Immediate posterior partial rehabilitations with axialand intrasinus tilted implants

Method: Ten patients missing premolars and molars have been included. After elevation of anterior sinus membrane with lateral approach, each patient received one axial anterior implant and one posterior fixture placed with a 30 degrees mesial inclination and intra-sinus insertion. Autogeous bone was positioned to fill the sinus cavity and to cover the exposed implant surface. Immediate prosthesis was positioned after 3 hours while a CAD/CAM final restoration was delivered 6 months later.

Result:  A total of 20 implants have been followed for an average of 28 months (range 20-35 months). No implants were lost. After 1-year, bone loss averaged 1.0 ± 0.4 mm and 0.9 ± 0.5 for axial and tilted fixtures, respectively (p>.05), reporting 100% implant and prosthetic success rates.

Conclusion: This approach allows the immediate treatment of posterior maxilla in case of reduce bone volume, representing an alternative technique to bone regeneration or short implants.

The innovative approach is related to the position of the posterior implant, which differently from other clinical studies it is not completely surrounded by bone.

Intra-sinus insertion results, in fact, in placing the most coronal and apical portions of the fixture in native bone, providing stabilization of these parts sustaining the highest level of mechanical stress, while the implant body would be placed inside the sinus cavity and covered by bone graft. Thanks to the 30 degrees inclination it is possible to engage multiple layers of cortical bone achieving high level of primary stability and getting a post-operative bone-to-implant contact similar to the one reached by shorter fixtures placed axially in native bone.