An occasionally irregular blog about orthodontics

Does AcceleDent speed up Invisalign treatment?

By on March 12, 2018 in Recent posts with 4 Comments
Does AcceleDent speed up Invisalign treatment?

AcceleDent is a device that is supposed to speed up orthodontic treatment. Does it have an effect on Invisalign treatment? This trial gives us the answer.

AcceleDent is a device that vibrates the teeth with the intention of increasing the speed of orthodontic tooth movement.

I have posted about AcceleDent several times. In these posts I have mentioned that there have been four trials into the effectiveness of AcceleDent. Three of these studies have found no evidence that AcceleDent has an effect on the rate of tooth movement. The other study did find an effect but this investigation was seriously flawed. Seminars in Orthodontics published this paper.

While these studies have looked at the effect of AcceleDent on fixed appliance treatment. There have been no studies that have investigated whether vibration influences the speed of aligner treatment. I was, therefore, very interested to see this new study in the AJO-DDO. I am going to look at this study very closely  because I think that it could be important.

Effect of supplemental vibration on orthodontic treatment with aligners: A randomized trialMina Katchooi et al

Am J Orthod Dentofacial Orthop 2018;153:336-46

https://doi.org/10.1016/j.ajodo.2017.10.017

A team from Seattle did this study.

The aim of this study was to find out whether AcceleDent enabled faster orthodontic treatment by allowing Invisalign patients to change aligners every one week. The study team also asked if there were any differences in alignment, oral health quality of life and pain.

What did they do?

They did a multi centre 2 arm parallel randomised triple blinded trial with a 1:1 allocation ratio. The PICO was

Participants: Adults (18 years or older) with malocclusions involving fewer than 25 sets of aligners.

Intervention: AcceleDent Aura device which was active

Comparator: AcceleDent Aura device which had been altered so that the vibrations would not be transmitted to the teeth.

Outcome: The percentage of participants who successfully completed their initial series of aligners as planned using a 1 week change interval. They also measured pain and quality of life with questionnnaires. Finally, they measured compliance with the AcceleDent devices.

I think that the outcome was unusual and I shall discuss it later in this post. However, it is worth explaining this carefully. They asked all the participants to change their aligners every week. At each visit they carefully checked the fit of the last aligner. If it was not an adequate fit, they removed the patient from the study and they continued with a two weekly aligner change. As a result, they made the assumption that if the aligners fitted, the teeth were moving quicker. This means that if the vibration was having an effect, more patients in the AcceleDent active group would complete treatment.

Two experienced operators did all the treatment in their private offices.

They carried out a sample size calculation which was relevant to their outcome. The patients, operators and assessors were all blinded to the allocation. They did a good randomisation, concealment and allocation. Their statistical analysis was relevant.

What did they find?

27 adults entered the study and only one discontinued treatment. They collected data on all the patients.

They did not find any differences between the groups at the start of treatment.

At the end of the study they found that 10 (77%) of the AcceleDent active group and 11 (85%) of the AcceleDent sham group completed treatment. That is there was no difference in the percentage of the patients in each group who were able to change their aligners every week.

They also found no difference in the change in alignment, pain and compliance between the two groups.

They stated;

“Our original hypothesis was that more patients would complete their aligners with the active vibration device, since the device would stimulate faster tooth movement and allow better tracking. To our surprise, we did not find a difference in completion rates”.

In other word they did not find evidence that suggested AcceleDent increased the rate of tooth movement.

What did I think?

Firstly, the investigators carried out this trial well and the study methods were all good. Importantly, the clinicians were experienced and the study was carried out in a specialist office/practice setting. As a result, the study has good generality.

I think that we need to look closely at the outcome measure. The ability to change aligners frequently is a surrogate outcome for faster tooth movement. Another approach would be to design a study in which we measured the time to complete treatment for each group of patients. However, I am not sure that this could be done for aligner treatment, because we rely on the aligners to move the teeth. This is not the case for fixed appliances, as the operator will adjust the treatment mechanics and wires as treatment progresses.

As a result, it appears that the outcome measure that they used was sensible and relevant to aligner treatment. The investigators also pointed out that during their trial Align recommended that aligners could be changed every week. They pointed out that if 7 day changes are shown to be effective then it may be necessary to change aligners every three days to test whether vibration has an effect. This could go on for ever!

Summary

Having thought about this trial and the outcome very carefully. I can only conclude that there is an absence of evidence that AcceleDent increases the speed of tooth movement. This absence is now becoming overwhelming…

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There Are 4 Comments

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  1. vicki vlaskalic says:

    Thx Kevin –
    agree it does look like a well conducted study. Would have liked to have seen a 3rd group, not biting into anything (I am an avid chewie (or sqeezy) fan and feel that initial seating of an aligner aids expression of movement, or at least minimises inaccurate expression- so this test may eliminate a possible benefit of the appliance in terms of movement enhancement. Also would like to see how much movement was expressed compared to that programmed as a measurable objective assessment of degree of finish as opposed to finishing a course of treatment, irregularity index or visual sense of aligner fit, although these are all used out in the field so relevant. Maybe that could be a follow up as they probably have that data available.

    This week, I really want to read your blog, concur and sleep! (its late in Aus when your blog is posted). But I just cant stop thinking about your sentence: “The ability to change aligners frequently is a surrogate outcome for faster tooth movement.”. I wonder if this is always true or accurate? Perhaps this may not be true, depending on the rate of force decay in any given aligner material, on any given tooth, in any given patient.?…, Hypothetically; if an aligner had 0.25mm maximum linear activation, and the ligament has about the same in compression, perhaps the tooth movement (crown would be different to root) would be expressed in the first few hours, first day or first 2 days as some studies have found (plastic force decay curve is not as NiTi). That means the rest of the aligner wear time may be somewhat “dead” time in terms of tooth (or majority of) movement? So, humour me, if changing aligners more frequently may not impact on the initial tooth movement phase of aligner wear but only lessen the “dead” phase ….does it still hold to say “The ability to change aligners frequently is a surrogate outcome for faster tooth movement.”….or perhaps it should be as you begin to discuss “The ability to change aligners frequently is a surrogate outcome for faster treatment time?” ..
    As someone who has changed Invisalign aligners weekly for years with no accessory device (sorry Tony:(), believes that wearing a “spent” aligner longer does not aid in moving a tooth into the desired direction but in deforming the aligner to make it look like it fits the teeth, and who customises wear time depending on clinical progress, I see huge benefit in learning more about the force decay curve in aligner materials we use , and in learning what is actually happening physiologically in terms of movement throughout the aligner wear period – active and non active movement. The great thing is that we can measure movement versus activation so much easier with digitally programmed appliances so that they may become truly customised by the practitioner. So exciting! GN.

  2. One has to wonder how this study ever made it into the pages of the prestigious Am J Orthod Dentofacial Orthop. There was no quantification whatsoever. Pardon my cynicism, but I wonder if this particular paper would ever have been published if the findings supported the use of accelodent?

  3. John McDonald says:

    Kevin,
    Is there a typo in your description of the study? Did they change aligners every week rather than the (standard at the time) 2 week interval as you state in your “Aim of the Study” sentence.

    • Kevin O'Brien says:

      Yes, you are correct. The usual time was two weeks and they tested one week changes.. I have made this more clear in the text. Thanks for pointing this out.

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