title: Effect of sputter-coating on cracking of root-end surfaces after ultrasonic retrograde preparation--a SEM study of resected root apices and their respective impressions.
abstract: The aim of this study was to evaluate in vitro the effect of sputter-coating for SEM analysis on the formation of cracks on root-end surfaces after retrograde cavity preparation with ultrasonic tips. Root-end cavities were prepared with either Satelec S12/90 degrees D diamond-coated or S12/90 degrees non-coated stainless steel retrotips. Impressions were taken before and after retrograde cavity preparation. The resected root apices and their respective impressions were examined using a scanning electron microscope, and the presence, extension and numbers of cracks were recorded after each procedure. The number of cracks observed directly on the ultrasonically prepared root-end surfaces was larger than that observed in their respective impressions taken after root-end cavity preparation, which suggests that cracking was mostly produced by the sputter-coating process required for SEM analysis. Impressions of the root-end cavities prepared with non-coated ultrasonic stainless steel retrotips showed a greater incidence of cracks (3/10 impressions) than those that replicated cavities prepared with diamond-coated retrotips (1/10 impressions). No statistical difference was found between the diamond and stainless steel retrotips.
authors.affiliation: Department of Endodontics, Bauru Dental School of Bauru, University of São Paulo, Brazil. bramante@fob.usp.br
authors.forename: Clovis M
authors.initials: CM
authors.lastname: Bramante
authors.forename: Ivaldo Gomes
authors.initials: IG
authors.lastname: de Moraes
authors.forename: Norberti
authors.initials: N
authors.lastname: Bernardineli
authors.forename: Roberto Brandão
authors.initials: RB
authors.lastname: Garcia
authors.forename: Cláudio Urra
authors.initials: CU
authors.lastname: Pidero
authors.forename: Ronald
authors.initials: R
authors.lastname: Ordinola-Zapata
authors.forename: Alexandre Silva
authors.initials: AS
authors.lastname: Bramante
mesh_terms: D006801:Humans; D008855:Microscopy, Electron, Scanning; D018915:Root Canal Preparation; D019227:Tooth Apex / Q000648:ultrastructure*