title: In-vitro performance of CAD/CAM-fabricated implant-supported temporary crowns.
abstract: OBJECTIVE
  The aim of this study was to investigate the in-vitro performance and fracture resistance of a temporary computer-aided designed and computer-aided manufactured polymethylmethacrylate (CAD/CAM-PMMA) material as implant or tooth-supported single crown with respect to the clinical procedure (permanently bonded/temporarily cemented).
  
  
  METHODS
  Sixty-four crowns were fabricated on implants or human molar teeth simulating (a) labside procedure on prefabricated titanium-bonding base ([TiBase] implant crown bonded in laboratory, screwed chairside), (b) labside procedure ([LAB] standard abutment and implant crown bonded in laboratory, screwed chairside), (c) chairside procedure ([CHAIR] implant crown bonded to abutment), and (d) reference ([TOOTH] crowns luted on prepared human teeth). Crowns were made of a CAD/CAM-PMMA temporary material (TelioCAD, Ivoclar-Vivadent). For investigating the influence of fixation, half of the crowns were permanently (P) or temporarily (T) bonded. Combined thermal cycling and mechanical loading (TCML) was performed simulating a 5-year clinical situation. Fracture force was determined. Data were statistically analyzed (Kolmogorov-Smirnov test, one-way ANOVA; post hoc Bonferroni, α = 0.05).
  
  
  RESULTS
  All restorations survived TCML without visible failures. Fracture results varied between 3034.3 (Tooth-P) and 1602.9 N (Tooth-T) [TOOTH], 1510.5 (TiBase-P) and 963.6 N (TiBase-T) [TiBase], 2691.1 (LAB-P) and 2064.5 N (LAB-T) [LAB], and 1609.4 (Chair-P) and 1253.0 N (Chair-T) [CHAIR]. Tested groups showed significantly (p < 0.001) different fracture values. Failure pattern was characterized by fractures in mesial-distal, buccal-oral, or mixed (mesial-distal/buccal-oral) directions, with differences for the individual groups.
  
  
  CONCLUSIONS
  Temporary CAD/CAM crowns showed no different in-vitro performance but provided different fracture results that depended on cementation, screw channel, and type of abutment.
  
  
  CONCLUSIONS
  All bonded and screwed PMMA crowns were in a range where clinical application seems not restricted.
authors.affiliation: Department of Prosthetic Dentistry, University Medical Center Regensburg, 93042, Regensburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Rosentritt
authors.affiliation: Department of Prosthetic Dentistry, University Medical Center Regensburg, 93042, Regensburg, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Raab
authors.affiliation: Department of Prosthetic Dentistry, University Medical Center Regensburg, 93042, Regensburg, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hahnel
authors.affiliation: Department of Prosthetic Dentistry, University Medical Center Regensburg, 93042, Regensburg, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Stöckle
authors.affiliation: Department of Prosthetic Dentistry, University Medical Center Regensburg, 93042, Regensburg, Germany. verena.preis@ukr.de.
authors.forename: Verena
authors.initials: V
authors.lastname: Preis
mesh_terms: D002484:Cementation; D017076:Computer-Aided Design; D003442:Crowns; D059605:Dental Implant-Abutment Design; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003794:Dental Restoration, Temporary; D003799:Dental Stress Analysis; D006801:Humans; D066298:In Vitro Techniques; D008422:Materials Testing; D008963:Molar; D019904:Polymethyl Methacrylate
chemical_list: D019904:Polymethyl Methacrylate
keywords: Abutment; CAD/CAM composites; Fracture resistance; Implant crown; PMMA, temporary; Provisional, chewing simulation