August 18, 2015

Class II treatment and skeletal change: Did we know the answer in 1967?

Class II treatment: a paper from 1967

In this post I am going to review a paper that the AJO published  in June 1967. This was the summer of love in San Francisco, the Beatles had just released Sgt Pepper, the Rolling Stones had released their psychedelic album “Their Satanic Majesty’s”.

Unknown-3I was 10 years old and enjoying the long hot summer and re-enacting the goals that Geoff Hurst scored when England won the World Cup a year before. You may ask why I am reminiscing about these times?


This is because Jayne Harrison, from Liverpool Dental School,  sent me a paper that was an early trial of class II treatment. I have been aware of this study,as it has appeared in several systematic reviews.  I would like to review it today because it is  useful to look back into our history.

Sven Olaf Jakobsson, who was based in Stockholm, wrote this paper

Cephalometric Evaluation of Class II treatment

Sven Jakobsson

AJO 1967: 53; 446-457.

In the introduction he outlined  the dilemmas, at that time, in the treatment of class II malocclusion. They were remarkably similar to those of today. He decided to carry out a study to answer

“Is it possible to alter the skeletal pattern”?

His literature review was good and concise.

What did he do?

He took a sample of 33 young people aged 8 to 9 years old with Class II Division 1 malocclusion. He stratified them by developmental age and dental morphology. He then,  randomly allocated them to either i) Headgear ii) an activator and iii) untreated control.

He took cephalograms at the start of treatment and 18 months later.

His only outcome was cephalomatric measurement directed at evaluating skeletal change, and he followed current practice by providing a large amount of detail and multiple cephalometric tables. He carried out a simplistic statistical analysis with multiple testing. This increased the risk of false positives.

What did he find?

It was difficult to follow the many cephalometric findings that he outlined. So I just concentrated on a few relevant points. essentially he found the following:

  1. Headgear moved A point posteriorly, but this was not clinically significant
  2. No treatment had an effect on mandibular growth
  3. Treatment reduced the overrate

Importantly the skeletal were changes were very small and most of the treatment change was dento-alveolar. This is beginning to sound familiar!?

What did I think?

I felt that this was a very interesting and somewhat humbling paper, when you consider that this work was done almost 50 years ago. I have several comments to make.

Firstly, Dr Jakobbson was clearly ahead of his time in adopting trial methodology and it is worthwhile considering this paper as a classic.

Nevertheless, there are significant issues with methodology compared to the way that we analyse and present trials. But we have to remember that this study was carried out many years ago.

It is also worth considering that this study, to a degree, does add to current knowledge. Importantly, its methodology was replicated by the well-known, more recent, Class II studies. I also find it very ironic that we are still debating whether  is functional appliances influence facial growth, when we knew the answer in the long hot summer of 1967 many years ago…

Finally, this shows that there is little new in orthodontics and we tend to follow cycles of research and invention. This was illustrated to me by Paul Hanrahan (Queensland, Australia) who sent me this Patent, for a vibrational mouth pad orthodontic appliance that increased the speed of tooth movement, reduce root resorption and discomfort!

Related Posts

Have your say!

  1. Hilarious !
    What’s old is new again.
    Just think of all the time and money wasted on research over the decades.

  2. Well done on raising this. The paper brings back a memory of when I reviewed it as part of a literature review as an MDSC student. There were others as well. It didn’t take long to work out the better the methodology the less the functional appliance stimulated mandibular growth. I any case, it stimulated me to head over to Michigan to Lysle in 1992. To quote Al Gore out of context – An Inconvenient Truth. Being of similar age, I recall the Beatles album. More significant than England winning the cup was St Kilda beating Collingwood by one point in the Australian Football Grand final

  3. That is why I still practice Tweed. It worked then and it works now.

    • Well said! One day in the near future we shall go back to non-angulated and non-torqued bracket systems with greater emphasis on archwire manipulation; and “researchers” at that point in time would hail it as the most versatile appliance.

