Expression of collagen I, collagen III and MMP-1 on the tension side of distracted tooth using periodontal ligament distraction osteogenesis in beagle dogs.

OBJECTIVE

To investigate the expression changes of collagen types I and III (Coll I and III) and matrix metalloproteinase-1 (MMP-1) in the periodontal ligament on the tension side of the distracted tooth using periodontal ligament distraction osteogenesis in beagle dogs.

METHODS

Twenty Beagle dogs were randomly divided into five groups of four dogs each according to their experimental periods. Dogs in each group were subjected to five days (T1), 10 days (T2), or 15 days (T3) of force loading, or 15 days of force loading with 10 days (T4) or 90 days (T5) of retention. For dogs in each group, the first premolar movement was achieved in the lower arch on one side (Exp) using periodontal distraction osteogenesis and on the other side (Con) using the conventional orthodontic method. The orthodontic movements of the first and third premolars in each group were measured at indicated time. Coll I and III expressions were determined by Picrosirius red staining and HE staining while MMP-1 expression was examined by immuno-histochemical staining.

RESULTS

Fifteen days of force loading resulted in faster movement of the first premolar on the Exp side, but no difference in the third premolar movements between the Exp and Con sides. Periodontal ligament tissue on the tension side was remodelled faster on the Exp side than on the Con side. The quality of the newly formed bone was acceptable. Coll III and MMP-1 in the periodontal ligament tissue reached a higher expression peak at an earlier time point on the Exp side than on the Con side. Significant difference also existed in the Coll I expression between the Exp and Con sides (P<0.05). During force loading, the Coll I expression first decreased and then increased on the Exp side, but increased continuously on the Con side. After 90 days' retention, collagen expressions showed no significant difference between the two sides (P>0.05) and the expression level of MMP-1 returned to normal on the two sides.

CONCLUSION

Rapid tooth movement accompanied with local upregulation of Coll I, Coll III, and MMP-1 was achieved in the early stage of periodontal distraction osteogenesis. The rapid tooth movement is in accordance with the physiological remodelling process.