Dental functional appliances are orthodontic devices designed to correct irregularities in the alignment of the teeth and jaw, particularly focusing on issues relating to how the upper and lower jaw fit together (malocclusion). These appliances work by utilizing the natural muscle action produced when eating, speaking and swallowing to apply gentle pressure to the teeth and jaw, promoting proper positioning and alignment over time. They are commonly used in orthodontic treatment for conditions such as overbites, underbites and crossbites. Examples of dental functional appliances include palate expanders, headgear, Herbst appliances and bite plates. These appliances can help improve chewing function, speech clarity and overall facial aesthetics by guiding proper jaw growth and development.