Grinding of composite cores using diamond burs with different grit sizes: the effects on the retentive strength of zirconia crowns
Braz. j. oral sci
;
19: e201574, jan.-dez. 2020. ilus
Article
in English
| BBO, LILACS
| ID: biblio-1116249
ABSTRACT
Aim:
To evaluate the retention of Y-TZP crowns cemented in aged composite cores ground with burs of different grit sizes.Methods:
Sixty composite resin simplified full-crown preparations were scanned, while 60 Y-TZP crowns with occlusal retentions were milled. The composite preparations were stored for 120 days (wet environment-37°C) and randomly distributed into three groups (n=20) according to the type of composite core surface treatment. The groups were defined as CTRL (control No treatment), EFB (extra-fine diamond bur [25µm]), and CB (coarse diamond bur [107µm]). The grinding was performed with an adapted surveyor standardizing the speed and pressure of the grinding. The intaglio surfaces on the crowns were air-abraded with silica-coated alumina particles (30 µm) and then a silane was applied. The crowns were cemented with self-adhesive resin cement, thermocycled (12,000 cycles; 5/55°C), stored (120 days) and submitted to a retention test (0.5mm/min). The retentive strength data (MPa) were analyzed using one-way analysis of variance and Tukey test, as well as Weibull analysis. Failures were classified as 50C (above 50% of cement in the crown), 50S (above 50% of cement in the substrate) and COE (composite core cohesive failure).Results:
No statistical difference was observed among the retention values (p=0.975). However, a higher Weibull modulus was observed in the CTRL group. The predominant type of failure was 50S (above 50% of cement in the substrate composite).Conclusion:
The retention of zirconia crowns was not affected by grinding using diamond burs with different grit sizes (coarse/extra-fine) or when no grinding was performed
Full text:
Available
Index:
LILACS (Americas)
Main subject:
Surface Properties
/
Zirconium
/
Dental Bonding
/
Dental Prosthesis Retention
/
Composite Resins
Language:
English
Journal:
Braz. j. oral sci
Journal subject:
Dentistry
Year:
2020
Type:
Article
Affiliation country:
Brazil
/
Italy
Institution/Affiliation country:
Faculty of Odontology/BR
/
Franciscan University/BR
/
University of Bologna/IT
/
University of Santa Maria/BR
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