Source:Dental Materials
Author(s): Lisa Bodden, Nina Lümkemann, Valerie Köhler, Marlis Eichberger, Bogna Stawarczyk
ObjectiveThe aim of this study was to investigate the impact of a heating/quenching process on the optical, mechanical and thermodynamic properties of filled (20%_4000) and unfilled PEEK films (0%_2000 and 0%_4000). Heating/quenching was performed to simulate thermoforming as possible method to process thermoplastic polymers for dental application.MethodsFor the investigation, films of different PEEK qualities (0%_2000, 0%_4000, 20%_4000) were produced using isostatic pressing (n=10/quality). From each PEEK film, round specimens (n=20/PEEK film) with a diameter of 34mm were cut and following parameters were determined: translucency (T%), Martens-Hardness (HM), indentation modulus (EIT), glass transition temperature (TG), melting temperature (TM) and enthalpy of fusion (ΔHf). Same specimens were exposed to heating/quenching using defined parameters. Afterwards, T%, HM, EIT, TG, TM and ΔHf were determined again. Data were analysed using Kolmogorov–Smirnov test, univariate ANOVA followed by post-hoc Scheffé test with partial eta squared (ηp2), Kruskal–Wallis and Mann Whitney U test. Level of significance was defined to 95%.ResultsMaterials showed significant differences for all investigated parameters in the initial state, except of TG (p=0.249). The heating/quenching process showed a significant increase on T% for the unfilled materials 0%_2000 and 0%_4000. HM and EIT decreased significantly through heating/quenching for all materials. Moreover, heating/quenching showed a reduction of TG for 0%_2000 and 20%_4000, while TM decreased for 0%_2000 and 0%_4000. ΔHf confirms different crystallinities of tested materials.SignificanceThe heating/quenching process showed a significant impact on all investigated parameters. The highest impact was found for mechanical properties resulting in decreased values of HM and EIT.
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