Orthodontic Retention – finding the answer?
This is a guest post by Simon Littlewood on the difficult subject of orthodontic retention. He is one of the World’s experts on orthodontic retention. It is a really good read! Simon works in Bradford, North of England…
At a recent dinner party someone asked me what question I most wanted answered. Without hesitation I said “What’s the best way to retain our orthodontic results”. There were no other orthodontists at the party, so there was an embarrassing silence. As you are reading this post, this suggests that you are more interested than my dinner guests. So let me expand further.
Why is it so important?
There are many important questions in orthodontics, for example “how best to speed up treatment”, and “which is the best type of appliance?” Interesting questions, but they become less important if the end result relapses.
Relapse is often unpredictable. It also seems to continue over a long period. This leads many clinicians to advise their patients to wear retainers for “as long as they want straight teeth”. If we are asking for this sort of long-term commitment from our patients, we need to be sure the retainers do the job and are safe.
Providing evidence-based retention
An evidence-based approach means taking into account the best research evidence, clinical expertise and patient’s values, expectations and circumstances. Our Cochrane Review looking at the best research evidence for retention last year concluded:
“We did not find any evidence that wearing thermoplastic retainers full-time provides greater stability than wearing them part-time”
Secondly, we found that there was insufficient high quality evidence to make further recommendations. This second conclusion often frustrates clinicians (including me!). However, this is due to Cochrane’s use of a stringent quality assessment called GRADE (Grading of Recommendation, Assessment, Development and Evaluation). This means we can only make firm conclusions if we are certain that we can trust the result, and that any further research in this field is unlikely to change our conclusions. As a result, I have learnt to read beyond the conclusions of Cochrane reviews, as there is often lots of other useful information in the review that I can use clinically. Kevin O’Brien has nicely summarized the retention Cochrane Review in a previous blog.
Are RCTs the only way to investigate retention?
RCTs remain the gold standard for comparing different interventions, for example, different types of retainers or even comparing retainers to no retention at all. Retrospective research, while generally easier to undertake, is subject to more bias and we can therefore be less confident in the findings. However, one area where retrospective studies are useful is in reporting unusual side effects. An example in retention research is the unwanted side effect of bonded retainers that become active and can lead to compromised periodontal support.
How can we research patients long-term?
Most current retention RCTs provide information after 6-24 months. This is useful information, but with life-long retention, it only gives us some of the answers. Recalling patients years later to measure relapse is difficult. Perhaps, we need a smarter way of following patients up in the long-term. In an era of smartphones, apps and selfies, I wonder if there is a better way to monitor long-term post-treatment changes?
Are we asking the right questions?
Our main outcome measure in the Cochrane retention review was Little’s Irregularity Index. This has its imperfections, but for most clinicians this provides an understandable measure of crooked teeth. But is this important to patients?
Asking patients to wear retainers indefinitely adds to the burden of their care. They have to be responsible for wearing and looking after the retainer, as well as getting it checked, repaired and replaced, which may have financial costs. Patients may be more interested in ease of use, costs, comfort, how simple it is to look after, and whether the retainer keeps their teeth straight enough for what they want.Future research with patients may identify what is really important to them about retainers. We should then use this information as an outcome in trials, along with our more traditional measurements of stability.
Retention research – is it worth it?
We’ve already established that retention research is challenging, so is it worth the effort? The answer of course is yes, particularly if we focus on outcomes that are important to our patients. This is because almost everything else we do in orthodontics is compromised unless we can hang onto the result.
I need to know the best way to retain my orthodontic result for every one of my patients. I also need to know so that I don’t embarrass myself at future dinner parties. If I ever get invited again…
Emeritus Professor of Orthodontics, University of Manchester, UK.
Have your say!
The word ‘retention’ is out of date IMHO. Let’s talk about homeostasis like any other system in the human body, and get a fuller understanding of the complex phenomenon that we are trying to capture –
I agree with you Dave, the body ages and changes as we live a life. I feel the word relapse is overused and used incorrectly as many teeth don’t return to their original positions, they migrate over time due to mesial drift and OB returning. I feel retention protocols should be structured to reduce the changes that occur during a life, mainly controlling OB’s that tend to deepen and thus create lower anterior crowding again. The analogy I use for my patients is: your retainers are like anti-wrinkle cream, use them and you will have less wrinkles in your teeth!
I think you are right Dr Chapman – we are fitting retainers to reduce post-treatment changes as a result of relapse (teeth back towards where they started) but also to resist normal age changes. It’s useful information for our patients to know, to encourage to look at longer term use of retainers to resist these age changes.
