[Analysis of the plaster casts of Class II division 1 non-extraction patients treated with Alexander technique].

OBJECTIVE: To investigate the changes of arch width and arch length in Class II division 1 non-extraction patients treated with Alexander technique. METHODS: Dental casts of 21 Class II division 1 non-extraction patients treated with Alexander appliance were taken before (T1) and after treatment (T2). All the casts were laser scanned. The arch width and arch length were digitally measured. The differences of arch width and arch length between T1 and T2 were recorded and analyzed. RESULTS: The upper arch length decreased from (32.82 +/- 2.51) mm to (31.97 +/- 2.17) mm (P < 0.05). The lower arch length increased from (27.53 +/- 2.61) mm to (28.80 +/- 1.81) mm (P < 0.05). The intercanine width in the upper arch changed significantly from T1 to T2. The intermolar width in the upper and lower arches increased significantly from T1 to T2. CONCLUSIONS: Class II division 1 non-extraction patients could be treated successfully by increasing the upper arch width.