Abstract
Aim: To investigate how different surface treatments affected surface roughness, wettabilty and bonding of polyetherketoneketone (PEKK) to various veneering materials.
Material and Methods:
Three pretreatment groups of 120 disc-shaped PEKK specimens (10 x 4 mm) were assembled. Group (control) A: No treatment, Group B: Air abrasion, and Group C: Sulfuric acid etching. Then specimens were further divided into three subgroups according to type of veneering materials. Subgroup I: PEKK veneered with hybrid ceramics (Vita Enamic), subgroup II: PEKK veneered with lithium disilicate (IPS E.max CAD), and subgroup III: PEKK veneered with zirconia (Prettau anterior). A 3D non-contact optical profilometer was used to measure surface roughness (Ra), and SEM was used to analyze surface morphology. For contact angle measurements, wettability was assessed using static sessile drop method. Additionally, two classes before and after thermocycling were developed for each subgroup. Using a universal testing system, shear bond strength (SBS) was measured immediately and after thermocycling, and a stereomicroscope was used to investigate the failure modes.
Results: Surface roughness was dramatically increased (P<0.001) by air abrasion. According to the wettability results, sulfuric acid produced better contact angles than air abrasion. Regardless the veneering material, sulfuric acid etched group had the highest shear bond strength. Regardless surface treatment, Prettau zirconia had the highest shear bond strength values, followed by Vita Enamic and IPS E.max CAD with significance. All examined groups showed a significant decrease in SBS following thermocycling.
Conclusions: Durable bond can be achieved with PEKK etched for one minute with sulfuric acid.