Six-year extension results of a randomized trial comparing transcrestal and lateral sinus floor elevation at sites with 3-6 mm of residual bone

Objectives: To comparatively evaluate the 6-year outcomes of transcrestal and lateral sinus floor elevation (tSFE and lSFE, respectively).Methods: The 54 patients representing the per-protocol population of a randomized trial comparing implant placement with simultaneous tSFE versus lSFE at sites with a residual bone height of 3-6 mm were invited to participate in the 6-year follow-up visit. Study assessments included: peri-implant marginal bone level at the mesial (mMBL) and distal (dMBL) aspects of the implant, proportion of the entire implant surface in direct contact with the radiopaque area (totCON%), probing depth, bleeding on probing, suppuration on probing, and modified plaque index. Also, the conditions of the peri-implant tissues at 6-year visit were diagnosed according to the case definitions of peri-implant health, mucositis, and peri-implantitis from the 2017 World Workshop.Results: Forty-three patients (21 treated with tSFE and 22 treated with lSFE) participated in the 6-year visit. Implant survival was 100%. At 6 years, totCON% was 96% (IR: 88%-100%) in tSFE group and 100% (IR: 98%-100%) in lSFE group (p = .036). No significant intergroup difference in patient distribution according to the diagnosis of peri-implant health/disease was observed. Median dMBL was 0.3 mm in tSFE group and 0 mm in lSFE group (p = .024).Conclusions: At 6 years following placement concomitantly with tSFE and lSFE, implants showed similar conditions of peri-implant health. Peri-implant bone support was high in both groups and was slightly but significantly lower in tSFE group.