Objective: To investigate the effects, indications and clinical significance of single maxillary extraction orthodontics used for class II division 1 malocclusions.
Methods: 14 class II division 1 patients were treated by single maxillary extraction orthodontics, the cephalometric data before and after treatment were analysed by statistical methods.
Results: After treatment, 1. the angle 1-FH had decreased by 11.03 degrees and the angle 1-MP had increased by 3.07 degrees; 2. The mandibular length had increased by 3.30 mm; 3. the upper and lower lip were retruded by 2.65 mm and 1.64 mm respectively. Statistical significance (P < 0.001-0.05) was found between the means before and after treatment.
Conclusions: Single maxillary extraction orthodontics is suitable for class II division 1 patients with less labial tipping of lower incisors and less lip protrusion.