should focus on eliminating microorganisms in root canals. A number of materials have historically been used in endodontic treatments, but unfortunately, none of these have been able to satisfy the total requirements of an ideal sealer [1, 2]. For more than 70 years Calcium Hydroxide has an important role in antimicrobial endodontic therapy. It is used both to preserve pulp vitality (direct or indirect pulp capping), root fracture repair, closure of immature apex, root resorption treatment. Calcium hydroxide enhances the formation of a calcified tissue barrier when used as capping material in the canal or can be used in contact with the pulp or healthy periodontal tissue [3]. Many studies indicate the use of calcium hydroxide as an antiseptic in cases where a root canal is infected due to OH ions which can diffuse dentinal tubules in both the infected and the periodontal space directly acting on microorganisms [4] .The use of calcium hydroxide is limited by the incomplete removal thereof, a residue covering 20 to 45% of the ductal wall, even after irrigation with NaOCl or EDTA. As the remaining calcium hydroxide can shorten setting time of sealer-sized zinc oxide eugenol based, can affect root filling quality and increases the risk of micro-infiltrations it is important to remove all residual calcium hydroxide [5]. This study aims to evaluate the removal of calcium hydroxide in root canals using two techniques: - Irrigation with NaOCl 5.25% associated with manual mechanical instrumentation, - Passive Ultrasonic Irrigation associated with manual mechanical instrumentation. Experimental part For evaluation were used 30 acrylic endo training blocks Endo 943-100 Training Blocks DIADENT Group International, each having a tapered root canal 0.65 and two accessories root canals (fig.1). The channels were filled with injectable Calcium hydroxide respectively Calxyd, SpofaDental, Czech * email: biriscarmen74@yahoo.com Republic, beyond apex to ensure a full obturation of the root canal (fig 2). -I. - 5.25% NaOCl irrigation using special needles, Endo- Eze, Ultradent, USA placed as close to the apex as two- thirds of the working length. Instrumentation with manual master needle, ISO 40, through circumferential drive and withdrawal. At the end of the preparation the channels were dried with paper points. -II. 5.25% NaOCl irrigation using Passive Ultrasonic Irrigation technique. For irrigation a thin endodontic ultrasonic loop ISO 40 was used. The endodontic ultrasonic loop was placed as close to the apex as two-thirds of the working length and acted 30 s for each irrigation. Fig.1 Endo training block Fig.2 Canal filled with Calcium Hydroxide - 2 weeks after root canal filling Ca(OH)2 was removed of channels (fig.3) using 2 techniques: Fig.3 Endo trainer free of Calcium Hydroxide