The Effect of Additional Silane Pre-Treatment on the Microtensile Bond Strength of Resin-Based Composite Post-and-Core Build-Up Material

The aim of this study was to evaluate the effect of additional silane treatment on the immediate and aged microtensile bond strength (µTBS) between resin-based composite (RBC) post-and-core build-up material and an RBC CAD/CAM block. Twelve sample blocks (12 mm × 14 mm × 9 mm) were prepared using RBC post-and-core build-up material and were divided into six groups: Kerr Silane Primer (Sil) + OptiBond eXTRa Universal adhesive (EXA); OptiBond eXTRa Universal Primer (EXP) + EXA; Sil + OptiBond Universal (OBU); OBU; Sil + OptiBond Solo Plus (OSP); and OSP. Each treated sample was luted to a CAD/CAM block using an NX3 Nexus Third-Generation instrument. After storage in 37 °C water for 1 week, microspecimens were fabricated, and μTBS was tested immediately or after further immersion in water at 37 °C for 6 months. The failure mode of each specimen was determined using stereomicroscopy and scanning electron microscopy. For the immediate groups, no significant difference in µTBS was found between specimens with or without silane treatment for each adhesive (p > 0.05). For the aged groups, silane treatment significantly decreased µTBS for OptiBond eXTRa Universal (p < 0.05). Our findings indicate that additional silane treatment prior to the application of adhesive did not enhance µTBS.