Effects of degree of dissociation of acid used on hydrolytic durability of ceramic primer

Abstract

In this study, effects of the degree of dissociation of acids on the hydrolysis rate of methoxy group in γ-methacryloxypropyltrimethoxysilane (γ-MPS) and the adsorption characteristics of γ-MPS on ceramic surfaces were studied using acetic, phosphoric, and hydrochloric acids. Hydrolytic stability of γ-MPS adsorption layer at the resin-ceramic interface was thus examined.29 Si NMR observations of acidactivated γ-MPS and contact angle measurements following ceramic surface silanization were performed. Bond strengths of resin to the silanized ceramic surfaces were measured. Statistical analyses of shear bond strength and contact angle data were performed. Increase in the degree of dissociation of the acid used increased the hydrolysis rate of methoxy group in γ-MPS, but lowered the contact angle to the silanized ceramic surface. Decrease in the contact angle increased the hydrolytic stability of γ-MPS adsorption layer.

Effect of the type of acidic monomer on the bond durability of two-bottle type ceramic primer

“…The present finding that degradation behavior differed between the 4-MET-activated and AA-activated ceramic primers is not consistent with the results of a previous study (8), although 4-MET has the same ability as AA to hydrolyze the methoxy group (Fig. 3).…”

“…2), because chemisorption of γ-MPS on the ceramic surface was limited by production of molecular species of hydrolyzed γ-MPS, namely, R-Si-(OCH 3 ) 2 (OH), R-Si-(OCH 3 ) (OH) 2 , and R-Si-(OH) 3 (9,13,15). The present finding that the contact angles for MDP-and PA-activated ceramic primers were greater than those for 4-MET-and AA-activated ceramic primers was probably due to the fact that MDP and PA yield more protonated protons as compared with 4-MET and AA, as the hydrolysis rate of the methoxy group in γ-MPS is strongly affected by the proton concentration of the activator solution (8,13).…”

“…The author and colleagues previously reported that the ceramic bond durability of the resin through the γ-MPS multilayer strongly depended on the type of acid used as an activator and increased as the degree of acid dissociation increased for acetic, phosphoric, and hydrochloric acids (8). The hydrolysis rate of the three methoxy groups in γ-MPS strongly depends on the proton concentration in the activator solution and the production of completely hydrolyzed γ-MPS species.…”

“…In accordance with previous studies (5,8), two-bottle experimental ceramic primers comprising silane solution and activator solution were prepared by using γ-MPS, 4-MET (purity 97%), MDP (purity 97%), AA, and PA. The components and compositions of the silane solution and activator solutions are summarized in Table 2.…”

“…As described previously (5,7,8), the fracture mode for each specimen was classified into three categories (Table 3).…”