A summary post on “how do we make orthodontic tooth movement faster”? AcceleDent and Osteoperforation
How do we make teeth move faster?
This is another summary of my previous posts and is on “how can we make orthodontic tooth movement faster”? If we all had a wish list of our hopes to improve orthodontic treatment, I am sure that the development of a method to make teeth move faster would be close to the top. While there have been several recent innovations, are they as good as they seem?Over the years there have been many attempts to increase the speed of orthodontic tooth movement. These have ranged from developments of new wires and “innovative” developments of old bracket designs. Unfortunately, clinical research does not support the benefits that have been promoted. It appears that bone and bone cells do not recognise the new technology. An alternative approach has been to attempt to influence the biology of the bone and this has recently led to the development of surgically facilitated tooth movement and other methods to speed up tooth movement. The first part of this post is about the surgically facilitated methods and the second is on the use of vibratory force.
Surgically facilitated orthodontic treatment:A systematic review.
Eeike J Hoogeven at all
AJO-DDO 2014: 45:4 Supplement 1
This review is concerned with the use of corticotomy and dental distraction.
What did they do?
They aimed to discover whether:
- Surgically facilitated orthodontic treatment increased the velocity of tooth movement
- There were any risks from this form of treatment.
They clearly stated the inclusion criteria and included RCTs, CCTs and case series with more than five patients. As a result, this was not a “classical” systematic review that only included trials. It is, therefore, important to consider the level of evidence presented in the review. It is to the authors credit that they considered this factor in the presentation of the results.
What did they find?
They identified 505 studies and after filtering for relevance and quality they finally included 18 studies. Of these, 4 were RCTs (but 3 were split mouth, see this blog post for consideration of split mouth designs). They graded these as moderate levels of evidence, all the other studies were classified as being low levels of evidence.
What did they find?
I felt that in some ways the findings were disappointing as they could not combine data from the studies. This was because of the problem of heterogeneity between the studies. This is common in many reviews, but is a characteristic of oath studies, because we do not all measure the same outcomes in our research. Furthermore, as the quality of studies were only moderate or low their conclusions were provisional and represented a high level of uncertainty.
In summary, it appears that corticotomy facilitated orthodontic treatment may temporarily enhance the speed of tooth movement, but this was not consistent. Importantly, no evidence of harms was detected. While these results seem promising, there is a clear need to carry out more high quality research. We are not in a position to be certain that this treatment works.
Another systematic review
This review was then followed by a Cochrane systematic review. This was done by a team based at The Royal London Dental School, in Whitechapel, London, UK and Corfu, Greece. Whitechapel is the area of London famous for Jack the Ripper and Corfu is a beautiful Greek Island.
Fleming PS, Fedorowicz Z, Johal A, El-Angbawi A, Pandis N
Cochrane Database of Systematic Reviews 2015, Issue 6. Art. No.: CD010572. DOI: 10.1002/14651858.CD010572.pub2.
This was a Cochrane review so we can assume that it is of high quality because of the requirements of Cochrane editorial policy. I have covered how to read systematic reviews previously in this post. How to read a systematic review
What did they do?
They set out to evaluate the effect of surgically assisted orthodontics on the duration and outcome of orthodontic treatment. They used standard systematic review methodology when they searched the literature, identified the papers, applying the selection criteria, data extraction and evaluation of bias.
What did they find?
After an extensive literature search and exclusion of many studies, they selected 4 randomised trials that involved a total of only 57 patients. The interventions that were evaluated were essentially variants of corticotomy and micro osteoperforation. They pointed out that no study followed patients to the end of their treatment. As a result, they could not answer their primary question.
The results of these trials were confined to the rate of retraction of canine teeth. While this does measure tooth movement, this is only for one phase of treatment and we must consider that this is only a surrogate measure for total tooth movement.
They found that tooth movement was slightly quicker with surgically assisted orthodontics over a period of one month. The mean difference was 0.61mm (CI 0.49-0.72).
They also pointed out that the studies were not of high quality and were subject to various forms of bias.
Overall, they concluded that there was limited research that underpins this treatment but there may be some promise in these new methods. New research needs to be carried out before these methods can be widely accepted.
What did I think?
