The repair of critical-size defects with porous hydroxyapatite/polyamide nanocomposite: an experimental study in rabbit mandibles

Rectangular nHA/PA specimens before implantation.

Critical-size (15mm×10mm) bicortical defect created on the lateral aspect of the mandible.

Macroscopic documentation of the bone samples 4, 12 and 24 weeks after nHA/PA implantation (a, b, c) and blank controls (a′, b′, c′). Arrows denote the defect area.

Radiographs of defect site in rabbit mandibles 4, 12 and 24 weeks after nHA/PA implantation (a, b, c) and in blank controls (a′, b′, c′). Arrows denote the defect area.

X-ray grey scale was compared between specimens implanted with nHA/PA and those in controls (mean±SD; n=5; *P<0.05).

Histological cross-sections of newly formed bone 4, 12 and 24 weeks after nHA/PA implantation (a, b, c) and in blank controls (a′, b′, c′). The pore spaces of nHA/PA were filled with bone marrow (a, b, c), showing that the interconnected pore structure could provide a channel for body fluid. Masson staining (magnification: 200×). N: nHA/PA bone substitute; O: osteoid; L: lamellar bone; F: fibrous and connective tissue; W: woven bone.

Characteristic distribution of the fluorescent dyes tetracycline (yellow) and calcein (green) in the central area of the defect 4, 12 and 24 weeks after nHA/PA implantation (a, b, c) and in blank controls (a′, b′, c′). (magnification: 100×). N: the side of nHA/PA; B: new-formed bone; arrows denote the Haversian canals. (For interpretation of the references to color in this figure legend, the reader is referred to the web version of the article.)

Histomorphometry of newly formed bone tissue in the specimens 4, 12 and 24 weeks after operation. Parameters for osteogenic activity, DDL and MOSW, mineralization level, MAR and MLT were compared between specimens implanted with nHA/PA and those in controls. Three areas in each section were analysed for the data acquired (mean±SD; n=18;*P<0.05).