The ALF appliance in New York City has so many positive benefits. Not only does it not interfere with speech or proper tongue positioning as it expands your palate, but it also helps to create a healthy foundation for accurate mandibular positioning, enhanced airway space, and a sound bilateral TMJ relationship. So, how does it work? The ALF appliance at Park Avenue Orthodontics: Dr. Janet Stoess-Allen uses a light, natural, continuous force to open the sutures of the maxilla for lateral expansion and also anterior protraction.