I thought that this was a good detailed review that identified that surgically assisted orthodontics may have some potential. However, it is important for us to consider that the most important outcome, from a clinical point of view, is the total treatment duration and this was not evaluated by any of the studies.
I also thought that it was important to find that the differences that they detected in tooth movements were small. I am not sure how this would translate to a complete course of treatment.
We must also evaluate these findings with respect to the risks of treatment, for example, pain and discomfort and the overall cost of treatment.
While these have been systematic reviews, I thought that I should also have a look in detail at a trial that was carried out to evaluate the effect of micro-perforation
Effect of micro-osteoperforations on the rate of tooth movement: Alikhani et al
American Journal of Orthodontics and Dentofacial Orthopedics: 2013 144: 639-48
I thought that this was an interesting paper and while I have been critical, I think that there may be something to the technique that they have tested.
This paper can be found at: http://goo.gl/BCpgTS
Need for speed
This was an interesting study that reported on a method of speeding up tooth movement by influencing the biology. The authors propose that the main controlling factor of the rate of tooth movement is bone turnover. They build on the fact that bone turnover is controlled by osteoclastic activity and that anything that increases this should, theoretically, increase the rated of tooth movement. As the presence of local cytokines increase osteoclasts, then they propose that increasing cytokines by causing local trauma, should increase osteoclast activity and rate of tooth movement. As a result, traumatizing the alveolar bone at the site of tooth movement with micro perforations (MOPS) should influence tooth movement.
This hypothesis was investigated in a small-scale trial and this is the subject of this interesting paper.
This was an RCT which was driven by a sample size calculation based on a difference of a 50% change in the rate of tooth movement. It was good to see a trial based on a meaningful difference!
They took a sample of 20 adults with Class II Division 1 malocclusion and randomly allocated them to a control group and an intervention group. The intervention group received (MOPS) on one side their upper arch, this involved making 3 small holes in the bone with a special punch (see picture below). On the other side they did not receive an intervention. This was, therefore, a split mouth group.
They took impressions at the start of canine retraction, then carried out the MOPS and retook the impressions one month later. They measured tooth movement from the study casts, they also took samples of gingival crevicular fluid and measured patient pain/discomofort one month later.
They measured tooth movement directly from the study casts by measuring the distance from the canine to the lateral incisor. I had problems with this because I was concerned that the lateral incisor was not a stable point and I would have liked to see a more sophisticated measurement technique, for example, 3D model superimposition on the palatal rugae and measurement. This is now an established technique that is accurate and easy to carry out.
I was also confused in their analysis. They compared the tooth movement of the control group and the untreated side of the MOPS patients against the treated side of the MOPS patients. This resulted in several problems, the most important being in a split mouth design where you cannot be certain that the intervention (on one side) is not going to influence the other side of the mouth. This is particularly relevant to orthodontics where the teeth are all joined together by an appliance. However, they did point out that there were no differences between the control group and the unoperated side for the MOPs patients. Nevertheless, this was simply confusing and I could not really see why they did not randomize patients to MOPS and control. I am also not sure the implications of their study design on the sample size, as they did not discuss this in their paper.
The other major problem that I had was that they presented their tooth movement data in the form of graphs and not figures and this is plain confusing. I have taken the relevant figures from estimates that I made from the graphs and this suggests
|Tooth movement mm in 28 days|
|Orthodontics only||0.5 mm (SD=0.3)|
|Orthodontics plus MOPS||1.0.mm (SD=0.2)|
There is a clear difference between the groups and it may appear that MOPS has increased the rate of tooth movement. But from reading this paper I am far from certain because of the methodological issues that I have highlighted.
They also concluded that MOPS may reduce treatment time by 62%. I could not find a basis for this statement in the paper.
So what did I think?
I think that this is an interesting paper and it should be definitely be read in detail. Will it change practice now? No, there is not sufficient evidence from this paper because of the small sample size and the methodological issues. However, this paper is important because it is a step towards a scientific evaluation of this technique. The next step is to run a full trial in which patients are allocated to orthodontics only or MOPS with an outcome of the time to complete the courses of treatment.
We will then have an answer to the theory behind the treatment. This is not a difficult study to do and I look forward to seeing this carried out.
