Macrodontia Associated with Mandibular Distraction Osteogenesis.

Infants diagnosed with Pierre Robin sequence frequently have airway obstruction. In severe cases of obstruction, mandibular distraction osteogenesis (MDO) can alleviate the airway blockage through elongation of the mandible and subsequent anterior placement of the tongue. However, there are several complications associated with MDO in the very young child. Among those are injuries to teeth that develop in the area of the MDO osteotomies. Such injuries include distalization and/or morphologic anomalies of primary and permanent molars. We describe a case of an unusual macrodontia of the primary mandibular left second molar in a six-year-old male who underwent MDO as an infant. We believe that the mesial-distal elongation of the crown of the primary second molar occurred through distraction histogenesis of the tooth structures during the distraction of the mandible. We discuss the importance of preoperative planning to minimize such damages to the developing dentition.