The Effect of Surface Treatments on the Shear Bond Strength of Polymer-Based Material for Pediatric Crown Alternatives

Polyetheretherketone (PEEK) crowns offer a provisional option for esthetic restorations in pediatric patients. PEEK has mechanical properties similar to dentin but exhibits low bond strength with luting cements. This study aimed to evaluate the effect of different surface treatments on the bond strength between PEEK and four luting cements by measuring shear bond strength (SBS). Sixty specimens were divided into three surface treatment groups: control, sandblast, and 98% sulfuric acid, and further divided into four cement subgroups: methyl methacrylate (MMA)-based resin cement, composite-based resin cement, resin-modified glass ionomer cement (RMGI), and glass ionomer cement (GI). Failure modes and treated surfaces were examined using scanning electron microscopy (SEM), and wettability was assessed through water contact angle. Both surface treatment methods showed significantly higher SBS than the control. The combination of sulfuric acid treatment with MMA-based resin cement demonstrated the highest bond strength (11.25 ± 1.86 MPa), while the second highest value was observed with sandblasting combined with MMA-based resin cement. These values were significantly higher than other groups and exceeded the clinically acceptable SBS threshold of 10 MPa. SEM analysis revealed that sandblasting created irregular fissures with large grooves and cracks for improved micro-retention, while sulfuric acid treatment produced a complex fiber network with sponge-like porosities. Within the limits of this in vitro study, MMA- and composite-based resin cement application with sandblast or sulfuric acid surface treatment proved effective bonding methods.