Effects of local osteoprotegerin gene transfection on orthodontic root resorption during retention: an in vivo micro-CT analysis.

OBJECTIVES

External root resorption (ERR) is a serious complication of orthodontic treatment. Aim of this study was to evaluate the effects of local osteoprotegerin (OPG) gene transfection on ERR during retention.

MATERIAL AND METHODS

Eighteen 6-week-old male Wistar rats were divided into three groups. All the rats were subjected to 2 weeks of orthodontic tooth movement followed by a 2-week retention period. During retention, the three groups of rats received local OPG gene transfection (OPG transfection group, n=6), mock vector transfection (mock group, n=6), or no injections (control group, n=6). ERR of all three groups was evaluated with in vivo micro-CT analysis at three different time points: baseline, the last day of orthodontic tooth movement, and the last day of retention.

RESULTS

In the OPG transfection group, there was no significant difference between ERR at the baseline and ERR on the last day of retention. By the last day of retention, the repair ratio of ERR in the OPG transfection group was statistically higher in relation to the repair ratio of the other groups (p<0.001).

CONCLUSION

The results indicated that local OPG gene transfection significantly enhanced the repair of ERR during retention. Local OPG gene transfection might therefore be a useful tool for ERR repair during retention.