title: Appearance of the root canal walls after preparation with NiTi rotary instruments: a comparative SEM investigation.
abstract: The aim of this study was to evaluate, in vitro, with scanning electron microscope (SEM), the appearance of root canal walls shaped by three different rotary NiTi techniques and one conventional manual technique in human extracted teeth. Four different instruments were used: K3, Hero 642, RaCe and K-file. Each sample was irrigated with 5 ml of 5% NaOCl and 5 ml of 3% H2O2 and EDTA, Rc-Prep (1 ml). Each sample was prepared for SEM observation and analyzed in the coronal, middle and apical third, comparing its aspect with a predefined scale of four different parameters: presence of smear layer, pulpal debris, inorganic debris and surface profile. The apical third showed significantly more pulpal and inorganic debris, smear layer and a high number of surface profile irregularities. No significant difference was found at the coronal, middle and apical thirds between manual and rotary techniques for inorganic debris, smear layer and surface profile. Much pulpal debris were found in the apical third for K3 and RaCe compared with Hero 642 and K-file. In conclusion, mechanical rotary techniques with NiTi instruments produced quite similar results compared with a conventional manual technique using K-files. The present study demonstrated that dentin and pulpal debris, the morphology of smear layer and surface profile were only partially influenced by the type of endodontic instruments. The apical third was the anatomical area with greater amount of debris and smear layer.
authors.affiliation: Endodontics Unit, Department of Dental Sciences, University of Bologna, Alma Mater Studiorum, Via S. Vitale 59, Bologna, Italy. prati@alma.unibo.it
authors.forename: Carlo
authors.initials: C
authors.lastname: Prati
authors.forename: Federico
authors.initials: F
authors.lastname: Foschi
authors.forename: Cesare
authors.initials: C
authors.lastname: Nucci
authors.forename: Lucio
authors.initials: L
authors.lastname: Montebugnoli
authors.forename: Silvia
authors.initials: S
authors.lastname: Marchionni
mesh_terms: D000704:Analysis of Variance; D003722:Dental Alloys / Q000737:chemistry; D003782:Dental Pulp / Q000648:ultrastructure; D003786:Dental Pulp Cavity / Q000648:ultrastructure*; D003804:Dentin / Q000648:ultrastructure; D004867:Equipment Design; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009532:Nickel / Q000737:chemistry; D012388:Root Canal Irrigants / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation*; D016369:Smear Layer; D012973:Sodium Hypochlorite / Q000627:therapeutic use; D018709:Statistics, Nonparametric; D014025:Titanium / Q000737:chemistry; D019227:Tooth Apex / Q000648:ultrastructure
chemical_list: D003722:Dental Alloys; D012388:Root Canal Irrigants; C040654:titanium nickelide; D009532:Nickel; D014025:Titanium; D012973:Sodium Hypochlorite