Headgear compliance as assessed by a temperature-sensitive recording device: a prospective clinical study

Abstract

Objective:
To accurately describe compliance in headgear wearing time by using a temperature- and force-sensitive device over an 8 month period of use in a prospective clinical manner.

Materials and methods:
Twenty children with Class II malocclusion aged 8-12 years were randomly selected for treatment with cervical headgear. The headgears were equipped with an electronic module, which measured temperature and force, and patients were instructed to wear the headgear 12 hours daily. The recorded values were analysed to determine the number of days the headgear was used, the number of hours per day it was worn, and the percentage of compliance (100 per cent corresponding to 12 hours daily).

Results:
The average treatment period was 8.4 months with 5.8 months of effective use. When effectively used, headgear was worn 8.7 hours a day (compliance of 73 per cent). Including days where it was not worn, compliance was 6.4 hours (54 per cent). The appliance was used on average 0.5 hours during the day (8 am-8 pm) and 5.9 hours during the night (8 pm-8 am). Very low compliance was recorded during July and August.

Conclusion:
The average compliance with cervical headgear use was 54 per cent of the 12 hour prescription. The headgear was effectively used only 5.8 months over the study period, with roughly 30 per cent of no use. Headgear was used almost exclusively during evening and night-time. During the summer period, compliance was particularly poor.

Full text

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Original article
Headgear compliance as assessed by a
temperature-sensitive recording device: a
prospective clinicalstudy
Luis HuancaGhislanzoni, Sofian Ameur, GregoryS. Antonarakis and
Stavros Kiliaridis
Department of Orthodontics, University of Geneva, Geneva, Switzerland
Correspondence to: Luis Huanca, Université de Geneve, 1, rue Michel-Servet, CH-1211 Genève 4, Switzerland. E-mail: luis.
huancaghislanzoni@unige.ch
Summary
Objective: To accurately describe compliance in headgear wearing time by using a temperature-
and force-sensitive device over an 8month period of use in a prospective clinical manner.
Materials and methods: Twenty children with ClassII malocclusion aged 8–12years were randomly
selected for treatment with cervical headgear. The headgears were equipped with an electronic
module, which measured temperature and force, and patients were instructed to wear the headgear
12 hours daily. The recorded values were analysed to determine the number of days the headgear
was used, the number of hours per day it was worn, and the percentage of compliance (100 per
cent corresponding to 12 hours daily).
Results: The average treatment period was 8.4months with 5.8months of effective use. When
effectively used, headgear was worn 8.7 hours a day (compliance of 73 per cent). Including days
where it was not worn, compliance was 6.4 hours (54 per cent). The appliance was used on average
0.5 hours during the day (8 am–8 pm) and 5.9 hours during the night (8 pm–8 am). Very low
compliance was recorded during July and August.
Conclusion: The average compliance with cervical headgear use was 54 per cent of the 12 hour
prescription. The headgear was effectively used only 5.8 months over the study period, with
roughly 30 per cent of no use. Headgear was used almost exclusively during evening and night-
time. During the summer period, compliance was particularly poor.
Introduction
Headgear appliances are still a popular choice for treating ClassII
malocclusion in children, being used by 62 per cent of American and
Canadian orthodontists according to a recent survey (1).
Like every removable appliance, headgear is compliance depend-
ent and patient cooperation is a key factor in achieving treatment
goals. From the beginning of its use, clinicians felt the need to assess
patient collaboration in order to understand the reasons for unsatis-
factory treatment outcomes besides attributing failure to biological
factors. In fact, the lack of an objective method of measuring coop-
eration makes it difcult to describe the ‘dose–effect’ relationship
between headgear use and molar distalization.
In 1974, Northcutt introduced timing measurements, with a
headgear timing device (2) being used as a tool to objectively meas-
ure patient compliance. He found that his patients self-reported 11
hours of daily use of headgear, while their actual wear time was
only of 6.5 hours over the 12 hours per day prescribed (54 per cent
compliance) when they were unaware they were being recorded.
After revealing the recording tool to his patients, he reported a net
increase in the use of headgear with a doubling of the weekly hours
of use. Even though the precision of these specic headgear timers
was called into question later (3) because of patients attempting to
falsify results, Northcutt’s input (2) highly inuenced research into
compliance behaviour.
