**Acknowledgements**

The authors thank Dr. Macarena Gonzales-Chaves for her technical advice in histomorphometrical studies and Mr. Ricardo Orzuza for his technical advice in animal care. We also would like to thank University of Buenos Aires, School of Dentistry, Department of General and Oral Biochemistry, Buenos Aires, Argentina for conducting the densitometric evaluations, and University of Buenos Aires, School of Dentistry, Department of Clinical Operative and Prosthesis II, Buenos Aires, Argentina for their assistance in the use of the facilities.

This research was partially funded by National Council of Scientific and Technical Research (CONICET)-University of Buenos Aires. Institute of Immunology, Genetics and Metabolism (INIGEM). School of Pharmacy and Biochemistry- Clinical Hospital "José de San Martín," Buenos Aires, Argentina, and Odontit Implant Systems, Argentina. Synergy Bone Matrix and Bio-Oss were kindly provided by Odontit Implant Systems, Argentina.
