September 16, 2019

Treatment of Anterior Open Bite improves quality of life!

This post is about a fascinating trial that showed an improvement in the quality of life in children following Anterior Open Bite treatment. It is one of the first trials to show this important effect, and its results are significant.

One of the main aims of orthodontic treatment is to improve the  quality of life of our patients. While day to day, clinical experiences suggest that this is the case. Unfortunately, research evidence underpinning this belief is lacking. This is because there are only a few clinical trials that have investigated this problem. Most of the previous studies have been cohorts that do not have an untreated control. I was, therefore, really interested to see this new trial. A team from Brazil did the study, and the AJO-DDO published the paper.

They did an excellent introduction on the effect of Anterior Open Bite on oral health quality of life. Importantly, they drew attention to the fact that most previous studies have been observational and lack an untreated control.  They approached rectifying this problem by carrying out a simple and very effective randomised controlled trial.

What did they ask?

They did the study to answer this question:

“What was the effect of Anterior Open Bite treatment on the oral health quality of life of a group of 8-10-year-old children”?

What did they do?

They carried out a prospective RCT with a 1:1 allocation of treatment. Unfortunately, they did not register the trial or publish the protocol before the trial started. I shall expand on why this is important later.

The PICO was:

Participants: 8-10-year-old children with an AOB caused by non-nutritive sucking whose 4 incisors and first molars had erupted.

Intervention:   This was a fixed palatal crib (FPC) from a palatal arch banded to the first molars.

Control: No treatment.

Outcome: Oral Health-Related Quality of Life (OHRQoL) measured by the CPQ 8-10questionnaire.

The CPQ8-10is a validated questionnaire that assesses the quality of life in 4 domains. These are oral symptoms, functional limitations, emotional well-being and social well-being.  It also contains questions on children’s overall perception of their oral health and well being.

The children completed the questionnaire at baseline, 3 months after starting treatment, and one month after removal of the appliance (FPC).  For the control group, they completed the questionnaire at baseline, 3 months and 12 months later.  Therefore, the data collection time points were similar.

They did a precise sample size calculation.  The randomisation was preprepared, and they concealed the allocation using sealed opaque envelopes.  I thought that their statistical analysis was appropriate. It was also great to see that they stated a clinically significant effect size of 0.5-0.8 being moderate, and any measurement greater than 0.8  was a substantial change.

What did they find?

They randomised 40 patients to each group, and all the participants completed the trial. At the start of the study, there were no differences in the demographics of the two groups of participants.

When they looked at the OHRQoL scores before treatment, they found that there was a difference between the groups for social well being with the higher ratings for the control group.  However, this difference was not clinically significant as it was only 0.1.

They presented their data in a rather complex table. As a result, I decided to highlight the main findings. I shall look at them during treatment and 3 months after treatment had been completed.

During treatment

The control group showed a substantial negative impact on the quality of life in emotional well being (5.73, 95% CI= 4.5-9.6), social well being (5.53, 95% CI= 3.62-7.44) and overall (3.9, 95% CI=-0.45-8.25).

The treated group had a higher negative impact on oral symptoms and functional limitations.

Before and after orthodontic correction

Overall, AOB correction improved the overall perception of OHRQoL by 91.4%, effect size 3.7 (large). Importantly, when the AOB had not been treated, there was a negative impact of 20% with an effect size of 1.0 (large).

The authors felt that this difference represented harm to the control group. This was a critical conclusion to make.

They concluded:

“Anterior open bite treatment of children aged 8-19 years had a positive impact on the OHRQoL, whereas the failure to treat this condition had a negative impact”.

What did I think?

I thought that this was a good well thought out and clearly written trial. The overall design was good with clear descriptions of randomisation, concealment and blinding.  The sample size was also large enough to detect any differences in the outcome measures.

However, I was a little disappointed to see that they did not present any data on whether the AOB treatment was successful.  It would be interesting to see this published at some point. Another point that concerned me was that the study was not registered.  This is becoming increasingly important as this simple step ensures that the outcome measures etc. are not changed after the study has started.

Important findings

I thought that an excellent feature of this study was that they did not use cephalometric or other “orthodontist” based outcome measures.  This is important because they measured values that were important to our patients.  In this respect, it was also interesting to see that they stated the clinically important effect sizes.

