Dentoskeletal Changes Produced by Growth Modification Appliances in Treatment of Skeletal Class II Malocclusion

Twin block appliance (RFA) was introduced by William Clark in 1988. Many modifications for this appliance have been introduced lately. It has been named twin block for the characteristic of two unattached maxillary and mandibular plates with acrylic bite blocks, which makes 70o angle when come in contact with each other. Delta clasps are added for better retention of the appliance. This appliance plays a vital role in the treatment of mandibular retrognathia

AdvanSync2 (Ormco Co., Glendora, Calif) is a FFA being introduced recently as an advancement of Herbst appliance. It is a molar-to-molar appliance, connected by a telescopic rod, which allow for simultaneous treatment with braces. It is much smaller in size than the conventional Herbst appliance and reduces treatment duration up to six to nine months. It is much more acceptable by the patients as they complain less about sores and discomfort, and is esthetically pleasant since it's not visible in the mouth. Short arms of this appliance help to decrease irritation and discomfort of the patient, and helps to advance the mandible in a constant forward direction to encourage growth, and reduce malocclusion.