Short vs standard implants associated with sinus floor elevation: a randomized controlled trial

Objective: the present equivalence two-arm parallel randomized controlled trial aimed to compare survival and marginal bone loss (MBL) of short implants (≤6 mm) and standard implants (≥8.5 mm) associated with sinus floor elevation (SFE). Methods: adult patients with partial edentulism with occlusal stability in the sinus area and intermediate bone height were selected in this double-blind trial (patient and outcome assessment). Patients were randomly allocated into two groups: standard length implants with SFE (control) or short implants (test). Clinical and radiographic assessments were made at the time of implant placement, 6 months, and annually thereafter up to 2 years after loading. The inter-examiner agreement was analyzed using intraclass correlation coefficient (ICC). One-way ANOVA, Kaplan-Meier, and Log-rank tests were used to compare implant survival (primary outcome) and MBL (secondary outcome) (P<0.05). Results: eight short implants and six standard implants were placed (mean age of patients was 47 ±12.5 years). The implant survival rates were 87.5% for short (one 5 mm implant failed at 7 months) and 100% for standard implants with no statistically significant difference between groups (P=0.4). The mean MBL after 1 year was 0.30 ±0.62 mm for short and 0.21 ±0.36 mm for standard implants (P=0.123). The inter-examiner agreement was set in 0.831. Conclusion: survival of short implants and standard implants associated with SFE was similar after two years of clinical service. Trial registration: Registered on 27-03-2018 at ClinicalTrials.gov (NCT03479333). Funding: This study was partially funded by Capes Finance Code 001 and #88881.187933/2018-01. TPC is partially funded by National Council for Scientific and Technological Development (CNPq - Brazil). The funders had no role in the study design, data collection and analysis, decision to publish or preparation of the manuscript.Keywords: bone resorption; dental implants; sinus floor augmentation; survival.