Orthodontic Wire in Onychocryptosis

Orthodontic Wire in Onychomycosis

Biomechanical Principles, Clinical Evaluation, and Comparison with Molecular Memory Fiber

Dental Access Guide • Podiatry in Practice

Estimated reading time: 10 minutes

Quick Answer

Orthodontic wire remains one of the most widely used options in onychomycosis due to its high customization capacity and control over the corrective force exerted on the nail plate. However, its selection should not be based solely on wire diameter.

Nail thickness and elasticity, degree of curvature, technique employed, patient's clinical response, and the professional's experience are factors that directly influence material choice.

Although larger diameter wires exhibit greater rigidity, current scientific literature does not establish a universal protocol relating specific diameters to nail plate characteristics. Thus, the choice must always be individualized and based on biomechanical principles and clinical evaluation.

Technical Note

Important: This article is for educational purposes and brings together concepts from biomechanics, onyxis, and scientific literature on the conservative treatment of onychocryptosis. Currently, there are no international guidelines determining which orthodontic wire diameter should be used for each nail type. Therefore, clinical decisions must be individualized and based on the assessment of the responsible professional.

Introduction

Onychocryptosis, popularly known as ingrown nail, is one of the most frequent nail alterations in podiatric practice. It is characterized by the penetration of the lateral border of the nail plate into the periungual tissues, triggering pain, inflammation and, in more advanced cases, infection and granulation tissue formation.

Among the available conservative approaches, orthonyxia stands out for seeking to gradually correct nail curvature without the need for surgical procedures in many cases.

Various systems can be employed, such as molecular memory fibers, composite lamellae, prefabricated staples, and metallic wires. Among them, orthodontic wire remains one of the most versatile alternatives due to the possibility of fabricating personalized orthoses for each patient.

Despite widespread clinical use, it is common to find questions about which wire to use. Many professionals focus their attention only on wire diameter, when, in reality, selection involves a series of biomechanical and clinical factors.

This article presents these principles objectively and based on currently available evidence.

What is Orthonyxia?

Orthonyxia is a set of conservative techniques used to gradually modify the curvature of the nail plate through the application of continuous and controlled mechanical forces.

Its principle is similar to that observed in orthodontics: small forces, applied continuously, promote progressive tissue adaptations over time.

The objective is not to "force" the nail immediately into a new position, but to induce a gradual correction, respecting the biological response of the nail plate and surrounding tissues.

How does orthodontic wire work?

When used in the Omega (Ω) technique or other metallic orthosis modalities, the wire functions as a small spring.

During its fabrication, the professional introduces controlled deformations into the wire. After its fixation on the nail, these deformations generate an elastic force that tends to slowly guide the plate to a less curved configuration.

This process occurs progressively and can be adjusted throughout the treatment according to the observed clinical response.

Biomechanics of the Nail Orthosis

Biomechanics is the area of science that studies the application of mechanical laws to biological systems.

In orthonyxia, understanding these principles helps the professional understand why different orthoses can exhibit distinct behaviors, even when made with seemingly similar wires.

Simply put, the mechanical behavior of an orthosis depends on the interaction between several factors.

Wire Material

Wires can be produced from different metal alloys. The best known are:

• stainless steel;
• nickel-titanium (NiTi);
• other special alloys.

Each material has its own elastic properties, influencing how the orthosis stores and releases energy.

Diameter

From the point of view of materials mechanics, larger diameter wires exhibit greater rigidity. This means that small variations in diameter can significantly alter the wire's resistance to deformation.

However, greater rigidity does not necessarily mean better clinical results.

Useful Length

Another frequently overlooked factor is the effective length of the wire. In general terms, the greater the free length of the wire, the greater its elastic deformation capacity tends to be.

Orthosis Geometry

The way the wire is shaped modifies its mechanical behavior. In the Omega technique, for example, the central loop functions as an adjustment element for activation.

Activation Intensity

Even using the same wire, two professionals can produce orthoses with different behaviors, as the activation intensity also influences the final force exerted by the orthosis.

What factors influence the mechanical behavior of the orthosis?

The action of the orthodontic wire does not depend on a single factor. It results from the combination of:

• type of metal alloy;
• diameter;
• useful length;
• orthosis geometry;
• activation intensity;
• nail plate elasticity;
• patient's biological response.

