title: 1-stage versus 2-stage lateral sinus lift procedures: 1-year post-loading results of a multicentre randomised controlled trial.
abstract: OBJECTIVE
  To compare the efficacy of 1-stage versus 2-stage lateral maxillary sinus lift procedures.
  
  
  METHODS
  Sixty partially edentulous patients requiring 1 to 3 implants and having 1 to 3 mm of residual bone height and at least 5 mm bone width below the maxillary sinus, as measured on CT scans were selected. They were randomised according to a parallel group study design into two equal arms to receive either a 1-stage lateral window sinus lift with simultaneous implant placement or a 2-stage procedure with implant placement delayed by 4 months, using a bone substitute in three different centres. Implants were submerged for 4 months, loaded with reinforced provisional prostheses, which were replaced, after 4 months, by definitive prostheses. Outcome measures, assessed by masked assessors, were: augmentation procedure failures; prosthesis failures and implant failures; complications; and marginal peri-implant bone level changes. Patients were followed up to 1 year after loading. Only data of implants placed in 1 to 3 mm of bone height were reported.
  
  
  RESULTS
  Two patients dropped out from the 1-stage group and none from the 2-stage group. No sinus lift procedure failed in the 1-stage group but one failed in the 2-stage group, the difference being not statistically significant (P = 1.00). Two prostheses failed or could not be placed in the planned time in the 1-stage group and one in the 2-stage group, the difference being not statistically significant (P = 0.51). Three implants failed in three patients of the 1-stage group, versus one implant in the 2-stage group, the difference being not statistically significant (P = 0.28). Two complications occurred in the 1-stage group and one in the 2-stage group, the difference being not statistically significant (P = 0.61). One year after loading, 1-stage treated patients lost an average of -1.01 mm (SD: 0.56) of peri-implant bone and 2-stage sites about -0.93 mm (SD: 0.40). There were no statistically significant differences in bone level change between groups 1 year after loading (-0.08 mm 95%CI: -0.33 to 0.18 P = 0.56).
  
  
  CONCLUSIONS
  No statistically significant differences were observed between implants placed according to 1- or 2-stage sinus lift procedures. However this study may suggest that in patients having residual bone height between 1 to 3 mm below the maxillary sinus, there might be a slightly higher risk for implant failures when performing a 1-stage lateral sinus lift procedure.
authors.forename: Pietro
authors.initials: P
authors.lastname: Felice
authors.forename: Roberto
authors.initials: R
authors.lastname: Pistilli
authors.forename: Maurizio
authors.initials: M
authors.lastname: Piattelli
authors.forename: Elisa
authors.initials: E
authors.lastname: Soardi
authors.forename: Carlo
authors.initials: C
authors.lastname: Barausse
authors.forename: Marco
authors.initials: M
authors.lastname: Esposito
mesh_terms: D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000209:etiology; D018786:Bone Substitutes / Q000627:therapeutic use; D003094:Collagen; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D019094:Dental Prosthesis, Implant-Supported; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000601:surgery; D008297:Male; D008437:Maxilla / Q000000981:diagnostic imaging / Q000601:surgery; D008567:Membranes, Artificial; D008875:Middle Aged; D008903:Minerals / Q000627:therapeutic use; D016348:Osseointegration / Q000502:physiology; D011183:Postoperative Complications; D016037:Single-Blind Method; D059546:Sinus Floor Augmentation / Q000379:methods*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
chemical_list: C106416:Bio-Gide; C077540:Bio-Oss; D018786:Bone Substitutes; D015921:Dental Implants; D008567:Membranes, Artificial; D008903:Minerals; D003094:Collagen