“…The evaluation items included the following: the abutment morphology; the height of the abutment teeth and clearance to the occlusal tooth surface of antagonist before www.nature.com/scientificreports/ setting crown (for the space of occlusal thickness of PEEK crown); the condition of PEEK crown in the oral cavity at the time of cementation; occlusal contact, margin conformation, and adjacent surface contact condition; occlusal contact condition and the condition of PEEK crown in the oral cavity after six months; cracking, fracture, dehiscence, occlusal contact, pain, secondary caries, occlusal surface condition, surface texture, discoloration and staining, plaque adhesion, marginal gingiva, occlusal surface condition of the dental antagonist indicating changes in the condition of the surface of dental antagonist due to wear or occlusal wear, adjacent surface contact condition and crown condition for the need for retreatment, and patient satisfaction. In addition, masticatory ability [29][30][31][32] , occlusal force, and occlusal pressure were measured 33 as oral functions.…”