biostudies-literatureUnknown12Direk A<h4>Background</h4>The aim of this study was to compare the fracture strength and fracture modes of post-cores produced with CAD-CAM from modified polyetheretherketone (PEEK) materials with other custom-produced post-cores.<h4>Methods</h4>Sixty human mandibular first premolars with equal root sizes were used. The teeth were divided into six groups (<i>n</i> = 10), and root canal treatment was performed. The teeth were separated from the roots over 2 mm from the cemento-enamel junction. As a result of the decoronation process, a 1 mm wide shoulder line was obtained for all teeth. For the fracture strength test, 10 mm deep post spaces were created on the teeth with a 1.6 mm diameter driller. Post-core groups consisted: everStick^® glass fiber post-core (Group GF), zirconia post-corPeerJe18012https://www.ebi.ac.uk/biostudies/studies/S-EPMC11380836biostudies-literatureFracture strength of cad-cam milled polyetheretherketone (PEEK) post-cores <i>vs</i> conventional post-cores; an <i>in vitro</i> study.PMC11380836Tekin SKhurshid ZDirek AfalseFracture strength of cad-cam milled polyetheretherketone (PEEK) post-cores <i>vs</i> conventional post-cores; an <i>in vitro</i> study.<h4>Background</h4>The aim of this study was to compare the fracture strength and fracture modes of post-cores produced with CAD-CAM from modified polyetheretherketone (PEEK) materials with other custom-produced post-cores.<h4>Methods</h4>Sixty human mandibular first premolars with equal root sizes were used. The teeth were divided into six groups (<i>n</i> = 10), and root canal treatment was performed. The teeth were separated from the roots over 2 mm from the cemento-enamel junction. As a result of the decoronation process, a 1 mm wide shoulder line was obtained for all teeth. For the fracture strength test, 10 mm deep post spaces were created on the teeth with a 1.6 mm diameter driller. Post-core groups consisted: everStick^® glass fiber post-core (Group GF), zirconia post-cor2024-01-01T00:00:00Z20242025-04-05T14:38:49.971Z2025-04-05T14:38:49.971ZS-EPMC113808363924754110.7717/peerj.18012