Effect of self-etching ceramic primer on the bond strength of feldspathic porcelain repair

The purpose of this study was to evaluate the effect of a self-etching primer on the bond strength of feldspathic porcelain with composite resin. Forty-eight feldspathic porcelain specimens (13 mm × 13 mm × 2 mm) were sectioned from CAD/CAM blocks. Specimens were randomly divided into 4 groups (n = 12) as regards to surface treatment method; HF acid etching (HFE), Monobond Etch and Prime (MEP), sandblasting (SB), and MEP + SB. After silane application for group HFE and SB, an adhesive bond was used as a bonding agent in all groups. Composite resin cylinders were build up onto the specimens. Specimens were stored in distilled water, thermocycled 5–55 °C for 5500 cycles, and subjected to shear bond strength (SBS) test in a universal testing machine. Data were statistically analyzed by Kruskal-Wallis and Mann Whitney U test (α=.05). Type of failures was evaluated under optical microscopy and surfaces were examined by SEM at ×500 and ×2500 magnifications. There was a significant difference among groups. (p = .019) HF group had the highest mean SBS value (17.54 ± 2.98 MPa) which was significantly higher than other groups (p<.05). Followed by the MEP + SB group (14.68 ± 3.41 MPa), SB group (13.98 ± 3.34 MPa) and MEP group (12.75 ± 2.33 MPa). Nevertheless, the HFE group significantly has higher SBS value than other groups all of the tested surface treatment methods have reached the convenient bond strength values for repair. Although MEP showed clinically acceptable SBS values, further researches with another type of porcelains should be tested.