A comparison of two methods of removing zinc oxide-eugenol provisional cement residue from the internal surface of cast restorations.
OBJECTIVE
Remnants of provisional cement on the internal surface of cast restorations can have an adverse effect on the performance of the definitive luting agent. The purpose of this study was to evaluate the effect of eugenol-containing temporary cement removal by an ultrasonic or an organic solvent on the retentive strength of metallic rings cemented to amalgam cores using zinc phosphate cement.


METHODS
A total of 36 cylindrical amalgam cores measuring 5.9 x 6 mm were made by condensing amalgam in brass molds for use in this in vitro study. Thirty-six cylindrical spaces measuring 6 x 6 mm were machined in the center of cast rods of Rexillium III alloy to create simulated retainers. The amalgam cores were divided into two groups and provisionally cemented in these cylindrical spaces (retainers) using zinc oxide-eugenol cement. After separation of the cores from the retainers, one group was cleaned with an ultrasonic cleaning device with water and the other group was cleaned with Solitine organic solvent. All specimens were then cemented with zinc phosphate cement and the samples were stored at 100% humidity in a 37 degrees C water bath after which they were tested with a DARTEK testing machine at a 0.02 cm/minute cross head speed. The data were analyzed using the Independent t-test.


RESULTS
The statistical analysis revealed a significant difference between the two groups (p<0.0005) with the ultrasonic group having significantly higher separation forces than the Solitine group.


CONCLUSIONS
Specimens treated with the ultrasonic cleaner showed a higher mean separation force (282.2 MPa) than the solvent group (439.5 MPa).


CONCLUSIONS
Despite the convenience of using an organic solvent for cleaning the internal surface of cast restorations, the ultrasonic cleaning method is more effective for removing zinc-oxide temporary cement.
Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran. mosharraf@dnt.mui.ac.ir
Ramin
R
Mosharraf
Bahram
B
Soleimani
Mehdi
M
Sanaee-Nasab
D002858:Chromium Alloys; D003442:Crowns; D003722:Dental Alloys; D003723:Dental Amalgam; D001840:Dental Bonding; D017005:Dental Debonding / Q000379:methods*; D003794:Dental Restoration, Temporary; D003799:Dental Stress Analysis; D005054:Eugenol; D012997:Solvents; D014465:Ultrasonics; D015034:Zinc Oxide; D015035:Zinc Oxide-Eugenol Cement; D015036:Zinc Phosphate Cement
D002858:Chromium Alloys; D003722:Dental Alloys; D012997:Solvents; D015035:Zinc Oxide-Eugenol Cement; D005054:Eugenol; C076899:Temp-Bond; C036884:Rexillium III; D015036:Zinc Phosphate Cement; D003723:Dental Amalgam; D015034:Zinc Oxide