Why Compare Retainer Types?

Dental retainers are currently divided into two categories: fixed retainers and removable appliances.

For bonded retainers, the latest industry innovation is the custom-made PEEK wire. A metal-free, biocompatible, imaging-invisible, and virtually unbreakable polymer, it ensures 24/7 stabilization.
Metallic alternatives — multi-strand wire in stainless steel or titanium, as well as older rigid bars — remain economical or historical, but are susceptible to wear, imaging artifacts, and an increased risk of breakage or discomfort.

Regarding removable appliances, the Essix retainer tray focuses on lightness, the Vivera extends its lifespan with three identical copies, while the Hawley retainer still allows for minor post-treatment corrections.
Clinical data, however, is unequivocal: in 2025, the majority of removable retainers fail in the long term because they rely entirely on patient motivation. Discover everything there is to know about fixed retainers in our complete guide dedicated to retainer wires.
Faced with this challenge, practitioners are turning to fixed solutions like PEEK, which are more reliable, impossible to forget, and without risk of breakage.

Fixed Retainer Wires

It was once believed that aligners would replace fixed retainers. Practical, discreet, and easy to produce, they seemed to tick all the boxes. However, with hindsight, the clinical reality has become quite different: according to Pratt’s study (2010), nine out of ten patients stop wearing them before three years.

Today, fixed retainers are regaining their full place in stabilization protocols. Always active, invisible from the front, and most importantly, impossible to remove, they ensure retention independent of patient motivation.

eZtain Custom PEEK Retainer Wire

The latest arrival in the world of dental retention, PEEK retainer wire (polyetheretherketone) is gradually establishing itself as the best alternative to traditional metal alloys.

This space-grade material is now attracting orthodontists with its unique properties, perfectly suited for long-term retention. Machined to micron precision from a digital impression, this lingual wire integrates with surgical precision to the patient’s arch — thus eliminating the need for manual bending still common with traditional metal wires.

Metal-free, it is completely biocompatible, radiolucent, and MRI-compatible — thus eliminating imaging artifacts as well as allergy problems related to Nickel present in traditional metal wires.

Multi-strand Metal Wire

Long considered the standard in fixed retention, this twisted stainless steel wire has been used by generations of orthodontists. Flexible, adaptable, and economical, it has served for decades to keep teeth aligned after treatment.

But with clinical hindsight and current requirements, its limitations are becoming increasingly apparent. The twisted structure more easily retains plaque and complicates hygiene. Its metallic composition, enriched with nickel, can cause allergic reactions and poses a problem during MRI examinations.

Finally, it requires annual check-ups and eventually a complete replacement. At a time when orthodontists are aiming for lifelong retention that is more reliable and without constraint for the patient, this type of wire is starting to lose ground.

The Retainer Bar

Not to be confused with a classic lingual wire: the retainer bar is a more rigid and thicker device, often used in the 90s and 2000s. It is welded or bent to be bonded only to the canines, without adhering to the central teeth. Result: the incisors can still move slightly over time.

While it was long appreciated for its solidity and quick placement, it now presents several disadvantages. It interferes with the tongue, can irritate or impair speech, and remains visible when the mouth is opened wide. Like its more recent metallic equivalent, it also creates artifacts during MRI examinations.

The dental retainer bar, now outdated, has been replaced by the multi-strand wire, which is more flexible and discreet, and then by custom PEEK: a modern solution that combines comfort, durability, and MRI compatibility — a real turning point in post-orthodontic stability.

Summary Table — The Different Types of Fixed Retainers

*With rigorous hygiene and annual check-up visits.

Removable Retainers

Presented as a comfortable and modern innovation, removable retainers were long perceived as the future of post-treatment stabilization. They are removed for eating, brushing teeth, traveling… On paper, everything seemed simpler.

But in reality, their effectiveness relies entirely on patient compliance. And on this subject, the figures speak for themselves: at two years, fewer than one in two patients still wear them three nights a week ; at three years, it’s less than 10% (Pratt study, 2010). Too easy to forget, too dependent on motivation, they expose patients to a real risk of relapse.

