Interfacial Bond Study of a Novel Light Cured Hard/Soft Nightguard

Objective: Demonstrate that the interfacial bond (IB) between light curable laminate of EclipseÒ clear hard resin (CHR) and Eclipse Resilient Resin (RR) is robust.

Methods: Laminate IB was assessed by evaluating the effect of thermocycling and hydration on the flexural properties and coffee stain on the bond line. RR/CHR laminates were cured in the Eclipse Processing Unit (EPU) by both the 1-step cure (10 min) and 2-step cure (RR 4 min + CHR 10 min). The control was an elastic acrylic resin (Impak, Vernon-Benshoff) / pour acrylic (GC Pour-N-Cureä ) processed per manufacturer's directions. Specimens were finished with 600grit SiC paper (2.85mm X 11mm X 85mm). Appliances were finished using normal denture polishing techniques. Coffee stain solution was 10g instant coffee/200mL water (37°C-88+ hrs). Statistical analysis was performed by ANOVA (a =0.05).

Results: 1) flexural properties of RR/CHR laminates are superior to Impak/GC pour acrylic, 2) flexural properties of the RR/CHR 1-step and 2-step cure were unaffected by thermocycling, 3) RR/CHR residual flexural properties after hydration were superior to the control, 4) no delamination occurred between RR/CHR layers as a result of hydration or thermocycling, and 5) RR/CHR IB is stain resistant.