This first part of my summary has been about methods that may influence the biology of tooth movement. The second part is concerned with a new approach of applying vibrational force to the bone to increase the speed of tooth movement. So lets look at AcceleDent..
What about Acceledent?
For those who are not aware of this new technology, this is an intra oral device that applies vibration for 20 minutes a day to the teeth of patients who are having orthodontic treatment. The aim of Acceledent is to increase the speed of orthodontic treatment and reduce discomfort.
A large amount of information to both patients and dentists is provided on the Acceledent website. The effects of Acceledent are clearly stated on the front page as
“Through the use of gentle mini pulses, called SoftPulse technology, bone remodelling is accelerated, allowing teeth to move up to 50% faster”.
“Faster tooth movement may decrease the duration of your orthodontic treatment and may help make your orthodontics more comfortable”.
I feel that it is interesting that these are rather cautious, for example “up to 50% faster”. This is similar to my Broadband contract with that is advertised as “up to 250Mb” but in reality I get about 30Mb!
Lets have a look at the evidence
Acceledent, to their credit, have been very helpful and they have provided a large amount of information on their website. This is in several main sections and I shall start with the case reports on labial orthodontics studies. There are three case reports that are presented by orthodontic “Key Opinion Leaders” .
For each case the pre-treatment estimated treatment time is presented along with photographs of the treatment and the actual treatment time with Acceledent. These are nicely presented case reports, however, as I have previously discussed in other posts, this is not a strong level of evidence. But they are interesting.
There is another section on scientific evidence. In this section they listed 6 papers describing animal studies. These were concerned with the effect of vibrations on both tooth movement and sutural growth. I am no “scientist” but I think that they provided useful information. They also emphasised to me that if I were a dog or mouse and I was fitted with a brace, I was not going to be long on this earth, as I was going to be sacrificed in the name of orthodontics!
The final section was on clinical evidence and I was much more interested in this. So I had a really good look. Importantly, these papers were not from the orthodontic scientific literature but were published in “professional dental magazines”, for example, Aesthetic Dentistry Today. These were a mixture of expert opinion and single case reports. Again a low level of evidence.
What about research?
It is good news to see that AcceleDent funded a research study into the effectiveness of their appliance. This was carried out by a group in Texas, USA. This was published in Seminars in Orthodontics and not in any of the mainstream scientific journals.
Dubravko Pavlin, Ravikumar Anthony, Vishnu Raj, , Peter T. Gakunga,
Seminars in Orthodontics: doi:10.1053/j.sodo.2015.06.005
This trial was carried out by a team from Texas which has a very good record of research in basic science. Dr Pavlin, the lead author, is a consultant to AcceleDent.
The aim of this study was to determine whether vibration produced by the AcceleDent device increased the rate of tooth movement in patients with fixed orthodontic appliances.
What did they do?
They randomly allocated 45 patients, aged 12 to 40 years old, to receive treatment with an AcceleDent device or a sham. All patients were maximum anchorage and this was reinforced by the placement of a temporary anchorage device. They carried out a sample size calculation. Random allocation and concealment were good. Orthodontic residents treated the patients.
Some of the patients had canines separately retracted, while for some the teeth were retracted en masse.This added to the complexity of the study.
They measured space closure directly in the patient’s mouths. They also carried out an analysis of measurement error using a typodont.
They analysed the data using an intention-to-treat models and per protocol model and presented the following data.
|Smart clip||Victory||Difference (95% CI)|
|Treatment time (months)||25.1||25.8||0.68 (-1.4,2.7)|
|Number of visits||19.9||20.3||0.4 (-1.4,2.2)|
They finally stated
“the effect of vibrations in the AcceleDent group was 48.1% above the baseline value, which demonstrates a significant clinical benefit”.
What did I think?
I felt that this was very poorly carried out and reported trial I do not have sufficient space to provide a very detailed criticism, but my main concerns are
- The age range [12-40y] of the patients was very wide with a small sample.
- They provided little information on the method of measurement of tooth movement apart from that it was directly in the patients mouth using digital calipers. They measured from the canine to the TAD, but it is not clear how they did this. this. I think that more detail is essential.
