Accuracy of polyvinyl siloxane ether and other impression materials in full-arch implant rehabilitation with varying angulations: A comparative <i>in vitro</i> study

This study evaluated the accuracy of digital and conventional impressions using different materials in fully edentulous jaws with implants at varying angulations. Two master models were fabricated: one with four parallel and another with four implants placed according to the all-on-4 protocol. Impressions were obtained using three materials-polyvinyl siloxane (PVS), polyether (PE), and polyvinyl siloxane ether (PVSE)-and a digital scanner (TRIOS 4). Conventional impressions were cast, scanned with an extraoral scanner, and compared with the reference models via Geomagic Control X software. In the parallel model, digital impressions exhibited significantly greater deviation values than PE (p=0.016). In the angulated model, PE demonstrated significantly lower deviation values compared to PVSE (p=0.007) and digital impressions (p=0.016). Deviation values increased with implant angulation in all groups, except PVSE, which showed no statistically significant difference. Polyether provided the highest accuracy. Implant angulation adversely affected accuracy across most impression methods.