Method: An acidic phosphate monomer (MDP) or a resin monomer (BisGMA) was added into a silane primer (Porcelain Primer, Bisco), resulting in the MDP/silane or BisGMA/silane molar ratios of 0.5/1, 0.75/1, and 2/1, respectively. Silica-base lithium disilicate (IPS e.max, Ivoclar Vivadent) was etched with Porcelain Etchant (4%HF, Bisco) for 25 seconds, rinsed with deionized water and dried. The lithium disilicate samples were treated with one coat of Porcelain Primer (control) or modified Porcelain Primer, left undisturbed (5 minutes), cleaned by ethanol bath ultrasonication (2 min), and dried. The contact angle was measured on the ceramic surface with a water droplet using a contact angle meter (NRL-CA Goniometer, n=5). The data were analyzed statistically by one-way ANOVA and student-t tests (p<0.05).
Result: Mean water contact angle values (standard deviation). Means with different letters are statistically different (p<0.05).
Molar Ratio (Additive/Silane) |
MDP/ Silane |
BisGMA/Silane |
No Primer (negative control) |
6.6 (2.2)g |
|
0 /1 (pure silane primer) |
88.4 ( 2.1)a Bisco Porcelain Primer; 84.8 (13.6)ab 3M RelyX Ceramic Primer |
|
0.5 /1 |
14.0 ( 3.1)f |
65.0 (15.1)b |
0.75/1 |
17.6 ( 2.5)ef |
39.0 ( 8.4)c |
2 /1 |
26.6 ( 6.8)d |
8.6 ( 2.6)g |
Conclusion: The addition of resin (BisGMA or MDP) significantly inhibited the efficacy of the silane primer. A silane primer should not be mixed with any other resin monomers.