- They carried out an analysis of the measurement error on a typodont. This is a poor approximation to the clinical situation. They then only measured correlation and did not provide any information on the average error of the measurement. This is essential for a tooth movement study, where any differences detected may be small. We, therefore, have no idea whether the measurement error was greater than the differences they detected between the groups. I could not understand why this was not reported.
- They reported that the AcceleDent group tooth movement was 1.16mm/month, this was not very different from the control group tooth movement of 0.93 mm/month used in their sample size calculation.
- They stated that the difference in the rate of truth movement was 48%. But this was only 0.37 mm/month. 48% of not very much is not very much! Importantly, this is not of clinically significant difference. Make up your own minds on whether the results are being “spun” here.
- They provided limited information of the statistical analysis that they used and it seems that there were a relatively large number of covariates given the small sample size.
- The 95% confidence interval of all the measurements was very large and reflected a high degree of uncertainty. For example, from table I under ITT the difference ranged from -0.07 [favors control] to 0.81 mm/month (favours control). But in the abstract they reported this differently.
- The confidence interval of the difference between the means included zero and this suggests no significant difference. They ignored this when they discussed their findings.
- This paper was not written according to the CONSORT guidelines.
In summary, in my academic opinion this study is significantly flawed in both its execution and reporting. Importantly the conclusions are not really supported by the data.
A better trial was then published…..
It was, therefore, interesting and very relevant that another study team studied AccelDent and published this in the high profile Journal of Dental Research.
In addition to coming to a different conclusion to the Pavlin study, this trial was completely different in its scientific content, methodology, writing, presentation and quality of the journal.
NR Woodhouse et al. London.
Journal of Dental Research, May 2015; vol. 94, 5: pp. 682-689. DOI: 10.1177/0022034515576195
What did they do?
This was carried out by a study team based in London and the south-east of England. They tested the null hypothesis that vibration does not increase the rate of tooth movement. They included participants under 20 years old, with mandibular incisor irregularity, requiring extractions and fixed appliance treatment. The participants were randomly allocated to;
•AcceleDent and fixed appliance
•Sham AcceleDent and fixed appliance
•Fixed appliance only.
Experienced orthodontists treated the patients in a standardised way. The primary outcome was the rate of tooth alignment and the secondary outcome was time to complete alignment. They collected data at the following stages of treatment:
•Start of treatment
•initial alignment, defined as the placement of 018 Ni Ti wire.
•Final alignment; defined by completing gauge spent in 019 x 025 stainless steel wire.
An examiner, who was blinded to the allocation measured alignment from dental casts using Little’s index . The sample size calculations clear, randomisation and concealment was are good. The statistical analysis was appropriate.
What did they find?
They found that the use of AcceleDent, either as an active or a sham, had no effect on the rate of alignment or time to full alignment. The only explanatory variable was the initial irregularity index. The greater the initial crowding the greater time to alignment.
They also express their data in terms of a survival curve and I have reproduced this here. This again shows that AcceleDent did not have an effect on tooth movement.
The discussion was a very good précis of the current knowledge of methods to accelerate tooth movement. They pointed out that the study was high-level evidence. They also pointed out that the inbuilt timers in the AcceleDent devices did not work, but this would not influence the result. Some may say that the study does not take into account the amount of use of the AcceleDent and the device may not have had an effect because the patients did not wear it. However, this was a study carried out in the “real world” of orthodontic practice where out patients do not always co-operate and this adds validity to the results.
What did I think?
I thought that this was a well carried out and reported trial that was published in a very high-quality journal. My only criticism is that they reported on the proximal outcome (alignment) and the most important outcome should be the complete duration of treatment. In this respect, I hope that they continue this study until the end of treatment for the patients.
The authors did not have any conflicts of interest and it is also to AcceleDent’s credit that they provided all the devices for the study.
This study was very different from the one carried out by Pavlin et al. I cannot help thinking that this must be due to the poor quality of the previous study. It is also worth pointing out that a recent study has revealed that 97% of head to head trials sponsored by industry give results that favour the sponsor’s drug. The whole issue of the running and reporting of industrial funded trials is covered very well in a great book by Ben Goldacre who is a UK based researcher. Details of this can be found here. This is another link to a recent paper that he has produced. He makes great points and we need to learn from his work.
