Headgear therapy in children with Class II malocclusion and the role of compliance on treatment outcome: A nine-month randomized controlled trial

OBJECTIVES

To evaluate three-dimensional movements of maxillary teeth during headgear treatment in Class II growing children, using digital analytical tools, and to determine the effects of compliance on these movements.

MATERIALS AND METHODS

A 9-month parallel-group randomized controlled trial was carried out on 40 children with Class II malocclusion, aged 8-12 years, half assigned to receive a cervical headgear and half to a no-treatment group, using block randomization. Subjects in the treatment group were instructed to wear the headgear for 12 hours daily and monitored using an electronic module. After 9 months, the following dental outcomes were measured: first maxillary molar distalisation, rotation, tip and torque, arch depth, and interpremolar and intermolar distances. Caregivers and participants were not blinded to group assignments, but those assessing outcomes were. Linear regression models were used to detect differences between groups and correlation coefficients to find correlations between compliance and dental outcomes.

RESULTS

All 40 included patients were analysed. A significant difference in molar distalisation was observed between the treatment (1.2 mm) and control groups (-0.2 mm). Arch depth change was also increased to a larger extent in the treatment groups (1.3 mm vs 0.1 mm), as was the interpremolar distance (1.9 mm vs 0.4 mm). In contrast, no significant differences in molar rotation or torque change were observed. With regard to compliance, average compliance was 55%. A significant correlation was found between molar distalisation and compliance in the treatment group.

CONCLUSIONS

Headgear therapy has significant effects on molar distalisation, arch depth, and arch width. Compliance has a significant positive effect on molar distalisation.

Cervical headgear therapy and sleep-related attributes

INTRODUCTION

The study aimed to assess (1) the effect of the treatment with cervical headgear on patients' sleep-related attributes and well-being and (2) whether these sleep-related parameters (ie, sleep quality and quantity) were associated with patients' compliance during the orthodontic treatment.

METHODS

The study protocol was based on a prospective longitudinal quasi-experimental design. Participants (n = 26; 9 males; mean age, 12.4 ± 1.68 years) were patients in the Postgraduate Orthodontic Clinic, National and Kapodistrian University of Athens. All patients received treatment with a cervical headgear having an embedded TheraMon microsensor. Sleep was assessed by wrist-worn actigraphy for 59 ± 19 days. The Epworth Sleepiness Scale was used to assess average daytime sleepiness, whereas we used the Athens Insomnia Scale for insomnia symptoms. Oral health-related quality of life (OHRQOL) was assessed by the Oral Health Impact Profile (OHIP-14).

RESULTS

Patients slept on average 7.35 ± 0.42 h/d. Compared with the lowest sleep duration recommended for their age group, patients had an average chronic sleep deficit of 1.40 ± 0.49 h/d. Patients wore the headgear 90.9% of the days for 10.40 ± 4.17 h/d. However, only 7 (28%) patients reached or exceeded the wear-time recommendation of 12 h/d. In contrast, 2 (8%) patients wore headgear <5 h/d, 11 (44%) 5-10 h/d, and 12 (48%) patients wore headgear >10 h/d. Aggregated by participants, the median Epworth Sleepiness Scale score during the study was 3.40 (interquartile range [IQR], 4.85; range, 0.2-13.6), the median Athens Insomnia Scale score was 3.00 (IQR, 4.25; range, 0-7), and the median Oral Health Impact Profile score was 1.40 (IQR, 4.17; range, 0.0-20.8). Compared with patients who wore the orthodontic appliance >7.8 h/d, patients who wore it <7.8 h/d had worse average daytime sleepiness (P = 0.050) and worse OHRQOL (P = 0.019).

CONCLUSIONS

Orthodontic treatment with cervical headgear has no substantive negative effect on sleep attributes (quantity and quality), average daytime sleepiness and OHRQOL. However, poor compliance with orthodontic treatment seems to be associated with higher levels of daytime sleepiness.

Effects of force magnitude on dental arches in cervical headgear therapy

AIM

To study the influence of different force magnitudes on dental arches in cervical headgear (CHG) treatment.

MATERIAL AND METHODS

In this controlled clinical trial, patients (n = 40) were treated with CHG with light (L, 300 g, n = 22) or heavy force (H, 500 g, n = 18) magnitude. Subjects were asked to use CHG for 10 hours a day for 10 months. The outer bow of the CHG facebow was raised 10-20 degrees and the inner bow expanded 3-4 mm. Adherence to instructions and force magnitude were monitored with an electronic module (Smartgear, Swissorthodontics, Switzerland). Impressions for study models were taken before (T1) and after (T2) treatment and the study models were scanned into digital form (3Shape, R700 Scanner, Denmark). Measurements were made using the digital models (Planmeca Romexis, Model analyser, Finland).

