The current trial was designed to investigate the possible initial net skeletal and dental effects of treatment with FLMGM by a comparative evaluation of treated and untreated Cl II/1 malocclusion subjects. The null hypothesis stated that there were no significant differences in dentofacial changes between FLMGM group and control group.

The study was prospective controlled clinical trial conducted at the department of Orthodontics, between May/2009 and June/2011. The protocol of study was approved by the council of scientific research and postgraduate studies.

The original study sample included 43 patients (25 treated, 18 untreated). Of the 43 patients initially enrolled, 38 completed this trial and comprised the final sample, and 5 (4 treated, 1 untreated) were excluded . All patients and parents gave prior informed consent to their inclusion in the investigation.

Patients of both groups were followed on a parallel basis during a period of 8 months and included in the trial regardless of achievement of a Class I incisor relationship. All patient of treatment group (n=21) were treated with FLMGM, and treatment was continued beyond this time point if the Class II malocclusion was not fully corrected and clinical objectives were not achieved. On the other hand, no orthodontic treatment was performed during that duration for the subjects of control group (n=17), and most of control subjects were offered suitable treatment at a later date.

For each patient, a direct digital lateral cephalogram was taken pre- and post- treatment/observation using PAX 400 (VATECH CO., Korea) with the same settings. Cephalograms were digitized on screen and analyzed in a blind manner by the same orthodontist using a cephalometric software (Viewbox, 3.1.1.13, Kifissia). . All linear measurements were reduced to life size (enlargement: 7.54%).

Pretreatment equivalence, changes occurring during the examination period in each group and comparison of changes observed in both groups were tested for significance with t-tests using SPSS . P values of less than 0.05 were considered statistically significant. To assess the method error, twenty cephalograms were randomly picked from both groups and redigitized and analyzed by the same orthodontist after 1 month, and the method error was calculated by Dahlberg's formula.

Inclusion Criteria:

Before treatment, each patient fulfilled the following criteria:

1. Cl II/1 malocclusion with an overjet greater than 4 mm.
2. Mild to moderate Class II Skeletal pattern (A-N-B > 4°) with retrognathic mandible (S-N-B < 76°).
3. Growth potential. Fishman skeletal maturation indicator (SMI) method28 was used to assess the hand-wrist radiographs, and only patients in the peak of the pubertal growth spurt, which occurs on average between SMIs 4 to 7,29 at the beginning of the treatment/observation period were invited.

Exclusion Criteria:

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Using Bland formula (1995)