PURPOSE: Rehabilitation of the edentulous posterior maxilla with dental implants often poses difficulty because of insufficient bone volume caused by pneumatization of the maxillary sinus and by crestal bone resorption. Sinus grafting technique was developed to increase the vertical height to overcome this problem. The present study was designed to evaluate the sinus floor augmentation with anorganic bovine bone (Biocera TM) using histomorphometric and clinical measures. PATIENTS AND METHODS: Thirteen patients were involved in this study and underwent total 14 sinus lift procedures. Residual bone height was > or=2mm and < or=6mm. Lateral window approach was used, with grafting using Bio-ceraTM only(n=1) or mixed with autogenous bone from ramus and/or maxillary tuberosity(n=13). After 6 months of healing, implant sites were created with 3mm diameter trephine and biopsies taken for histomorphometric analysis. The parameters assessed were area fraction of new bone, graft material and connective tissue. Immediate and 6 months after grafting surgery, and 6 months after implantation, computed tomography (CT) was taken and the sinus graft was evaluated morphometric analysis. After implant installation at the grafted area, the clinical outcome was checked. RESULTS:Histomorphometry was done in ten patients. Bio-ceraTM particles were surrounded by newly formed bone. The graft particles and newly formed bone were surrounded by connective tissue including small capillaries in some fields. Imaging processing revealed 24.86+/-7.59% of new bone, 38.20+/-13.19% connective tissue, and 36.92+/-14.51% of remaining Bio-ceraTM particles. All grafted sites received an implant, and in all cases sufficient bone height was achieved to install implants. The increase in ridge height was about 15.9+/-1.8mm immediately after operation (from 13mm to 19mm). After 6 months operation, ridge height was reduced about 11.5+/-13.5%. After implant installation, average marginal bone loss after 6 months was 0.3+/-0.15mm. CONCLUSION: Bio-ceraTM showed new bone formation similar with Bio-Oss(R) histomorphometrically and appeared to be an effective bone substitute in maxillary sinus augmentation procedure with the residual bone height from 2 to 6mm.