title: Five-Year Results of a Randomized Controlled Trial Comparing Patients Rehabilitated with Immediately Loaded Maxillary Cross-Arch Fixed Dental Prosthesis Supported by Four or Six Implants Placed Using Guided Surgery.
abstract: OBJECTIVE
  To compare the 5-year clinical and radiological outcomes of patients rehabilitated with four or six implants placed using guided surgery and immediate function concept.
  
  
  METHODS
  Forty patients randomly received four (All-on-4) or six (All-on-6) immediately loaded implants, placed using guided surgery, to support a cross-arch fixed dental prosthesis. Outcome measures were survival rates of implants and prostheses, complications, peri-implant marginal bone loss, and periodontal parameters.
  
  
  RESULTS
  No drop-out occurred. Seven implants failed at the 5-year follow-up examination: six in the All-on-6 group (5%) and one in the All-on-4 group (1.25%), with no statistically significant differences (p = .246). No prosthetic failure occurred. Both group experienced some technical and biologic complications with no statistically significant differences between groups (p = .501). All-on-4 treatment concept demonstrated a trend of more complications during the entire follow-up period. A trend of more implant failure was experienced for the All-on-6 treatment concept. Marginal bone loss (MBL) from baseline to the 5-year follow-up was not statistically different between All-on-4 (1.71 ± 0.42 mm) and All-on-6 (1.51 ± 0.36 mm) groups (p = .12). For periodontal parameters, there were no differences between groups (p > .05).
  
  
  CONCLUSIONS
  Both approaches may represent a predictable treatment option for the rehabilitation of complete edentulous patients in the medium term. Longer randomized controlled studies are needed to confirm these results.
authors.affiliation: Private practice, Rome, Italy. me@studiomarcotallarico.it.
authors.forename: Marco
authors.initials: M
authors.lastname: Tallarico
authors.affiliation: Department of Surgical Microsurgical and Medical Sciences, Dentistry Unit, University Hospital of Sassari, Sassari, Italy.
authors.forename: Silvio Mario
authors.initials: SM
authors.lastname: Meloni
authors.affiliation: Private practice, Rome, Italy.
authors.forename: Luigi
authors.initials: L
authors.lastname: Canullo
authors.affiliation: University of Trieste, Trieste, Italy.
authors.forename: Martina
authors.initials: M
authors.lastname: Caneva
authors.affiliation: Private Clinic BSC, Verona, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Polizzi
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D015921:Dental Implants; D017266:Dental Prosthesis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016896:Treatment Outcome
chemical_list: D015921:Dental Implants
keywords: CAD/CAM technology; atrophic maxilla; atrophy; clinical research; computer-assisted; cone beam CT; edentulous atrophic maxilla; edentulous maxilla; immediate function; immediate loading