title: Long-term evaluation of the influence of smear layer on the apical sealing ability of MTA.
abstract: The aim of this in vitro study was to investigate the effect of the smear layer on apical microleakage in teeth obturated with mineral trioxide aggregate (MTA). Fifty single-rooted central maxillary teeth were used in this study. All teeth were instrumented to size 60 by using the step-back technique. The selected teeth were randomly divided into 2 groups (n = 20). In the first group (smear [+]), the teeth were irrigated with only NaOCl (5.25%). In the second group (smear [-]), the teeth were irrigated with ethylenediaminetetraacetic acid (EDTA) (17%) and NaOCl (5.25%) to remove the smear layer. The teeth were then filled with MTA. The computerized fluid filtration method was used for evaluation of apical microleakage. The quantitative apical leakage of each tooth was measured after 2, 30, and 180 days. Statistical analysis was done with the Mann-Whitney U and Wilcoxon signed ranks tests. At the end of this study there was no difference in 2 days between the groups, but removal of the smear layer caused significantly more apical microleakage than when the smear layer was left intact for 30 and 180 days (P < .005). Within the constraints of this study it can be concluded that the apical microleakage of MTA is less when the smear layer is present than when it is absent.
authors.affiliation: Faculty of Dentistry, Department of Restorative Dentistry, Karadeniz Technical University, Trabzon, Turkey. tahsiny@hotmail.com
authors.forename: Tahsin
authors.initials: T
authors.lastname: Yildirim
authors.forename: Hasan
authors.initials: H
authors.lastname: Oruçoğlu
authors.forename: Funda Kont
authors.initials: FK
authors.lastname: Cobankara
mesh_terms: D017607:Aluminum Compounds / Q000737:chemistry / Q000627:therapeutic use*; D017610:Calcium Compounds / Q000737:chemistry / Q000627:therapeutic use*; D002614:Chelating Agents / Q000627:therapeutic use; D001840:Dental Bonding; D003763:Dental Leakage / Q000145:classification; D003804:Dentin / Q000648:ultrastructure; D004338:Drug Combinations; D004492:Edetic Acid / Q000627:therapeutic use; D005899:Glass Ionomer Cements / Q000627:therapeutic use; D006801:Humans; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry / Q000627:therapeutic use*; D012387:Root Canal Filling Materials / Q000737:chemistry / Q000627:therapeutic use*; D012388:Root Canal Irrigants / Q000627:therapeutic use; D012389:Root Canal Obturation / Q000379:methods; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D017640:Silicates / Q000737:chemistry / Q000627:therapeutic use*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D013997:Time Factors; D019227:Tooth Apex / Q000648:ultrastructure*
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D002614:Chelating Agents; D004338:Drug Combinations; D005899:Glass Ionomer Cements; C515713:Ketac Molar Easymix; D010087:Oxides; D012387:Root Canal Filling Materials; D012388:Root Canal Irrigants; D017640:Silicates; C086631:mineral trioxide aggregate; D004492:Edetic Acid; D012973:Sodium Hypochlorite