Saba Qureshi explains the benefits and potential problems of fixed retainers, and whether she believes they are worth the effort.
It never ceases to amaze me how much orthodontic appliances, be they fixed or removable, can change a smile. We can put teeth pretty much where we want, within biological limits and reason of course. But keeping them there is another matter…
Once active treatment is finished, the battle against relapse begins as we enter the retention phase, forever chasing the elusive being that is long-term stability.
The waters are pretty muddy when it comes to retention. Rather than a professional consensus with regards to the ideal retention regime, through experience, trial and error, most clinicians formulate one that suits them and their patients best.
The majority of orthodontic patients will have a combination of fixed and removable retainers.
While removable retainers are easy enough (as long as they are worn), fixed retainers can be somewhat problematic.
Fixed retainers were first introduced in the 1970s, usually comprising a round stainless steel or rectangular blue elgiloy wire bonded to the lingual surfaces of the canines only.
While there have been several generations of fixed retainers over the years, they all still come with the same baggage.
Problems associated with fixed retainers
Placement
Placing fixed retainers is not for the faint hearted. You have to battle against the patients’ tongue and soft tissues, while maintaining exceptional moisture control.
Visibility and access can also cause issues, particularly when dealing with retroclined lower incisors. Upper fixed retainers need to be ideally placed to avoid occlusal interferences.
Oral hygiene
Studies have shown that fixed retainers frequently cause increased accumulation of plaque and calculus.
Failure
There are several types of bonded retainer failure.
Failure of the tooth-adhesive interface ranges from 3.5 to 53%, and is greater in the maxillary arch when compared to the mandibular.
Metal fatigue can occur with long-term retainer wear resulting in breakages along the length of the retainer without it debonding from the tooth surface.
The majority of failures occur within the first two years following placement.
Distortions
Unexpected torque movements can lead to displacement of teeth or occurrence of dehiscence.
Design
Failure rates of fixed retainers bonded to six lower anterior teeth is far lower at 9 to 14% than for those bonded solely to lower canines, which is reportedly 13 to 37.7%.
So, how do we address these issues to provide better outcomes for our patients?
Solutions
Placement
Many find using adjuncts such as cheek retractors and lab-made jigs helps aide placement. Others use a combination of floss and orthodontic elastics to hold the fixed retainer in place while adhesive is placed.
Oral hygiene
Patients must be shown how to supplement their regular oral hygiene routine with small-gauge interdental brushes or Superfloss for interproximal cleaning. This reduces the build-up of plaque and, ultimately, calculus in this region.
I often tell patients that excellent oral hygiene is a prerequisite for fixed retainers.
Failure
There should be careful consideration of the suitability of patients for fixed retainers; the care they took with their braces/aligners may be a useful indicator.
Instructions to avoid biting into hard foods with front teeth should be given. Of course, occlusal clearance should be built into treatment plans where upper fixed retainers are deemed necessary.
Distortions
Ensure fixed retainers are passive when placed, give patients clear instructions for care of the bonded retainer and consider the best materials for each case.
My go-to bonded retainer wire is Ortho-flextech which does not accept active bends.
Design
If fixed retainers are required, aim for lower failure rate designs by bonding to all teeth behind which the fixed retainer will be placed.
Are fixed retainers worth the effort?
Given the high failure rate and complexities of placing and maintaining fixed retainers, do I think they are worth the effort?
In some cases, certainly. I feel that patients with median diastemas, rotations, and severely displaced lower incisors benefit from fixed retainers, and I still offer them in these scenarios.
But I monitor my patients carefully throughout their treatment with regards to their suitability for fixed retainers, and they are informed at their initial consultation of the certain criteria needed to be met prior to their placement.
This ensures complete clarity on the pros and cons of fixed retainers, and the work required to maintain them. This allows patients to make an informed decision as to whether a fixed retainer is something they wish to commit to.
Catch up on previous Straight to the Point columns:
- Buccal corridors: who cares?
- Eating disorders and orthodontics
- Orthodontic trends: fads versus facts
- NHS referral guidelines
- The periodontally compromised patient.
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