OrthO tribunE | OctObEr 2009 industry clinical 11 Analyzing the modus operandi of the trAinEr System Appliances By German Ramirez-Yañez, DDS, MDSc, PhD Part 2 of three A s suggested by the name, the appliances of the TRAINER System™ just train or exercise the muscles at the craniomandibular system (CMS) to physiologically load the bones, stimulating growth and development in the structure composing the CMS. Through development of the maxilla, the mandible and the dental arches, as well as by re-educating tongue posture, the teeth tend to position better and align correctly. The effects produced by the trainers on the maxilla and mandible have been demonstrated through scientific studies (Usumez et al. 2004; Ramirez-Yañez et al. 2007), as well as through clinical cases successfully treated with these appliances and reported in the literature (Ramirez-Yañez GO and Faria P. 2008; Kanao et al. 2009). Currently, there is ongoing research with the TRAINER System Appliances focusing on understanding their effect on the muscular activity of the masticatory and facial muscles, as well as further investigation of the positive effect the appliances can have in mouthbreathing patients and on some altered oral functions, such as swallowing. In the following sections, the modus operandi of the TRAINER System Appliances are explained, considering separately their effect on the three dimensions of the mouth: sagittal, transverse and vertical. Scientific literature supporting the physiological concepts involved in the effects produced by the trainers is presented to further support the concept that the TRAINER System Appliances (including the MYOBRACE®) are a viable alternative in treating malocclusion. Frans & Proffit 2004) that all action maintained for more than six continuous hours produces an effect on the CMS. The trainers maintain the mandible in a forward position for 10 to 12 hours during the night, keeping the muscles protruding the mandible stretched. This makes the blood vessels in the muscle decrease their diameter, which hinders sufficient blood flow, therefore decreasing the gas and substance exchange in the muscle through the blood. This situation produces muscular tiredness due to an accumulation of lactic acid in the muscle. A similar physiological process occurs in our body when people initiate an exercise routine at the gym, and muscles that had not been used for a certain period are activated. This is the reason a patient wearing any of the trainers complains of muscular soreness on the face and mouth during the first couple weeks of treatment. When the appliance is taken out of the mouth, the muscles protruding the mandible fall into hyper-contractibility (involuntary and repeated contractions of the muscles), which moves the mandible forward and backward. This explains why at the beginning of treatment (about three to four weeks), patients report that in the morning when they remove the TRAINER (or MYOBRACE) from the mouth, they g OT page 12 AD Sagittal growth and development (antero-posterior) The effect produced by the TRAINER System Appliances is in part similar to those functional appliances designed to stimulate mandibular growth and development by bringing the mandible forward into an edge-to-edge position (bionator, monoblock, twin-block, etc). By placing the mandible in such a position, the muscles protruding the mandible are stretched (masseter, medial pterigoid and lateral pterigoid muscles). The TRAINER Appliances are recommended to be worn one to two hours during the day and 10 to 12 hours at night while sleeping. It was explained by Van der Linden and colleagues (Van der Linden,