Clear Retainer Wire: PEEK or Metal? A Comparison

Important note: the eZtain retainer wire is not completely transparent. It is made of white PEEK, designed to blend with natural enamel. This finish currently offers the most discreet and aesthetic option available in orthodontics, but no device is completely invisible.

 

5 minutes to choose the solution that will protect your new smile for life.

Once teeth are perfectly aligned through braces or aligner treatment, it is essential to maintain their position. Without fixed retention, the gums and bone surrounding the teeth remember their old position. Without retention, they will then gently “pull” the teeth back to their original place.

To prevent this, orthodontists place a thin bonded retention bar – the now well-known “retainer wire” – on the inner surface of the teeth. Long made of stainless steel, this bar has naturally evolved towards PEEK, an advanced medical polymer already used in orthopedic surgery. More discreet, more comfortable, and metal-free, it embodies the new generation of retainer wires.

Same function, but two very different materials: comfort, discretion, biocompatibility… This comparison helps you understand the stakes and choose the solution best suited to your situation.

Why compare clear and metal retainer wires?

The post-treatment retention phase is crucial: without it, over 83% of patients experience a relapse within five years. The choice of retention material is therefore not a mere technical detail.

It influences both your mouth’s tolerance, daily comfort, the device’s discretion, as well as maintenance routines, debonding risks… and the cost if a repair becomes necessary.

In recent years, the classic metal wire has gradually given way to PEEK retention wire. This white, almost transparent, custom-milled medical polymer brings a new generation of retention: more discreet in the mouth, more comfortable, and metal-free.

• increased comfort, thanks to its smooth surface and natural flexibility,
• discreet aesthetics, close to the natural tooth shade,
• full MRI compatibility, without interference during medical imaging examinations.

In contrast, the stainless steel wire remains the historical standard: robust, proven, and placed immediately at the end of treatment, but manually shaped and susceptible to breaking after a few years.

In this article, we will therefore compare these two options point by point, to help you make an informed choice, based on your priorities: health, comfort, aesthetics, or simplicity.

Factor #1: Oral Tolerance & Medical Safety

A retainer wire will remain in place for years; its material must therefore be tolerated by your tissues and compatible with your medical examinations.

eZtain / PEEK (metal-free option)

PEEK is an implantable grade polymer — meaning a material used to manufacture medical implants placed inside the body. It releases no metallic particles, does not irritate the mucous membrane, and contains no nickel, the most common allergen in orthodontics. Its radiotransparency, in other words, the fact that it does not block rays during examinations, puts an end to pre-MRI removals: even for high-resolution brain imaging, the bar remains in the mouth.

“With this type of material, we can say goodbye to wire syndrome. It avoids the need for removal for potential MRIs or scans, which, of course, represents a considerable advantage.”

Testimonial from Dr. Céline Freyss

Traditional Metal Retainer Wire

Stainless steel has decades of proven use: it remains safe for the majority of patients. However, it contains nickel; thus, about 1% of wearers develop local irritation or a persistent metallic taste. The main drawback of metal wire, however, appears in the long term: in the event of an MRI, it can create artifacts (image distortions), which often leads the radiologist to request its temporary removal.
As the replacement of a metal retainer wire after an MRI is not covered by CPAM, the patient faces a difficult choice: to finance the re-placement themselves to preserve their teeth alignment, or to forgo it and risk seeing their smile change over time.

Factor #2: Clear Retainer Wire vs. Metal: Which is More Discreet?

Clarification: eZtain PEEK is not transparent like glass. Its matte white shade limits reflections and harmonizes with most tooth shades, offering a much more discreet visual result than a metal wire.

Clear PEEK Retainer Wire

Milled in a white shade, the eZtain PEEK bar blends with enamel; no gray halo, even on translucent incisors. Its matte surface does not reflect light and remains stable over time: no yellowing, no shadow under flash photography. Patients often say they “forget about it” within the first week.

Traditional Metal Retainer Wire

Placed on the tongue side, the stainless steel bar is not very visible from the front, but an attentive eye may notice a silvery glint against the light, or especially when opening the mouth wide.

Factor #3: In-mouth Sensation and Daily Comfort

Once the bar is placed, what you feel daily matters as much as its strength. Let’s talk about comfort, speech, and sensations.

Clear PEEK Retainer:

Within the first few days, the clear PEEK retainer wire becomes unnoticeable. It does not rub against the tongue, causes no discomfort when speaking or metallic sensation, and does not react to hot or cold.

