Properties of a Newly Developed Self-Adhesive Composite for Aligner Attachments

Objectives: Kuraray Noritake Dental Inc. has developed a new self-adhesive, flowable composite for aligner attachments (SA-100R). SA-100R includes the original MDP adhesive monomer (10-methacryloyloxydecyl dihydrogen phosphate) and a unique AMIDE monomer to enhance bond strength to enamel, allowing direct application without a bonding agent. This study compared the properties of SA-100R with three commercially available composite systems for aligner attachments: Composite A, Composite B and Composite C. A prototype composite excluding MDP and AMIDE monomers from the components of SA-100R (SA-100R NC) was prepared and compared as a negative control product.
Methods: Shear bond strength to bovine enamel was evaluated based on ISO 29022 standards. For SA-100R and SA-100R NC, a phosphoric acid etching agent was applied to the enamel surface. A cylindrical mold was placed on the etched surface, then a composite was filled and light-cured. Other composites were applied after treatment with bonding agents according to the instructions from each manufacturer. Specimens were stored under three different conditions: 1) 37°C water for 10 min (10 min); 2) 37°C water for 24 h (24 h); or 3) 37°C water for 24 h followed by thermocycling (4–60°C, 1 min each, 20,000 cycles: TC20000). Shear bond strength was then measured (n=5/group).
Results: The results are summarized in Table 1. Data were analyzed statistically by one-way ANOVA and Tukey’s tests (p<0.05).
Conclusions: SA-100R demonstrated comparable or higher bond strength to bovine enamel under all conditions compared to other composite systems for aligner attachments without a bonding agent. SA-100R NC showed significantly lower bond strength than SA-100R, indicating that MDP and AMIDE monomers contributed to the high bond strength. This study suggests that SA-100R can be expected to provide consistent clinical performance and reduce placement times for aligner attachments.