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Published on: September 19, 2020
Effect of surface silica content on primer‑dependent resin bonding to nanoceramic‑filled polyetheretherketone
Szu-Yu Lai1, Chenxuan Wei2, Chian-Yu Chen3
1School of Dentistry, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan; Research Center of Digital Oral Science and Technology, College of Oral Medicine, Taipei Medical University, Taipei, Taiwan.
Objectives:
This study aimed to elucidate how silica layers on nanoceramic‑filled polyetheretherketone (CF-PEEK), derived from silica‑coated alumina airborne‑particle abrasion (SC‑APA) treatment, combined with clinically relevant cleaning and primer chemistries, influence the CF-PEEK-resin bonding performance and durability, thereby refining evidence‑based bonding strategies.
Methods:
CF-PEEK specimens were treated using SC‑APA and subjected to various cleaning protocols. Their surface morphology, wettability, and roughness were characterized using field‑emission scanning electron microscopy, contact angle measurement, and profilometry. The crystal structure, functional groups, and chemical states were analyzed using X‑ray diffraction, attenuated total reflectance Fourier‑transform infrared spectroscopy, and X‑ray photoelectron spectroscopy. Shear bond strength (SBS) was measured for an untreated control and four primer treatment groups using a single veneering composite, with and without thermocycling, and interfacial failure modes were examined microscopically (α = 0.05).
Results:
SC‑APA reduced the contact angle of CF- PEEK to 15.05° and increased its surface energy to ∼75.67 mN/m, forming a microretentive, silica‑rich surface (22.37 wt% Si) with an amorphous siloxane layer. Cleaning procedures significantly modified this surface; some protocols increased the contact angle (∼72°-74°), decreased surface energy, and reduced silica coverage (7.24-11.21 wt%), whereas in the uncleaned state, optimal reactivity was preserved. When used for bonding, SC‑APA combined with a methyl methacrylate/urethane dimethacrylate (MMA/UDMA) primer produced the highest SBS (16.12 MPa) and retained 14.49 MPa after aging, whereas other groups showed > 40% reduction and markedly lower strength.
Significance:
SC‑APA converts CF-PEEK into a silica‑rich, chemically activated substrate with reactive siloxane sites. Immediate bonding with an MMA/UDMA primer provides superior strength and durability, supporting SC‑APA as a reliable surface‑conditioning strategy for CF-PEEK in dental applications.