This study compares two types of dental appliances a fixed Twin Block appliance and a conventional (removable) Twin Block appliance used to treat a bite problem called skeletal Class II malocclusion in growing children and teenagers. In this condition, the lower jaw is positioned further back than the upper jaw. Both appliance types work by guiding the lower jaw forward during growth. The study uses 3D imaging (cone beam computed tomography, or CBCT) before and after treatment to measure how each appliance affects the bones of the jaw, the teeth, the soft tissue profile of the face, and the jaw joint (temporomandibular joint). The goal is to determine whether the fixed or the conventional version of the appliance produces better treatment outcomes.