Can a special archwire shorten treatment?
This is a guest post by Peter Miles who is a Specialist Orthodontist in Australia. It is clinician’s viewpoint about recent claims being made about a special archwire increasing the speed of tooth movement.
What are the claims?
Claims of accelerated treatment are certainly not new to orthodontics. The approaches to accelerated treatment range from;
- a mechanics perspective. For example self-ligating brackets claiming to reduce friction and more efficiently move teeth.
- to procedures claiming to alter the patient’s biological response. For example, vibration, micro-osteo perforations.
This Blog generally covers the literature published in the mainstream orthodontic journals. However, we live in the era of the internet, social media, blogs (such as this one) and e-journals. All of these allow rapid dissemination of information without the ‘impediment’ of peer review. This latest claim about archwires resulting in faster treatment prompted me to write this post.
The article discusses how the authors have changed to a wire sequence (0.016” SmartArch, 0.018”x0.025” SmartArch, 0.019”x0.025″ ss). They find this more efficient in terms of both numbers of appointments and treatment time compared with what they did previously.
Furthermore, they state this eliminates multiple appointments and 3 to 4 months of initial levelling and aligning to reach their working wire. I feel that these claims are not correct. I will address them by considering the science and art of wire properties and their sequence.
The wire sequence
If we examine the literature, we can see that this archwire sequence is not new. For example, fourteen years ago Nicky Mandall and her team examined three-wire sequences in the 0.022” slot system. They found that the most efficient wire sequence was a three-wire sequence (0.016″ NiTi, 0.018”x0.025” NiTi, 0.019”x0.025”ss). David Tidy also recommended this back in 1989 when the working archwire was achieved in only 4 months with two archwire changes in 0.018” slot system.
So it would seem the improved efficiency noted in this article is more likely to be caused by the change in the decisions they made on their wire sequence and appointment intervals.
We all know that Nickel-titanium archwires have an unloading plateau that allows them to remain active over an extended period without retying or reactivation. In clinical practice, this means that we can increase the time between appointments from 5-6 weeks to 8, 10 or 12 weeks (depending upon the initial alignment and type of movements). This has been my clinical experience for the past 25 years using this method. I have written about efficient wire sequences and appointment intervals when writing about the claims made regarding self-ligation back almost ten years ago.
Efficiency vs claims of speed
I propose that many of the claims of faster treatment are actually changes in practice ‘efficiency’. We are not moving the teeth any faster. We are simply making better decisions about which wire sequence to use and the appropriate appointment interval for them to work. Obviously, this varies depending upon the indications for an individual case. But as pointed out in previous research, one of the main factors in treatment efficiency are the decisions we as the Orthodontist make.
Emeritus Professor of Orthodontics, University of Manchester, UK.