Comparative stress analysis of BioHPP and PEKK CAD/CAM frameworks in mandibular All-on-Four fixed-detachable prosthesis on its supporting implants

Purpose: Aim of this simulation study to evaluate stresses induced on supporting implants by different framework materials BioHPP and PEKK in mandibular implant supported fixed-detachable prosthesis following all-on-4 concept using strain gauge analysis.
Material and methods: For this study, 3D printed model simulating completely edentulous mandibular arch with 4implants placed in all-on-4 configuration to support fixed-detachable prosthesis were constructed. According to framework material of screw-retained fixed-detachable prosthesis: Model I: framework made from Bio-High Performance Polyether (BioHPP) while Model II: framework made from Poly-ether-ketone-ketone (PEKK). Strain gauges were installed at mesial of central implants and distal to distal implants. Bilateral and unilateral load was applied starting from 0-60 N. Microstrains were recorded at each strain gauge with enough time elapsed between tests. The process was repeated 5times for each group, average strains were recorded and statistically analyzed.
Results: Individually results for both models showed unilateral loading induced more stresses compared to bilateral loading. Statistical significant higher microstrains were induced at distal of distal implants than mesial of central ones in both unilateral and bilateral loading. Comparing the two models although less stresses were detected in model II (PEKK framework) compared to model I (BioHPP framework) statistical analysis of data revealed significant difference at distal aspect of distal implants in both unilateral and bilateral loading.
Conclusion: Within limitation of this simulation study, using polyether-ketone-ketone (PEKK) for constructing the framework of prosthesis lead to favorable stress distribution and reduces stresses induced to supporting implants. Further clinical studies are required to confirm this finding.