title: Immediate loading of 2 (all-on-2) versus 4 (all-on-4) implants placed with a flapless technique supporting mandibular cross-arch fixed prostheses: preliminary results from a pilot randomised controlled trial.
abstract: OBJECTIVE
  To evaluate the clinical outcome of 2 implants versus 4 implants placed flapless in fully edentulous mandibles and immediately restored with metal-resin screw-retained cross-arch prostheses.
  
  
  METHODS
  Sixty patients from two different centres were randomised: 30 to the allon- 2 group and 30 to the all-on-4 group. To be immediately loaded, implants had to be inserted with a minimum torque of 40 Ncm. Outcome measures were prosthesis and implant failures, and biological and biomechanical complications.
  
  
  RESULTS
  Flaps were raised in 18 patients. Two implants in 2 patients did not reach the planned insertion torque and were immediately replaced by larger diameter ones. Four months after loading, no drop-out or implant failure occurred. One biomechanical complication occurred in the all-on-2 group versus 4 in the all-on-4 group. There were no statistically significant differences between groups for complications. There were no differences between centres.
  
  
  CONCLUSIONS
  These very preliminary results, just 4 months after loading, suggest that immediately loaded mandibular cross-arch fixed dental prostheses can be supported by only 2 dental implants. Longer follow-ups (around 10 years) are needed to understand whether cross-arch mandibular prostheses can be successfully supported by only 2 dental implants.
authors: Department of Peridontology and Implantology, Univeristy of Bologna, Italy.
authors: Gioacchino
authors: G
authors: Cannizzaro
authors: Pietro
authors: P
authors: Felice
authors: Elisa
authors: E
authors: Soardi
authors: Vittorio
authors: V
authors: Ferri
authors: Michele
authors: M
authors: Leone
authors: Marco
authors: M
authors: Esposito
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016301:Alveolar Bone Loss; D003758:Dental Implantation, Endosseous / Q000379:methods*; D015921:Dental Implants; D017267:Dental Prosthesis Design; D017268:Dental Prosthesis Retention / Q000295:instrumentation; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D057893:Immediate Dental Implant Loading; D008297:Male; D008334:Mandible / Q000601:surgery; D008875:Middle Aged; D010865:Pilot Projects; D011183:Postoperative Complications; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants