Effect of Surface-Treatments on Bond-Strengths of Maxcem to Ceramic Substrates

Recently, a dual-cure self-adhering resin cement Maxcem (MAX, Kerr) was introduced with much simplified cementation procedures to various dental substrates. Objective: to evaluate the effect of various surface treatments on shear bond strengths (SBS) of MAX to three porcelain substrates: Vita VMK-95 feldspathic porcelain (VMK, Vident), Vitablocs Mark II (Vitablocs, Vident), ProCAD Block (ProCAD, Vivadent); and a Zirconia-based ceramic substrate: LAVAä (LAVA, 3M ESPE). Methods: All substrates were first polished with 600 grit SiC paper, air-abraded with aluminum oxide and then subjected to one of the following surface treatments: (i) no further treatment (control); (ii) 9.5% HF (Gresco Products Inc.) etching; (3) 9.5% HF etching + Silane primer (Kerr). Bonding was conducted with a jig (Ultradent) having a cylindrical mold (D=2.38mm) into which MAX was condensed and allowed to self-cure. The bonded specimens (n=5 per group) were stored in de-ionized water (37°C) for 24 hours before being debonded on an Instron mechanical tester using shear force. Results: ANOVA analysis revealed that HF etching significantly (p<0.05) increased (doubled) the SBS's to all porcelain substrates (VMK, Vitablocs and ProCAD), but slightly decreased SBS to zirconia-based LAVA (not statistically different). Additional Silane application after HF etching significantly (p<0.05) increased the SBS to Vitablocs, had no significant (p=0.05) effect on SBS to VMK, and significantly decreased (p<0.05) the SBS to LAVA.

Additional Surface Treatments

Shear Bond Strength, MPa

VMK

Vitablocs

ProCAD

LAVA

No (control)

9.9±6.0^b*

11.6±2.1^c

10.6±2.1^b

19.3±2.7^a

HF

25.8±3.7^a

23.0±4.0^b

23.0±3.5^a

16.8±3.4^a

HF + Silane

25.3±4.1^a

30.9±5.0^a

27.5±2.4^a

7.3±2.0^b

*Means with the same letter within the same column are not statistically different at p=0.05.

Conclusions: HF etching was the most effective surface treatment for enhancing the adhesion to all porcelain substrates in this study (VMK, Vitablocs, and ProCAD). For LAVA, the best adhesion was achieved with just air-abrasion without additional surface treatment.