Dr Littlewood, thanks for your post. you stated ” In an era of smartphones, apps and selfies, I wonder if there is a better way to monitor long-term post-treatment changes?” There is a Paris based company that has developed a very sophisticated software system called Dental Monitoring. After enrolling the patient into your data base you can monitor all phases of treatment including a retention phase A digital scan of the patient is required to obtain quantitative findings that i use on some of my patients to see if teeth are moving after i place retainers. They also offer photo monitoring that does not give any quantitative data but allows for a visual overview. the software lets you be automatically notified of any perceived change from one photo/video session to the next. you get to pick the intervals that your patient submits the photos . i hope this will get some researchers some food for thought for their next project. best, Dr William Dabney Richmond,VA USA
Dr Dabney – thanks for highlighting this. I was aware of the Dental Monitoring software as a means of monitoring treatment, but I hadn’t considered it as a means of monitoring post-treatment changes in the long-term. If there is an ability to measure changes accurately with this software, then perhaps there is potential of some research to see if this is a cost-effective, patient-friendly and successful means of monitoring stability in the long-term. Thanks for the useful comment!
Dr Littlewood, I will have someone reach out to you from the company to explain the program. i believe they would welcome you and your students to propose a research project. Bill Dabney
Part of the problem is our and the patient’s (sometimes) obsession with keeping everything straight, sort of a sunk costs fallacy (we got them so perfect so now we can’t let them move). Anyway, just out of interest I wonder if anyone has any research showing any bad side effects of long term retention. I ask this because I saw a case that looked like severe anterior root resorption possibly caused by years of wearing essix retainers that were (again possibly) moving the teeth back and forwards, or jiggling the teeth if you will. Is it possible that all essix retainers will jiggle the teeth to some extent so may in fact promote root resorption? I don’t suppose we know. Maybe we are lucky that most patients don’t wear their retainers forever.
Retention needs to be considered an integral part of orthodontic treatment, not simply an afterthought, and patients must be made aware from the outset of their treatment how critical their co-operation will be in maintaining straight teeth. A new approach to retention underpins a national campaign launched by the British Orthodontic Society this month and is fronted by Simon Littlewood. Backed up by video and animation, the intention is to generate a viral #HoldthatSmile campaign to build awareness amongst patients that retainers are for life. Please take a look here: https://www.bos.org.uk/Orthodontic-Retention and feel free to share!
I have no conclusive answer after 41 years of orthodontics………I use U wrap-around Hawley and a full arch anterior spring aligner. Sometimes I’ll use a lower solid wire bonded retainer. I have no other insight other than what I have read in the literature….
Just curious —how does one become a “world expert in retention “?
Also —it is my belief that ,given the projected life span of many of our pts.,it should be made clear that one or more “tidy ups “/maintenance alignments would be almost inevitable .This would usually take the form of plastic aligners.
It is not realistic to expect our interventions ,even with excellent and ongoing retainer wear ,to “last a lifetime”.
We would not expect our colleagues to be able to provide a similar “lifetime “result eg.replacing amalgams ,resurgerising re Knee replacements ,revisionary ,cataract surgery etc.
We expect too much of our interventions and should be practical and honest .Taking such an approach is very stress reducing for the clinician in terms of expectation management.
Clinical tip —do not use the word “retreat “try using “minor revisionary procedure “.
Is there evidence to show that the quality of the final result enhances long-term stability?
First, I loved that comment that retainers are “anti-wrinkle” cream for your teeth. I will use that for sure.
As far as the idea of “forever” retention, after 37 years of practice, I am a firm believer in forever retention. Allow me an anecdote: I had a 14-year-old teenage girl transfer in with braces on and she had about a year’s tx left. I suggested that it would be a good idea to wear retainers on a part-time basis at least until she was done with high school (age 18). She explained to me that her previous ortho told her she would need a year’s retention. So I finished tx and placed her into a removable upper and fixed lower. After a year, she told me she wanted the lower off. So I removed it and gave her a clear plastic Essix style lower retainer and told her to wear it enough to keep it fitting and I reminded her and her mother that this was their idea, not mine. 3 years later she is back (age19) complaining that her lower teeth are moving. I looked and they looked fine. Really. I asked her how she knew they were moving and she replied that when she ran her tongue across the inside of the lower front teeth, they felt different. That is what we are up against ridiculous expectations. Luckily, most patients are not like that. So I told her and mom that we could redo the lower alignment and I quoted a fee. Mom was aghast that I wanted to charge them. To which I replied that it was their idea to stop wearing retainers. So you can see patients think the teeth will stay straight once the braces come off.
One more comment, if you will allow.
Early in my career, I came under the influence of Dr. Zachrisson. I felt he had a lot of answers to the retainer question.
My standard retention protocol is to have the patient use a removable upper Essix style unless settling was needed then a wrap around Hawley. The type of lower retainer though is critical. I like the fixed 3-3 bonded just to the canines. ala Dr. Z. The fixed 3-3 is very hygienic and durable. If you’ve achieved normal OB/OJ with your treatment, it holds the upper and lower teeth straight so for that reason I love it. I tell patients especially adult patients that I intend to leave the lower fixed retainer in place until they start looking at nursing home brochures for themselves. They laugh but they get it. Whenever I take off a lower fixed 3-3, I always take a very thin diamond disc and break contact from 3-3. This seems to prevent movement once the fixed is removed.