1-stage versus 2-stage lateral maxillary sinus lift procedures: 4-month post-loading results of a multicenter randomised controlled trial.
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 of bone width below the maxillary sinus, as measured on CT scans, were randomised into two equal groups 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 3 different centres. Implants were submerged for 4 months and loaded with reinforced provisional prostheses, which were replaced, after 4 months, by definitive prostheses. Outcome measures were augmentation procedure failures, prosthesis failures, implant failures, complications and marginal peri-implant bone loss assessed by a blinded outcome assessor. Patients were followed up to 4 months 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 1 failed in the 2-stage group, the difference was not statistically significant (P = 1.00). Two prostheses failed or could not be placed in the planned time in the 1-stage group and 1 in the 2-stage group, the difference was not statistically significant (P = 0.51). Three implants failed in 3 patients of the 1-stage group versus 1 implant in the 2-stage group, the difference was not statistically significant (P = 0.28). Two complications occurred in the 1-stage group and 1 in the 2-stage group, the difference was not statistically significant (P = 0.61). There were no statistically significant differences in bone loss between groups at loading (0.05 mm). Sites treated in 1 stage lost an average of 0.56 mm (SD: 0.36; 95% CI: -0.70 to -0.42; P < 0.001) of peri-implant bone and 2-stage sites approximately 0.61 mm (SD: 0.34; 95% CI: -0.74 to -0.48; P < 0.001).


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 a residual bone height between 1 and 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.
Department of Periodontology and Implantology, University of Bologna, Bologna, Italy.
Pietro
P
Felice
Roberto
R
Pistilli
Maurizio
M
Piattelli
Elisa
E
Soardi
Gerardo
G
Pellegrino
Valeria
V
Corvino
Marco
M
Esposito
D000328:Adult; D000368:Aged; D016301:Alveolar Bone Loss / Q000209:etiology; D015519:Bone Density; D001857:Bone Matrix / Q000637:transplantation; D018786:Bone Substitutes / Q000627:therapeutic use; D003094:Collagen; D059605:Dental Implant-Abutment Design; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D019232:Dental Restoration Failure; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007576:Jaw, Edentulous, Partially / Q000534:rehabilitation / Q000601:surgery; D008297:Male; D008437:Maxilla / Q000601:surgery; D008567:Membranes, Artificial; D008875:Middle Aged; D008903:Minerals / Q000627:therapeutic use; D016348:Osseointegration / Q000502:physiology; D059745:Piezosurgery / Q000295:instrumentation; D011183:Postoperative Complications; D059546:Sinus Floor Augmentation / Q000009:adverse effects / Q000379:methods*; D016896:Treatment Outcome; D014945:Wound Healing / Q000502:physiology
C106416:Bio-Gide; C077540:Bio-Oss; D018786:Bone Substitutes; D015921:Dental Implants; D008567:Membranes, Artificial; D008903:Minerals; D003094:Collagen