  4. What has been will be again, what has been done will be done again; there is nothing new under the sun: Ecclesiastes 1:9
    Every generation has to reinvent the wheel. What did those old farts know anyway, and we all wanted to think we could grow mandibles. We even added facial orthopedics to our journal’s name.

  5. Per your concise synopsis of what SJ found in his 1967 trial regarding Tx effect upon A-point position (“1. Headgear moved A-point posteriorly, but this was not clinically significant”), I think it might be noteworthy to mention a few things:
    1.) consistent with your ‘times-have-changed’ observation’ ( “….there are significant issues with methodology compared to the way that we analyse and present trials”), per what we now clearly understand about the baseline retro-position of A-point in most ‘modern’ (post-industrial) skeletal class II’s (McNamara-Angle Orthod. 1982 et al), any additional retrusion of A-point (i.e., as was the case with SJ’s headgear cohort) in a child whose A-point is already too far back, would not be a good thing…..because;
    2. maxillary skeletal insufficiency, in ALL Angle classes of malocclusion, can have deleterious effects upon posterior naso-pharyngeal airway architecture and ability to habitually breathe through the nose during sleep and wakefulness (references upon request).

    • At last a comment by someone who is looking beyond the teeth. Are dentists/orthodontists afraid of stepping outside the oral cavity?

      • Dear Helen-Great question about reluctance (fear?) to extend our knowledge , expertise….and curiosity, ‘beyond the teeth’. Contemporary dental and medical curriculums were initially established in the early 1900’s, Flexner (1910 for medicine) and Gies (1926 for dentistry), and neither educational framework, to this day, require didactic exposure to the basic life sciences of Evolutionary Biology and/or Anthropology, and thus most physicians and dentists are incapable of understanding modern disease etiologies beyond their proximate causes, versus ultimate reasons. Until this changes, healthcare professionals, and the patients that they serve, will be at a marked disadvantage per this fundamental knowledge void.

  6. What is your opinion on the age of the patients in the sample? I think that Jim McNamara and his camp would argue that the results were exactly as expected due to the treatment being administered before peak mandibular growth. If the study were done around the time of peak growth (however you determine that), do you think that the numbers would be different as McNamara/Baccetti/Franchi have reported?

  7. Kevin, I don’t think it is ironic that we’re still debating the same answer about the effectiveness of Cl II mechanics. I think it is ironic that we are still asking the same question about it.

    Bertrand Russell said, “The greatest challenge to any thinker is stating the problem in a way that will allow a solution.”

    To wit, instead of asking “Is it possible to alter the skeletal pattern?”, why don’t we ask, “Has the skeletal pattern already been altered?”, and this not by the hands of the skilled orthodontist, but by his ignorance in allowing the stressors of the modern environment to have their way with the growing human face?

    If we consider that the Class II face has already been altered by poor nutritional factors, poor body and oral postures, struggling to breathe whether from the increasing incidence of asthma, allergies, URT inflammation, strains to the cranial bones, and the hinderance of sleep-related growth factors, then the question of whether we can undo all that damage simply by holding the mandible forward for 9 months seems quite inadequate.

    It would be like saying “Pushing on a car door that’s been in an accident is inadequate to get the car running again”.

    We must change the questions we’re asking if we’re going to get answers that will help this next generation of children grow up healthier than their parents.

    • Amendment to my remarks (since my friend brought me up short)…. please strike the words “by his ignorance in” and replace with “by ignoring and”…. by ignoring and allowing the modern world to have its way with our children’s faces without making an attempt to mitigate these factors.

      Is that better?

  8. For a long time, I have been arguing (quietly) that functional appliances do what they do by jumping the bite and holding the floating mandible to the maxilla (hence the advertised need for a good occlusion or a retention activator) until the condyle grows back into the fossa–a mortgage on mandibular position repaid without dentoalveolar compensation by the usual excess of condylar growth. Accordingly, it is interesting–to me, at least–that although Jakobsson found no effect on mandibular size (Co-Gn), he did find an activator-effect on mandibular position (Ar-Gn). QED, sort of….

Leave a Reply

Your email address will not be published. Required fields are marked *