Head1=Head2=Head1=Head2/Head1
European Journal of Orthodontics, 2019, 1–5
doi:10.1093/ejo/cjz036
Original article
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Indeed, it revealed how indirect methods of compliance assess-
ment are weak and unreliable. Orthodontists can simply deduce
compliance from clinical parameters like tting of the appliance,
oral hygiene, appraisal of molar mobility, space created between
teeth, and by comparing the treatment progress with initial treat-
ment records (4). Orthodontists’ predictions of effective compliance
tend to overestimate actual wearing time by patients (5). Patients
and parents are even worse judges of their actual cooperation level
and tend to report that they wear headgear very close to the number
of hours prescribed by the orthodontist (6,7), especially if they are
unaware of being recorded (2,5). In particular, those patients who
are not aware of being recorded, tend to report themselves as very
compliant with the orthodontist’s request. Indeed, they are generally
the least honest about assessing actual wearing time and, as a conse-
quence, the least compliant (4).
A recent systematic review reports 5.0 hours per day of difference
between self-reported and objectively assessed removable appliance
wear (8). Some authors afrm that knowledge of being recorded by
a device may produce a positive inuence on patient cooperation (9).
In the early 1990s, a new quartz-based timer to assess headgear
compliance was developed by Cureton etal. (10) with similar results
to those found by Northcutt (2). During the same period, microelec-
tronic monitoring of wearing time was rst applied to functional
appliances (11). Results were very similar to headgear use in terms of
absolute timing (7.7 hours of wear per day) and relative use (50–60
per cent of the time prescribed by the orthodontist). However, timing
of prescribed use is not evidence-based and depends on the doctors’
education and beliefs, ranging between 12 and 14 hours for most
removable appliances (12).
Later, in the early 2000s, headgear equipped with modern record-
ers was used to assess collaboration. ABrazilian cohort of patients
showed average compliance of 5.6 hours when unaware of being
recorded, and 6.7 hours when made aware, out of the 14 hours pre-
scribed by the orthodontist (4). The evidence regarding the role of
awareness on compliance use is, by the way, uncertain as suggested
by some authors (13,14).
A Dutch group of patients showed identical results, with 5.6
hours of average daily use over a 1month observation period. By
excluding the results from blank days, when headgear was not used
at all (12 out of 29 on average), the wearing time increased to 7.6
hours (5). Al-Moghrabi etal. reported an average headgear use of
5.8 hours per day on a systematic review based on six studies (8).
More recently, a microelectronic sensor was developed to be
embedded into removable appliances (15). It has been used to meas-
ure wearing time of functional appliances and active plates. Results of
wearing time range from 8 to 10 hours on average, out of 14 to 16
hours of prescribed use, with the rate of actual wearing time versus
prescribed wearing time ranging between 55 and 65 per cent (16–18).
Most of the studies in the literature have observation windows
ranging from 1 to 3months (4,17–19), with a few exceptions extend-
ing to 6–8months (13,20). The aim of our study was to accurately
describe compliance in headgear wearing time by using a tempera-
ture- and force-sensitive device over an 8month period of use.
Material and methods
Studydesign
This is a prospective clinical cohort study assessing objective com-
pliance over an 8 month observation period. The present study
was approved by the local research ethics board (CER 12-250). All
patients and their parents gave informed consent.
Setting
Patients were selected randomly and prospectively from the ortho-
dontic clinic of the University of Geneva. The recruitment period
lasted 9months (from March to December 2016), and the observa-
tion period ended on September 2017.
Participants
Inclusion criteria were: 8–12-year-old children with a ClassII mal-
occlusion (at least edge-to-edge bilateral molar relationships and an
overjet of 6mm or more), a positive overbite, in the mixed denti-
tion, with the maxillary second permanent molars not yet erupted,
an A point–nasion–B point angle greater than 4degrees, and non-
extreme vertical skeletal patterns. Children with tooth agenesis, a
compromised periodontium, previous orthodontic treatment, on
systemic medication, or medically compromised were excluded from
the study.
Variables and measurement
Children were instructed to use headgear for 12 hours a day over the
study period of 8–9months. The headgear was equipped with a temper-
ature- and force-sensitive module (Smartgear, Swissorthodontics AG,
Cham, Switzerland) that recorded data every 15 minutes (Figure1).
The triggering range of the force measured by the sensor is 100–500g.
The patients were aware of being recorded since they were
instructed about the recording module at the time of appliance
delivery. Asingle operator (SA, postgraduate resident) adjusted the
headgear and followed up the patients every month. The same set of
instructions was given to every patient and their parents with regard
to appliance wear, and motivational written reminders were also
given to all patients at each appointment.
