Short implants versus bone augmentation for placing longer implants in atrophic maxillae: One-year post-loading results of a pilot randomised controlled trial.
OBJECTIVE
To evaluate whether short (5.0 to 8.5 mm) dental implants could be a suitable alternative to longer (at least 11.5 mm-long) implants placed in atrophic maxillae augmented with autogenous bone for supporting dental prostheses.


METHODS
Twenty-eight patients with fully edentulous atrophic maxillae, whom had 5 to 9 mm of residual crestal bone height which was at least 5 mm thick, measured using computerised tomography (CT) scans, were randomised into two groups either to receive 4 to 8 short (5.0 to 8.5 mm) implants (15 patients) or autogenous bone from the iliac crest to allow the placement of at least 11.5 mm-long implants (13 patients). Bone blocks and the windows at the maxillary sinuses were covered with rigid resorbable barriers. Grafts were left to heal for 4 months before placing implants which were submerged. After 4 months, provisional reinforced acrylic prostheses or bar retained overdentures were delivered. Provisional prostheses were replaced, after 4 months, by definitive screw-retained metal-resin cross-arch restorations. Outcome measures were prosthesis and implant failures, any complications, peri-implant marginal bone level changes and patient satisfaction. Patients were followed up to 1 year after loading.


RESULTS
All patients were rehabilitated with implant-supported prostheses but two patients dropped out from the augmented group. One bilateral sinus lift procedure failed for infection, although short implants could be placed. One implant failed in the augmented group versus two short implants in two patients (Fishers exact test P = 1.00; difference in proportions = 0.06; 95% CI -0.28 to 0.17). All failures occurred before loading. Significantly more complications occurred in augmented patients: eight complications occurred in 5 augmented patients (all of them complained of pain 1 month after bone harvesting from the iliac crest) versus no complications in the short implant (Fisher's exact test P = 0.013; difference in proportions = 0.38; 95% CI 0.11 to 0.65). Both groups presented a significant peri-implant marginal bone loss at 1 year after loading (P < 0.0001); -1.05 (0.20) mm for short implants and -1.01 (0.16) mm for the augmented group, respectively, with no statistically significant differences between the two groups (mean difference -0.04 mm; 95% CI -0.22 to 0.14; P = 0.59). All patients were fully satisfied with the treatment and would have it again.


CONCLUSIONS
This pilot study suggests that short implants may be a suitable, cheaper and faster alternative to longer implants placed in bone augmented with autogenous bone for rehabilitating edentulous atrophic maxillae, however, these preliminary results need to be confirmed by larger trials with follow-ups of at least 5 years.
Marco
M
Esposito
Carlo
C
Barausse
Roberto
R
Pistilli
Gilberto
G
Sammartino
Giovanni
G
Grandi
Pietro
P
Felice
D020341:Absorbable Implants; D000328:Adult; D000368:Aged; D001284:Atrophy; D064592:Autografts / Q000637:transplantation; D016025:Bone Transplantation / Q000379:methods; D003758:Dental Implantation, Endosseous / Q000379:methods; D015921:Dental Implants; D017267:Dental Prosthesis Design; D019094:Dental Prosthesis, Implant-Supported; D003781:Denture Retention / Q000295:instrumentation; D003828:Denture, Overlay; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007575:Jaw, Edentulous / Q000534:rehabilitation / Q000601:surgery*; D008297:Male; D008437:Maxilla / Q000473:pathology / Q000601:surgery*; D008567:Membranes, Artificial; D008875:Middle Aged; D017060:Patient Satisfaction; D010865:Pilot Projects; D011183:Postoperative Complications; D016037:Single-Blind Method; D059546:Sinus Floor Augmentation / Q000379:methods*; D016896:Treatment Outcome
D015921:Dental Implants; D008567:Membranes, Artificial