Sinus lift surgery in severely resorbed maxillae: One-year follow-up

Materials and methods: Twenty-six wide-diameter implants with a rough surface over their entire length were inserted during 13 consecutive sinus lifts. Radiographic analysis was preoperatively requested for each patient. After Schneiderian membrane elevation, a magnesium-enriched hydroxyapatite (Mg-e HA) and collagen-based scaffold with a porous 3-D structure was used to prevent perforation during implant placement. Sinus grafting was performed using a biomimetic Mg-e HA. No membrane was used to cover the buccal window. The preoperative residual bone height ranged between 1 and 4 mm (mean value: 2.5 mm; SD: 1.0 mm).

After 6 months of healing, uncovering was carried out and the definitive restoration was seated after 2 weeks. In order to monitor the stability changes, resonance frequency analysis was performed and ISQ (Implant Stability Quotient) values were collected at the first surgery (baseline, T₀), at the abutment connection (T₁) and at the 1-year follow-up (T₂).

In order to measure bone changes, the patients underwent panoramic radiographs after 2-year follow-up. Image analysis software calculated the grafted bone height changes at the level of the implant site, comparing preoperative and follow-up panoramic radiographs.

Results: No postoperative complications were observed. The mean ISQ value was 42.5 (SD: 2.7) at T₀, 75.3 (SD: 8.2) at T₁ and 81.5 (SD: 2.6) at T₂. Statistically significant differences (P ≤ 0.005) regarding mean ISQ values were found between T₁ and T₀, as well as between T₁ and T₂. After 12 months of functional loading, only 1 implant was lost (cumulative survival rate: 96.15%). During the same observation period, the mean radiographic vertical height of the grafted sinus floor was 11.05 mm (SD: 2.10 mm), with a mean gain of 8.50 mm.

Conclusion: Within the limitations of this study, despite preoperative critical residual bone height, maxillary sinus lift restoration using a biomimetic Mg-e HA and an Mg-e HA/collagen-based scaffold with a porous 3-D structure seems to be a reliable procedure.

Editorial note: The full article was published in the 1/2018 issue of the Journal of Oral Science and Rehabilitation.

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