This immediate comfort comes from its manufacturing: the wire is digitally custom-milled, based on a scan of your mouth. It therefore precisely matches the shape of your teeth, without approximate adjustment.

Conversely, the metal wire is still often bent by hand.

Traditional Metal Retainer Wire

The metal wire is very thin and generally does not impede speech. But its rigidity is more noticeable when the tongue touches it: some patients describe a “hard” wire sensation or a slight rubbing.
If a bonding point detaches, a strand can then straighten and become sharp — which requires prompt intervention (see our dedicated article on debonded retainer wire).

For individuals prone to bruxism — meaning those who unconsciously clench or grind their teeth, often during sleep — the metal wire endures repeated pressures. This mechanical stress significantly increases the risk of twisting or breakage, often requiring the wire to be replaced sooner than expected.

Factor #4: Long-term Durability and Resistance to Unexpected Events

A retainer wire that breaks or twists loses its retention role. It is then necessary to consult quickly, because without active retention, teeth can start to move in just a few days.

The Clear PEEK Retainer Wire – Flexible and Ultra-Durable

The PEEK wire is both flexible and strong. It can flex slightly when clenching teeth or eating something hard, then return to its place without deforming. This elasticity significantly reduces the risks of breakage or a “twisted wire.”

In practice, orthodontists observe that there is no longer an emergency with this type of wire, even several months after placement.

Another advantage: PEEK does not rust, stain, or deteriorate upon contact with saliva — it remains stable and clean over time.

“I am impressed by the reliability of these retainers; I recommend them without hesitation.”

Testimonial from Dr. Gauthier Bodart

 

Traditional Metal Retainer Wire

Metal wire is very rigid, which ensures good initial stability. But if it undergoes an impact — such as a blow to the teeth, or a very hard food — it can permanently bend. In this case, it no longer retains the teeth correctly and must be re-bonded.

Some wires are braided to be a little more flexible, but over time, each small strand can wear out. Occasional breakages can therefore appear after several years, especially in people who clench or grind their teeth at night.

Factor #5: Ease of Maintenance and Daily Hygiene

A poorly cleaned retainer wire can quickly accumulate deposits and promote plaque formation. Good hygiene is therefore essential to maintain healthy gums… and fresh breath.

Clear PEEK Retainer Wire:

The clear PEEK retainer wire is custom-milled from an ultra-smooth polymer block. Unlike braided metal wires, its surface has no roughness: dental plaque and tartar adhere much less to it.

Result? the wire remains visually clean longer, and daily maintenance is simplified.

• Recommended routine: careful brushing with a soft toothbrush and interdental brushes once a day.
• Check-ups: a professional cleaning (scaling) every year is usually sufficient — PEEK does not heat up on contact with ultrasonic devices, which facilitates maintenance.

Traditional Metal Retainer Wire

Metal wire, especially if braided, has small spaces where food debris and plaque tend to accumulate. Over time, this can promote the formation of tartar or gingival inflammation if cleaning is not rigorous.

The gray shade of the wire also makes it more difficult to detect stained areas or yellowing composite.

• Recommended routine: thorough brushing morning and evening, use of interdental brushes, and sometimes flossing by threading under the wire.
• Check-ups: regular professional cleaning (scaling) is important, as tartar can attach more easily between the strands and at the bonding points.

Criterion	Metal Wire	PEEK Wire (eZtain)
Surface	Braided, with micro-interstices	Ultra-smooth, without roughness
Plaque Adhesion	Retains more food debris and plaque	Fewer deposits, naturally cleaner surface
Stain Visibility	More difficult to detect (gray shade + yellowing composite)	White shade: stained areas more easily identified
Maintenance Routine	Toothbrush + interdental brushes + dental floss recommended	Toothbrush + interdental brushes are sufficient in most cases
Professional Cleaning (Scaling)	Regular professional cleaning (scaling) recommended	Quick professional cleaning (scaling), the material does not heat up under ultrasound

Factor #6: Cost, Placement, and Management in Case of Unexpected Events

Find our special report on the cost of a retainer wire here.

eZtain Clear Retainer – Digital Workflow & Short Lead Time

The PEEK retainer wire is custom-manufactured using a 100% digital workflow. It all begins with a digital impression: a simple intra-oral scan, performed in the clinic in less than a minute.
The exact shape of your teeth is then transmitted to our specialized laboratory, which mills the wire from a polymer block according to the 3D plan of your oral cavity. The manufacturing and delivery time is then 5 to 7 business days.

