PMMA in HOF: Properties, Risks and Retreatment

Among filler materials, PMMA holds a place of its own. It does not behave like an absorbable gel: part of what is injected stays in the tissue for good. For the orofacial harmonization (HOF) professional, the subject comes up in two situations: deciding whether to use the material, and seeing a patient who already received it, often from another professional, and who arrives with a concern. This guide explains properties, risks and retreatment logic at a review level. Indication, technique and management are decisions for the qualified professional, according to the product leaflet, regulations and the rules of their professional board in Brazil.

What is PMMA?

PMMA (polymethylmethacrylate) is a synthetic polymer that has been known for decades in other medical contexts. As a filler, it is presented as microspheres suspended in a carrier, usually an absorbable gel. The reasoning behind its use is as follows: the carrier gives immediate volume and is absorbed over time; the microspheres stay in the tissue, and the body forms a tissue response around them, which contributes to support.

In other words, part of the effect comes from the injected material and part from the body's response to it. This design explains the advantages described for the product (durability) and also its risks (permanence).

How does PMMA differ from other materials?

This difference changes the consent conversation. With hyaluronic acid, there is the possibility of stepping back. With PMMA there is not, and the patient needs to understand that before any decision. See also permanent fillers: what is known.

What are the reported risks?

The clinical literature describes early and late complications. At a review level:

1. Nodules and irregularities. They can be palpable or visible, from material accumulation or a tissue response.
2. Granulomas. A chronic inflammatory reaction to the material, which can appear months or years after the injection, sometimes suddenly.
3. Migration and displacement. The material can move from its original site and change contours.
4. Asymmetry. Because volume is hard to adjust once placed, corrections are complex.
5. Infection and biofilm. As with any injectable, they can occur, and late diagnosis is a challenge. See infection and biofilm after filler.
6. Vascular compromise. As with other materials, intravascular injection is a risk, and the lack of a specific antidote for PMMA makes prevention even more important.
7. Hypersensitivity reactions. They can occur, and the patient's history is relevant.

The most striking feature of these risks is timing: they can appear long after the procedure, sometimes with a trigger such as infection, trauma, vaccination or an immune change. For that reason, follow-up of a patient who has PMMA should be understood as ongoing.

When is the material a good idea, if ever?

This is a difficult and controversial decision in the field. Some professionals use the material in very specific situations, with their own training, while others choose not to use it at all, preferring reversible materials. This text makes no recommendation for or against. What safe practice suggests is:

• Be clear about the indication and the absorbable alternatives.
• Obtain specific consent, in plain language about permanence and late risks.
• Consider the patient's profile, avoiding indicating it to someone who wants an immediate result and may change their expectations.
• Follow the case long term.
• Review your professional board's rules and the product's regulatory status.

How do you see a patient who already has PMMA?

This is more common than it seems. The patient arrives with an old material, sometimes from another professional, sometimes with no information about what was injected. The approach starts with the history.

When the patient does not know what was injected, the exam and history give clues, but not certainty. If you are unsure about the nature of the material, avoid injecting another product in the area without further assessment. The general reasoning about unknown products is in dissolving filler: criteria for indication.

What if the patient with PMMA wants a new filler?

There are two questions: the PMMA area and the rest of the face.

• In the PMMA area, the professional assesses whether there is room for another material and whether there is a risk of interaction, inflammation or an unpredictable result. Many choose to avoid the area or to discuss it with experienced colleagues.
• In other areas, prior PMMA does not prevent treatment, but you should know the patient may have a different immune response, and step up vigilance.

In both cases, the history and the consent must be clear in the patient record.

How do you manage late complications?

Managing PMMA nodules and granulomas requires experience and, often, a multiprofessional team. In broad terms, management may include:

• Detailed clinical assessment to tell inflammatory reaction, infection and material accumulation apart.
• Complementary tests depending on the case, at the discretion of the responsible physician.
• Medical treatment, such as anti-inflammatory therapy, when indicated.
• Surgical intervention in selected cases, generally by a professional trained for it.
• Referral to a specialist service when the complexity goes beyond your experience.

In none of these scenarios is hyaluronidase the answer for PMMA. It may be useful only if hyaluronic acid is also present in the same area. See also late hyaluronic acid nodule and adverse event reporting.

How do you communicate with the patient?

A patient with a complication from a permanent material is usually anxious and often angry at the previous professional. Avoid commenting on colleagues' work and focus on what can be done now. See communicating a complication to the patient.

What should go in the patient record?

The patient record should contain: the material's history (when, where, who, how much), exam, photos, the risk conversation, specific consent, follow-up plan and referrals. If you are the one using the material, record the lot, expiry date and product registration. The informed consent needs to mention permanence, late risks and the difficulty of reversal. For the legal dimension, see civil liability.

Takeaway

PMMA is a long-lasting material, with risks that can appear late and no simple reversal. Whoever uses it needs training, specific consent and ongoing follow-up. Whoever receives a patient who already has the material needs a good medical history, a careful exam, the humility to ask for help and caution with new injections in the area.