Development of a new single-bottle multi-purpose primer for bonding to dental porcelain, alumina, zirconia, and dental gold alloy

This study investigated the bonding efficacy of a combined primer application which comprised a silane coupling agent, an acidic adhesive monomer, and a dithiooctanoate monomer, as well as the influence of shelf life on bonding. Five experimental primers (coded as Si-P-SS-1 to Si-P-SS-4, and Si-SS as the control) were prepared using 20.0–40.0 wt% 3-methacryloyloxypropyltriethoxysilane (3-MPTES), 0–7.44 wt% 6-methacryloyloxyhexyl phosphonoacetate (6-MHPA), and 0.50 wt% 10-methacryloyloxydecyl 6,8-dithiooctanoate (10-MDDT). After 24-hour storage at 23°C (Initial) and 2-month storage at 50°C (Aged), tensile bond strengths (TBSs) of a resin cement (ResiCem, Shofu Inc., Kyoto, Japan) to primer-treated porcelain, alumina, zirconia, and Au alloy were measured. With the Initial and Aged primers of Si-P-SS-1 to Si-P-SS-3, there were no statistically significant differences in the mean TBSs (MPa) [porcelain: 21.7–29.2; alumina: 21.4–25.3; zirconia: 20.3–24.5; and Au alloy: 23.4–27.6] among these three primers (p>0.05), but they were significantly higher than that of the control primer (p