Sunday, 8 August 2010

Masticatory muscle activity in children with a skeletal or dentoalveolar open bite.

The article is published at the European Journal of Orthodontics of this August, and it aims to compare the electomyographic characteristic of masticatory muscles, in children 6-11 years of age. The group that made the study is from Sao Paolo, Brazil


  • 15 children with skeletal anterior open bite (SAOB)
  • 15 children with dentoalveolar open bite (DAOB)
  • and 15 children of normal occlusion as a control group (CG)
The first weakness of the study arrises at the introduction of the article. The differentiation of skeletal to dentoalveolar open bite in an age of 6-11 years is not an easy task. Quoting the article's introduction, "In a dentoalveolar open bite, the disorder occurs during tooth eruption and alveolar growth." both of those two have not ceased at the age of 11 that is the highest age of the sample.

But let's get to the interesting part of the results of this article:

The EMG of maseter and temporalis muscle, were measured in a number of situations such as chewing gum, clenching, chewing peanuts and so on.

  • The EMG activity was significantly higher on the CG, when compared to SAOB, and DAOB
  • When clenching the DAOB group had a higher muscle activity, compared to the SAOB group
  • However on the rest of the activities there was no difference on the EMG.

As prior studies imply, so this study, puts the interest on patients with anterior open bites to the myofunctional activity. It has been suggested that functional capacity of masticatory muscles can enhance facial growth (Kiliaridis et all 2003), as for example increased activity, leading to sutural growth and bone apposition, with growth of the maxilla on the transverse, and association with anterior rotation growth type.

Clinical evaluation of masticatory activity, could determine a different treatment protocol and a different retention regime.

Simple exercises during treatment, such as lip seal exercises and/or swallowing exercises, along with chewing exercises, might seem from some orthodontists pointless or with minor results, but could actually help as a tool on those challenging cases, as long as the specialist believes in them, and as long as the patient carries them out, during the orthodontic treatment but also during the retention period.


Reference article:

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