Directly Printed Aligners are effective for mild/moderate malocclusions.
Recent advancements in clear aligner treatment include the development of Directly Printed Aligners (DPAs). This innovation reduces the need for specific manufacturing steps, particularly printed models. As a result, it may offer advantages such as lower costs and less environmental waste. Additionally, there could be potential for improved precision in manufacturing and increased efficiency.
Unfortunately, research on direct-printed aligners is still limited. Therefore, I found this new study on direct-printed aligners to be useful. A multinational team did this research.
Directly printed aligner therapy: A 12-month evaluation of application and effectiveness
Vanessa Knode et al
AJO-DDO advance access: https://doi.org/10.1016/j.ajodo.2024.08.013
I would like to declare an interest in that I know several of the authors well.
Fortunately, this paper is open-access, meaning anyone can read it. If you’re interested, download a copy, as I found its introduction and overall discussion to be very valuable in understanding the current status of aligner research.
What did they ask?
They did this study to
“Evaluate the clinical effectiveness and efficiency of Direct Printed Aligners (DPA) in correcting moderate malocclusion”.
What did they do?
They retrospectively evaluated 54 patients treated by one experienced orthodontist with a direct-printed aligner system.
The operator prescribed aligners for a full 22 hours a day, with each aligner being worn for seven days. Importantly, no more than 5 aligners were made per batch. He reviewed the patients every five weeks.
The operator took records at the start and finish of treatment.
The primary outcome measure was the Peer Assessment Rating (PAR) score. This is a valid measure of treatment outcome.
The team carried out relevant multivariate and univariate statistics.
What did they find?
The study involved 54 participants aged between 14 and 64 who exhibited various types of malocclusion. The primary reasons for treatment were as follows: finishing (66.7%), managing relapse (26%), and comprehensive treatment (9.3%). In most cases, the operator did not use any auxiliaries or attachments.
Interestingly, 60% of the patients did not require any refinements.
When they looked at the pre-treatment PAR scores the mean was 17 ±2.25. The final mean score was 2.25 ± 1.15.
The multiple regression suggested that there was a weak association between the final PAR score and the total number of aligners.
The conclusion was.
“Directly printed aligners can be used to manage mild to moderate malocclusions and produced a significant reduction in the PAR scores”.
What did I think?
This study provided valuable insights into the effectiveness of directly printed clear aligners. When I looked at the PAR scores, it was clear that the participants had mild to moderate starting malocclusions. Crucially, the final scores indicated that the operator did high-standard treatment. This finding reinforced my belief that aligners can effectively address mild to moderate malocclusions.
Additionally, it was encouraging to see the use of a valid, established outcome measure. This is a step forward from using predicted vs. actual tooth movements because it provides information on the actual outcome of treatment.
This was a good study that was valuable. Nevertheless, it faces a common issue in aligner research: it is a retrospective study. As a result, there is considerable uncertainty in the data due to the potential for selection bias. The authors acknowledged this limitation in their discussion.
We need prospective research to provide more robust information on the effectiveness of Directly Printed Aligners. Nevertheless, this study does offer some useful limited information. Additionally, it provides data that investigators can use for sample size calculations in future prospective research.
Emeritus Professor of Orthodontics, University of Manchester, UK.
I noted that aligners were made in batches of 5 and the patients reviewed every 5 weeks. Does that mean that after let’s say 5 aligners the case was reviewed and new scans done to which another batch of aligners were made? Essentially this would mean that refinements to the treatment were being done ‘on the fly’ so to speak whereas mass produced aligners companies the start to finish aligners are produced at the start. Could this account for the fact that 60% of patients did not require refinements. I did not get to read the paper so this I guess is more of a question than a comment.
The Real Person!
The Real Person!
Ashvin Avinash Sharma Basically, we decided to keep a roughly 6-week interval for aligner check-ups, resulting in about 5 aligners per check-up cycle. In some cases, we produce more aligners, but we still check progress after around 6 weeks. If everything fits well, we continue as planned – if not, we scan, create a new setup, and deliver a new aligner, often by the next day. Jean-Marc Retrouvey once called this “constant refinement,” as you’re continually adapting to the current situation. Neal Kravitz referred to this as the “Rule of 5,” which inspired us. Perhaps 5 is a bit low – somewhere between 5 and 10 seems ideal.
In retrospect, we probably shouldn’t have referred to this as “refinement” in our study, as it was more like continuous adaptation until we achieved the desired outcome. This flexibility is a major advantage of in-office production – I can respond instantly.
The Real Person!
The Real Person!
Dear Sir,
Thank you for highlighting this paper. This reinforces two things for me –
1. Being obsessed with control of treatment in Orthodontics is not going away soon. It was this ‘continuous refinement’ that gave such healthy results. With the Orthodontist in control, the patient benefits and the computer cannot say ‘no’.
2. The technology for predicting tooth movement is probably as accurate as weather prediction mathematical modelling at this point in time. In the short term it gives reliable outcome but the long range forecast of making 20-40+ aligners with a single scan is probably asking too much from the software. Hopefully after collating millions of ‘continuous refinement ‘ scans and deploying advanced AI algorithms will overcome this issue in the near future.
The only cause for concern would be more accurate definition of mild to moderate malocclusion, for which hopefully the computer will still need input from an expert human.
Thank you always.
Yours sincerely,
Mr Karun Sagar
Dear Sir,
First of all thank you for this interesting, timely and well written blog post. Also I much apprecite in general the work you do in this blog, it is a force of good in orthodontics and a much valued beacon of evidence based orthodontics!
This scientific base is all the more important in the field of aligners.
(One small, respectul addition about a minor typo in the blue framed part: Vanessa is I beleive Knode, not Vanessa Node.)
Thank you for your work!
Yours sincerely,
Marton Zsoldos
The Real Person!
The Real Person!
Thanks for the kind comments and also for pointing out my careless mistake. I would like to blame my grammar checker, but I need to be more careful with technology!