Bond strength of resin cements to leucitereinforced ceramics

Resumo

The aim of this study was to evaluate the shear bond
strength (SBS) of two resin cements to four leucite-reinforced
ceramics. Material and methods: Forty ceramic blocks (4 mm wide,
14 mm length and 2 mm thick) were used and the samples abraded
with aluminum oxide (90 µm). The samples were divided into eight
groups (n = 5). Two resin cements (conventional RelyX ARC and
self-adhesive RelyX U100 – 3M ESPE) were bonded to Creapress
(CRE-Creation/Klema), Finesse All-Ceramic (FIN-Dentsply/ Ceramco),
IPS Empress Esthetic (IEE-Ivoclar Vivadent) and Vita PM9 (PM9-
Vita). For all groups and in each ceramic block, after application
of 10% hydrofluoric acid and silanation, three Tygon tubings were
positioned over the ceramics, which were filled in with the resin
cements (light-cure for 40 s). The tubings were removed to expose
the specimens in format of cylinders (area: 0.38 mm2) and samples
were stored in relative humidity at 24±2 °C for one week. After
this period, each sample was attached to testing machine and the
specimens were submitted to shear bond test (applied at the base
of the specimen/cement cylinder with a thin wire/0.2 mm) at speed
of 0.5 mm/ min, until failure. The results were analyzed by two-way ANOVA (resin cements and ceramic systems) and Tukey test (p<0.05).
Results: The means (SD) were (in MPa): ARC + CRE = 32.1±4.3;
ARC + FIN = 28.3±3.7; ARC + IEE = 25.9±4.4; ARC + PM9 =
22.2±2.1; U100 + CRE = 38.0±5.2; U100 + FIN = 36.9±2.8; U100
+ IEE = 38.4±2.9; U100 + PM9 = 34.3 ±7.3. U100 showed higher
SBS to ceramics than ARC. U100 had higher SBS when applied
on IEE ceramic than on PM9. For ARC, SBS obtained with CRE
was higher than with IEE and PM9. Conclusion: RelyX U100 can
provide higher SBS to leucite-reinforced ceramics than conventional
resin cement. The resin cements applied on the PM9 ceramic surface
resulted in lower SBS.