Treatment of children with ectopic eruption of the maxillary first permanent molar by cervical traction

The sequelae of extraction of the second deciduous molar due to irreversible ectopic eruption of the maxillary first permanent molar are mesial tipping of the permanent molar and subsequent space loss. The purpose of this study was to evaluate the effects of early treatment with the Kloehn type of cervical headgear. Forty-six children with ectopic eruption were treated. The mean age at the start of treatment was 8.3 years (range, 6.5 to 9.9 years) and the mean treatment time was 0.8 year (range, 0.5 to 1.0 year). Nineteen variables from orthopantomograms, lateral head films, and dental casts were analyzed by one-way analysis of variance. The registrations were made at the start of treatment, at the end of treatment, and 1 year posttreatment. The treatment resulted in distal tipping of the first permanent molar to a good occlusion in all children. The s-n-ss angle decreased during treatment in all children, and a mean proclination of the maxillary incisors of 3 degrees was registered. Proclination was independent of the type of occlusion and was unchanged 1 year posttreatment. The ss-n-sm angle was also reduced during treatment and was unchanged 1 year posttreatment. The most favorable time for treatment seems to be when the second premolar is close to eruption or erupting at the end of the treatment period. Because of the risk of inhibited sagittal growth of the maxilla with this type of treatment, careful cephalometric evaluation is considered important before the start of treatment.