During placement, the practitioner uses a 3D-printed positioning key, which allows for very fast, precise bonding, without manual adjustment. The entire procedure (sandblasting, bonding, photopolymerization) takes less than 10 minutes.

Key points

• Custom manufacturing from a digital scan
• Average lead time: 5 to 7 days
• Fast and precise guided placement

Traditional Metal Retainer Wire

The metal wire, shaped directly in the chair on the day of appliance removal, initially withstands stress well, but remains susceptible to impacts and wear over time. A bend or breakage can occur, requiring intervention to restore retention. These unexpected events are generally simple to manage, but can accumulate over several years and represent a significant cost once the initial coverage is exceeded.

Key points?

• Immediate placement, but precision dependent on manual shaping
• Risk of incidents over the years, with possible non-reimbursed costs

Health Insurance Coverage (France)

In France, most supplementary health insurance plans reimburse the additional cost of a clear PEEK retainer bar provided that the material is mentioned in the initial quote given to the patient.

• If the choice of PEEK occurs after the end of treatment, the orthodontist may have to bill for the bar as “unlisted”; in practice, this remains rare, but the out-of-pocket cost then depends on the mutual insurance contract.
• Therefore, remember to specify your preference when the retention quote is established to ensure coverage.

The choice of a clear PEEK retainer therefore rarely incurs an additional cost compared to a metal bar, provided it is mentioned in the initial quote.

This makes it a higher quality health-wise alternative, without major financial impact in most cases.

The metal retainer wire, however, remains the standard procedure for orthodontic treatment completion. Like PEEK, it is included in the protocol when treatment begins before age 16, with a reimbursement of 70% of the agreed-upon rate (i.e., €135 based on €193.50). The out-of-pocket cost (approximately €58) depends on the patient’s mutual insurance.

FAQ

Choosing Your Retainer Wire Wisely – The Comparative Table

Criterion	Metal Wire	PEEK Wire (eZtain)
Material	Stainless steel, contains nickel	Medical PEEK polymer, metal-free and allergen-free
Oral Tolerance	Well tolerated but risk of irritation or nickel allergy	Hypoallergenic, completely biocompatible
MRI compatibility	Sometimes incompatible, removal necessary depending on the case	100% MRI compatible, no removal required
Aesthetics	Discreet but can create glare or a gray shadow	White, invisible, or A2 shade close to enamel
Daily Comfort	Rigid, can bother the tongue or poke if bent	Flexible, smooth, forgotten within the first few days
Durability over time	Good retention, but risk of bending or breakage after several years	Very good resistance, bends without deforming, fewer emergencies observed
Hygiene & Maintenance	Retains more plaque in the strands, requires meticulous cleaning	Smooth surface, reduces tartar accumulation, simplified maintenance
Placement / Logistics	Immediate chairside placement, re-bonding possible within the day	Digital scan + lab fabrication (5–7 days), rapid and guided retainer wire placement
Replacement	Wire available in clinic, easy replacement	Custom fabrication, lead time required for replacement
Pricing / Reimbursement	Included in the overall quote, reimbursed within six months post-treatment (if 16 years old)	Covered by mutual insurance if planned in the initial quote (otherwise not covered)

Summary: Choose with Confidence

Warning: no retainer wire is truly invisible, and the eZtain PEEK retainer is no exception. However, it significantly reduces the visual impact in the mouth compared to metal wires, even on translucent incisors.

Do you value the aesthetics, comfort and durability of your retainer wire?
→ The PEEK retainer wire, offered by eZtain, is a high-end solution, discreet, custom-made, and perfectly tolerated.

Do you prefer a solution that is immediately available, with a more accessible cost and proven clinical track record?
→ Metal wire remains a reliable option, provided you accept a slightly visible aesthetic and maintain rigorous hygiene.

In all cases, the stability of your treatment depends primarily on your regularity in maintenance and check-up visits.

Discuss your priorities with your orthodontist to choose the most suitable device for your profile.

Notes: eZtain uses white medical-grade PEEK. This material is not transparent, but its color and finish are designed to offer the best possible discretion while ensuring tolerance and longevity.

Health Information – educational content.
The advice above does not replace a professional examination. If in doubt, consult your orthodontist.