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”.
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
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:
- Headgear moved A point posteriorly, but this was not clinically significant
- No treatment had an effect on mandibular growth
- 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!
Emeritus Professor of Orthodontics, University of Manchester, UK.