The study aims to evaluate the clinical and radiological behavior, the histological and morphometrical components, the expression of proteins related to bone formation, and the analysis of markers of reparative mesenchymal stromal cells, after using a biphasic phicogenic biomaterial in comparison with anorganic bovine bone.

A randomized split-mouth clinical study is designed to include patients in need of two-stage bilateral maxillary sinus floor elevation. Patients are assigned to receive a mix of autogenous bone and a biphasic phycogenic biomaterial in one maxillary sinus and a mix of autogenous bone and xenograft bovine hydroxyapatite in the other maxillary sinus. Cone-beam computerized tomography (CBCT) scans are performed before sinus floor elevation and 6 months after the procedure to assess the bone gain. Bone core biopsies are obtained at the site of implant placement 6 months after the floor elevation. Histological sections are subjected to histomorphometric and immunohistochemical evaluation of differentiation markers.

Inclusion Criteria:

• Partially edentulous patients.
• Kennedy class I in the upper jaw.
• Less than 5 mm of residual crestal bone to the maxillary sinus.
• Need for the replacement of teeth with dental implants.

Exclusion Criteria:

• Sinus pathology (sinusitis, mucocele, cysts).
• Smokers.
• Previous long-term (>3 months) use of drugs known to affect bone metabolism, such as bisphosphonates.