Apical root resorption in patients treated with en-masse retraction using skeletal anchorage system versus conventional method

Purpose: To compare external apical root resorption EARR in orthodontic patients treated with en-masse retraction with skeletal anchorage (miniscrews) versus two step procedures.
Patients and methods: Forty patients were randomly divided into two equal groups. Group I consisted of 20 patients were treated by using mini-screw anchorage and en-masse retraction, while, group II, 20 patients were treated with two-step retraction and conventional methods of anchorage reinforcement. Lateral cephalometric and digital panoramic radiographs were used to evaluate treatment changes just before (T1) and immediately after (T2) retraction of the maxillary anterior teeth.
Results: A significant positive correlation between age and root resorption. Shorter treatment duration was needed in group I with insignificant difference between both groups. Significant root resorption in maxillary central, lateral incisors, canines and first molars was found in both groups just after retraction. A significant root resorption was found for maxillary centrals and first molars in mini-implant group compared to conventional anchorage group. Upper first molars were intruded (-1.8 mm, P=0.041) in mini-implant group with no significant distalization (P=0.016) compared to conventional anchorage group. Upper incisors were significantly retracted (-7.8mm, P=0.001) and intruded (-2.3mm, P=0.017) in comparison to other group.
Conclusion: Skeletal anchorage system tends to permit more root resorption than conventional anchorage procedure. A significant retraction and intrusion of maxillary incisors, and a significant intrusion and lack of distalization of maxillary first molars by using skeletal anchorage system during en-masse retraction was found when compared with conventional anchorage procedure.