At the end of the treatment period, the recorded values were
exported from the electronic modules into an Excel spreadsheet.
They were then analysed to determine the number of days the head-
gear was used, the number of hours per day, and the percentage of
compliance (100 per cent compliance representing 12 hours of use
per day, as prescribed by the orthodontist).
The headgear was considered used when force was above zero
(and temperature close to the human body temperature range of
35–37degrees). Two investigators (LH and SA) indipendently exam-
ined the software outcomes in order to identify the sensor’s possibly
erroneous records (21). Afull agreement was found between the two
Figure 1. Headgear–sensor combination on a patient (picture published with
permission https://orthowalker-kieferorthopaedie.ch/produkt/smartgear/—
last accessed 27 April 2019).
European Journal of Orthodontics, 20192
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investigators in attributing the measures to the ‘in use’ or ‘not in use’
category.
Studysize
A sample size of 20 patients was calculated based on the ndings of a
similar study (5). The power of the study was calculated to detect at
least 1mm of molar distalization. The results of this study are object
of a different paper that also includes a control group. Acontrol group
is not applicable to the present study focussed on compliance only.
Statistical methods
Statplus (AnalystSoft Inc., Walnut, California, USA) was used to calcu-
late box plots for compliance, effective compliance (compliance dur-
ing days of effective use of the appliance, not including those where
the appliance was not worn at all), monthly compliance, hourly com-
pliance, weekday versus weekend compliance, and daily versus nightly
hours of use. Spearman’s correlation coefcient (non-parametric) was
used to assess the relationship between the number of times per day
the headgear was inserted and effective compliance, as well as to assess
the correlation between days of non-use and effective compliance.
Results
Twenty ClassII malocclusion children were included in the present
prospective cohort study, 11 girls and 9 boys, with an average age
of 10.2years [standard deviation (SD) 1.2years]. The average treat-
ment period was 252 days (8.3 ± 0.6 months). All data from all
participants during the observation period were analysed.
Actual headgear use (at least once per day) was on average
5.8months (70 per cent of the time), whereas headgear was not used
at all for 2.6months (30 per cent of the time) on average (Figure 2).
The average daily compliance, including days of non-use, was 6.4
hours (54 per cent of the 12 hours prescribed wear; Figure 3), while
when excluding blank days (days of no use), the daily effective wear
of headgear was 73 per cent or 8.7 hours of daily usage (Figure2).
Patients who skipped most days of headgear use were also those
who recorded the lowest effective compliance: Spearman’s correla-
tion between effective/net compliance and blank day of no use was
−0.63 (Figure 2).
The appliance was used (inserted in the mouth) on average 1.8
(±1.0) times per day. Spearman’s correlation between effective com-
pliance and blank days of no use was 0.77 (Figure 3).
The monthly compliance rate is reported in Figure 4. The com-
pliance was consistent on months going from October to May (72
per cent of use on average) while it dropped from June to September
with a minimum in July (33 per cent on average).
The hourly report of compliance is reported in Figure 5. Night
hours going from midnight to 7 am showed an average compliance
over 50 per cent. The compliance during day time was close to 0
especially in the period going from 11 am to 8pm.
When dening daytime as 8 am–8 pm, the number of hours of
use was 0.5 hours versus 5.9 hours of use at night-time as dened by
8 pm–8 am. When comparing weekdays (Monday–Friday) to week-
ends, there was virtually no difference (54 versus 51 per cent of aver-
age compliance, respectively).
Discussion
Quantifying the compliance in relation to headgear use has been a
recurrent topic in orthodontic literature since Northcutt used his
timing device (2). This question is still of interest as headgear rep-
resents a very common choice for orthodontists (1). It is indeed dif-
cult to answer this question with conviction since numerous factors
may determine patient cooperation. Our study focussed on a multi-
ethnic pool of patients living in a large Swiss city, and our ndings
may be extended to similar demographic situations.
Previous investigations (2,4,5,10) reported an average use that
ranged between 5 and 7 hours per day, following a prescribed recom-
mended wear time of 12 hours. These values were registered despite
the fact that patients were aware of being recorded. Our ndings
(6.4 hours corresponding to 54 per cent of the 12 hours prescribed
time) were very close to the 50–55 per cent of compliance reported
in the literature and to the 5.8 hours reported by Al-Moghrabi etal.’s
Figure 2. (a) Proportion of days of no use (percentage). (b) Effective
compliance (percentage) excluding days of no use. (c) Correlation between
days of no use and effective compliance.
