July 24, 2023

A massive Cochrane review on the non-surgical methods to speed up tooth movement.

Over the past decade, many researchers have searched for the holy grail of a non-surgical method to speed up tooth movement. This question was first raised several years ago, and several methods were developed. Since then, research has been carried out into these new techniques and has come to several clear conclusions. These have now been summarised in this Cochrane Review. I hope that we can consider this to be the last word and hopefully not return to this question.

Non-surgical adjunctive interventions for accelerating tooth movement in patients undergoing orthodontic treatment (Review)

El-Angbawi A, McIntyre G, Fleming PS, Bearn D

Cochrane Database of Systematic Reviews 2023, Issue 6. Art. No.: CD010887.

DOI: 10.1002/14651858.CD010887.pub3.

What did they ask?

They did this systematic review to ask.

“What is the effect of non-surgical adjunctive interventions on the rate of orthodontic tooth movement and the overall duration of treatment”?

What did they do?

The team carried out a systematic review to Cochrane standards. Firstly, they did electronic and relevant additional searches of the literature. This was followed by identifying relevant papers, assessing the risk of bias with the Cochrane Risk of Bias tool, evaluating the certainty of evidence with the GRADE tool, data extraction, and meta-analysis.

They confined the search to randomised controlled trials. Notably, they excluded split-mouth designs.

The PICO was;


People of any age have orthodontic treatment with fixed or removable appliances.


Any non-surgical intervention to accelerate tooth movement.


Any form of orthodontic treatment without using non-surgical interventions.


The primary outcome was the duration of orthodontic treatment. Secondary outcomes were the number of visits needed, rate of reduction in arch alignment, rate of orthodontic tooth movement in mm/month, and improvement in occlusion.

What did they find?

This was an update of a Cochrane review that they did in 2015. At that point, they identified only 2 studies for inclusion. In this update, they found 41 records that reported on 23 studies. These were all parallel-group RCTs. Fourteen studies compared two groups, eight looked at three, and one compared four groups.

The trials included 1027 participants with an age range from 8 -50 years. Most studies involved fixed appliance treatment, and three evaluated clear aligners.

Helpfully, the team classified the interventions into two categories: light vibrational forces and photobiomodulation (Low-level laser therapy and light-emitting diode). Twelve studies looked at vibration, 10 evaluated low-level light therapy, and two studied light-emitting diode therapy.

When they looked at the risk of bias, they found that no study had a low risk of bias in all the domains. I felt this was primarily because of the lack of blinding of the operator and participants. There were other concerns with the lack of blinding of the outcome assessment and selective reporting. This meant that the overall certainty of the evidence was low.

They provided a large amount of data on the nature of the papers, the interventions, the control, and the many outcomes they evaluated. I will choose the outcomes that I feel are relevant to my practice. These are the treatment duration, outcome, complete alignment, and participants’ perception of pain and discomfort. This is what they found.


There was no evidence that the duration of orthodontic treatment was reduced or increased by applying vibratory forces compared to a control. The mean difference was 0.6 months (95%CI=-2.44 to 1.22). (Two studies with 73 participants). Low certainty evidence.

Similarly, there was no evidence that the number of adjustments was increased or decreased.

When they looked at the rate of tooth movement during alignment, they used the information from 4 studies involving 221 participants. They found no differences and suggested that.

“the available low certainty evidence does not support the use of vibration in increasing the rate of orthodontic tooth movement”.

There was no evidence that vibration influenced the perception of pain.

Similar conclusions were drawn for all the other outcomes.

Low-level light therapy and LED.

No study reported the effect of this intervention on the total treatment duration.

Four studies with a high risk of bias reported shorter alignment duration. The mean difference was 48.5 days shorter with light therapy. It also appeared that this reduced the number of visits by 2.25 visits. This was very low-certainty evidence,

There was no effect on pain perception.

Their overall conclusions were

“From the evidence available there was no evidence of  benefit from the use of vibrational forces or photobiomolation on the reduction of treatment duration. However PBM may reduce the length of the early stages of treatment and increase the speed of tooth movement”.

“Studies that evaluate the effects of these interventions on the total duration of treatment are needed”.

What did I think?

This was a highly detailed and well-produced systematic review that was done according to the very high standards of the Cochrane Collaboration. As a result, it is an excellent addition to the literature.

As with other Cochrane reviews, the included trials are at high risk of bias. This is because orthodontic trials do not blind the operators. However, it is almost impossible to achieve this in orthodontic trials. As a result, I take a pragmatic approach when I read orthodontic Cochrane reviews and I am not too concerned if this is the only reason for the allocation of high risk of bias.

The most compelling information this review reveals is a lack of evidence for the claimed effects of the vibratory devices. Furthermore, when we look at light devices, the effect sizes are small, and we do not know if this makes a difference to the complete course of treatment. Which, of course, is the most important outcome measure.

Final comment

My other conclusion is that at the end of all this, some practitioners, companies, and their KOLs made considerable amounts of money from these interventions.  Unfortunately, their claims were then accepted by non-critical orthodontists. Now that investigators have done the trials, we know that these developments are simply unfulfilled hopes and dreams.

Let’s see if we can avoid the same mistake by looking more carefully at future developments in orthodontics.

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Have your say!

  1. In my delusional dream of Utopia with Open Science, I see a world where RCTs are accepted for publication prior to the research being started with the statistical analysis stated. The research is then done and published with effect size and confidence intervals (CI). Once this is published and with positive effect size and CI the ‘new’ method can be put on the market, this would mean fewer risks for the patient and some chance the ‘new’ approach will be more beneficial than the previous one.
    Perhaps KOLs need to clearly state ‘while I once advocated accelerated orthodontics using ….., I was proven wrong.’ The honesty might be novel. Hold KOLs to account, force them to accept their own mistakes to reduce the risk of you believing them on their next discovery.

  2. Another interesting opinion, Kevin. It solidifies the concept that a Cochrane review is canonical for orthodontists. However, a Cochrane review (2011) found very unreliable evidence that Flossing reduces plaque. The review could not find any studies on the effectiveness of flossing combined with brushing. So, do orthodontists recommend against the need for flossing?
    Regarding vibration, I’m not convinced the protocols adopted in animal studies are appropriate clinically. In addition, ‘orthodontic’ tooth movement, which invokes inflammation, is not the same as physiologic tooth movement (e.g. post-orthodontic relapse). Moreover, orthodontic tooth movement is a secondary phenomenon, downstream from bone remodeling. So the question about vibration/tooth movement cannot be fully addressed until the effects, if any, of appropriate vibrational protocols on bone remodeling have been elucidated.
    Finally, I have a hunch that frequency specific modulation might have potential orthodontic applications in the future. PhD, anyone?

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