Sinus lift without graft material – stability of the increased bone volume (4–8 years follow up study)

Abstract

Background Implant-supported prosthetic restorations in the severely atrophic posterior maxilla have been successfully performed for the last 2 decades with various sinus augmentation techniques. The use of grafting material is widespread practice (Jensen et al. 1996) but studies (Lundgren 2004, Thor 2007, Cricchio 2011, Volpe 2011 Riben 2012, Fermergard 2012, Si 2013) have demonstrated that the elevation of the Schneiderian membrane with simultaneous implants placement result in bone formation. Aim/Hypothesis The aim of the study is to evaluate the quantity and the stability of the increased bone volume around implants inserted in a void space created by the elevation of the sinus membrane without adding any bone grafting material. Material and Methods Sixty-eight implants with a residual bone height requiring sinus lift were placed from January 2009 to January 2014. The sinus mucosal lining was elevated implants were installed in the residual subantral bone without adding any bone grafting material. Radiographs were performed (at T0, T0, 6 m, and every years as soon as is possible) to evaluate bone formation and the stability of bone volume around implants. The length of implants was used as a reference point for measurements. Results All implants were functional after 6 months. The survival rate at 8 years is equal to or greater than that reported when using biomaterials. These results are in agreement with the recent studies. Radiographic examination demonstrated new bone formation in 98.2% of the cases after 6 months. Average bone gain in the sinus was 5.81 ± 2.22 mm after a minimum of 6 months. The results are comparable with those of the literature. The bone gain is sometime lower because the implants used are on average shorter than in the reference studies. At T0, 92.86% of the implants were radiographically covered with less than 8 mm of bone. At T0, 6 months, only 12.50% had a bone level <8 mm. Bone volume remains stable from one to 8 years (98.4%). In only one of the implant is a clear resorption giving a pyramidal structure very likely compatible with a long-term survival of the implant. Studies denouncing resorption are animal studies with no loading implant. Conclusions and Clinical Implications Our investigation shows that sinus membrane elevation and simultaneous implant placement without the use of additional bone grafting material is a predictable technique for Sinus lift (Riben 2016, Stefanski 2017). According to the study, we assume that bone gain volume remains stable. Progression and clinical appearance of peri-implantitis in this new living bone seems more predictable and allow earlier care. Further human long-term studies on the stability of the bone volume are necessary .