Introduction:
Rehabilitation of the posterior maxilla with limited vertical bone height is a clinical challenge in implant dentistry. While the lateral sinus lift with delayed implant placement was long considered the gold standard, the transcrestal approach and the development of short and extra-short implants have reduced the need for invasive grafting. However, when residual bone height is ≤5 mm and bone density is low, achieving primary stability remains difficult, as insertion torque values are often below the traditionally recommended 20 Ncm. Long-term evidence in such scenarios is limited.
Materials and Methods:
A retrospective review was conducted of patients treated between 2017 and 2020 with short and extra-short implants (BTI Biotechnology Institute, UnicCa® surface) in posterior maxillae with residual bone height ≤5 mm and final insertion torque ≤15 Ncm. All implants were placed using the biological drilling technique at low speed, with transcrestal sinus elevation and grafting with autologous bone collected during drilling mixed with PRGF-Endoret. A two-stage protocol was followed, with second-stage surgery at 5 months and progressive loading. Radiographic evaluation of marginal bone loss was performed with standardized panoramic radiographs.
Results:
Seventeen patients (20 implants) with a mean age of 60.8 years were followed for a mean of 5.9 years. No implant failures occurred, yielding 100% survival. Mean marginal bone loss was 0.45 mm mesially and 0.43 mm distally. Correlation between insertion torque and bone loss showed weak, non-significant trends.
Conclusion:
Within the limitations of this study, extra-short implants placed with insertion torque ≤15 Ncm in posterior maxillae with ≤5 mm residual bone achieved excellent survival and minimal bone loss at medium-term follow-up.