Abstract: Objective To analyze the histomorphometry differences of condylar cartilage osteogenesis under altered masticatory loading, and to study the mechanism of masticatory loading on condylar development in growing rabbits. Methods sixteen 15-day-old rabbits were randomly divided into two groups and fed different kinds of food, such as solid diet (n=8) and soft diet (n=8). ALL the growing rabbits were weaned at 28-day-old. Tetracycline (50mg/kg), calcein (20mg/kg) and were given intramuscularly on the 28-day-old and 33-day-old. The rabbits were sacrificed on the 38-day-old. The specimens of condyles were embedded in methylmethacrylate. Undecalcified hard tissue slicings (20mm) were then made and observed with a fluorescence microscope. We measured the cartilage osteogenesis thickness and the histomorphometry parameters of the condyle in two groups and did statistical analysis. Results The statistical analysis showed that there was significant difference in the cartilage osteogenesis thickness, percent trabecular area, trabecular number, trabecular thickness and trabecular separation in the two groups (P<0.05). The solid diet groups exceeded those of the soft diet groups except trabecular separation. The mineral appositeion rate of solid diet groups [ (3.25±0.02)μm / d ] was higher than soft diet groups [ (2.37±0.02)μm / d ]. Conclusion The condylar cartilage osteogenesis in growing rabbits soft diet groups was weaker than hard diet groups. Mastication is an important factor which affecting the growth of the condylar cartilage osteogenesis.

Key words: Condyle, Cartilage osteogenesis, Mastication