Mucogingival considerations in orthodontic treatment.

Alterations in the mucogingival complex will occur during orthodontic tooth movement, but these are independent of the apico-coronal width (height) of the gingiva. The integrity of the periodontium can be maintained during orthodontic therapy also in areas that have only a minimal zone of gingiva. In terms of changes in the position of the soft tissue margin and in gingival dimensions, the important factors to consider are the direction of the tooth movement and the bucco-lingual thickness of the gingiva. Lingual tooth movement will result in an increased bucco-lingual thickness of the tissue at the facial aspect of the tooth which results in coronal migration of the soft tissue margin (decreased clinical crown height). Facial tooth movement, on the other hand, will result in a reduced bucco-lingual tissue thickness and thereby a reduced height of the free gingival portion and an increased clinical crown height. The risk for development of recession type defects in conjunction with orthodontic tooth movement is present only if the tooth has been moved out of the alveolar bone housing, ie, when an alveolar bone dehiscence has been created.