July 10, 2018

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.

Efficacy of piezocision-based flapless corticotomy in the orthodontic correction of severely crowded lower anterior teeth: a randomized controlled trial

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
Piezocision 53.3 12.5 47.5-59.47
Control 131.41 38.5 113.1-149.7

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.

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Have your say!

  1. Avatar

    this is very good study and results. this inspire us to start with piezocision in private practice too. but my only concern is , once crowding is corrected, how much time we need to wait on ss wire to prevent relapse as this is rapid movement and rapid movement requires longer retention time..
    but still this is quite useful..
    thank you for keeping updated.

  2. Avatar

    The authors should also have included a sham treatment group in which the incisions and placement of inactive instrument was performed.

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    Dear Kevin,
    In the last 20 years, I do, in my private clinic, see my adult patients every 10-14 days. Yes, every 10-14 days! I found that on the average, it is not only decreases the length of the treatment time considerably, I did not see more root resorptions then previously. Unfortunately the data that we based our root resorption concepts are from studies that have the streetlight effect and most of them cannot serve as a base to reality. Unfortunately, for years I and my literature reviews on the subject served as a base to false clinical data. My 2 reviews publications were in the list of the most cited publications from 2000-2015, therefore lately I published a disclosure saying that those reviews were based on short term studies that actually have nothing to do with apical root shortening, as you referred to. It is not surprising to see many others fall in that trap. There is no in-vivo study that demonstrated real apical root shortening. Surface resorption from orthodontics load is only the expression of the defense mechanism of the PDL bone and roots to the immediate changes and most of it actuaaly remodeled. The truth is that the profession has to rout its way in the field and find other ways to explain why the apex is sometimes becomes shorter.
    I personally don’t think that the procedure describes is a minimal invasive one and therefore I will never (in the very few years left for me to serve my patients) offer such a treatment to any patient, however, this is my point of view, I believe that others will argue with me.

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    It has been noted already that this represents time to alignment. in a 20 months treatment time a reduction of 2.5 months will move it, on average, to 17.5 months.Does this translate into further reduction during the remaining treatment time? There is some evidence that these types of adjunctive surgeries need to be redone every 4 months or so. Hence the initial rapid increase in tooth movement that dissipates with time. So the discussion with the patient will be that if he/she will like to likely accelerate his/her treatment by around 2-3 months for X amount of dollars. But what about the additional cost of the surgery? Then for the patient the potential reduction in treatment time may come as likely an actual increase in price. Where I am going with this is that there is an additional cost of surgery that seems to reduce treatment time by 2-3 months. Not all patients will go for it but some will. With any surgical treatment there is risk of complications. That should also be accounted for.

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    Dear Naphtali, as you are reducing treatment time with more frequent activations then the amount of root resorption would be potentially reduced as total treatment time is one of the strong predictors for root resorption. Nowadays I consider genetic predisposition as the single most important factor to facilitate orthodontically induced root resorption. The cementum is a wonderful quite accommodating tissue. How much it repairs itself is fascinating.

    • Avatar

      Dear Carlos,
      In the last 30 or so years orthodontic root resorption (ORR) was my main research. The problem is that the literature does not differentiate between the apical root shortening which is seen following treatment and ORR seen in different areas of the root, following activation, which major parts of it remodelled without any clinical signs. There is not even one RCT study that dmonstrates with evidents the relationship between time and apical root shortening. It might be logical that time is an issue, but it was never proven scientifically.

  6. Avatar

    The procedure itself is invasive as it cuts bone, and even worse it cuts bone without a good view of where the cut is. Esp. in crowded cases with many different root angulations I see a certain risk of damaging the roots and all that to speed up the alignment a little ? Bone heals reasonably fast = I suspect that there is not a longterm effect on the treatment unless you repeat the procedure. The faster you do your ortho, the less time muscles and soft tissue have to adapt to the new situation ( advancement, retraction, expansion, whatever ) = I would expect a higher risk of relapse. For these reasons, I personally don´t see a major advantage. But these are just my 2 cent.

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    This is a similar result to some of the Wilcko studies that have shown an initial increase in rate of tooth movement.

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    Cutting the bone improves speed of movement. Go figure, that’s basic logic that’s been in effect in many forms for centuries. Why orthodontics have only just figured it out, I have an inclination. Should we be cutting and weakening bone to move teeth into places there isn’t enough bone to hold them permanantely : no. Will there be consequences to ‘localised trauma’ yes obviously, but we won’t do any real research into it

  9. Avatar

    “Minimally invasive technique”——take another look at the video supplied !!??
    Again ,thanks for the article review.

  10. Avatar

    Great study, but IMHO the major reason for surgical intervention in such a situation is that the ETIOLOGY of the crowding is a discrepancy between tooth size and alveolar bone volume, especially when viewed in the bucco-lingual dimension. This, in my experience, virtually every crowded case presents with dehiscences and fenestrations which are then made worse as the arch is expanded. The consequence of course is future recession and relapse.
    The procedure PAOO (Periodontally Accelerated Osteogenic Orthodontics, or POPA, Pre Orthodontic Periodontal Augmentation) has two objectives; IMHO, augmentation of the deficient alveolar bone, to improve, and enhance biotype and thus minimize the risk of future recession, and two, induce deliberate trauma to help convert the grafted bone to vital new patient bone, and at the same time set up the RAP effect, the result of the deliberate trauma (corticotomy) into the cortical bone.
    My other concern with a blinded technique is root engagement and damage.

    Colin Richman DMD (Periodontics, Implants and POPA)
    Atlanta Georgia.
    PS: I am new to the blog and look very forward to future publications. Approximately one third of my practice relates to the Perio-Ortho Interface especially POPA.

  11. Avatar

    Kevin, regarding the piezocision technique for acceleration of orthodontic therapy, I would like for you to take a look at an article in the January-February issue of Orthodontic Practice US Volume 9 No. 1 by Noha Ali El-Ashmawi, et al on the effect of surgical corticotomy vs low level laser therapy on the rate of canine retraction in orthodontic patients. Corticotomy showed an initial acceleration but diminished rapidly and neither technique showed an advantage over the other. Larry White

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