Piezocision increases the speed of tooth movement a lot!: A new RCT
Researchers are carrying out many studies into methods of increasing the rate of tooth movement. This new study shows a remarkable effect of localised trauma.
I have posted many times on the research being carried out into reducing the length of orthodontic treatment. In general, this has shown there are no or minimal effects of any of the interventions. Nevertheless, one of the most promising techniques may be piezocision. This is done by making small interproximal cuts in the alveolar bone. It is classified as a minimally invasive techniques.
A team from Damascus, Syria did this study. The EJO published their paper.
Omar Gibreal et al
European Journal of Orthodontics, 2018, 1–8 doi:10.1093/ejo/cjy042
In their introduction they point out that previous investigators have looked at the effects of piezocision on non-extraction cases. They decided to look at extraction treatment by asking this question;
“What was the effect of piezocision on the rate of correction of lower anterior crowding”?
Here is a video of piezocision, in case you have not seen it before.
What did they do?
They did a two arm parallel group RCT. The PICO was;
- Participants: Adult orthodontic patients with severe mandibular crowding (Little’s index greater than 10). They required the extraction of two lower first premolars.
- Intervention: Fixed appliance treatment with piezocision.
- Control: Fixed appliance treatment with no other intervention.
- Outcome: The primary outcome was the overall time to alignment of the lower anterior teeth. This was defines as when the LLI was less than 1mm and it was possible to insert a 19×25 ss wire.
This study was unique, as the patients were seen every two weeks. As a result, they hoped to take advantage of any possible effect of piezocision and the standard 4-6 week interval would not achieve this.
They did a sample size calculation. A member of staff who was not involved with the research prepared the randomisation and allocation concealment using sealed envelopes.
They did not blind the operator or the patients. However, the outcome assessor did not know the treatment allocation.
They did not do an ITT analysis and their statistical analysis was confined to simple univariate statistics. I would have liked to see a regression that took the amount of pre-treatment crowding into account. However, the journal referees did not consider this a problem.
What did they find?
The two groups were similar at the start of treatment. When I looked at the final results I thought that they were remarkable. The most important was that piezocision resulted in a mean time to alignment of 53 days (1.7months). Whereas, fixed appliances aligned the teeth in 131 days (4.3 months). This is a 59% reduction in alignment time! Interestingly, they also showed that the greatest effect of the piezocision was within the first month.
They did not report confidence intervals in the paper and I have calculated them.
|Time to alignment (days)||SD||95% CI|
This shows that the CIs are rather narrow and means that we can have confidence in the data.
What did I think?
I thought that this was an interesting small trial. In many ways it is similar to the other studies that have been done in terms of sample size and methodology. The investigators did the trial well and I did not find any major issues.
Nevertheless, I was surprised to find such a large effect size. I also felt that the treatment time for the control group was small. When I considered reasons for this, the most obvious is that they saw the patients every two weeks. I would have liked to see another arm of the study in which the appointments were at a standard interval, such as, 4-6 weeks. This could have given us more information on the burden of care using piezocision and the effect of two weekly appointments.
I think that another important issue is that they did not report any harms, for example, loss of vitality and root resorption. These may be worsened by the short treatment intervals, but this is just clinical conjecture.
We also need to remember that the only conclusion that can be drawn from this study is that piezocision, with appointment every two weeks, can reduce treatment time to alignment. We cannot conclude that piezocision results in a reduction in the total duration of treatment. This is a question that needs answering in future research.
Finally, this is a remarkable result and it would be interesting to see if future studies replicate these results. This may be an exciting development.
Emeritus Professor of Orthodontics, University of Manchester, UK.