October 05, 2015

Two years of the blog: What do we know about functional appliance treatment?

Two years of the blog:  What do we know about functional appliance treatment?

In this post I am going to continue with the theme from last week and make this post a summary of some of the most popular and relevant posts on Class II treatment.  This will be last post for a couple of weeks, as I am having a herniated cervical disc removed on later this week and I will not be allowed to type for a few weeks!

The treatment of young people with Class II malocclusion makes up about 40% of the case load of most orthodontists and we are fortunate in that it is one of the areas of orthodontic treatment that has been researched to a high level.  These studies range from the “classic” early treatment RCTs to more recent trials of treatment that is carried out in adolescence.  There has also been a Cochrane systematic review that has combined the findings of these studies.

I will start with a bullet point list of the current findings of this research

  • There are limited advantages to providing early orthodontic treatment of Class II malocclusion.  However, there may be reduction in the incidence of trauma.  Early treatment could also be provided to reduce teasing and bullying, but only if a child is being teased or bullied.
  • Most of the reduction in overjet is achieved by tooth movement. There is minimal skeletal change and this cannot be predicted.
  • When we provide treatment in adolescence  there is nothing wrong with extracting upper first premolars and reducing the overjet. This treatment is practiced all over the world in countries where functional appliances are not so extensively used.
  • There are no differences in the treatment result of fixed and removable functional appliances
  • There is greater patient co-operation with fixed functionals than removable
  • The Twin Block is the most popular functional appliance in the UK.
  • There is no point in putting on or leaving off the labial bow on a Twin Block.
  • If headgear is used to “drive Class II molars distally” the average length of the “drive” is 1.6mm
  • No one can grow a mandible!

I have provided many posts on this clinical problem and I have made a list of the most popular and relevant to this summary here:

Unknown-2What do we know about Class II orthodontic treatment ? A new Cochrane Systematic Review

This post is a summary of the most important points in our Cochrane review. I concentrated mostly on the findings that we reported on the prevention of incisal trauma. We concluded that early treatment did reduce the chance of incisal trauma, but that there was a degree of uncertainty in the data and that this should be explained to patients and their parents.

Early Class II treatment: Part 1: The wheel keeps turning. Uncertainty and the Pyramid of Denial

Early Class II treatment. Part 2: Are we clinician scientists or barber surgeons?

These posts were summaries of a presentation that I and Professor Jonathan Sandler did at the American Association of Orthodontists congress in May 2015.  We addressed the issue of early treatment and rather bluntly stated that questions about this treatment had been answered and that there was not much to debate on this issue.

A brief guide to removable functional appliance treatment

This was one of the first posts that I did that was really directed towards a clinical guide. Again, I did this with Jonathan and it includes examples of his excellent clinical work interspersed with evidence.

Removable functional appliances do not change skeletal pattern to a clinically meaningful amount

 This was concerned with a review of a systematic review that provided more information that functional appliances do not change skeletal pattern.

September Orthodontic Clinical Trials review

This was one of my first posts and I reviewed an interesting small trial published in the excellent Orthodontics and Craniofacial research.  This provided useful information on the effects of a removable functional appliance.

I hope that these posts provide a useful summary of our current knowledge on the treatment of Class II malocclusion.  I also hope that in a few weeks, the blog will be back to normal.  This style of post has been widely read and I will repeat them from time to time, as I think that it is useful to provide summaries.

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Have your say!

  1. It goes virtually without saying how much the orthodontic community loves your blog.

    Might I suggest you acquire a copy of Dragon’s Naturally Speaking dictation software to reduce your time typing. Works pretty well after you train it to recognize your voice.

    • Hi Charlie, thanks for the nice message. I am currently using Dragon dictate and it is working very well. But I need to try harder with it, as I am sure that it can do a lot more!

