Purpose: To investigate the physical and mechanical behavior of polyether ether ketone (PEEK) before and after thermocycling and its potential use as a more durable prosthetic component for implant-supported and -retained removable dental prostheses (I-RDP).
Materials and methods: Roughness and surface hardness were evaluated in specimens obtained using the subtractive method (n = 20) with Ø 9 mm and 2 mm of thickness, and retention force was measured in attachments with Ø 4 mm and 3 mm of height. For fatigue resistance test, a polyurethane matrix with two ball-abutment implants (MDL, Intra-Lock International) was used to simulate the mandibular alveolar ridge. A total of 40 attachments (n = 20 pairs) were captured in acrylic resin blocks using a technique analagous to the direct clinical pick-up of overdenture female attachments and submitted to 2,900 insertion/removal cycles to simulate 24 months of overdenture use. Physical analyses were performed by Fourier transform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and differential scanning calorimetry (DSC) before and after thermocycling (5° C to 55°C for 10,000 cycles). After normal distribution was verified by Shapiro-Wilk test, one-way analysis of variance (ANOVA) was applied to analyze the surface roughness and hardness, and two-way ANOVA with Bonferroni adjustment was used to assess the retention force (α = .05).
Results: Thermocycling did not change the PEEK surface roughness or hardness (P > .05). As for the retention force, the highest average was observed after the thermocycling test (P = .006).
Conclusion: Based on the FTIR, XRD, and DSC results, PEEK crystallinity decreased after thermocycling, and the physical and mechanical behavior of this polymer was compatible with the proposed application, attesting that it is a component of greater durability for I-RDPs.
