IADR Abstract Archives
Mechanical Properties of Thermo-pressed Polyetheretherketone as a Denture Material
Objectives: Since the injection moulding technique was adopted to fabricate thermoplastic products, the injection moulding condition might influence the processing parameters. Polyetheretherketone (PEEK) has been highlighted as having the potential for dental application despite the wide choice of polymer materials that are already broadly acceptable. However, no systematic studies have reported PEEK mechanical properties as a denture material. Therefore, the present study will investigate the mechanical properties of thermo-pressed PEEK using injection moulding technique. Assess the impact strength, tensile strength, and flexural properties (4-point bend test) of PEEK after processing at two different mould temperatures compared to PMMA.
Methods: Samples (n=10) were prepared for Izod test according to (ASTM-D-256/ISO-180), tensile test (ISO 527), and 4-point bend test (ISO 1567). They were produced using thermopress 400 unit (Bredent, Germany). PEEK-Optima®NI1 (Invibio Ltd.) of 143˚C (Tg) and 380˚C (Tm) was injected at 175 and 200(±3)˚C mould temperatures, while Polymethylmethacrylate (PMMA/control) of 280˚C (Tm) processed at 40(±3)˚C mould temperature (Bre.Crystal-HP,Bredent). Impact specimens were notched with V-shape notch-cutting depth 2(±0.1)mm, base-radius 0.25(±0.05)mm, and testing was carried out using impact tester machine (Tinius Olsen, IT-503). A Lloyd testing machine (2000, England) was used for both tensile and 4-point bend tests. Tensile specimens tested at 50mm grip-to-grip distance and crosshead speed of 30mm/min. Whilst 4-point specimens tested at a crosshead speed of 5(±1)mm/min with 50(±0.1)mm distance between the supports centres. The force of the loading plungers for bend test was increased uniformly from 5N up to 100N. All study specimens were stored in water before the tests [37˚C, 50(±2)h] and then statistically analyzed (ANOVA, P<0.05).
Results: There was statistical significant difference between the mechanical properties of injected PEEK compared to PMMA (P<0.05), as shown in table (1).
Conclusions: PEEK processed at 175 and 200˚C mould temperatures showed the most promising mechanical properties as a denture material compared to conventional PMMA.
Methods: Samples (n=10) were prepared for Izod test according to (ASTM-D-256/ISO-180), tensile test (ISO 527), and 4-point bend test (ISO 1567). They were produced using thermopress 400 unit (Bredent, Germany). PEEK-Optima®NI1 (Invibio Ltd.) of 143˚C (Tg) and 380˚C (Tm) was injected at 175 and 200(±3)˚C mould temperatures, while Polymethylmethacrylate (PMMA/control) of 280˚C (Tm) processed at 40(±3)˚C mould temperature (Bre.Crystal-HP,Bredent). Impact specimens were notched with V-shape notch-cutting depth 2(±0.1)mm, base-radius 0.25(±0.05)mm, and testing was carried out using impact tester machine (Tinius Olsen, IT-503). A Lloyd testing machine (2000, England) was used for both tensile and 4-point bend tests. Tensile specimens tested at 50mm grip-to-grip distance and crosshead speed of 30mm/min. Whilst 4-point specimens tested at a crosshead speed of 5(±1)mm/min with 50(±0.1)mm distance between the supports centres. The force of the loading plungers for bend test was increased uniformly from 5N up to 100N. All study specimens were stored in water before the tests [37˚C, 50(±2)h] and then statistically analyzed (ANOVA, P<0.05).
Results: There was statistical significant difference between the mechanical properties of injected PEEK compared to PMMA (P<0.05), as shown in table (1).
Conclusions: PEEK processed at 175 and 200˚C mould temperatures showed the most promising mechanical properties as a denture material compared to conventional PMMA.