Effects of surface treatments and cement types on the bond strength of porcelain-to-porcelain repair.
Abstract: Purpose: The purpose of this in vitro study was to evaluate the effects of four surface treatments and two resin cements on the repair bond strength of a ceramic primer. Material and methods: Eighty-eight pairs of disks (10 and 5mm in diameter, 3mm thickness) were prepared from heat-pressed feldspar ceramics (GC Initial IQ). After being stored in mucin-artificial saliva for two weeks, ... read morethe 10-mm disks were divided into 4 surface treatment groups (n=22) and then treated as follows: (1) no treatment (control); (2) 40% phosphoric acid; (3) 5% hydrofluoric acid + acid neutralizer + 40% phosphoric acid; (4) silica coating + 40% phosphoric acid. The 5-mm disks were treated with 5% hydrofluoric acid + 40% phosphoric acid. The two sizes of porcelain disks, excluding the control group, were primed with Clearfil Ceramic Primer. The specimens in each group were further divided into 2 subgroups of 10 each, and bonded with Clearfil Esthetic Cement (CEC) or Panavia F 2.0 Cement (PFC). The specimens were stored in distilled water at 37°C for 24 hours, theromcycled for 3000 cycles at 5- 55°C, and stored at 37°C for an additional 7 days. Shear bond strength (SBS) was measured with a universal Instron machine at crosshead speed of 0.5 mm/min until fracture. Statistical analysis of the results was carried out with a two-way ANOVA and Tukey HSD test (á =.05). Debonded specimen surfaces were examined under an optical microscope to determine the mode of failure. Results: The statistical analysis showed that the SBS was significantly affected by surface treatment (P<.001) and resin cement (P=.002). For treatment groups bonded with CEC, the SBS (MPa) values were (1) 2.64 ±1.1, (2) 13.31 ± 3.6, (3) 18.88 ± 2.6, (4) 14.27 ± 2.7, while treatment groups cemented with PFC, the SBS (MPa) values were (1) 3.04 ± 1.1, (2) 16.44 ± 3.3, (3) 20.52 ± 2.2, (4) 16.24 ± 2.9. All control specimens exhibited adhesive failures, while mixed types of failures were observed in phosphoric acid-treated group. The other groups revealed cohesive and mixed failures. Conclusions: The results of this study showed that etching with hydrofluoric acid, followed with phosphoric acid in conjunction with Panavia F 2.0 cement, provided superior repair bond strength.
Thesis (M.S.)--Tufts University, 2011.
Submitted to the Dept. of Other.
Advisor: Gerard Kugel.
Committee: Hiroshi Hirayama, Roya Zandparsa, Ronald Perry, and Matthew Finkelman.
Keyword: Dentistry.read less