The biocompatibility of PMMA material makes it great for denture manufacturers.

Poly(methyl methacrylate), or PMMA, is known by many Different names, including Plexiglas and acrylic. The biocompatibility of PMMA material has gained it the medical moniker of “bone cement.”

PMMA is often used as a lighter, shatter-resistant alternative to glass in everything from windows, aquariums and hockey rinks. Therefore, it’s hard to fathom that this easy-to-process, low-cost, versatile material is also used in dentures, bone implants and more.

Despite being formed by polymerizing methyl methacrylate (MMA) — an irritant and possible carcinogen — PMMA is extremely biocompatible. This biocompatibility can be attributed to PMMA’s resistance to:

• Temperatures stress
• Chemical reactions
• Human tissue
• Bioprocesses

As bone cement, PMMA is used to fill in the gaps between implants and bones. PMMA material is good for this procedure because it is biocompatible and simple to polymerize within a hospital environment.

However, a better understanding of material intelligence can help answer whether PMMA is always a good option for in vivo implants.

Though PMMA Material Is Biocompatible, Is It Always the Best Medical Option?

The biocompatibility of PMMA material makes it a go-to option to anchor implants to bone. But is it the best option?

In an operation room, bone cement is made from a powder and a liquid. The powder is composed of MMA copolymers while the liquid contains MMA monomers and chemical accelerators and inhibitors.

Mixing the powder and liquid creates a putty which can be applied between the bone and the implant. Think of the putty like the grout between tiles: It anchors the implant to the bone.

However, there are a number of reasons why PMMA material is not ideal for this job:

1. PMMA’s fracture toughness is between 0.7 MPa∙m1/2 and 1.6 MPa∙m1/2, while bone’s fracture toughness is between 3.5 MPa∙m1/2 to 6.6 MPa∙m1/2.
2. PMMA has a high polymerization temperature.

The difference between the fracture toughness of PMMA and bone can lead to impacts breaking the cement in scenarios where the bone or implant is unaffected.

Also, research has shown that, due to exothermic polymerization, the putty can reach temperatures above 80 C outside the body and around 50 C inside the body, damaging the bone. This translates to a longer recovery time for patients.

Furthermore, small amounts of unpolymerized MMA can remain in the cement. These components can find their way into the rest of the body causing hypotension.

PMMA may have its issues as bone cement, but it’s still the best material option in many situations. However, researchers are looking for a better material for bone cement purposes.