Maxillary sinus floor augmentation using a nano-crystalline hydroxyapatite silica gel : case series and 3-month preliminary histological results

The aim of this case series is to histologically examine a new hydroxyapatite in sinus lift procedure after 3 months. Ten 2-stage sinus lifts were performed in 10 healthy patients having initial bone height of 1-2 mm and bone width of 5 mm, asking for a fixed implant-supported rehabilitation. After graft material augmentation, a rough-surfaced mini-implant was inserted to maintain stability of the sinus widow. A bioptical core containing a mini-implant was retrieved 3 months after maxillary sinus augmentation with NanoBone (R) and processed for undecalcified histology. From the histomorphometric analysis, NanoBone (R) residuals accounted for the 38.26%+/- 8.07% of the bioptical volume, marrow spaces for the 29.23%+/- 5.18% and bone for the 32.51%+/- 4.96% (new bone: 20.64%+/- 2.96%, native bone: 11.87%+/- 3.27%). Well-mineralized regenerated bone with lamellar parallel-fibred structure and Haversian systems surrounded the residual NanoBone (R) particles. The measured bone-to-implant contact amounted to 26.02%+/- 5.46%. No connective tissue was observed at the implant boundary surface. In conclusion, the tested material showed good histological outcomes also 3 months after surgery. In such critical conditions, the use of a rough-surfaced mini-implant showed BIC values supposed to be effective also in case of functional loading. Although longer follow-up and a wider patient size are needed, these preliminary results encourage further research on this biomaterial for implant load also under early stage and critical conditions.