Comparision of the dentofacial effects between power-arm face bow and the new system used for unilateral molar distalization at upper arch

Comparision Of The Dentofacial Effects Between Power-Arm Face Bow And The New System Used For Unilateral Molar Distalization At Upper ArchThe purpose of this study was to evaluate the effects of a new method (Ata headgear) developed to provide unilateral maxillary molar distalization and power-arm face bow, which is a type of unilateral face bow and to compare the effects of both applications and growth and development. There were three groups in this study. One of which was a control group and the other two were application groups. Each group consisted of 17 patients; 14 females and 3 males, a total of 51 patients.It was conditioned that the subjects were all in permanent dentition with their second molars fully erupted and they had asymmetrical class II molar relationship with no skeletal problem prior to the study. The subjects in each group were paired by sex, skeletal age, and chosen skeletal parameters to make the groups.In power-arm face bow application, both of the maxillary first molars were banded. The long outer arm where molar distalization is required, bended 20 degree outward and the short outer arm where molar distalization is not required terminated at the mesial of maxillary first molar. Cervically directed force of 350-400 gr per side was applied. In Ata headgear application, maxillary first molar and the other side maxillary second molar were banded. Cervically directed force (350-400 gr per side) was delivered to the first molar on one side where molar distalization is not required and to the second molar on the other side where molar distalization is required by bilaterally symmetrical face bow.36 Once the desired molar relationship was obtained ın both applicaton group, molar distalization was terminated.Lateral cephalograms, posteroanterior cephalograms, hand-wrist radiographs, panoramic radiographs and orthodontic models were taken from patients at the beginning and end of the study. Parametric and nonparametric tests were used for the statistical evaluation of the data depending on the results of distribution fit analysis whether it was a normal distribution or not.In both application group, the amount of distalization for banded maxillary molars and the amount of distal tipping of banded molar where molar distalization is required were found to be statistically significant. In transversal plane, power arm face bow caused buccal movement on banded molars and Ata headgear caused palatinal movement on banded molars. In three groups, skeletal structures showed statistically insignificant change except for the increase of anterior and posterior face heights in power-arm face bow application group and control group.In conclusion, both power-arm face bow and Ata headgear applications were effective on asymmetrical distalization.Key words: Asymmetrical distalization; Unilateral face bow; Unilateral class II molar relationship; Ata headgear; Power-arm face bow