Pattern of microimplant displacement during maxillary skeletal expander treatment: A cone-beam computed tomography study.

OBJECTIVE

To analyze the microimplant (MI) displacement pattern on treatment with a maxillary skeletal expander (MSE) using cone-beam computed tomography (CBCT).

METHODS

Thirty-nine participants (12 males and 27 females; mean age, 18.2 ± 4.2 years) were treated successfully with the MSE II appliance. Their pre- and post-expansion CBCT data were superimposed. The pre- and post-expansion anterior and posterior inter-MI angles, neck and apical inter-MI distance, plate angle, palatal bone thickness at the MI positions, and suture opening at the MI positions were measured and compared.

RESULTS

The jackscrew plate was slightly bent in both anterior and posterior areas. There was no significant difference in the extent of suture opening between the anterior and posterior MIs ( > 0.05). The posterior MI to hemiplate line was greater than that anteriorly ( < 0.05). The apical distance between the posterior MIs was greater than that anteriorly ( < 0.05). The palatal thickness at the anterior MIs was significantly greater than that posteriorly ( > 0.01).

CONCLUSIONS

In the coronal plane, the angulation between the anterior MIs in relation to the jackscrew plate was greater than that between the posterior MIs owing to the differential palatal bone thickness.