Shear Bond Strength of Self Adhesive Cements

Self adhesive cements are becoming popular due to the reduced number of steps required for cementation.  New self adhesive cements continue to develop and improve but further testing is required.

OBJECTIVE: To measure shear bond strength to zirconia disks of seven commercially available and a new adhesive cements.

METHODS: The surface of  80 Cercon discs (d=10mm, thickness=4mm) was wet ground with 320-grit SiC abrasive paper (Wehmer 108, IL, USA ) for 1min, followed by air-abrasion with 25mm AL₂0₃ (Kavo American Corp., IL, USA). They were randomly assigned to eight groups, 10 each. Light cured composite rods (Z100/A2, 3M ESPE, MN, USA), ( d ~ 2.35mm) were prepared and were abraded with 25mm AL₂0₃ for 2s, followed by applying adhesive bonding agent (Clearfil SE, Kuraray USA, Inc., NY, USA) and light curing for 20s. Rods were cemented to Zirconia using self adhesive cements (G-Cem/GC [G], RelyX Unicem Aplicap/3M ESPE [UA], RelyX Unicem Clicker/3M ESPE [UC], BisCem/BISCO [B],  Multilink Sprint/Ivoclar-Vivadent [MS], MaxCem/Kerr [M], Experimental Cement/Kuraray [K], Panavia F2.0/Kuraray [P]) following manufacturer's instruction with constant weight of 400g and cured for 20s (Coltolux Coltene/Whaledent, OH, USA, 750 Mw/cm²). Samples were incubated at 37C for 24h, thermocycled between 6 and 60⁰C with a 15s dwell time for 1000cycles and debonded using a universal testing machine (Instron 5565, MA, USA) with crosshead speed of 1mm/min. The results were analyzed with ANOVA followed by Tukey/Kramer (p=0.05). Samples were evaluated by SEM (ISI, SX-30, MA, USA).

 RESULTS: Mean± SD in MPa.

G	UA	UC	B	MS	M	K	P
11.4±1	14±4	12.4±4	8.3±2	8.6±2	5.8±1	14.8±5	10.5±2

Tukey/Kramer post hoc test showed no significant difference (p>0.05) between experimental cement (K) and G-Cem, Panavia F 2.0, Unicem cements. CONCLUSION: Self adhesive cements continue to develop but further improvement should be continued. This study was supported in part by Kuraray.