However, they remain useful in certain cases, particularly for temporary retention or progressive treatment endings. But for serious, “lifelong” stabilization, orthodontists are now turning to fixed solutions, especially PEEK retainers — which are more reliable and more convenient for daily life.

Nevertheless, it is still useful to know the three types of removable retainers still offered in certain particular cases.

Essix Retainer Tray

The Essix tray is a thin, transparent shell, made from an impression or scan of the patient’s teeth. It covers the dental arch and is generally worn at night, like a discreet mouthguard, to keep the teeth aligned after orthodontic treatment.

Thin and transparent, it is generally worn at night. Its main advantage lies in its simplicity: no glue, no lingual adaptation, and inexpensive replacement when it wears out or is lost. The downside is twofold: a short lifespan (one to two years) and effectiveness intimately linked to patient discipline; as soon as the nightly routine is abandoned, teeth can migrate.

Vivera Retainer

Produced in a series of three by the same chain as Invisalign aligners, the Vivera uses a polyacrylate material thicker than Essix. The manufacturer immediately provides three identical trays, extending the protection period to approximately five years when replacements are judiciously spaced. The distribution of pressure across the entire arch limits the risk of isolated micro-movements, but daily wear is required. Its cost, higher than that of an Essix, is justified by the announced longevity and manufacturing precision.

Hawley Retainer

Originating from traditional orthodontics, the Hawley retainer combines a palatal resin base and a U-shaped labial wire that conforms to the edge of the incisors. Solid and adjustable, it allows for the correction of potential micro-relapses by a simple adjustment of the wire. In contrast, its bulk sometimes interferes with phonation, makes it visible when speaking, and prompts many patients to abandon it prematurely. Its current relevance is limited to cases requiring minor occlusal adjustments that the tray could not achieve.

Summary Table — Removable Retainers

*Compliance rate according to Pratt’s instrumental study 2010.

2025 Trends: Towards “Zero Breakage, Zero Forgotten”

The convergence of clinical data on late relapse and the advent of digital machining have profoundly altered post-treatment retention strategy. Practitioners are now seeking devices that maintain teeth without voluntary patient intervention, whether for wear compliance or repair visits.

This evolution also addresses new clinical challenges: management of nocturnal bruxism, long-term prevention of orthodontic relapse, and the search for truly passive dental stabilization.

In this context, the transition is accelerating: bonded retainer wires remain the norm, but metal alloys are gradually giving way to custom PEEK, capable of offering mechanical resistance, invisibility, MRI compatibility, and total absence of nickel.
The result? No more emergencies for broken wires, unexpected appointments, or repeated replacements. Once placed, the retainer remains in place, without constraint, without complicated maintenance — and above all, without stress.

What is the Best Dental Retainer?

For an adult, the most reliable solution is a custom PEEK fixed wire: it contains no metal, does not break, remains invisible, and does not interfere with MRI. Metal wires and aligners remain valid, but they require more repairs or wear compliance.

What are the Disadvantages of Retainer Wires?

A wire fixed to the teeth facilitates plaque accumulation; it requires careful brushing with interdental brushes. Metallic versions can break or debond (2-3% per year), create MRI artifacts, and, when they contain nickel, cause rare skin allergies.

Practical FAQ

Conclusion

The stabilization phase is no longer the “appendix” it was twenty years ago: it determines the longevity of a treatment whose time and cost are already substantial. Aligner wear statistics show that truly durable retention must be independent of patient motivation. With this in mind, fixed retainers remain essential, and the transition to high-performance polymers marks a decisive advance. The custom PEEK wire developed by eZtain combines mechanical safety, invisibility, and full compatibility with medical imaging; it thus meets current clinical requirements while freeing the practitioner from breakage emergencies.

In light of these criteria, the eZtain PEEK wire today combines all the qualities of the best retainer wire for those aiming for long-term, maintenance-free stability.

To learn more, consult our complete guide to retainer wires, as well as our articles dedicated to placement and maintenance.

The information in this article is provided for educational purposes; it does not replace the personalized examination and advice of a qualified orthodontist.