An occasionally irregular blog about orthodontics

Straight teeth at the speed of light?

By on August 3, 2017 in Recent posts with 4 Comments
Straight teeth at the speed of light?

Straight teeth at the speed of light?

This guest post is written by Padhraig Fleming who is an experienced orthodontic researcher and clinician based in London (South of England). This is about photobiomodulation making teeth move faster…or not…

As an avid blog reader, I am delighted to contribute to Kevin’s blog. Many recent posts have focused on approaches to hasten orthodontic treatment– the present study considers the use of photobiomodulation and is published in a non-orthodontic journal. It may therefore have passed many of us by.

Investigators have developed a range of approaches in an attempt to reduce orthodontic treatment times. These range from invasive surgery to less aggressive but potentially costly non-surgical adjuncts. High-level research studies assessing the effectiveness of these approaches have predominantly given fairly lukewarm results with most exposing little benefit. Furthermore, repeated procedures may be needed to produce sustained surgical acceleration of tooth movement. This is a prospect that might raise anxiety in many patients and  may come at a biological cost. As such, an effective non-surgical means of reducing treatment times has potential merit.

This group from Dubai carried out this study published in ‘Lasers in Medical Science’. According to the authors, photobiomodulation involves delivery of light at wavelengths of 600 to 1200 nm inducing increased ATP production. It is thought that this local delivery leads to a rise in energy levels within adjacent osteoclasts and osteoblasts and they proliferate and differentiate. This results in acceleration of orthodontic tooth movement.

Decrowding of lower anterior segment with and without photobiomodulation: a single center, randomized clinical trial. 

Nahaz AZ et al.

Lasers Med Sci. 2017; 32:129-135. doi: 10.1007/s10103-016-2094-5.

What did they do?

They conducted a two-group parallel randomised controlled trial with a 1:1 allocation as follows:

 Participants: Mandibular Little’s irregularity index of ≥2 mm and ≤10 mm

Intervention: Orthodontic treatment with self-ligating brackets with supplemental LED photobiomodulation using an OrthoPulse device (Biolux) for 20 minutes daily

Control: Orthodontic treatment with self-ligating brackets

Outcome:  Time taken to reduce Little’s irregularity index to below 1mm

They allocated 20 participants to each group. But they did carry out a sample size calculation.  They concealed the allocation by using a sealed envelope system.  One operator placed all the appliances with a 0.016” heat-activated NiTi wire, followed by a 0.018” NiTi used in all participants. They reviewed the patients every 2 weeks. They ensured that the data analysts were blind to group allocation.

 What did they find?

They found no  differences between the groups at the start of treatment in relation to age or irregularity index, although the data was a little sparse. The mean time to align the lower anteriors was 68.3 days (SD 28.7) in the test group but was 87.8 days (SD 24.7) in the control group. This difference was statistically significant (P= 0.043), with the authors alluding to a 22% reduction in alignment time related to the use of photobiomodulation.

 What did I think?

This is yet another study assessing the utility of adjuncts in speeding up treatment. I am beginning to wonder whether these adjuncts have preoccupied us as researchers a little more than they should. As a result, maybe we are not focusing on some of the more important arbiters of treatment time and outcome? Surely, for example, extraction decisions and timing may be more influential? We have written a paper on this recently (https://progressinorthodontics.springeropen.com/articles/10.1186/s40510-017-0168-y).

In their discussion the authors neatly place their findings in the context of analogous studies, which found acceleration of the order of 30-34%. They do, however, point out that initial alignment is just one element of orthodontics and that further research focusing on space closure or indeed on overall treatment time might be more instructive.

They included patients who promised to be good and use the devices at least 80% of the time. Unfortunately, we know that many of our patients fall short of this standard, introducing some bias.

I also can’t help thinking that the sample size here is also low, the standard deviations are large and there was attrition in both groups. I therefore wonder whether these impressive between-group differences would be borne out in a larger sample and in other settings.

 What can we conclude?

Photobiomodulation has the potential to speed up tooth movement. However, we need to carry out further  research to prove the  value of this approach. It would be ideal if this could chart the course of treatment as a whole.

I remain to be convinced that the use of photobiomodulation is justified and will await further studies before my patients begin to ‘see the light’.

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  1. Peter Miles says:

    Hi Padhraig and Kevin. Without handing over 35 Euros to read the whole article, I wasn’t sure from your description if the clinicians were blinded to group allocation? If not blinded then very open to bias. Also, how did they assess that the irregularity was down to 1mm without measuring it or taking models at every visit? Finally as to compliance, unless objectively measured you can’t be sure. If they covered all these bases then it is indeed worthy of further investigation. If not, especially without blinding, then it is potentially misleading and the study would need to be repeated.

  2. Kevin. Agree with further study. I participated in the early testing and used several afterwards periodically when patients inquired and my conclusion was that patient variability was greater than accelerated vs non accelerated variability.

  3. Dr. Jose L. Rath says:

    Hello , please tell me how much, is the Orthopulse Biolux.
    Thanks

  4. This is an interesting synopsis which raises a couple of generic points when reviewing literature:
    1. One of the conclusions of the reviewer is that “the sample size here is also low”. This is untenable. The authors clearly undertook a power calculation of sample size prior to the study. The thought that the sample size is too small is based on belief and not on the scientific evidence presented. To refute the overall claim of the authors, colleagues that doubt the veracity of the outcome need to repeat the study to show there was no statistical difference, instead of picking holes in the findings of the current study, which is unacceptable to their beliefs. It’s about evidence not opinion. But let’s broaden the discussion a little. Do the reviewers accept the theory of evolution? I do on a scientific basis even tho’ new hominid evidence is based often on a sample size of one (1). On the other hand my personal beliefs are based on metaphysical (Sikh) philosophy, which is not part of this discussion.
    2. To determine the veracity of the claims in the paper presented, we need to ask a scientific question: Is there a mechanism on which the current findings could be predicated? Now we need to look at structure/function of the target tissues. It’s well known that the PDL (periodontal ‘ligament’) is replete with collagen. We also know collagen undergoes cross-linking as it matures. This does NOT apply to the PDL. Studies have shown that the PDL has one of the highest rates of tissue turnover in the body. It’s possible that photobiomodulation supplies biochemical energy that affects that tissue behavior enabling enhanced tooth movement. PhD anyone?

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