The aim of the present research was to evaluate and compare distribution of chewing movements of the young individuals with normal occlusion and malocclusion according to the male and female gender and to compare the movements. Furthermore, examination of whether a difference exists on chewing movements according to the gender was also addressed. Materials and methods: This is a prospective clinical study carried out on totally 63 individuals including 43 patients with malocclusion and an age

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... erage of 16.79 years whose growth and development terminated partially and 20 individuals with normal occlusion and age average of 24.77 years who did not have any orthodontic treatment. Totally 63 individuals including 25 individuals with skeletal and dental Angle Class I, 18 individuals with skeletal and dental Angle Class II before and at sixth month of the orthodontic treatment and 20 individuals as the Control group were enrolled into the research. The gender difference of totally 17 males including 8 Class I males and 9 Class II males and 26 females including 17 Class I females and 9 Class II females with normal occlusion were evaluated. Finally, association between 17 Class I and Class II males and 26 females were checked. Chewing movements obtained through a Jaw Tracker were used in the present study. Chewing Opening Time (msec), Chewing Closing Time (msec), Chewing Occlusion Time (msec), Total Chewing Time (msec), Vertical Chewing Length (mm), Chewing Opening Velocity (ms) and Chewing Closing Time (ms) were analysed. In consideration of equal number of samples (n=n1=n2) and states of different number of samples, paired sample t-test and Wilcoxon test were used to compare averages of two dependent groups whereas independent sample t-test and Mann Whitney U test were utilized for comparison of two independent groups. Results: Although there was not any statistically significant difference detected between occlusion duration and total chewing cycle as well as average open velocity (mm/sec), statistically significant differences were found between opening, closing chewing velocities and average closing velocity (mm/sec) (P<0.01). For female patients, statistically significant results were obtained in distance between opening and closing and opening and closing velocities. Moreover, statistically significant difference was detected between closing of males and females at the onset of the treatment and at sixth month. It was detected that malocclusion has a statistical significance in chewing difference between the genders during initial treatment and other parameters were not important. A similar association was also found between changes at initial treatment and at month 6.