October 03, 2022

Should we recommend early overjet reduction to prevent trauma?

There has been a large amount of research into early Class II treatment. This post is about a recent update on therapy preventing incisal trauma.

We have previously posted about this subject several times. I posted a detailed discussion on the risks and prevention of trauma back in 2013. Several people made great comments in the discussion. These reinforced the general feeling that there was some evidence for early treatment. However, the evidence was not strong and we needed to factor this into discussions with our patients. In 2018 we updated our Cochrane review on Class II treatment and suggested:

“Early treatment resulted in  a 12% reduction in the incidence of incisal trauma”.

Some time has passed, so I thought this update was timely.

A highly respected team from London, South of  England, and Zurich, Switzerland, did this study. This group also runs the excellent Evidence Based Orthodontics Facebook, which is a breath of fresh air!

The British Dental Journal published the paper.

Should we recommend early overjet reduction to prevent dental trauma?

Martyn T. Cobourne, Andrew T. DiBiase, Jadbinder Seehra and Spyridon N. Papageorgiou

BRITISH DENTAL JOURNAL | VOLUME 233 NO. 5 | September 9 2022

This team also runs the excellent evidence-based orthodontics course and Facebook group, it is worth following.


What did they ask?

They did this review to:

“Explore the association between early overjet reduction and dental trauma in the context of current best evidence”.

What did they do?

This was a review of the literature. It is essential to realise that this was not a systematic review. However, this focused review included evidence from trials and systematic reviews. Importantly, this was done to provide general advice to a non-specialist reader.

What did they think?

They provided great concise information in this paper. Firstly, the team pointed out that early treatment effectively reduces overjets. Nevertheless, treating early is no real advantage at the end of all care in adolescence. This conclusion is generally accepted and is not controversial.

They then looked closely at the trauma data from the large Class II studies conducted at UNC, Florida, and the UK. In addition, they included data from a more recent study that looked at early headgear activator treatment.

They reported this data in a Forest plot. They stated:

“In simple terms, the risk of incisor trauma was reduced by around a half (from 25.5% to 14.2%) in children having their overjet corrected early. But there was a large variation around these trials”.

They rightly pointed out that the data from these studies used different criteria for trauma. Notably, there was an overall lack of clinical detail in the type of trauma. As a result, the data was of low to moderate quality.

They also drew attention to the following.

  • The most significant trauma risk is at an age far too early to start any treatment. So even early therapy at age 9 won’t help these children.
  • The data suggest that headgear is more protective than functional appliance treatment.
  • On an individual basis, only the North Carolina trial found any significant difference in trauma between groups. This trial also had the most potential bias (KOB note).

Their overall conclusion was:

“We should not advocate early treatment for all children with Class II malocclusion. We should consider starting early when we think that there is an increased risk of dental trauma”.

What did I think?

I was very interested in a detailed and sensible analysis of this data. I spent many years looking at this problem in our own large trial and close involvement with the earlier Florida and UNC trials. Firstly, I would like to consider their comments on the trauma data from these three large trials.

I believe they correctly point out that we used different criteria for trauma in our studies. If we could turn the clock back to the late 1980s and early 1990s, we would have coordinated these studies better. However, in those days, large RCTs were new to orthodontics. In fact, we used a book on RCTs to plan the UK study. In effect, we were not as good at identifying the importance of outcome measure selection and sample sizes as we are now.

As a result, there is a degree of uncertainty around the trauma data.

Nevertheless, we cannot discard this data. Instead, we should factor this into discussions with our patients. This is also their conclusion when they suggest we should identify children at risk of trauma.

We, therefore, need to consider how we identify this risk. It is easy to suggest that if a young person is a skateboarder, they may be at higher risk. But what about contact sports? They are unlikely to play full-contact rugby, and the risk of trauma from football is low. I am not sure about the “hardball” sports of baseball and cricket for fielders. A lot of trauma takes place at the swimming pool! Perhaps a solution is to follow lacrosse, where mouthguards and helmets are compulsory for all players. We must also remember that trauma commonly occurs in playgrounds without identified sports. As a result, the situation is even more complex!

