Purpose: To evaluate the treatment effect of headgear for distal movement of maxillary first molars to correct the crowding caused by molar anterior displacement.
Methods: 12 crowding cases were treated with headgear combining with fixed appliances if necessary. Cephalometric radiographs and casts were taken and analyzed before and after treatment. SPSS13.0 software package was used for paired-samples t test.
Results: The crowding of upper arch was significantly decreased (P<0.05), the amount of crowding decrease was from 3.0 mm to 6.0 mm, the average crowding decrease of 12 cases was 4.52 mm. The decrease was mainly due to the distal movement of the first upper molar, the amount of decrease of Ptm-U6 was from 1.2 mm to 3.5 mm, the average was 2.14 mm.
Conclusion: Distal movement of the first upper molar by headgear is one of the effective way to solve the upper crowding.