What is the best treatment method for Anterior Crossbites: fixed or removable appliances?
A new trial of treatment methods for anterior crossbites
Every now and then someone publishes a paper that is directed at answering a common clinical question and they use simple straightforward trial methodology. Today in the EJO I came across this great simple study into the best method of correcting anterior cross bites. It was carried out in the University of Malmo, Sweden.
I am also pleased to see that the The EJO is rapidly improving as an orthodontic journal, as it is publishing more good quality clinical research and trials. However, the content is restricted behind a pay wall. I wonder if this could be changed and open access to the journal is provided? We’re looking at you European orthodontic Society!
Anna-Paulina Wiedel and Lars Bondemark
EJO 2015: 123-127. Doi:10.1093/ejo/cju005
What did they ask?
The introduction was very relevant and concise. They raised a very simple question which was
“Is it more effective to use a removable or a fixed orthodontic appliance to correct an anterior cross bite”.
What did they do?
They carried out a very simple randomised trial in which 64 patients were randomised to receive treatment either by a removable appliance or fixed appliance. Randomisation concealment and blinding were good. Two specialist orthodontists and a post-graduate student under supervision treated the patients.
The primary outcome measure was whether they corrected the cross bite. Secondary outcome measures were the treatment duration and dropout rate. They also collected outcomes on other dental measurements, but I am not going to go into these in this post. They collected data at the start and end of treatment and they analysed the data from all the patients regardless of the outcome.
The removable appliance was a standard acrylic plate with a spring to procline the upper incisor. The fixed appliance was bonded to the anterior teeth and the primary molars or premolars, if they had erupted.
There was an adequate size calculation and the statistics were simple univariate tests. Although, if I was being very critical I would have liked to see a multivariate regression analysis. Nevertheless, they adopted simple outcome measures and the groups were matched at the start.
What did they find?
They randomised 62 patients into the two groups and all but one completed the trial. They found that all the cross bites in the fixed appliance group and all except one in the removable appliance group were corrected Therefore, in terms of the primary outcome measure there were no differences between the two treatments.
However they did find that the average duration of treatment was 1.4 months shorter with fixed appliance The average treatment time being 6.9 months for the removable appliance group and 5.5 months for the fixed appliance group.
The discussion was straightforward. It was clear that there were no differences between the two appliances. They also pointed out that the difference the length of treatment was not really clinically significant. I agree with them
What did I think?
I thought this was a really interesting and well carried out small study. It is also great example of how a common question can be answered with minimal resource and yet provide very useful clinical information.
If I am going to be critical(and I may being too critical?). One area that they did not evaluate was cost effectiveness, and I wonder if there was a difference in cost between the two treatment. I would also like to have seen some information on patients perceptions of the two appliances.
Will this change my practice?
Over the years I have used removable appliances to correct anterior cross bites and only occasionally used fixed appliances. I’m not really sure of the rationale behind my decision. Perhaps this was because I’ve always done it that way! I think from now on I will use more fixed appliances as it does seem more simple and straightforward in terms of treatment mechanics.
Wiedel, A., & Bondemark, L. (2014). Fixed versus removable orthodontic appliances to correct anterior crossbite in the mixed dentition–a randomized controlled trial The European Journal of Orthodontics, 37 (2), 123-127 DOI: 10.1093/ejo/cju005
Emeritus Professor of Orthodontics, University of Manchester, UK.