Figure 3. (a) Average compliance (percentage). (b) Average times of use of
the headgear per day. (c) Correlation between times of use and compliance.
Figure 4. Compliance on a yearly basis over the 12months.
L. Huanca Ghislanzoni etal. 3
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systematic review (8). Values were higher (8.7 hours corresponding
to 73 per cent of compliance) when considering effective compliance
(excluding days of non-use). When patients remember or are willing
to use their appliance, their compliance is fairly good, which is likely
to take place during the evening and night-time.
In fact, by having recordings available every 15 minutes, we
closely investigated the use behaviour on a daily basis over 24 hours.
Daily use (8 am–8 pm) was negligible as it was only half an hour on
average. This was signicantly different from the 6 hours of aver-
age evening and night-time use (8 pm–8 am). The ndings leave no
doubt that patients wear their headgear at night only and that daily
users are the exception. When looking for differences in use of head-
gear between week/schooldays and weekends, we found a very small
(3 per cent) yet statistically signicant difference, with more compli-
ant use of the headgear during schooldays.
Patients did not wear their headgear for an average of 2.6months
during the treatment period, which represents 30 per cent of the
total time of observation. As the observation period was evenly dis-
tributed throughout the year, it was possible to observe a typical
drop of compliance during the warm summer period (from June to
September in Switzerland). The months when the lowest compliance
was recorded were July and August, which corresponds to the school
holiday time for Swiss students. Not surprisingly, patients are far less
motivated to cooperate during their relaxation and vacation time.
Some of them completely forgot to wear their headgear during the
entire vacation time (or more likely they simply forgot it athome).
We also tried to relate compliance and patient behaviour. Patients
inserted their headgear on average 1.8 times per day (the moment of
insertion and disinsertion could be detected thanks to the tensile force
that was recorded). There was a high correlation between average com-
pliance and number of times the headgear was inserted (Spearman’s
correlation coefcient= 0.77). Patients who wore headgear just once
per day scored compliance values up to 40 per cent, while those using
headgear two to three times per day scored compliance ranging from
50 to 80 per cent. Interestingly, the only outlier who inserted the head-
gear ve times per day on average was also the most compliant patient
(85 per cent), with an average use of more than 10 hours perday.
Compliance assessment is an important factor that needs to be
assessed ideally any time a removable appliance is used. Data col-
lected in the present study allow to better understand minor nuances
of the attitude of patients when using headgear. The results are far
from encouraging. Further investigations should try to identify the
role of compliance in relation with clinical results of headgear use.
Limitations
A possible limitation of the study is the absence of a control group.
Acontrol group exists for evaluating the dental effect of headgear
therapy but it is not possible to compare compliance between a
group using an appliance and a control group out of therapy. Afur-
ther limitation may be the cost of the sensor as it is proposed at 200
Swiss Francs, with a guaranteed durability of 1year.
Conclusions
During 8 months of observation, average compliance of headgear
use was 8.7 hours of wear per day (73 per cent of the 12 hours
prescribed) on those days when the headgear was used. Indeed, the
headgear was never used on 30 per cent of the days (it was effectively
used only 5.8months over the 8.4months of the treatment period).
By including these blank days, the average compliance dropped at
6.4 hours per day. Not surprisingly, during the summer period, com-
pliance was particularly low. The compliance factor should be care-
fully considered when planning to correct a ClassII malocclusion
through headgear as the lack of compliance may play an important
role on the clinical outcomes.
Acknowledgements
Thanks to Dr Luca Signorelli for the precious support.
Conflict of interest
The authors declare the absence of conict of interest.
References
1. Tüfekçi, E., Allen, S.B., Best, A.M. and Lindauer, S.J. (2016) Current
trends in headgear use for the treatment of ClassII malocclusions. The
Angle Orthodontist, 86, 584–589.
2. Northcutt,M. (1974) The timing headgear. Journal of Clinical Orthodon-
tics, 8, 321–324.
3. Banks,P.A. and Read,M.J. (1987) An investigation into the reliability of
the timing headgear. British Journal of Orthodontics, 14, 263–267.
4. Brandão, M., Pinho,H.S. and Urias,D. (2006) Clinical and quantitative
assessment of headgear compliance: a pilot study. American Journal of
Orthodontics and Dentofacial Orthopedics, 129, 239–244.
