title: Evaluation of the fit of CAD/CAM abutments.
abstract: OBJECTIVE
  This study aimed to compare the fit of computer-aided design/computerassisted manufacture (CAD/CAM) abutments provided by a single system with proprietary prefabricated abutments on various implant systems.
  
  
  METHODS
  Titanium CAD/CAM abutments were compared with prefabricated abutments on five different implant types. The samples were embedded in epoxy resin, sectioned longitudinally, and polished. Scanning electron microscopy was used to measure the gap between the implants and abutments at the connecting flanges and internal features. Independent t tests were used to compare data.
  
  
  RESULTS
  A mean difference of 1.86 μm between the gold synOcta and CAD/CAM abutments on the Straumann Standard Plus implant was observed to be statistically significant (P = .002). Less than 0.4 μm of difference was found between the CAD/CAM and prefabricated abutments for the remaining implant types, and statistical significance was not observed. Mean differences of 34.4 μm (gold) and 44.7 μm (titanium) were observed between the CAD/ CAM and prefabricated abutments on the Straumann Standard Plus implants, which were statistically significant (P < .001). A mean difference of 15 μm was also observed between the CAD/CAM and prefabricated abutment on the NobelReplace implant, which was statistically significant (P = .026). All other groups had less that 4 μm of difference, and statistical significance was not observed.
  
  
  CONCLUSIONS
  The CAD/CAM abutments appeared to have a comparable fit with prefabricated abutments for most of the systems evaluated. Design differences between the abutment connections for both Straumann implants were observed that affected the fit of internal components of the implant-abutment connections.
authors.forename: Adam
authors.initials: A
authors.lastname: Hamilton
authors.forename: Roy B
authors.initials: RB
authors.lastname: Judge
authors.forename: Joseph E
authors.initials: JE
authors.lastname: Palamara
authors.forename: Christopher
authors.initials: C
authors.lastname: Evans
mesh_terms: D017554:Carbon Compounds, Inorganic / Q000737:chemistry; D017076:Computer-Aided Design; D000044:Dental Abutments; D059605:Dental Implant-Abutment Design; D018772:Dental Marginal Adaptation; D003764:Dental Materials / Q000737:chemistry; D003775:Dental Polishing / Q000295:instrumentation / Q000379:methods; D017267:Dental Prosthesis Design; D018130:Diamond / Q000737:chemistry; D006047:Gold Alloys / Q000737:chemistry; D006801:Humans; D008422:Materials Testing; D008855:Microscopy, Electron, Scanning; D017655:Silicon Compounds / Q000737:chemistry; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry
chemical_list: D017554:Carbon Compounds, Inorganic; D003764:Dental Materials; D006047:Gold Alloys; D017655:Silicon Compounds; D012822:Silicon Dioxide; D018130:Diamond; D014025:Titanium; C022088:silicon carbide