Microtensile bond strength of a resin cement to a novel fluorcanasite glass-ceramic following different surface treatments.
OBJECTIVE
This study evaluated the effect of surface treatments on the bond strength of fluorcanasite and lithium disilicate glass-ceramics, with the possibility of eliminating HF etching of these ceramics.


METHODS
Fifteen blocks of an experimental fluorcanasite and a lithium disilicate glass-ceramic (IPS e.max CAD) were assigned to one of the following three surface treatments: (1) machined with 60 microm finish, (2) machined and grit blasted, (3) machined and HF etched. The ceramic blocks were duplicated in composite resin (Spectrum) and cemented together with a resin luting agent (Variolink II). Thirty microbars per group (1.0 x 1.0 x 20 mm) were obtained and subjected to a tensile force at a crosshead speed of 0.5 mm/min using a universal testing machine until failure. The mode of failure was determined using scanning electron microscopy. The appropriate bonding procedure was assessed for durability by storing in water at 100 degrees C for 24 h. Statistical analyses were performed with ANOVA and Tukey's test (P<0.05).


RESULTS
Machining alone significantly increased the bond strength (MPa) of the fluorcanasite (27.79+/-6.94) compared to the lithium disilicate (13.57+/-4.52) (P<0.05). HF etching resulted in the lowest bond strength (8.79+/-2.06) for the fluorcanasite but the highest for the lithium disilicate (24.76+/-9.38). Regarding durability, the machined fluorcanasite (15.24+/-5.46) demonstrated significantly higher bond strength than the machined and HF etched lithium disilicate (12.28+/-3.30).


CONCLUSIONS
The fitting surface of the fluorcanasite glass-ceramic should retain the machined finish and be directly treated with silane. The use of HF acid is contraindicated.
Pollington
Sarah
S
Department of Adult Dental Care, University of Sheffield, United Kingdom. s.pollington@sheffield.ac.uk
Fabianelli
Andrea
A
van Noort
Richard
R
D000134:Acid Etching, Dental / Q000379:methods; D020906:Air Abrasion, Dental; D000704:Analysis of Variance; D001840:Dental Bonding; D003775:Dental Polishing; D003776:Dental Porcelain / Q000737:chemistry; D003799:Dental Stress Analysis; D005898:Glass; D006858:Hydrofluoric Acid; D018020:Lithium Compounds; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D019279:Resin Cements; D012821:Silanes; D017640:Silicates / Q000737:chemistry; D018709:Statistics, Nonparametric; D013499:Surface Properties; D013718:Tensile Strength
D018020:Lithium Compounds; D019279:Resin Cements; D012821:Silanes; D017640:Silicates; C481899:fluorcanasite; D003776:Dental Porcelain; C103502:Variolink; D006858:Hydrofluoric Acid