      Best wishes: Kevin

  2. Dear sir I do believe in functional appliance as it is the best preventive orthodontic treatment. I am treating certain patients with the twin block and they are giving excellent results. Even one patient who was wearing the twin block for almost two years (since he was not frequently visiting me) had great results even though he was wearing the appliance less frequently. What I have noticed in this appliance is that it gives a real good initiation of the forward growth of the mandible which in the future is very helpful in the fixed orthodontic treatment….

    • The beautiful thing about Dr. O’Brien’s blog, and his approach to reviewing the literature is to help us not have to use statements like: “I do believe in functional appliance.” If our profession wishes to maintain its position of respect, we need to be critical of our treatment and outcomes. This means we don’t assume that the mandibular growth we observed while the patient was in treatment was necessarily due to our treatment. Treatment benefits need to be proven.

      • Thank you sir for the reply and your comment is duly noted. I totally agree with you sir as the treatment benefits should be proved. The reason why I had commented for this blog is that I appreciate this appliance on the way it helps in the mandibular movement as it is improving the patient’s occlusion as well as myo-facial changes.

  3. Dear Kevin, Hope you will recover soon! Thank you for all your blogs!

  4. Firstly Kevin, have I wish you as least pain as possible and a speedy recovery. And, yes, love your blog.

    This argument has been around for over a century and in its modern context, significant research has existed for about 30 years as described by Lysle Johnston in Science and Clinical Judgement (about) 1985. It seems all Class II modalities elicit similar responses, elastics and even headgear. If there is a need for those lower incisors to come a long way forward then perhaps a functional and non-extraction approach should be reconsidered.
    The questions that remain are the extra cost of any treatment justifiable? Costs include lab fees, chair time, further impressions, psycho-social cost of impaired speech, discomfort, travel time, discomfort- pain, lost opportunity for doing something else in that time?
    Early treatment when some of your dot points apply is indicated but when those points don’t apply: Are functional appliances a cost or a saving when treating a Class II patient? Does the severity of the molar relationship influence the economics?

  5. Excellent summary. Easy to understand and very informative.

  6. Kevin, sorry I missed you at the WFO, but it was well-attended with a great variety of subjects. I’m not sure I will get by to the UK anytime soon. Traveling has become a real hassle, mainly because of the huge airports one has to traverse. Hope the operation has success. I have avoided the same operation thus far, but the malady seems to be a vocational hazard.


  7. Dear Kevin,
    first of all ,thank you for your huge contribution in improving our clinical activity, and thanks for giving us the scientific support needed to navigate the sea of orthodontics wizards!
    I am always very excited to read your blog and I would like to ask you a judgment about a new publication on classes II which seems to give support to “growing mandibles.” (Treatment Effects of Removable Functional Appliances in Pre-Pubertal and Pubertal Class II Patients: A Systematic Review and Meta-Analysis of Controlled Studies.
    Perinetti G, Primožič J, Franchi L, Contardo L.
    PLoS One. 2015 Oct 28;10(10):e0141198. doi: 10.1371/journal.pone.0141198. eCollection 2015.)
    I personally am tired of hearing talk about this and that device and the effects on growth, I’m tired of hearing about cephalometric effects, I ask you: there will never be a step into the future?
    Best regards

    • I agree that the ceph study probably has done its time in orthodontic particularly that involving functional appliances. I will blog this paper next week!

      • In this regard, do you believe that you can use other valuation methods? e.g. what do you think of the validity Arnett ‘s Soft Tissue Cephalometric Analysis?.
        In the future, Do you think you could assume the systematic use of standardized assessments of the patient’s soft tissue (e.g with only digital photo) without resorting to unnecessary Rx?

  8. In this regard, do you think you can find other methods of evaluation? e.g. what do you think of the validity of analysis performed on the pateient’s soft tissues(Arnett ‘Soft Tissue Cephalometric Analysis, for example) .I believe that in future we must develop analysis of soft tissues ( for example only on the patient’s digital and calibrated photos) without resorting to unnecessary and harmful radiation.
    Thanks again

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