title: The effect of ultrasonic removal of various root-end filling materials.
abstract: OBJECTIVE
  To compare residual root-end filling material in apical root-end cavities following their removal with ultrasonic retrotips.
  
  
  METHODS
  Thirty single-rooted teeth were filled with Thermafil and AH Plus sealer. Root-ends were resected at 90 degrees, 3 mm from the apex. Root-end cavities were prepared with diamond burs and ultrasonic retrotips and filled with one of three filling materials: group I: Retro-TC (calcium silicate-based cement), group II: IRM (Dentsply, Germany), group III: Vitrebond (3M ESPE, USA). After 30 days of storage, ultrasonic retrotips were used to remove materials from the root-end cavities. The ultrasonic application time was fixed at 60 s. Polyether impressions and replicas of the root-ends were made. Root apices and replicas were examined by one operator under a scanning electron microscope. Remnants of residual materials were evaluated using a four-level scoring system; fractures, smear layer and exposed dentinal tubules were also examined.
  
  
  RESULTS
  Forty per cent of the specimens filled with Retro-TC revealed complete removal of the material with exposure of dentinal tubules, whilst 60% contained residual cement. Twenty per cent of specimens filled with IRM were completely devoid of material, whereas 80% had retained material. Ten per cent of specimens filled with Vitrebond retained a moderate amount of material whilst 90% had substantial retention of the material. Statistically significant differences were found (P < 0.05) amongst the three groups of materials.
  
  
  CONCLUSIONS
  Retro-TC was successfully removed in 40% of cases using ultrasonics retrotips for 60 s, whereas IRM and Vitrebond specimens had evidence of retained material in 80% and 90% of all specimens respectively.
authors.affiliation: Department of Dental Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Pirani
authors.forename: F
authors.initials: F
authors.lastname: Iacono
authors.forename: S
authors.initials: S
authors.lastname: Chersoni
authors.forename: J
authors.initials: J
authors.lastname: Sword
authors.forename: D H
authors.initials: DH
authors.lastname: Pashley
authors.forename: F R
authors.initials: FR
authors.lastname: Tay
authors.forename: S
authors.initials: S
authors.lastname: Looney
authors.forename: M G
authors.initials: MG
authors.lastname: Gandolfi
authors.forename: C
authors.initials: C
authors.lastname: Prati
mesh_terms: D017005:Dental Debonding / Q000295:instrumentation*; D019232:Dental Restoration Failure; D005899:Glass Ionomer Cements; D019220:High-Energy Shock Waves; D006801:Humans; D008768:Methylmethacrylates; D012086:Reoperation; D012184:Retrograde Obturation; D012387:Root Canal Filling Materials; D018915:Root Canal Preparation / Q000295:instrumentation*; D012823:Silicate Cement; D017211:Treatment Failure; D015035:Zinc Oxide-Eugenol Cement
chemical_list: D005899:Glass Ionomer Cements; D008768:Methylmethacrylates; D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; C067790:Vitrabond; D012823:Silicate Cement; C031667:IRM cement