What’s the best way to hold all a patient’s good work in place once a clear aligner treatment plan concludes? This article explores the rationale behind what type of retention, and protocols the dentist may choose, to ensure long term success of clear aligner treatment!
Retention is the phase of treatment where the teeth need to be maintained in their final intended positions after orthodontic treatment. Without retention, teeth tend to move and track back towards their original position, which is called a relapse.
Relapse occurs due to:
elastic recoil of the periodontal tissues,
pressure exerted from the oral and facial soft tissues,
occlusal forces, and/or
post treatment facial growth and development.
After orthodontic treatment, to prevent relapse, patients require retention, which may be:
fixed retention, and/or
removable retention.
The question about the best retention is interesting as the answer is not always clear. Unfortunately, there is no golden rule that can be applied with weak scientific evidence on the topic, therefore choice and protocols for retention depend on the dentists judgement. The only consensus is that retention is a long-term commitment and must be adhered to in order to prevent relapses of treatment.
In this regard, all patients want to know is how long they’ll have to wear the retainers. The answer to this is simple! How long would they like to keep their teeth straight? After disciplined retention wear for an “extended time” post orthodontic treatment, teeth will settle in their new position, but if we stop wearing our removable retainers or our fixed retainer de-bonds, the risk of our teeth moving increases. It is reasonable to assume that patients will have to wear retainers during the day and night for the first 4-6 months post treatment, after which they can be worn at night times. As long as the patients wear their retainers at night their teeth will not move back.
Factors to Consider
Given the importance of retention and lack of a golden rule, what type is best for your patient?
There are several factors to consider when deciding what type of retention should be used.
The most important factor to assess is the type of orthodontic movements that have occurred. Was there arch expansion? Were significant posterior movements required or limited to only anterior movements? Were medium-large spaces closed? How much crowding was there present? Empirically, dentists observe that where there has been a lot of initial spacing, especially between anterior teeth, these spaces tend to rapidly reopen, with cases observed with movement of teeth even during the day. So additional retention may be prudent in cases with large movements, posterior changes and particularly spacing cases. A clear removeable retainer, provided good patient compliance, would be the choice for retention in these cases. In spacing cases it is advisable to wear the retainers for a period of 6 months during the day as well as night.
Secondly, consider the level of compliance the patient showed during their treatment and what they will be expected to continue with. If they have been well compliant through treatment and you are completely confident in their continued compliance, clear retainers are likely to be sufficient. However, with ANY doubt that a patient will really wear them religiously (for people like myself that will mean every other Sunday lol), it’s optimal to use both a fixed lingual retention as well as wear clear retainers over it.
Advantages and Disadvantages
There are advantages and disadvantages to each type of retention, but the options are simplified if restricted to a clear retainer, or a lingual wire with a clear retainer. In our next article we will explore different types of wires and alternative options to bonding a metal wire for fixed retention.
The advantage of the fixed bundled wire is that the dentist does not require compliance, however it's harder to clean the teeth where the wire is bonded, with some patients simply bypassing that region when they floss/clean interdentally.
With regards to patient experiences with different retention types, a major factor is whether they were treated with clear aligner or metal braces. That is, it’ll be easier for patients who were treated with clear aligners to have clear removable retainers where as those generally treated with fixed appliances tend to get on better with fixed lingual retention.
For me, clear retainers instil confidence that the whole arch will be maintained, rather than just the limited teeth the fixed retainer is applied to.
Patient Indoctrination
Try to remind your patients at check-up appointments that they will need retention and that maintaining straight teeth does not end once the clear aligner treatment course ends!
Patients have invested time and money to achieve their desired smile and without adequate post treatment retention there is a high risk of undoing the hard work put in by your patient and your team.
How to place a fixed retainer that we recommend
This video demonstrates the process of utilising a variety of tools to place the Ortho-FlexTech (White Gold) retainer upon the mandibular arch.
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