Does 8-methacryloxyoctyl trimethoxy silane (8-MOTS) improve initial bond strength on lithium disilicate glass ceramic?

Objectives Dental ceramic surfaces are modified with silane coupling agents, such as γ-methacryloxypropyl trimethoxy silane (γ-MPTS), to improve bond strength. For bonding between lithium disilicate glass ceramic and resin cement, the objective was to investigate if 8-methacryloxyoctyl trimethoxy silane (8-MOTS) could yield a similar performance as the widely used γ-MPTS. Methods One hundred and ten lithium disilicate glass ceramic specimens were randomly divided into 11 groups (n = 10) according to pretreatment regime. All specimens were pretreated with a different solution composed of one or a combination of these agents: 10 or 20 wt% silane coupling agent of γ-MPTS or 8-MOTS, followed by a hydrolysis solution of acetic acid or 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP). Each pretreated surface was luted to a stainless steel rod of 3.6 mm diameter and 2.0 mm height with resin cement. Shear bond strength between ceramic and cement was measured after 24-h storage in 37 °C distilled water. Results 8-MOTS produced the same bonding performance as γ-MPTS. Both silane coupling agents significantly increased the bond strength of resin cement, depending on their concentration. When activated by 10-MDP hydrolysis solution, 20 wt% concentration produced the highest values (γ-MPTS: 24.9 ± 5.1 MPa; 8-MOTS: 24.6 ± 7.4 MPa). Hydrolysis with acetic acid produced lower bond strengths than with 10-MDP. Significance Silane coupling pretreatment with 8-MOTS increased the initial bond strength between lithium disilicate glass ceramic and resin cement, rendering the same bonding effect as the conventional γ-MPTS.