A systematic review provides us with useful information on early facemask treatment of Class III malocclusion

A systematic review provides us with useful information on early facemask treatment of Class III malocclusion

The interception of the development of malocclusion is one of the most interesting areas in clinical orthodontics. This post is my interpretation of a systematic review that looked at the effectiveness of early facemask treatment for Class III malocclusion. I feel that this study provides us with useful information that should help our patients.

A couple of months ago I highlighted a very good trial into the effect of early class III protraction headgear. This showed that the provision of early treatment reduced the perceived need for orthognathic surgery.  I felt that this was very useful finding and would certainly tip me towards providing early treatment. However, we should not base our treatment philosophies on one study and this is where this systematic review is very timely.

Early orthodontic treatment for Class III malocclusion: A systematic review and meta-analysis

See Choong Woon and Badri Thiruvenkatachari

Am J Orthod Dentofacial Orthop 2017;151:28-52

DOI: http://dx.doi.org/10.1016/j.ajodo.2016.07.017

Researchers from Manchester, North of England wrote this paper.

In their introduction, they pointed out that a team from Liverpool published a Cochrane review in 2013 into early Class III treatment. They did not find many trials and they concluded that more research was needed. This new paper is an update on this original review.

Their aim was to:

“Evaluate the effectiveness of orthodontic methods used in the early treatment of class III malocclusion”.

What did they do?

This was not a Cochrane review but they followed the strict Cochrane methodology. The PICO was:

Participants: Children between seven – 12 years of age with Class III malocclusion.

Intervention: Orthodontic treatment with fixed or removable appliances

Comparison: No treatment/delayed treatment

Outcome: Correction of the reverse overjet

I was very pleased to see that they did not sink into a morass of cephalometric data, as I felt that this was not necessary.

They confined their search to randomised controlled trials and prospective clinical controlled trials and carried out an electronic search to identify potential projects.

They evaluated the risk of bias with the Cochrane Risk of Bias tool for the RCTs and the Downs and Black checklist for the CCT’s.

What did they find?

After identifying a large number of potential publications they finally selected a sample of 15 papers, after applying the usual set of filters. They divided these into nine RCTs and 6 CCTs. When they looked at the risk of bias, they found that three of the RCTs were at low risk of bias and the remainder were classified as unclear risk of bias. All the CCT’s were classified as high risk of bias.

At this point, I think we should now consider that this level of bias means that the review is only likely to yield a moderate level of evidence.

The presentation of the data was rather complex and in view of the high risk of bias in the CCT’s, I decided to concentrate on the results from the randomised controlled trials that evaluated treatment versus an untreated control.

The most important finding was that the use of a protraction facemask compared  with no treatment showed a difference in ANB of 3.9° (95% CI 3.5 – 4.2). Importantly, only one study measured overjet change. This showed that the use of a facemask resulted in a difference of 2.5 mm (95% CI 1.2 – 3.79) when compared to no treatment

There was a high degree of heterogeneity between the studies. This arose from a degree of variation in the experimental protocols and this adds to the uncertainty on the results.

What did I think?

I thought that this was a good review that resulted in some clinically useful findings. Nevertheless, I found that interpretation of the data was difficult, so I decided to just look at the major clinical findings that were not subject to bias.  I was also more interested in the effect of treatment versus no treatment. As a result, I did not really consider the trials that compared two or more interventions. Some may think that I have excluded a lot of useful data in taking this step. But I always feel the simple approach to interpreting a paper yields more useful information.

What can we conclude?

I only looked at the data from the three randomised trials comparing facemask treatment with no treatment.  From these, I concluded;

“Early treatment with protraction face masks is likely to result in short-term clinically useful skeletal and dental change”.

However, we need to interpret this finding with a degree of caution. For example, we do not really know whether any of this change was maintained with further facial growth. We also need to remember that, because of the issues of bias and heterogeneity, there is still a degree of uncertainty in the results of this review.

Nevertheless, I think that the review gives us information that we can use to explain early Class III treatment to our patients and their parents. I feel I would be able to say the following;

“You have a problem that may be treated with early facemask treatment. There is a good chance that this will correct the way your front teeth meet. However, we do not know if any of the changes we get now will remain when you are 14 to 15 years old”.

We clearly cannot make claims about improving breathing, self esteem, and correcting facial growth by changing the environment etc!

They can then make a decision based on this information.  In many ways this is similar to the situation with early Class II treatment. In both these areas we now have some useful research findings.