关键词: Halterman矫治器, 上颌第一恒磨牙, 异位萌出, 儿童

Abstract: Objective    To investigate the therapeutic efficacy of a modified Halterman appliance in managing ectopic eruption of maxillary first permanent molars in children. Methods    This study enrolled 75 children with unilateral severe ectopic eruption of the maxillary first permanent molars，who received treatment in the Department of Pediatric Dentistry，Hefei Stomatological Hospital，from January 2023 to June 2025. All patients received intervention with a modified Halterman appliance. The treatment duration was recorded，and the retention rate of affected maxillary second primary molars was evaluated at 6 months after treatment. Pre- and post-treatment panoramic radiographs were used to measure and analyze the mesial tipping angle on the affected side and the healthy contralateral side and horizontal distance of maxillary first permanent molars on the affected side. Results    The mean treatment duration of the 75 children was（144.0 ± 47.4）d. The treatment duration of children with grade Ⅲ ectopic eruption（n = 36），grade Ⅳ ectopic eruption（n = 24），and those with loss of the affected second primary molar（n = 15）was（132.3 ± 41.2）d，（148.4 ± 58.5）d，（165.2 ± 42.4）d，respectively，with no statistically significant difference among the three groups（F = 0.690，P = 0.514）. At 6 months after treatment，the retention rates of the affected second primary molars in children with grade Ⅲ and grade Ⅳ ectopic eruption were 91.7%（33/36）and 37.5%（9/24），respectively，and the difference was statistically significant（χ2 = 20.119，P < 0.001）. After treatment，the mesial tipping angle and horizontal distance of the affected maxillary first permanent molars were significantly increased compared with the pre-treatment values，with statistically significant differences（t = 10.161，14.044，both P < 0.001）. The mean increase in mesial tipping angle was 21.9（17.5，26.2）°，and the mean distal horizontal movement was 3.3（2.8，3.8）mm. Before treatment，the mesial tipping angle of the affected maxillary first permanent molars was significantly smaller than that of the contralateral healthy side（t = 9.531，P < 0.001）；after treatment，no significant difference was observed in the mesial tipping angle between the two sides（t = 1.924，P = 0.067）. Conclusion     The modified Halterman appliance can effectively improve the inclination of severe ectopic eruption of maxillary first permanent molars in children and promote normal eruption of these teeth. Early clinical intervention is therefore recommended to lower the risk of premature loss of the second primary molars.

Key words: Halterman appliance, maxillary first permanent molar, ectopic eruption, children