This interaction explains why there is no universal table relating a given diameter to a specific nail type.

What has scientific literature already demonstrated?

Clinical Assessment Flowchart

                 PATIENT WITH INDICATION
                     FOR ORTHONYXIA
                            │
                            ▼
             Complete clinical assessment
                            │
        ┌───────────────────┼───────────────────┐
        ▼                   ▼                   ▼
 Nail plate        Nail plate elasticity      Degree of nail
    thickness                                 curvature
        └───────────────────┼───────────────────┘
                            ▼
                Technique selection
     (Omega, Fraser, fiber, VHO or other)
                            │
                            ▼
             Definition of initial
             corrective force intensity
                            │
                            ▼
             Installation and initial activation
                            │
                            ▼
              Periodic re-evaluations
                            │
                            ▼
       Adjustments according to clinical evolution

An important biomechanical principle

Perhaps the most important concept in this article is the following:

The goal of orthonyxia is not to apply the greatest possible force, but the smallest force capable of producing a gradual, predictable, and comfortable correction for the patient.

This principle aligns with the biomechanics used in other areas of health, such as orthodontics, where excessive forces can compromise the biological response of tissues.

Comparison: Orthodontic Wire × Molecular Memory Fiber

The evolution of orthonyxia has brought different materials for the fabrication of nail orthoses. Among the most used today are systems made with orthodontic wire and molecular memory fibers.

Although both have the same objective—to promote gradual correction of the nail plate curvature—their mechanical characteristics, application method, and adjustment possibilities are quite different.

For this reason, it is incorrect to state that one system is universally superior to the other. In many cases, both can produce excellent results when correctly indicated.

When does orthodontic wire stand out?

The main differential of orthodontic wire is its high customization capacity. Each orthosis can be custom-made for a specific patient, allowing adjustments in geometry, activation intensity, and force positioning.

Main advantages:

• ✔ Great freedom of fabrication.
• ✔ Possibility of different shapes (Omega, hooks, Fraser, etc.).
• ✔ Easy reactivation during treatment.
• ✔ Refined activation control.
• ✔ Low material cost.

Limitations:

• Orthosis fabrication requires manual skill, training, and more clinical time.
• Consistent results depend on the professional's experience.

When does molecular memory fiber stand out?

The fiber was developed precisely to simplify part of the procedure. Its main advantage lies in the speed of installation and the standardization of the system.

Main advantages:

• ✔ Quick procedure.
• ✔ Excellent aesthetics.
• ✔ Extremely discreet profile.
• ✔ Shorter learning curve.
• ✔ Good patient acceptance.

Limitations:

• As the fiber has its own mechanical characteristics, its customization capacity is usually lower when compared to orthoses made manually with metallic wire.

Main techniques using orthodontic wire

Several techniques employ metallic wires as a corrective element. Among the best known:

Omega (Ω) Technique

It is one of the most widespread techniques in Brazilian podiatry. It is characterized by the manual fabrication of a central loop in a shape similar to the Greek letter Ω, allowing control of the orthosis's activation during treatment.

• high customization;
• easy reactivation;
• low material cost;
• good clinical adaptation.

Fraser Technique

Originally developed for individualized corrections of nail curvature. The orthosis is custom-made for each patient, using metallic wires adapted to the nail's anatomy.

VHO (3TO)

A commercial system developed in Germany that uses specific metallic components to produce progressive corrective forces, following the manufacturer's own protocol.

Other variations

Several professionals have developed adaptations using unilateral, bilateral hooks, central loops, and personalized configurations—all following the same biomechanical principle of controlled force application.

What most influences treatment success?

It is common to imagine that the result depends only on the material used. In reality, the main factors are:

• Clinical evaluation: correct indication continues to be one of the most important factors.
• Installation technique: a correctly fabricated orthosis tends to better distribute forces over the nail plate.
• Follow-up: periodic re-evaluation allows checking clinical evolution and making adjustments when necessary.
• Patient adherence: home care, proper hygiene, and attendance at reviews directly influence results.

