The significance of the width and thickness of the gingiva in orthodontic treatment.

The results of the studies reviewed have shown that, while the apico-coronal width of the gingiva is unlikely to affect the development of a recession defect, the thickness of the marginal soft tissue may be essential for the prevention of soft tissue recession in conjunction with orthodontic therapy. The clinical implication of these findings is that tooth movement--particularly tooth movement in facial/lingual direction--should be preceded by careful examination of the dimensions of the tissues covering the "pressure side" of the teeth to be moved. As long as the tooth can be moved within the envelope of the alveolar process, the risk for harmful side-effects in the marginal soft tissue is minimal, irrespective of dimensions or quality of the soft tissue. If, however, the tooth movement is expected to result in the establishment of an alveolar bone dehiscence, the volume (thickness) of the covering soft tissue must be considered as a factor which may influence the development of soft tissue recessions during, as well as after, the phase of active orthodontic therapy. A thin gingiva may serve as a locus minorus resistentiae to developing soft tissue defects in the presence of bacterial plaque. This means that in tooth regions with a thin covering soft tissue, the patient must be encouraged to carry out effective but at the same time non-traumatic plaque control measures. If surgical intervention is considered in order to reduce the risk for development of soft tissue recession following orthodontic therapy, this should aim at increasing the thickness of the covering tissue (e.g. by the use of connective tissue grafts) and not the apico-coronal width of gingiva.