A POSTRETENTION STUDY OF PATIENTS PRESENTING WITH A MAXILLARY MEDIAN DIASTEMA

The purpose of this study was to assess postretention stability of max illary midline diastema closure, to search for predictors of relapse, and to test for associations between relapse and other postretention c hanges. The sample consisted of 35 patients with pretreatment diastema s ranging from 0.9 mm to 3.0 mm (mean 1.4, SD = 0.5) following eruptio n of the maxillary canines. Data were gathered from treatment charts, study models, periapical radiographs, and cephalograms taken pretreatm ent, posttreatment, and 1 to 26 years postretention (mean 11.4, SD = 6 .4). Measurable diastema relapse was observed in only 12 cases. The ma jority of the relapse was 0.6 mm or less, and maximum relapse was 3.0 mm. Abnormal frenums and/or intermaxillary osseous clefts did not appe ar to be risk factors for relapse, and no pretreatment predictors of r elapse could be established. The only posttreatment change associated with diastema relapse was proclination of the maxillary incisors (p<0. 01).