In summary, I feel that we should accept these findings and conclude that, at present, high-level evidence reveals that AcceleDent does not increase the rate of tooth movement.
A study on Pain and vibrational force
Shortly after this study was published another group carried out a study into the effect of vibrational force on orthodontic pain. This is my feelings on this study.
This study looked at whether the use of AcceleDent reduces orthodontic related pain.
If you did not read my post on “how to read a randomised controlled trial” I suggest that you have a quick look at it, as I hope that it provides a basis for my discussion of this and other papers over the next few weeks.
Dunn W et al. Angle orthodontist advanced access DOI: 10.2319/072115-492.1 OPEN ACCESS
The authors did a nice introduction that outlined the various methods of reducing orthodontic related pain and I would recommend that you read this, I found it very useful and interesting. These methods include analgesics, acupuncture, laser therapy, viscoelastic bite wafers and chewing gum. They pointed out that the last three methods may reduce compression of the periodontal ligament to eliminate oedema, inflammation and pain. This led them to introduce the concept that vibration may have a similar effect and this led to the present study.
What did they ask?
They investigated whether the use of AcceleDent reduced orthodontic pain in comparison to a control group of no treatment, during the first four months of orthodontic treatment.
What did they do?
This was a randomised controlled trial in which patients were randomly allocated to AcceleDent or no intervention for pain. They carried out a sample size calculation and enrolled a sample of 70 adult and child participants. The randomisation concealment and enrolments were satisfactory.
The participants in the study recorded their pain using visual analogue scales for the first seven days following adjustment and then weekly for the remainder of the month for four months. Importantly, they asked all the patient not to take analgesics.
What did they find?
In each group 29/35 (83%) completed the study. Six patients from each group were excluded. Four in each group were excluded because they used analgesics and two did not complete their pain diary.
They found that the use of Acceledent resulted in a statistically significant reduction in reported pain for both biting and overall pain. They represented this graphically and I have done a screen grab for overall pain. This illustrates their finding very clearly.
The discussion was very balanced and they suggested that the vibratory stimulation may increase blood flow to the PBL and reduce pain producing substance.
What did I think?
Firstly, I would like to discuss a major problem with this study which the authors also mentioned in their discussion. This was that they did not use a placebo. This is very relevant because there may be a placebo effect as the patients may have believed that they were doing something to reduce their pain. As a result, they perceived or recorded less pain. This is well recognised in all studies involving any form of pain reduction.
The authors felt that they could not have used a sham device because this may have influenced the reporting of pain. However, I cannot help feeling that this is exactly what a placebo should do.
My other concern is with the choice of no intervention as a control. This may be somewhat philosophical, but I wonder if it would have been a better study if they had compared the vibrating device with an analgesic (or other method of pain reduction). This would avoid the comparison of the potentially active intervention against nothing and make the study more “real-world”. I would also have ethical concerns in asking my patients not to take an analgesic after their appointments.
Finally, the authors point out that vibration may be safer than using analgesics. This may be the case, however, they did not address the considerable additional cost of Acceledent when compared to over-the-counter medication, bite wafers and chewing gum. I also had a look at some of the other papers reporting pain reduction and they reported pain reduction with both bite wafers and chewing gum. These would be far more economical than the Acceledent device.
As a result, I feel that this study is no more than an interesting exploratory study and their conclusions are not really supported by the data, particularly with respect to an evaluation of the placebo effect. Nevertheless, there needs to be a further study carried out making a comparison between the effect of vibratory force and analgesics or other methods of pain relief.
Overall summary on methods of speeding up tooth movement
You may think that I have been rather cynical about the introduction of these new techniques. I can assure you that this is not the case. I would clearly like to provide my patients with a method of speeding up their treatment and reducing pain. Unfortunately, the current research base needs improving before I buy into this new technology and I cannot recommend this to my patients. But let’s wait for new research and see if my conclusions change…in the meantime I hope that we can all be patient and not fall into the trap of adopting these methods and selling devices and procedures to our patients that currently have a very weak evidence base.
Emeritus Professor of Orthodontics, University of Manchester, UK.