Guided implant surgery and sinus lift in severely resorbed maxillae: A retrospective clinical study with up to 10 years of follow-up

Objectives In the posterior maxilla, due to the presence of maxillary sinus, residual bone height lower than 3mm is a critical factor that can affect implant stability and survival. The use of guided surgery may facilitate the surgical procedures and the implant insertion in case of severely resorbed maxillae. Moreover, it may have beneficial effects on the long-term survival and success of implant-supported restorations. This study aimed to evaluate implant supported restorations on severely resorbed maxilla (<3 mm) after sinus lift with collagenated xenograft and guided surgery. Methods Forty-three patients with need for implant rehabilitation and residual bone height between 1 and 3 mm were recruited. Surgical and prosthetical aspects were planned following digital approach with the use of Realguide 5.0 (3diemme, Varese, Italy). Lateral window sinus lift was performed and implants were placed simultaneously to the augmentation procedure with a tooth-supported pilot drill surgical template. A pre-hydrated collagenated porcine bone matrix was adopted as regenerative material. Computer-aided-design/computer-aided-manufacturing (CAD/CAM) restorations were delivered after six months of healing. Milled titanium chamfer abutments with CAD/CAM crowns were used. Bone height at implant site level was measured using an image software analysis applied to the pre- and post-surgical radiographs and at the follow-up. Biological and technical complications were recorded during all the follow-up periods. Results Fifty-four sinus were treated. After a mean follow-up time of 5.11 years (SD: 2.47), no implants were lost nor showed signs of disease. The mean pristine bone height was 2.07 mm (SD: 075). At the final evaluation the augmented sinus height was 12.83 mm (SD: 1.23). Two cases experienced minor perforation of the membrane, while five patients developed minimal post-operative complications, completely resolved with pharmacologic therapy. No mid-term biological complications were experienced by the patients. No cases experienced peri-implant mucositis and peri-implantitis during the whole follow-up period. Four patients (7.4%) faced an unscrewing of the prosthesis. Conclusions The present study showed the efficacy in the mid-term of the digital planning and the guided surgery in restoring severely resorbed posterior maxilla with dental implants.