Sinus augmentation with a nano-structured biomaterial: clinical and histological results

This clinical study was conducted to clinically and histologically evaluate the osteoconductive potential and other properties of a new entirely synthetic and nano-structured hydroxylapatite based biomaterial (NanoBone®) as a grafting material for sinus floor augmentation. This study was triggered by initial in vivo analysis of the host-biomaterial-interaction in the subcutaneous implantation model in Wistar-rats.

Methods:

15 sinus floor elevations were carried out in a total of 15 patients. Augmentation of the maxillary sinus floor was completed using merely the bone grafting material. After a healing period of 6 months, 45 CAMLOG® implants were placed. During this surgical intervention, 20 cylinder-shaped bone biopsies were taken from the augmented maxillary region using trephine burs. The healing process and bone-biomaterial-interface were analysed histologically.

Results:

The healing period progressed without any complications. General and specific histological analysis of the bone biopsies showed a high osteoclasts activity at the margin of the biomaterial which was well integrated into the newly formed bone. Tongues of newly formed bone were detected originating at the margin of bone-biomaterial-interface and reaching to the centre of the biomaterial while at the same time mineralized islands of different sizes with and without osteoblasts were detected in the centre of the biomaterial. In the course of the 6 months most of the biomaterial was replaced by new bone. When the implants were uncovered after an average healing phase of 6 months, 43 implants had become osseointegrated.

Conclusion:

This study demonstrates that new trabecular bone is formed after grafting with the nanocrystalline bone substitute after 6 month without the addition of autologous bone. Ongoing in vivo and in situ analyses are necessary to understand more thoroughly which biological pattern SiO2 is potentially responsible for the auto-mineralization tendency and the osteoconductivity of the material.