Osteotome Sinus Floor Elevation With or Without Grafting

The osteotome sinus floor elevation (OSFE) technique has been proved to be a predictable procedure for successful implant placement in posterior maxillae with limited bone height under sinus. OSFE is considered to be minimal invasive and minimal traumatic while having a limitation with regard to the residual bone height. According to the consensus conference in 1996, OSFE technique without bone grafting should be limited to RBH ranging from 7mm to 9mm. However, recent studies reported favorable results even with RBH of around 4mm. Moreover, there is still controversy regarding the necessity of a grafting material in order to maintain the space for new bone formation. Spontaneous bone formation was observed for OSFE without grafting by some researches. Due to the lack of randomized controlled trial (RCTs), there is still no clear guideline for implant therapy in posterior maxillae with limited bone height. Neither is there any evidence to recommend or contraindicate the application of grafting materials in combination with OSFE. The present RCT is aimed to evaluate the clinical success of OSFE with RBH of 2mm to 8 mm and to study whether the application of grafting material in combination with OSFE will be more favorable. The hypothesis is that the application of simultaneous grafting has no significant advantage in terms of clinical success. Spontaneous bone formation can be observed with implants placed using OSFE without grafting. 45 systemically healthy adults consecutively admitted for oral implant therapy will be randomly assigned to 2 test groups. Only one implant system will be used to minimize the implant-originated influencing factors. Bio-Oss® will be chosen as the bone substitute as it is currently the typical xenograft available. Autogenous bone will be also used as it is deemed as 'gold standard' for bone graft materials. A panoramic radiograph and cone-beam CT should be taken to assess the pretreatment bone height under sinus. For T1 group, the aut