Missing osteogenic effect of expanded autogenous osteoblast-like cells in a minipig model of sinus augmentation with simultaneous dental implant installation.

OBJECTIVES

With natural bovine bone mineral (BioOss) as carrier, the study aimed at investigating the effect of autogenous osteoblast-like cells on bone regeneration in an orthotopic (maxillary sinus) and an ectopic (muscle) site.

MATERIALS AND

METHODS

Autogenous osteoblast-like cells were isolated from iliac cancellous bone of six minipigs and expanded in an autogenous serum-supplemented osteogenic medium. After confirmation of osteogenicity, the expanded cells were precultivated on BioOss granules for 1 week. Four milliliter of cell-seeded BioOss were used for sinus augmentation of right sinus and a Straumann solid screw (dental) implant was simultaneously installed. The contralateral (control) side was filled with cell-free BioOss. Besides, 2 ml of the corresponding granules were placed in a pouch in the latissimus dorsi muscles bilaterally. Polychrome sequential labeling was performed postoperatively. Specimens were harvested at week 6. Undecalcified sections were evaluated with microradiography, fluorescence microscopy, histology and histomorphometry.

RESULTS

In the test side, the coronal part of dental implant demonstrated higher bone-implant contact (BIC) than the apical part (34.88+/-28.86% vs. 16.68+/-13.80%, P=0.039), as well as higher bone density (BD) in the corresponding zone (14.88+/-6.37% vs. 11.10+/-4.54%, P=0.021). However, the test side demonstrated no advantage over control side in either BD (12.25+/-4.22% vs. 8.45+/-11.04%, P=0.473) or BIC (24.15+/-21.97% vs. 22.05+/-19.00%, P=0.270). Rare bone was formed in the muscles in both sides.

CONCLUSIONS

The expanded autogenous osteoblast-like cells failed to enhance bone formation in the minipig model of sinus augmentation.