One year treatment effects of the eruption guidance appliance in 7- to 8-year-old children: a randomized clinical trial.

Background: The eruption guidance appliance (EGA) aims to correct sagittal and vertical occlusal relations concomitantly with alignment of the incisors. Few reports have been published on treatment effects with the EGA but no randomized studies have been available. Objectives: The aim was to find out if 1 year active treatment time with EGA was sufficient for achieving normal occlusal relationships and dental alignment in 7- to 8-year-old children. Participants, study design, and methods: Eligibility criteria for participants were: fully erupted upper central incisors, and Angle's Class I or Class II molar relationship combined with any of the following traits: deep bite, increased overjet >= 5 mm, moderate anterior crowding with overjet >= 4 mm. After screening of 148 children, 48 7- to 8-year-old children were recruited in the study. The participants were randomly assigned into a treatment group (N = 25) and a control group (N = 23). Children in the treatment group received treatment with the EGA for 1 year. The controls had no orthodontic treatment. Changes in overjet, overbite, Angle's Class, and crowding were used as primary outcome measures. Occlusal assessments were performed on dental casts obtained from all subjects at start of the study (T1) and after 1 year (T2). Lateral cephalograms were obtained from all subjects at T1 and from the treatment group at T2. All measurements on dental casts and cephalograms were carried out blinded. Results: Forty-six children completed the study. Mean overjet and overbite decreased significantly in the treated subjects during 1 year, in contrast to a slight increase in the controls. Class II molar relationship decreased from 46 to 4 per cent in the treatment group, with no significant change in the control group. Mandibular anterior crowding decreased significantly in the treated subjects, while the controls showed a slight increase. Conclusions: In short term, the EGA seems to be effective in correcting increased overjet and overbite, Class II malocclusion, and lower anterior crowding in the early mixed dentition. Followup data are needed to assess long-term effects of this treatment. Registration: This study was not registered.