Vibration does not speed up extraction space closure

I have blogged previously on appliances claiming to accelerate tooth movement and shorten orthodontic treatment. One of these is micro-vibration and an appliance using this principal is AcceleDent. I have previously researched this topic during initial alignment and now Part 2 has been published on extraction space closure.


I strongly believe in an evidence-supported approach to clinical practice and this study (as with all my research) was conducted in my orthodontic practice to answer the clinical question of whether this was a worthwhile technique to consider implementing for my own patients. Forty Class II adolescent patients planned to have premolar extractions in the upper arch were randomly assigned to using either the AcceleDent appliance or no appliance. The extraction space closure was measured over time so a rate of movement in mm/month could be calculated. So what did I find? There was no clinically (0.05 mm per month) or statistically significant difference in the rate of space closure (P = 0.74). Compliance was found to reduce over time and this is the subject of another paper to be published in the Journal of Clinical Orthodontics. However, even when compliance was accounted for there was still no clinically meaningful difference in the rate of space closure.

This article appears in the American Journal of Orthodontics and Dentofacial Orthopedics and anyone clicking on this link before February 14, 2018 will be taken directly to the final version of my article on ScienceDirect. No sign up, registration or fees are required – you can simply click, read and hopefully enjoy.

https://authors.elsevier.com/a/1WHqw3AGXGWWNM

PASSIVE SELF-LIGATING BRACKETS ARE BETTER - IT'S OBVIOUS?

This Blog topic was prompted by comments in Kevin O'Brien's excellent Blog regarding 'thinking about orthodontics'. Kevin was discussing evidence-based care and what we know versus what we don't know and how to apply our knowledge, skill and experience as clinicians in the treatment of our patients. Many suggestions were made about what we do and don't know but two comments in particular claimed that Passive Self-ligating (PSL) brackets were superior to conventional brackets during initial alignment in non-extraction treatment. I have also seen other claims in Facebook study clubs where the clinician states that in their experience, PSL brackets are superior for space closure in extraction cases (a future Blog topic). So is this evidence or their opinion and what is the evidence if any?

In 2006 I conducted the first prospective study comparing PSL brackets with conventional brackets in the lower arch in non-extraction cases. This was published in The Angle Orthodontist and I found that the PSL bracket was no better during initial alignment than a conventional bracket. Another non-extraction study published in the American Journal of Orthodontics in 2010 found there was no difference between PSL or Active SL brackets. Based upon this evidence in clinical trials this refutes the claim that PSL brackets are more effective in non-extraction cases during initial alignment. If we then include the evidence from extraction cases as well, this was summarised very nicely in another article in the American Journal of Orthodontics in 2014 where the data was plotted graphically (shown below) in a meta-analysis. The vertical line at zero ('0') represents no difference between brackets and the purple squares are the individual studies. What we are most interested in are the large green diamonds which represent the results combined together and as they overlap the zero line, this indicates there was no difference between any of the bracket types tested across the various studies during initial alignment. It seems the evidence is quite compelling that there is no advantage in PSL or ASL brackets over conventional brackets during initial alignment.

As the evidence clearly shows there is no difference between brackets, the choice of bracket then comes down to the personal preference of the clinician. BTW if you are interested in evidence-based orthodontics then I highly recommend subscribing to Kevin's Blog at http://kevinobrienorthoblog.com/

Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and was a part-time lecturer at the University of Queensland for 11 years and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'.

VIBRATION & ACCELERATED ORTHODONTICS - CLAIMS VERSUS EVIDENCE

Claims of faster treatment with 'special' quick or fast braces or appliances such as AcceleDent, OrthoPulse and others are appearing more and more in the market place and on Google. The companies hope their product can shorten treatment and heavily advertise so - but what is the evidence?

