An in vitro study on the efficacy of removing calcium hydroxide from curved root canal systems in root canal therapy

• Published in: International journal of oral science Vol. 9; no. 2; pp. 110 - 116
• Main Authors: Wang, Ying, Guo, Li-Yang, Fang, Hong-Zhi, Zou, Wen-Ling, Yang, Ying-Ming, Gao, Yuan, Yang, Hui, Hu, Tao
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.06.2017; Springer Nature B.V; State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, West China Hospital of Stomatology, Sichuan University, Chengdu, China%Department of Stomatology, The Third People's Hospital of Chengdu, Chengdu, China%State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, Department of Preventive Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China%State Key Laboratory of Oral Disease, National Clinical Research Center for Oral Diseases, Department of General Dentistry, West China Hospital of Stomatology, Sichuan University, Chengdu, China; Nature Publishing Group
• Subjects: Calcium; Calcium hydroxide; Calcium Hydroxide - chemistry; canal; Citric acid; Citric Acid - chemistry; Computed tomography; curved; Dental Instruments; Dental Pulp Cavity - ultrastructure; Dental research; Dentistry; Edetic acid; Edetic Acid - chemistry; Endodontics; Humans; hydroxide; In Vitro Techniques; irrigation; Lavage; Medicine; Oral and Maxillofacial Surgery; Oral hygiene; Original; original-article; Orthopedics; removal; root; Root Canal Irrigants - chemistry; Root Canal Preparation - instrumentation; Root canals; Sodium Hypochlorite - chemistry; Studies; Surface Properties; Surgical Orthopedics; system; Teeth; Ultrasonics; removal; calcium hydroxide; irrigation; curved root canal system
• ISSN: 1674-2818; 2049-3169
• DOI: 10.1038/ijos.2017.14

To compare the efficacy of various irrigants （citric acid, ethylenediaminetetraacetic acid （EDTA） and NaOCI） and techniques inremoving Ca（OH）2 in two types of curved root canal systems, simulated root canals with specific curvatures were used toinvestigate the effects of different irrigants and instruments on Ca（OH）2 removal, The optimal methods were verified on extractedhuman teeth. Simulated root canals were assigned to one of two groups based on the irrigation solution： 10% citric acid or2,5% NaOCI, Each group was divided into four subgroups according to the technique used to remove Ca（OH）2. The percentageof Ca（OH）2 removal in different sections of root canals was calculated. On the basis of the results obtained for the simulatedcanals, 10% citric acid and 17% EDTA were applied to remove Ca（OH）2 from the extracted human teeth with curved root canalsystems. The teeth were scanned by micro computed tomography to calculate the percentage of Ca（OH）2 removal in the canals.In simulated root canals, we found that 10% citric acid removed more Ca（OH）2 than 2.5% NaOCI in the 0-1 mm group from theapex level （P〈O.05）. Ultrasonic and EndoActivator activation significantly removed more Ca（OH）2 than a size 30 K file in theapical third （P〈 0.05）. However, there were no significant differences in any sections of the canals for 10% citric acid or 17%EDTA in removing Ca（OH）2 in extracted human teeth. We concluded that it was effective to remove residual Ca（OH）2 using thedecalcifying solution with EndoActivator or Passive Ultrasonic Irrigation in a curved root canal system. A protocol for Ca（OH）2removal was provided based on the conclusions of this study and the methods recommended in previous studies.