title: Conventional Versus Digital Impressions for "All-on-Four" Restorations.
abstract: OBJECTIVE
  This study aimed to evaluate the most accurate impression technique for "All on Four" restoration, comparing conventional (CIG) and digital impressions (DIG).
  
  
  METHODS
  Patients randomly selected for this study were required to be edentulous in at least one arch, presenting with severe posterior mandibular or maxillary atrophy. All patients underwent full-arch immediate-load rehabilitations, which were fixed to a total of four implants (two axial and two tilted). Following implant placement, patients were stratified into two groups. Conventional pick-up was carried out in the control group, and digital impressions were performed in the test group. Following prosthetic rehabilitation, patients underwent intraoral digital radiographs to check for the presence of voids at the bar-implant connection and to evaluate accuracy. Three-, 6-, and 12-month follow-up examinations were performed.
  
  
  RESULTS
  A total of 25 patients received immediately loaded "All-on-Four" prostheses (17 maxillary, 13 mandibular) supported by four implants (total 120 implants), of which five received both maxillary and mandibular prosthetic rehabilitation (three patients in CIG, two patients in DIG). No implant dropouts occurred, showing a survival rate of 100%. The digital impression procedure required significantly less time than the conventional procedure (P < .001).
  
  
  CONCLUSIONS
  Results demonstrate that it is possible to develop computer-aided design/computer-assisted manufacturing (CAD/CAM) cobalt-chromium full-arch rehabilitations with satisfactory accuracy using digital impression techniques.
authors.forename: Enrico
authors.initials: E
authors.lastname: Gherlone
authors.forename: Paolo
authors.initials: P
authors.lastname: Capparé
authors.forename: Raffale
authors.initials: R
authors.lastname: Vinci
authors.forename: Francesco
authors.initials: F
authors.lastname: Ferrini
authors.forename: Giorgio
authors.initials: G
authors.lastname: Gastaldi
authors.forename: Roberto
authors.initials: R
authors.lastname: Crespi
mesh_terms: D000328:Adult; D000368:Aged; D017076:Computer-Aided Design; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D003761:Dental Impression Technique; D019094:Dental Prosthesis, Implant-Supported; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods; D057893:Immediate Dental Implant Loading / Q000379:methods; D007575:Jaw, Edentulous / Q000534:rehabilitation; D008297:Male; D008334:Mandible / Q000601:surgery; D008437:Maxilla / Q000601:surgery; D008875:Middle Aged; D061848:Optical Imaging / Q000379:methods; D019252:Radiography, Dental, Digital / Q000379:methods; D011862:Radiography, Panoramic / Q000379:methods; D016019:Survival Analysis; D013997:Time Factors
chemical_list: D015921:Dental Implants