5. Bos, A., Kleverlaan,C.J., Hoogstraten, J., Prahl-Andersen,B. and Kuit-
ert,R. (2007) Comparing subjective and objective measures of headgear
compliance. American Journal of Orthodontics and Dentofacial Orthope-
dics, 132, 801–805.
6. Meyer-Gutknecht,H., Fritz,U. and Schott,T.C. (2014) Methods to evalu-
ate compliance of patients with removable appliances-survey results. Jour-
nal of Orofacial Orthopedics, 75, 144–153.
7. Cole,W.A. (2002) Accuracy of patient reporting as an indication of head-
gear compliance. American journal of Orthodontics and Dentofacial
Orthopedics, 121, 419–423.
8. Al-Moghrabi,D., Salazar,F.C., Pandis,N. and Fleming,P.S. (2017) Com-
pliance with removable orthodontic appliances and adjuncts: a systematic
review and meta-analysis. American Journal of Orthodontics and Dentof-
acial Orthopedics, 152, 17–32.
9. Cureton, S.L., Regennitter,F.J. and Yancey,J.M. (1993) Clinical versus
quantitative assessment of headgear compliance. American Journal of
Orthodontics and Dentofacial Orthopedics, 104, 277–284.
10. Cureton,S.L., Regennitter,F. and Orbell,M.G. (1991) An accurate, inex-
pensive headgear timer. Journal of Clinical Orthodontics, 25, 749–754.
11. Sahm, G., Bartsch,A. and Witt,E. (1990) Micro-electronic monitoring of
functional appliance wear. European Journal of Orthodontics, 12, 297–301.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
% use
0.0
0.1
0.2
0.3
0.4
0.5
0.6
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
Graphics of all patients' usage percent during day (24 hours)
0.0
0.1
0.2
0.3
0.4
0.5
0.6
Figure 5. Compliance on an hourly basis over 24 hours.
European Journal of Orthodontics, 20194
Downloaded from https://academic.oup.com/ejo/advance-article-abstract/doi/10.1093/ejo/cjz036/5506480 by guest on 31 May 2019

12. Witt,E., Bartsch,A. and Sahm,G. (1992) Recommended times for wear-
ing removable appliances–the results of a survey. Fortschritte der Kiefer-
orthopadie, 53, 124–130.
13. Arreghini,A., Trigila,S., Lombardo,L. and Siciliani,G. (2017) Objective
assessment of compliance with intra- and extraoral removable appliances.
The Angle Orthodontist, 87, 88–95.
14. Hyun, P., Preston, C.B., Al-Jewair, T.S., Park-Hyun, E. and Tab-
baa,S. (2015) Patient compliance with Hawley retainers tted with the
SMART(®) sensor: a prospective clinical pilot study. The Angle Ortho-
dontist, 85, 263–269.
15. Schott,T.C. and Göz,G. (2011) Wearing times of orthodontic devices as
measured by the TheraMon® microsensor. Journal of Orofacial Orthope-
dics, 72, 103–110.
16. Schott, T.C., Meyer-Gutknecht,H., Mayer,N., Weber,J. and Weimer,K.
(2017) A comparison between indirect and objective wear-time assessment
of removable orthodontic appliances. European Journal of Orthodontics,
39, 170–175.
17. Schäfer, K., Ludwig, B., Meyer-Gutknecht,H. and Schott, T.C. (2015)
Quantifying patient adherence during active orthodontic treatment with
removable appliances using microelectronic wear-time documentation.
European Journal of Orthodontics, 37, 73–80.
18. Kawala, B., Antoszewska,J. and Sarul,M. (2013) Application of micro-
sensors to measure real wear time of removable orthodontic appliances.
Journal of Stomatology, 66, 321–330.
19. Bos,A., Kleverlaan, C.J., Hoogstraten, J., Prahl-Andersen,B. and Kuit-
ert,R. (2007) Comparing subjective and objective measures of headgear
compliance. American Journal of Orthodontics and Dentofacial Orthope-
dics, 132, 801–805.
20. Talvitie, T., Helminen, M., Karsila, S., Varho, R., Signorelli, L. and Pel-
tomäki,T. (2019) Adherence to instructions and uctuation of force mag-
nitude in cervical headgear therapy. The Angle Orthodontist, 89, 268–274.
21. Pauls, A., Nienkemper,M., Panayotidis,A., Wilmes,B. and Drescher,D.
(2013) Effects of wear time recording on the patient’s compliance. The
Angle Orthodontist, 83, 1002–1008.
L. Huanca Ghislanzoni etal. 5
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