Maxillary canine retraction, periodontal surgery, and relapse.

Extraction spaces closed during the course of orthodontic therapy tend to re-open, whereas orthodontically rotated teeth are prone to relapse. One of the major causes of spaces opening between teeth is the supra-alveolar soft tissues which do not always adapt to the new tooth positions. Seven patients requiring extraction of upper first premolar teeth as part of their orthodontic treatment were selected for this study. Tattoo marks were placed in the attached gingivae close to the upper canine teeth. The canines were then retracted orthodontically across the extraction spaces. The left side was designated the control side and the right side the experimental side. Immediately after completion of retraction, the attached gingiva was surgically detached from the canine teeth on the experimental sides. The canines on both sides were retained in their new positions for 8 weeks following space closure. The amount of relapse or recoil of the gingivae was measured. In this study the gross gingival changes were similar to those described by Atherton and Kerr, Atherton, Edwards. The tattoo marks moved distally with the retracted canines. The amount of gingival movement was similar on both experimental and control sides and ranged between 49.4 percent and 82.4 percent of the retraction distance. Very little recoil or relapse of the gingivae occurred following surgical detachment from the canines. The results of this study indicate that the gingivae appear to adapt to the new tooth position and that relapse of canines retracted across extraction sites in the maxilla is not necessarily caused by the supra-alveolar soft tissues.