Dental arch effects after early and later timed cervical headgear treatment—a randomized controlled trial. (2nd January 2019) - Julku, Johanna
Summary: Background: Cervical headgear (CH) is a commonly used orthodontic appliance and its dentoalveolar changes are known. However, the effects related to gender and timing have gained less attention. Objectives: To examine dimensions of dental arches among children with Class II occlusion without posterior mandibular rotation according to timing of Kloehn-type CH treatment. Trial design: Prospective, randomized, parallel-group controlled trial. Methods: Sixty-seven seven-year-old children with a Class II occlusion were included in the study. The children were randomized into two equal-size groups in 1:1 ratio by sealed-envelope randomization. The early group (EG, n = 33) was treated between T0 and T1 (26 months), right after eruption of the first maxillary molars. The late group (LG, n = 34) was treated between T1 and T2 (24 months). The children were treated with CH until normal Class I occlusion on first molars was achieved. Impressions for dental casts were taken from all participants at T0, T1, and T2 . Blinding was applicable for outcome assessors. Changes in dental cast measurements were compared between the groups and genders using t -test, Mann-Whitney U -test, and repeated measures analysis of variance. Results: Of the children, 56 completed the study. The maxillary arch length and the transversal changes between the upper canines and upper first molars were significantly increased in EG at T0 −T1 ( P < 0.001). At T2, the transversal dimension between the upper first molars was larger ( P < 0.05), and in the lower arch the mandibular arch length ( P < 0.05) and the transversal dimension between the lower first molars ( P < 0.01) were increased in EG males compared to LG males. No harms were encountered. Conclusions: The male gender benefits most from early timing of the CH treatment, showing larger dimensions at the end of the follow-up. The results clearly indicated a wider and longer upper dental arch and spontaneous expansion of the lower dental arch after treatment. Clinical Registration: NCT02010346.