Effect of ultrasonic vibration on the removal of posts cast in different metal alloys
RPG rev. pos-grad
; 13(4): 287-291, out.-dez. 2006. ilus, tab
Article
in English
| LILACS, BBO - Dentistry
| ID: lil-529398
Responsible library:
BR501.1
ABSTRACT
The aim of this experiment was to evaluate the relative efficacy of ultrasonic instruments on the removal of posts cast in alloys with different stiffness (nickel-chromium and silver-tin alloys). Sixty roots of extracted bovine incisor teeth were sectioned, prepared and randomly divided into 4 groups (n=15) groups 1 and 2 received posts cast in Ni-Cr and groups 3 and 4 received posts cast in Ag-Sn. All posts were cemented with zinc phosphate cement. Groups 2 and 4 received ultrasonic vibration for 12 minutes. The force necessary for post removal was measured by an Instron universal testing machine. Data were statistically analyzed with ANOVA and when significant differences were found, means were compared using Tukey's intervals with a confidence level of 95%. The mean force (kgf) to remove posts of group 1 (67.84± 15.31) was statistically greater than groups 2 (46.95± 10.85), 3 (48.53± 8.49) and 4 (41.25± 11.40). There was no statistically significant difference among groups 2, 3 and 4. The ultrasonic vibration was effective in reducing the force required to remove posts cast in Ni-Cr (about 31% of reduction), but had little effect on posts cast in Ag-Sn (about 15% of reduction). Posts cast in Ni-Cr were also more retentive then posts cast in Ag-Sn when they were not submitted to ultrasonic vibration.
Full text:
Available
Collection:
International databases
Database:
BBO - Dentistry
/
LILACS
Main subject:
Zinc Phosphate Cement
/
Post and Core Technique
/
Dental Alloys
Type of study:
Evaluation study
Language:
English
Journal:
RPG rev. pos-grad
Year:
2006
Document type:
Article
Affiliation country:
Brazil
Institution/Affiliation country:
USP/BR