When we looked at these, it was clear that the orthodontic treatment had an effect on OHRQoL.  It was also logical to see that a reduction in this measure occurred for the treatment group shortly after their appliances were fitted. This represented any pain and discomfort associated with the treatment.  This results in the study having validity.

It was also interesting to see that the authors suggested that harm had come to the untreated control group. This was because there was a negative impact on their OHRQoL. This is a good point.  This can be reduced by periodically monitoring the data a trial and stopping the trial if harms are detected.  We should certainly consider this in future trials with an untreated control group.

This is one of a few orthodontic trials that have looked at OHRQoL and detected an improvement following treatment. It is great to see that orthodontic treatment has this effect. As a result, this study is important and provides us with great clinically relevant information.


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Have your say!

  1. Another interesting study. It was really a study of AOB treatment device, not AOB correction or cessation of the habit in 8-10 year olds.

    One group had treatment for a “problem” and the other group had their “problem” effectively ignored. There is no indication that the treatment was any more effective in correcting the open bite or stopping the habit. Which group would be more positive about their care? Hmmm.

    Reminds me of a study on acupuncture for pain. One group was taken into a warm treatment room and were treated with acupuncture and the other was ignored in the cold hospital waiting area. The acupuncture group had a reduction in the pain experienced.

    It would be interesting to see how the two groups in this AOB study compared after comprehensive treatment and whether there were differences in the treatment duration or complexity. That is, was the early treatment of benefit considering the possible increase in cost and duration of the total treatment, or of benefit in the long-term QoL.

    The results could be entirely due to a placebo effect. Perhaps a better study would have the control with a sham treatment and then compare the results. Or have a sham treatment, like a myofunctional mouthguard, and a control without any treatment and compare the QoL.

  2. Yes I agree these findings are hugely important, but it has to be acknowledged the greatest areas of improvement (and harm if left untreated) was the emotional and psychological aspects mainly eg: they could still eat and talk well enough to function satisfactorily.

    This study has several impacts IMHO which include significantly:

    1. All forms of Cosmetic Dentistry can have a huge impact positively upon Emotional and Psychological well being, especially where there is already a negative impact/awareness socially.

    2. Whilst for some time Orthodontic treatment in younger children has been frowned upon in the UK and/or past studies suggest no better clinical outcomes when looking at Cephs etc, so in limited NHS systems there is often no funding/allocation for two courses of Orthodontics.
    Where there is any emotional/psychological/socialising impacts, rather than waiting lists deferring into their teens and the person has already had their development damaged in several ways.

    I think it is a very interesting study, Holistically, also.

    Thanks for highlighting this progressive approach in this study.

    Yours also observationally,


  3. This is a very timely article as AOB is the topic for the AAO Winter Conference Feb. 7-9 in Austin, Texas. Dr’s Greg Huang, Jim Vaden and Richard Williams have put together a panel of speakers that will cover all treatment modalities and retention of AOB; our most challenging and least stable of cases. Registration is open now. Dr. Huang is hopeful to present the results of the PBRN (Practice Based Research Network) Open Bite Study where the committee has been gathering and evaluating information collected/submitted from Orthodontists in private practice. This will be a culmination of a study initiated several years ago. The 2020 WC should be one that all orthodontists will want to hear.

  4. Much more depressing is that open bites are avoidable when early treatment is given. Then the dentist would also know about the causal causes and would be able to explain accompanying symptoms such as respiratory diseases. A habitually open oral posture not only produces terrible dentures, it also lacks the space for a functioning respiration and mobility and body statics suffer from it. It is accepted with a sighted eye that sick people develop.

    It is astonishing that orthodontics is happy about this dubious study. The better way is early treatment starting with the infant. However, the dentist is only in demand as a competent advisor to refer mothers to MF therapists who, to top it all off, should also be trained. These are serious system errors in the medical understanding of growth and development that need to be corrected. Fränkel also provides the key to this: he was first and foremost a developmental biologist and described the necessary developmental steps in the temporal growth process very precisely. He gave the reasons why in the civilized world there are no necessary tonic developmental steps. The most serious is the closing of the mouth. When will medicine finally take care of the causes instead of straightening sick people’s teeth and rejoicing if they are “perhaps” a little bit ill afterwards?

    Not even that it can prove evidence based.

    Translated with

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