Mouth breathing and orthodontic intervention: Does the evidence support keeping our mouths shut?

It is believed that mouth breathing, particularly during early childhood, is associated with the development of various unfavorable craniofacial characteristics such as mandibular retrognathia, narrow high arch palates and alar bases, lip incompetence, increased vertical facial height, and mandibular plane angles. Today, there is significant debate and confusion pertaining to the role of orthodontists in identifying and managing mouth breathing, especially for young patients as early as 3 years old. Using the historical and contemporary evidence-based literature along with an ethical and pragmatic clinical perspective, the role of mouth breathing and early orthodontic intervention is put into perspective in this paper.