Sinus Reformation for Management of Maxillary Posterior Bone Atrophy

Implant rehabilitation in the posterior maxilla with critical residual bone height (≤6 mm) requires maxillary sinus floor augmentation techniques, although controversy exists regarding the necessity of heterologous bone grafts. Although some protocols consider grafting essential for osteogenesis, recent evidence suggests that modern implants, through a "tent-pole" effect, may eliminate this need, thereby avoiding its drawbacks (increased cost, surgical time, and risk of complications such as sinusitis). This retrospective study compares implant survival and complications between both techniques in patients with 4 to 6 mm of bone height undergoing immediate implant placement.

In this comparative retrospective study, 170 patients with posterior maxillary atrophy (4-6 mm residual bone height) undergoing lateral approach sinus lift with immediate implant placement were analyzed. Patients were divided into 2 groups: 80 patients without bone graft (group A) and 90 patients with heterologous bone graft (porcine-derived bone with collagen) (group B). Both groups exhibited homogeneous characteristics regarding controlled comorbidities. Patients were evaluated over 3 years, with periodic follow-ups and prosthetic loading at 4 to 6 months, analyzing implant survival and complications such as infections, sinusitis, and wound dehiscence.

After a 36-month follow-up, both groups showed similar implant survival rates (91.25% without graft versus 91.11% with graft), with 7 and 8 failures, respectively, distributed similarly over time. However, a notably different complication profile was observed: the graft group exhibited a significantly higher incidence of chronic sinusitis (5.56% versus 0%), twice the rate of local infections (5.56% versus 2.5%), and 3 times the rate of wound dehiscence (4.44% versus 1.25%).

Our study demonstrates that the sinus lift technique without bone graft offers equivalent implant survival to the conventional graft technique at 3 years, but with a markedly superior safety profile by significantly reducing postoperative complications, particularly chronic sinusitis. This advantage may be attributed to the "tent-pole" effect, where the implant itself maintains sinus membrane elevation, eliminating risks associated with graft material such as ostium obstruction, inflammatory reactions, and increased susceptibility to infections and dehiscence. In addition, omitting the graft reduces costs, simplifies the procedure, and eliminates risks linked to animal-derived materials, positioning it as a viable and safe alternative for patients with minimal residual bone height.

The results indicate that sinus augmentation with immediate implant placement without bone graft is a viable and safe therapeutic alternative for patients with a minimum residual bone height of 4 mm, demonstrating equivalent implant survival to the graft technique but with a significantly improved safety profile, resulting in reduced morbidity, greater patient satisfaction, and substantial cost savings associated with the procedure.