Is early headgear activator treatment for Class II problems effective?
We know that there is a limited advantage in providing early functional appliance treatment for Class II malocclusion. However, we are more uncertain about early functional and headgear treatment. This ambitious new trial provides us with useful information on this interceptive treatment.
Over the past 20 years, there have been some landmark trials on the early treatment of Class II malocclusion. Importantly, these studies come to similar conclusions. These suggest that early treatment has few advantages over one phase care in adolescence. While two of the studies looked at the effect of headgear, we have tended to concentrate on the impact of functional appliances. Interestingly, this new trial looked at early treatment with a headgear activator. As a result, I thought that it was fascinating and clinically relevant.
A team from Malmo, Sweden, did this trial. The European Journal of Orthodontics published the paper.
Jenny Kallunki et al. European Journal of Orthodontics, 2020, 1–9
What did they ask?
They did the study to find out this information:
“Does early headgear activator treatment influence overjet, overbite, improve the oral health quality of life, increase lip closure and reduce the incidence of incisal trauma”.
I thought that these aims were simple and straightforward. It also made me want to read the paper because it was not merely another cephalometric study (or so I thought!).
What did they do?
They did a randomized controlled trial with a 1:1 allocation of treatment. The PICO was
Participants: Children aged 8-10 years old with overjets greater than 6mm and Class II molar relationships.
Intervention: Early treatment with a headgear activator appliance. The clinician asked the participants to wear this for 10-12 hours per day. One specialist orthodontist treated all the participants.
Control: No treatment
Outcomes: Overjet, overbite, Oral Health Quality of life measured with the CPQ 8-10/11-14. Incidence of trauma and lip closure.
They collected the data at the start of treatment and approximately two years later for both groups.
They used pre-prepared randomization that they concealed in sealed envelopes. The study had an Intention to Treat design. As a result, they analyzed data for every patient, regardless of the outcome or completion of treatment.
Importantly, they did a sample size calculation that suggested that they needed 21 patients in each group.
The orthodontist used a standard appliance protocol. They reviewed the patients every eight weeks. When the operator achieved the treatment goals, they asked the patient to wear the appliance at night only for six months.
They assessed the outcomes blind.
What did they find?
Sixty patients started the trial. The mean treatment time was 1.1 years. Interestingly, in the treatment group, 27% of the participants discontinued their treatment.
I thought that the following data was critical.
This is the data at the end of the treatment/observation period (means and 95% Cis)
|Headgear activator||Untreated control||p|
|OJ Change||-3.5 (-4.6-2.5)||0.1 (-0.3-0.5)||0.001|
|OB Change||-0.3 (-0.7-0.2)||0.7 (0.3-1.2)||0.002|
|CPQ Change||-1.6 (-4.3-1.0)||-0.5 (-3.2-4.0)||0.97|
When they looked at trauma, they found that 11 of the participants had already experienced trauma to their incisors. At the end of the study, 4 in the control and 1 in the treatment group had experienced trauma. This difference was neither clinically nor statistically significant.
In terms of lip coverage, at the end of the trial, 27% of the treatment and 37% of the control group had reduced lip coverage. This difference was not statistically significant.
They also sneaked in a cephalometric measurement table. None of these measurements were interesting, clinically and statistically significant. This means that the treatment changes were mostly dento-alveolar. No mandibles were grown and no maxilla were retracted!
“Early treatment with a headgear activator is successful in reducing overjet and overbite. No other effects were detected”.
What did I think?
I thought that this was an exciting and clinically relevant study. The team used methods that were very similar to the classic Class II studies that were published in the 1990s. In this respect, it was interesting to see that their conclusions were very similar. These studies all concluded that early treatment could reduce overjets, and any other effects of treatment were not marked.
While these findings were similar to the other studies, we need to remember that the earlier studies followed the patients through to the end of all treatment (end of Phase II). I hope that this team can do the same. The results could be very interesting.
The study was well done and followed a standard RCT methodology. This was good to see.
I thought that the trauma results were interesting. Again, when the first studies reported on trauma, they did not find any effect of treatment on reducing trauma. This effect only became apparent when the trials were included in a systematic review. I am sure that when the next iteration of the Cochrane Review is done, this data will be added.
Their finding that most of the trauma had occurred before the treatment started agreed with the other trials. This finding does make us ask whether we should be starting treatment earlier to avoid trauma. However, this will add to the burden of care and may not be worth considering?
Finally, I think that this was a great study and will add to our knowledge that reinforces the fact that early treatment for Class II malocclusion is rarely indicated.
Emeritus Professor of Orthodontics, University of Manchester, UK.