Light archwire technique in Angle Class II Division 1 high angle extraction cases

Abstract

Objective To investigate the soft and hard tissue changes in Class Ⅱ Division 1 high angle extraction cases treated by light archwire technique with straight archwire appliance. Methods Seventeen Class Ⅱ Division 1 patients with high angle who met the including criteria were included into this retrospective study. Cephalometrics of pre and post treatment lateral films were traced by hands and its statistical analysis was performed via SPSS 15.0 software package. Results After treatment of the seventeen subjects, molar and cuspid relationships were Class I and normal overjet and overbite were established. ANB and U1-NA decreased by 1.18°and 19.13°respectively. L1-NB and L1-MP decreased by 6.42° and 5.28°. OP-MP and tilt angle of chin decreased by 0.19°and 3.99°. Prominence of chin increased by 0.46 mm. L6-MP increased by 0.98mm. These changes were statistical significant. However, vertical changes for incisors and upper molar showed no significant changes. Remarkable soft tissue change was noted after orthodontic treatment. FCA decreased by 4.56° and NLA increased by 16.48°.The prominence of upper and lower lips to aesthetic plane decrease by 4.93 mmand 3.99 mm. PosB'-FH increased by 6.88°. These changes showed statistical significance. Conclusions The Class Ⅱ Division 1 patients who were treated by light archwire technique with straight archwire appliance could get good control of the vertical dimension in high angle cases after four first premolars extraction and the profile could be improved significantly. Key words: High angle; Angle Class Ⅱ Division 1; Extraction; Straight archwire appliance; Light archwire technique