Objective: to evaluate the dentoskeletal effects of CAD/CAM 3D-Printed fixed twin block versus MARA appliances in the management of skeletal class II due to Mandibular Deficiency in Preadolescence Class II malocclusion is considered one of the most commonly observed problems among orthodontic patients, representing around one-third of the patients seeking orthodontic treatment reflecting a significant economic impact. Various removable and fixed functional appliances are commonly used to stimulate mandibular growth. Fixed Twin-block appliance has advantages compared with removable Twin-block and Herbst appliances. The mandibular anterior repositioning appliance is referred to as M.A.R.A. appliance.
Materials and method: The study design is a randomized controlled trial in which the control group and intervention groups will be assessed as parallel groups with a 1:1:1 allocation ratio. Sixty subjects will be enrolled in this research. They will be divided equally into three groups: untreated control, MARA group and Twin block group