Transverse Malocclusions: Etiology, Development, Diagnosis and Treatment

Abstract

Malocclusions that involve the transverse dimension are very common in the orthodontic office. They can be as simple as a crossbite of the posterior teeth or as severe as a Class III malocclusion with a mandibular asymmetry. Transverse malocclusions can vary from being a simple dento-alveolar problem to a more complex challenge as represented by a skeletal asymmetry that has developed after puberty and causing temporomandibular disorder (TMD) problems. In this review we shall address the most common types of transverse malocclusions and review their etiology and development. The most typical etiology of transverse anomalies will be discussed, and we will suggest diagnostic criteria to differentiate the individual malocclusions. We shall also introduce a frontal cephalometric analysis that relates to the anterior part of the face helping to differentiate between dento-alveolar and skeletal transverse malocclusions as well as determine the presence of dento-alveolar compensations. Furthermore, we shall suggest possible treatment approaches and the best timing of treatment for the most common types of transverse malocclusion. Finally, we shall present several cases with more unusual etiology including a case with mandibular asymmetry due to an anterior disc displacement of temporomandibular joint. A case with Class III malocclusion with mandibular overjet caused by maxillary stenosis will also be presented. Furthermore, we will show an example of a late developing mandibular asymmetry which is not an uncommon problem and document a case of excess mandibular growth with mandibular asymmetry and Class III malocclusion combined with posterior crossbite. This review will also address considerations that may affect the post treatment stability.