Effect of surface pretreatments on resin composite bonding to PEEK

Abstract

This study evaluated the effect of surface pretreatments on resin composite bonding to polyetheretherketone (PEEK). Four groups of surface pretreatment (no pretreatment, etched with 98% sulfuric acid, etched with piranha solution and sandblasting with 50 µm alumina) were performed on PEEK. Surface roughness, Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) analysis were examined. Shear bond strength (SBS) and interface characteristics were also evaluated after the specimens were bonded with resin materials. Two-way ANOVA analysis revealed significance on two main effects and interactions. Tukey's multiple comparisons test showed that the SBS of resin composite on PEEK were the highest in the group etched with 98% sulfuric acid and bonded with Heliobond ® (p<0.05). All pretreatments produced similar spectra of FTIR patterns. SEM demonstrated porosities and pitting from chemical etching, which suggested a significant influence on the adhesion between PEEK and resin materials.

Effects of different sulfuric acid etching concentrations on PEEK surface bonding to resin composite

“…In addition, the 80, 85 and 90% sulfuric acid etching in this study also improved the SBS of etched PEEK to resin composite. The 80% sulfuric acid groups showed significantly increase SBS values which were similar to that of piranha etching in a previous study 19) . While the 70% sulfuric acid etching did not improve SBS.…”

“…The application of 98% sulfuric acid etching for 60 s in this study showed almost the same SBS as the previous study 19) which employed the same protocol. This SBS exceeded other surface pretreatment such as the piranha solution 11,19) and sandblasting [18][19][20] . In addition, the 80, 85 and 90% sulfuric acid etching in this study also improved the SBS of etched PEEK to resin composite.…”

“…Previous studies revealed that sulfuric acid created sulfonate (−SO 3) groups in the polymer chains of PEEK [22][23][24][25] which chemically cross-linked to methylmethacrylate (MMA) dental adhesives 13,21) . Another study did not found chemical functional groups on PEEK after etching with 98% sulfuric acid for 60 s, but confirmed micromechanical bonding due to penetration of resin tags into pit and porous surface of PEEK 19) . The use of 98% sulfuric acid has been questioned to be used under clinical condition due to its strong oxidizing property.…”

“…It has been reported that sulfuric acid etching when used with resin cements exhibited greater shear bond strength (SBS) than hydrofluoric acid 16) , argon plasma 16) , air abrasion (50-110 µm) and silica coating 16,[18][19][20] . Most studies recommended the use of 98% sulfuric acid to modify chemical and physical surface of PEEK to improve bonding [16][17][18][19][20] . Previous studies revealed that sulfuric acid created sulfonate (−SO 3) groups in the polymer chains of PEEK [22][23][24][25] which chemically cross-linked to methylmethacrylate (MMA) dental adhesives 13,21) .…”

“…Surface pretreatments of PEEK prior to adhesive bonding have been investigated and demonstrated the improvement of bond strength between PEEK and resin composites [13][14][15][16][17][18][19][20][21] . It has been reported that sulfuric acid etching when used with resin cements exhibited greater shear bond strength (SBS) than hydrofluoric acid 16) , argon plasma 16) , air abrasion (50-110 µm) and silica coating 16,[18][19][20] . Most studies recommended the use of 98% sulfuric acid to modify chemical and physical surface of PEEK to improve bonding [16][17][18][19][20] .…”