Final thoughts?

Having carried out research and interpreted many papers in this area. I need to consider what I would do as a clinician. I would discuss the summary of this research with the young person with an increased overjet. Furthermore,  I would point out that there is a chance of them damaging their front teeth, and treatment may reduce this chance. But I would emphasise that we will not eliminate the possibility of trauma. It is up to them to decide. But at least we have some evidence.

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Have your say!

  1. If the issue is trauma as a result of organized sports activities, even prior to age 9, then perhaps a better use of funds would be in promote and/or regulate the routine wear of athletic mouthguards. Since “contact” sports (hockey, football, lacrosse) have moved towards more adoption of this regulation, we now see more trauma for so-called “non-contact” sports like basketball, soccer, golf, baseball, volleyball, pickle ball, and the like. Perhaps, early intervention for dramatically “air-cooled” incisors to reduce some potential for every-day trauma, sports-associated trauma, and maybe mitigating some “social issues with appearance” could be seen as beneficial. Otherwise, early treatment (Phase I) for Class II in “getting even with overjet” still end-up generally costing more, taking longer, and the results are no better or different — an evidence-based conclusion.

  2. Of keen interest and well done, thank you. In the USA the emphasis is not simply “consent”. The ethical and legal requirement is INFORMED consent. If I may add, in addition to your comments about discussing the overjet/trauma issue with the “young person”, it must be documented that parent, guardian, or person with “placement” was informed and acknowledged risk/benefit ratios of informed consent. IMO this is both an ethical as well as a legal responsibility. Legalities aside, non-biased communication will assuage the clinician’s self-doubt and regret of various outcomes.

    • Thanks you are absolutely correct, in the UK consent may be given or denied by the young patient, provided that the operator considers that they are “competent” to take the decision without their parents input. This is why this information is essential to gain good informed consent.

  3. If this information is conveyed to the families using language adapted to their real understanding and they decide to go ahead assigning their own value to the alternatives then it is their decision. When presenting it as a NNT of 10 for removable functional appliances or a NNT of 6 for headgears most parents will not go ahead. It is like only one in six or ten kids with similar increased OJ will avoid the direct dental trauma. When a significan financial cost is added then the likelihood further decrease. Also let’s not forget that occlusal traits like increased OJ do not show alone so decisions of managing or not an increased OJ are not so simple.

  4. Would you consider using a threshold measurement for the overjet such as 7mm, for example? And from this hypothetical value and above, would indicate early treatment?

  5. I fully agree with what Jay Bowmann said … it would be better to adopt greater awareness in the use of mouthguards during sports. Personally here in Italy they are used very little, too uncomfortable for our young “champions”, as if everyone had to be Cristiano Ronaldo!
    On the other hand, as Carols Flores says when I talk about the percentage reduction of trauma, I can’t be very convincing … “only 12%?” the patient’s mother replies! Maybe a little better with Hg I love … but just me, not the patients!
    In the end, the parents want to be told what to do and the discussion after having pitted all the evidence we have is always the same: what would you do doctor if you were his son?
    Maybe if my son had an ovj greater than 6-7mm, incompetent lips, knowing the risk of possible bullying I would treat him … but maybe I’m biased?

  6. Peter Barwick
    Agree with promoting mouth guards. Here we are mandated for basketball now, along with football, rugby football, hockey, field hockey etc. Also…one at a time on the trampoline!

    Perhaps a more useful variable, if possible, for future studies could be maxillary incisor retraction, rather than overjet. One of the appliance types mentioned tends more to procline mandibular incisors (if worn) which may have confounded the results?

  7. We need to explain pros/cons clearly so they can make an informed decision. But most importantly on this early treatment issue, we cannot forget the power of a simple treatment and the invaluable lifelong positive effects on a kids life it can have… and that is whats all about.

  8. I tend to treat an excessive overjet when the patient feels self-conscious about their appearance and are being teased. As was pointed out, many times by the time I see them, the maxillary incisors have already been traumatized.

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