When you are paying up to $1000 or even more for something you want to be sure or pretty sure it works... or not care about the $1000! Some clinicians and patients use the special brace or appliance and feel their treatment went faster and extol the virtues of the appliance while others do not see a difference, shrug their shoulders and move on. When we are told something is better/faster we look for that difference - some remember the ones that worked (the Believers) while others remember the ones that didn't (the Naysayers) and so we now have two camps, both with a biased perspective! This happened with self-ligating brackets where initially it was felt by some that they shortened treatment (and appeared in the media saying so) but later research revealed that in fact they were not (see my previous Blog on Braces claiming to be Fast)!

Currently some state that you can use #Invisalign clear aligners every week instead of every two weeks (as the manufacturers currently recommend) when using #vibration or other appliances. However many patients get away with weekly wear without these appliances anyway while others won't. There are current studies that suggest vibration accelerates tooth movement with braces while a better designed prospective trial finds no difference. I am currently running a randomized clinical trial on the vibration appliance, AcceleDent and the results of this will be available for publication later this year (2015) to further examine any effect of vibration during initial alignment and space closure so this will be discussed in a future Blog. Although the idea of vibration holds some merit, the evidence supporting it is currently of a lower quality while the higher level evidence from a prospective randomized trial finds no difference. More research is obviously required to clarify the debate and will be forthcoming over the next couple of years but it is the quality of the evidence that is important to answering this question.

Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and teaches orthodontics part-time at the University of Queensland and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'. Importantly, he has no financial interest in any products discussed in these Blogs.

QUICK OR FAST BRACES - DO THEY EXIST?

Claims of faster treatment are easy to make and we would all like this but is it realistic? In the 1960's and 70's Begg braces/brackets were very popular and were thought to provide faster treatment as they allowed very rapid tipping and alignment. However this was at the price of less control over the root position which took more time to recover later and so they are seldom used nowadays. Other bracket designs that allow tipping have been shown to actually be slower than conventional brackets when closing extraction spaces.

More recently self-ligating brackets such as the Damon bracket, Smart-Clip, In-Ovation, Quick and more were introduced with claims of faster treatment. This was marketed well and became quite popular but with little evidence to support the claims. Dr Miles conducted the first prospective clinical trial and found there was actually no difference during initial alignment which was later confirmed by other researchers. The most recent evidence suggests that despite the claims of faster treatment, the self-ligating brackets may actually be slower than conventional #braces by about 2 months! Braces claiming to be fast are use brackets and wires just like conventional systems and so would not be expected to be any quicker. They claim lower friction but this allows the greater tipping and lack of control seen in earlier systems that proved to be slower. Let's look at an analogy - when you build a house the frame goes up quickly but then seems to slow when the smaller jobs are taking place such as the painting, tiling, etc. - but you don't want to move into your new home without this done do you? The same with braces - the initial alignment of teeth can be quite rapid but these are the simple tipping movements and the roots have not been moved into their correct and more stable positions. Your bite may need correction with elastics or other techniques and this is also a slower movement. These are the ‘detailing’ stages of #orthodontics and are slower and less obvious but very important for the most aesthetic and stable result possible.

The skill of the practitioner in placing the brackets as accurately as possible and using the correct wires, mechanics and appointment intervals affect your treatment duration. However treatment time is also affected by patient cooperation (e.g. are you wearing your elastics as directed?) and biological variation – everyone is different and their teeth move at different rates and respond in varying amounts. The same wire and adjustments will have differing responses in different people and your orthodontist will adjust your treatment based upon what they observe. Even extremely precise methods of bracket positioning using computer-aided design and manufacture, or robotic wire-bending are prone to the same problems of variation in response. Orthodontists are aiming for the best outcome possible for you and this variation is why your #orthodontist cannot give precise times to the eternal question; "When am I getting my braces off?".

Dr Peter Miles is the orthodontist at Newwave Orthodontics in Caloundra, Australia and teaches orthodontics part-time at the University of Queensland and is a visiting lecturer at Seton Hill University in the USA. Peter is one of the editors and authors of the orthodontic textbook, 'Evidence-Based Clinical Orthodontics'. Importantly, he has no financial interest in any products mentioned in these Blogs.