Myths and Truths

Most common mistakes

• Choosing material based only on cost: although cost is important, it should not be the only criterion.
• Seeking to excessively accelerate correction: progressive treatments usually show better biological adaptation.
• Not re-evaluating the orthosis: reactivations are part of clinical follow-up in various systems.
• Ignoring patient-reported discomfort: persistent pain or significant increase in inflammation should be re-evaluated by the professional.

Frequently Asked Questions

Is orthodontic wire better than fiber?
There is no scientific consensus establishing absolute superiority. Each system has its own characteristics and can yield good results when correctly indicated.

Is orthodontic wire usually cheaper?
Generally, yes. The cost of the material is usually lower than that of various fiber systems, although orthosis fabrication requires more clinical time.

Is there an ideal diameter?
To date, scientific literature does not establish a universal diameter for each nail type.

Can I choose the wire only by observing nail thickness?
No. Thickness is only one of the factors considered in clinical evaluation.

What should truly guide the choice of orthonyxia system?

The choice of orthosis should stem from the patient's assessment and nail characteristics, and not just from the available material. The true objective is to define:

What force intensity does this clinical case require?

The wire is just one of the elements used to produce this force. Other factors also play a part: bend shape, useful length, technique employed, activation performed, and characteristics of the nail plate.

Decision-Making Flowchart

                 PATIENT
                     │
                     ▼
        Is there an indication for orthonixia?
                     │
          ┌──────────┴──────────┐
          │                     │
        NO                   YES
          │                     │
 Evaluate other approach     Evaluate the nail
                                   │
       ┌───────────────┬───────────────┬───────────────┐
       ▼               ▼               ▼
 Thickness         Elasticity      Curvature
       └───────────────┬───────────────┘
                       ▼
          Is there significant inflammation?
              │                 │
            YES               NO
              │                 │
Control inflammatory      Choose the most
process first           suitable technique
                               │
                               ▼
           Orthodontic wire • Fiber • Other system
                               │
                               ▼
                Conservative application
                               │
                               ▼
                Periodic reassessments

Choosing the most suitable technique — this is a much more scientifically defensible decision than simply selecting a wire diameter.

What science still doesn't answer?

• What is the best diameter for each nail type?
• Is there an ideal force for each case?
• Which system presents the best long-term results?
• In which situations does fiber outperform metallic wire?

These questions still depend on more robust comparative clinical studies.

What do we already know for sure?

• ✔ Orthonixia can be an effective conservative alternative in many cases of onychocryptosis.
• ✔ Correction occurs through the continuous application of mechanical forces.
• ✔ Clinical follow-up is an essential part of the treatment.
• ✔ Different techniques can produce satisfactory results when correctly indicated.
• ✔ Individual patient assessment remains indispensable.

Summary Table

Considerations for students

For those starting in orthonixia, it is natural to seek objective answers such as "which wire should I use?". However, clinical evolution shows that decision-making depends on multiple factors. Understanding biomechanical principles is more important than memorizing tables.

Considerations for experienced professionals

More experienced professionals often continuously adapt their techniques according to observed clinical response, nail evolution, patient comfort, and accumulated experience. This flexibility is part of clinical practice and does not replace the need for continuous scientific updating.

Conclusion

The orthodontic wire remains one of the main tools of modern orthonixia thanks to its versatility, customization possibilities, and activation control.

However, its selection should not be based exclusively on diameter or fixed rules. The available scientific literature shows that the biomechanics of the orthosis result from the interaction between the material used, the geometry of the orthosis, the activation performed, and the individual characteristics of the nail plate.

More than choosing a wire, the professional must understand the factors that influence the applied force and seek a gradual, comfortable, and predictable correction.

Bibliographical References

Books

• Baran R, Haneke E, Richert B. Baran & Dawber's Diseases of the Nails and their Management. Wiley-Blackwell.
• Richert B, Di Chiacchio N. Nail Surgery. Springer.
• Proffit WR, Fields HW, Larson B, Sarver DM. Contemporary Orthodontics. Elsevier.
• Burstone CJ. Classic publications on orthodontic biomechanics.

Articles

• Haneke E. Works on orthonixia and conservative treatment of onychocryptosis.
• Reviews published in Actas Dermo-Sifiliográficas on orthonixia and ingrown nail.
• Reviews on conservative treatment of onychocryptosis in dermatology and nail surgery journals.

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