Abstract:

Objective

To explore the mechanism of periodontal remodeling by observing the expression of nuclear factor-kappa B （NF-κB） in the periodontium of rat molars during orthodontic tooth movement.

Methods

56 male SD rats， 8 weeks old and （220±25） g in weight were randomly divided into 6 h， 12 h， 24 h， 3 d， 7 d， 14 d， 21 d， and were loaded with 50 gram orthodontic force on one side of the maxillary first molar to detect the expression NF-κB immunohistochemically， the first molar on the other side were used as the nonappliance control.

Results

A weakly positive expression can be detected in the controlled groups； in the experimental groups， the concentration increased from 6 h，reaching to the peak at the 3rd day and 7th d， and then decreased until the 21st d， at that time， the positive expressions is still higher than that of the controlled side. The expression of the NF-κB in the pressed zone was higher than that that in the tension zone.

Conclusions

NF-κB may participate in the inflammatory reaction in the early stage and the reconstruction of the periodontal tissue in the late stage during orthodontic tooth movement of the rat molars. NF-κB may also plays a more important role in osteoclasts， while its role in bone formation needs further exploration.

Key words: Orthodontic force, Sprague-Dawley rats, Nuclear factor-kappa B, Immunohistochemistry