RESULTS

During the treatment (T1-T2) the upper inter-canine distance increased by 2.83 mm (P = 0.000) and 2.60 mm (P = 0.000) in the L and H force magnitude groups, respectively. Upper inter-molar width increased by 3.16 mm (P = 0.000) and 2.50 mm (P = 0.000) in the L and H groups, respectively. Maxillary total arch perimeter increased by 6.39 mm (P = 0.001) and 6.68 mm (P = 0.001) in the L and H groups, respectively. In the amount of change over time, T1-T2, in the upper arch measurements, no significant difference was found between the groups. Lower inter-canine width increased by 0.94 mm (P = 0.005) and 1.16 mm (P = 0.000) in the L and H groups, respectively; no difference between the groups. Lower inter-molar distance increased by 2.17 mm (P = 0.000) and 1.11 mm (P = 0.008) in the L and H groups, respectively. At the end of the study, upper and lower inter-molar width was larger in the L group than in the H group (P = 0.039 and P = 0.022, respectively).

CONCLUSION

CHG therapy is an effective method for expanding and releasing moderate crowding of the upper dental arch. The lower arch spontaneously follows the upper arch in widening effects, and minor expansion can also be seen on the lower arch. In the L group, larger inter-molar width was achieved on the upper and lower arch; probably due to better adherence to instructions. Light force is recommended for use in CHG therapy.

The impact of force magnitude on the first and second maxillary molars in cervical headgear therapy

AIM

To study the effect of force magnitude on the maxillary first and second molars in cervical headgear (CHG) therapy.

MATERIAL AND METHODS

In this controlled clinical trial, patients (n = 40) were treated with CHG with a light (L, 300 g, n = 22) or a heavy force (H, 500 g, n = 18) magnitude. The subjects were asked to wear CHG for 10 hours a day for 10 months. The outer bow of the CHG facebow was lifted up for 10-20 degrees and the inner bow was expanded 3-4 mm. Adherence to instructions and force magnitude were monitored using an electronic module (Smartgear, Swissorthodontics, Switzerland). Panoramic and lateral radiographs before (T1) and after treatment (T2) were analysed using a Romexis Cephalometric module (Planmeca, Finland) focussing on the angular, sagittal, and vertical positions of the permanent first and second molars.

RESULTS

According to the cephalometric analysis of the maxillary first and second molars, distal tipping occurred during T1-T2 in the H group (P = 0.010 and 0.000, respectively), and the change was greater in the H group compared to the L group (P = 0.045 and 0.019, respectively). Based on the panoramic analysis, tipping occurred in the distal direction during therapy in the H group in the second molars compared to the midline or condylar line (P = 0.001 and 0.001; P = 0.008 and 0.003 on the right and left, respectively).

CONCLUSION

With heavy force magnitude, the maxillary first and second molars can tilt more easily in the distal direction even if the CHG was used less. Distal tipping of the molar can be considered to be a side effect of CHG therapy.

Improving headgear wear: why force level and direction of traction matter

Background

Empiric data on headgear wear are scarce. The aim was to examine a possible discrepancy between the duration of wearing and force application, and whether such a difference is influenced by force level or direction of traction.

Materials and methods

In this retrospective analysis, 122 consecutive patients were included. All were treated with headgear (three subgroups: high-pull headgear [n = 60], cervical-pull headgear [n = 32], and high-pull headgear in combination with an activator [n = 30]) and were monitored for three successive months using an electronic module. The device recorded chronographically the measured force magnitude and temperature, allowing to differentiate between the duration of headgear wear (recorded body temperature) and actual force application (recorded force).

Results

For all subgroups, the average recorded force application was lower than wear time (mean inactivity during wear: 15.9 ± 22.8 minutes/night). The direction of traction significantly influenced the extent and length of wear time without force application (P &lt; 0.001): patients with cervical-pull headgear were more prone to inactive wear time (27.7 minutes/night) than patients with high-pull headgear (13.7 minutes/night) or with headgear–activator (7.8 minutes/night). The observed inter-individual variability of inactive wear time was considerable (0–134 minutes/night). The mean applied force was highly significantly associated with inactive wear time (correlation coefficient: −0.575; P &lt; 0.001), and force levels below 250 g seem particularly related to episodes of inactivity.

Conclusions

There is a clear incongruity between the duration of headgear wear and the duration of force application. Inactive wear time is influenced by the direction of traction and force level applied. Clinicians should be aware of the likelihood of periods of inactive wear time and researchers should search for options to reduce or even eliminate these periods.