Biocompatibility: what it means in biomaterials
Quick facts
- Definition
- The ability of a material to coexist with the body without causing an unacceptable reaction.
- Does not mean
- Total absence of reaction or risk.
- Depends on
- Composition, purity, shape, site and each person's response.
- Related to
- Bioabsorption, immunogenicity and health registration.
- In facial harmonization
- Part of the choice of material and of the risk conversation with the patient.
Biocompatibility is the ability of a material to coexist with the body without provoking an unacceptable reaction. In facial harmonization (known in Brazil as HOF, orofacial harmonization), the concept applies to everything that stays in the tissue: hyaluronic acid, biostimulators, threads and other materials.
What does the word mean, and what does it not?
Biocompatible is not a synonym for "inert" or "risk-free". The body responds to any foreign body, to a greater or lesser degree. What is expected is a controlled, predictable response consistent with the use. For this reason the word describes an expectation, with individual limits.
| Statement | Appropriate? |
|---|---|
| "Material that is well tolerated in general" | Yes |
| "Causes no reaction at all" | No |
| "Safe for any patient" | No |
What influences compatibility?
- Composition and purity of the material.
- Shape, particle size and degree of cross-linking.
- Site and amount injected.
- Patient characteristics, such as history of allergy and autoimmune diseases.
- Contamination or failure of asepsis during the injection.
Biodegradability also counts: materials the body absorbs leave less residue than permanent ones, and permanent fillers raise specific concerns about late reactions.
What reactions can happen?
Even with a compatible material, hypersensitivity reactions, nodules and granulomas can occur. They are uncommon, but they exist, and they belong in the risk conversation.
Also called: biological compatibility.
Frequently asked questions
Can a biocompatible product cause an allergic reaction?
Yes. Biocompatibility indicates that the material is, in general, well tolerated, but hypersensitivity reactions, nodules and inflammation can still happen in some patients.