Dental arch effects after early and later timed cervical headgear treatment—a randomized controlled trial

Abstract

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.

Effect of cervical headgear on dental arch area, shape and interarch dimensions

“…In the present study, the headgear treatment was initiated earlier than in most other studies [14][15][16]. It is interesting that in the study of Julku et al [17] where early or later headgear treatment was compared, a larger effect was achieved in the dental arches in the early treatment group. When the treatment effect was compared between the genders, a larger effect was seen in boys.…”

Comparison of effects of cervical headgear treatment on skeletal facial changes when the treatment time is altered: a randomized controlled trial

“…The sample size calculation, screening and randomization as well as blinding have been described in detail in previous articles of this study (8,18).…”

“…The CH therapy was carried out by clinicians in community health centres. A more detailed description of the interventions is available in the previous articles (8,18).…”

“…A total of 56 children completed the second follow-up (T2). A more detailed description of the participants is available in the previous articles (8,18). Of the 67 subjects at the baseline, 6 subjects did not attend in either analysis T1 or T2, but they did not differ from those who did, in terms of group or gender, or any of the linear or angular measurements at T0.…”

“…There are a few reported differences between genders after CH treatment, but these are mostly considered to be gender-specific growth changes and not caused by CH treatment (4,13). Recent evidence has shown that when the timing of the treatment is altered, gender does have an effect on treatment outcomes (8,18).…”