ABSTRACT
The present study was conducted to evaluate the effect of horizontal activator on patients suffering from skeletal and dental class II division 1 malocclusion. The sample consist of 13 Iraqi patients of both genders at early adolescent period, 1 year before maximum growth spurt [12 years for females and 14 years for males]. The study aimed to evaluate the skeletal effect of horizontal activator treatment, examine the dental treatment modulation due to activator therapy, and determine the mode of activator treatment whether it is a skeletodental or a change in the glenoid fossa position. The main findings were that H-Activator treatment has orthopedic and orthodontic effect and its orthopedic effect is observed more on the mandible than the maxilla by increasing the length of the mandible with remodeling of the glenoid fossa. Moreover, its dental effect is more on the upper dentition than the lower dentition. This is mostly on the upper incisors by biomechanical forces applied by the appliance which is originally gained from the muscles of mastication, however, dental changes were insignificant