Effect of Aging and Thermocycling on Flexural Strength of PEEK as a Provisional Restoration for Full Mouth Rehabilitation – An in Vitro Study

Introduction: To compare the flexural strength of autopolymerizing poly methyl methacrylate resins (PMMA) resin, CAD/CAM milled PMMA and CAD/CAM milled poly ether ether ketone (PEEK) when used as provisional restorative materials for long span situations in full mouth rehabilitation after aging and thermocycling. Materials and Methods: Sixty samples (25 mm × 2 mm × 2 mm) were fabricated using autopolymerizing PMMA resin (GROUP I), CAD/CAM milled PMMA (GROUP II) and PEEK (GROUP III). The groups were subdivided into A and B and subjected to 7 days of aging and 500 cycles of thermocycling (subgroup A) and 14 days of aging and 1000 cycles of thermocycling (subgroup B), respectively, and flexural strength was evaluated using a three-point bend test. The data were analyzed with student t test and pair-wise comparison of mean values was done by ANOVA. Results: The flexural strength of PEEK subjected to 7 days of aging and 500 cycles of thermocycling (III (A) - 6628.70 MPa) was the highest among all groups followed by PEEK subjected to 14 days of aging and 1000 cycles of thermocycling (III (B) - 3760.50 MPa). Conclusion: The mean flexural strength of PEEK was statistically significant than the other two materials tested and hence can be recommended for use as a provisional restorative material for long span situations in full mouth rehabilitation. However, the mean flexural strength of PEEK reduced approximately by 44% when subjected to further aging.