April 10, 2017

Orthodontic treatment improves quality of life!

Orthodontic treatment improves oral health related quality of life!

We all assume that straightening teeth improves a person’s oral health related quality of life. While this concept is logical, it has lacked strong evidence. Until now…..

This is the first of my posts that has been translated into several languages.  The translations are in Italian, Russian, Spanish, Portuguese and Japanese. You can find them under the translated posts pull down menu..


I have been researching and studying the effects of orthodontic treatment for many years. During this time I have attempted to find evidence on whether orthodontic treatment improves oral health related quality of life. While this concept is a logical “hope and dream”, there have been few studies into this crucial outcome. This recent systematic review has taken a large step towards answering this important question.


Hanieh Javidi, Mario Vettore, and Philip E. Benson

Am J Orthod Dentofacial Orthop 2017;151:644-55


A team based in Sheffield, North of England, did this study.

What did they do?

They did a standard systematic review of the literature. Their aim was:

“to systematically review the current literature to identify changes in oral health quality of life (OHRQoL) before and after orthodontic treatment”.

The PICO was;

Participants: People aged 17 years or younger at the start of orthodontic treatment

Intervention: Any orthodontic treatment, even the weird stuff!

Comparator: Oral health-related quality of life before and after treatment. or a comparison group who have not undergone orthodontic treatment.

Outcomes: Oral health-related quality of life using a validated questionnaire.

Study design: randomised controlled trial, controlled clinical trial, prospective cohort, cross-sectional study or case-control study.  Pretty much anything!

They did a standardised literature search, identified papers, applied the relevant filters and carried out quality assessments of the papers they included. They put the data into several meta-analyses to come up with overall findings.

What did they find?

They initially found 1590 studies and reduced this to the final sample of 14 studies.

Importantly they did not find any RCTs. Eight studies were cohorts, one was a mixture of a cohort cross-sectional, three were cross-sectional and one was a cast-control.

The overall quality of the studies was moderate.

When I looked at their data, I found that most of the studies were “before and after” but this was a little difficult to work out. They produced nice Forest plots to illustrate their findings.

Overall they concluded that;

“oral health-related quality-of-life improves markedly after orthodontic treatment, particularly in the dimensions of emotional and social well-being”.

They wrote a nice discussion which was relevant to their findings. Importantly, they outlined some of the limitations of the research that they had carried out. I will expand on this.

What did I think?

Firstly I was reassured and pleased that, at last, we had a study that potentially shows a benefit of orthodontic treatment.

This study has several good points. I thought that it was a good systematic review of the relevant literature. Importantly, they did a thorough assessment of the papers and reported their findings accurately without exaggeration.

Nevertheless, we do need to consider some problems with the nature of the studies that they included. These are;

They could not find a randomised controlled trial. This is important. However, it is difficult to see how we could carry out a trial to answer this question. This is because it is not possible to allocate our patients to “treatment” or “no treatment”. As a result, all the studies were observational and did not yield a high level of evidence.

They classified the studies as moderate/low quality.  This is not unusual for orthodontic systematic reviews. We simply have to accept that this is the best evidence that we have, at present.

Most of the data was collected from “before and after” studies. While this may show a change in oral health-related quality of life, we cannot ignore the fact that this may have improved without treatment and simply changed with time.

Overall conclusions

If we put all these factors together I feel that they have done a good systematic review that provides us with the best evidence that we have. I am pleased that we can now say (with moderate confidence) that orthodontic treatment leads to a moderate improvement in oral health quality of life…which is nice

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Have your say!

  1. Thank you Professor for another great blog.
    What a (moderately) satisfying read!

  2. An interesting study based upon an ‘Opinion-based questionnaire’ of 213 subjects – in effect there is ‘moderate’ evidence for psychological improvements to perception for cosmetic aspects, would have perhaps been more accurate a reporting of this study?

    This is of course true for all aspects of Cosmetic Dentistry, from whitening to multiple crowns, bridges and veneers and from a patient-perspective, is worth any biological downsides, but let’s be clear, this study does NOT prove Oral Health parameters in the mouth improve, but the pychological well being brought about by cosmetic improvements ‘extra-orally’ as psychologically self-perceived by a few hundred participants completing a standardised questionnaire!

    The evidence-base quality within Orthodontics remains very low or clinically insignificant overall, though this study does show a way forward to appreciate benefits now regarded as ‘quality’ and give proper credit for ALL dentists’ cosmetic treatments to improve the psychological/social self-worth evaluations of our patients.

    Yours evidently,

    Tony Kilcoyne.

  3. What exactly does oral health quality of life mean? Just in case a patient or parent or NHS commissioner ask. Does it just mean that you’ll feel better with straight teeth because people don’t like having crooked teeth, aesthetically? Is there any more to it than that?

  4. Thanks for the blog post. I think it’s unlikely an RCT is going to be done in this area for the reasons stated. So what would the next best type of study be? And how many people would it need to involve to give it enough legitimacy?

    Stephen Murray
    Swords Orthodontics

  5. In the article we use the definition of oral health-related quality of life (OHQoL) provided by Locker and Allen, but I quite like the following, produced by the UK Department of Health in 1994, before the concept of OHQoL was really developed:

    ‘Standard of health of the oral and related tissues which enables an individual to eat, speak and socialise without active disease, discomfort or embarrassment and which contributes to general well-being.’

    The questionnaires used to assess OHQoL are carefully developed to identify problems from the patient’s viewpoint, usually in the areas of oral symptoms, functional limitations, emotional and social well-being and do not assess psychological well-being. For more explanation please see Benson et al. What is the value of orthodontic treatment? British Dental Journal 2015; 218: 185-190 DOI: 10.1038/sj.bdj.2015.43.

    In answer to Stephen’s comment about the appropriate research design, an RCT could be carried out in an area with a large waiting list and participants are randomised to either start treatment straight away or to remain on the waiting list. There are obviously practical and resource issues with this type of design. We are just about to start a cohort study, using questionnaires before and after treatment. We plan to recruit about 600 participants to a treatment group and compare the outcomes to a control group of over 300 participants on a waiting list, also followed up over time.

    • thanks for the reply – I’ll be interested to see the results of that. If it agrees with the overall findings of your systematic review and meta-analysis, then that may well put it to bed.

      Stephen Murray
      Swords Orthodontics

  6. Really the effect of orthodontic treatment solve the teeth related problems of people and improves the oral health related to quality of life. Thanks for sharing us.

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