The effect of ultrasonic removal of various root-end filling materials.
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.
Pirani
C
C
Department of Dental Sciences, Alma Mater Studiorum, University of Bologna, Bologna, Italy.
Iacono
F
F
Chersoni
S
S
Sword
J
J
Pashley
D H
DH
Tay
F R
FR
Looney
S
S
Gandolfi
M G
MG
Prati
C
C
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
D005899:Glass Ionomer Cements; D008768:Methylmethacrylates; D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; C067790:Vitrabond; D012823:Silicate Cement; C031667:IRM cement