As medicine and technology have advanced through in recent years, the materials available for surgical implants have evolved with improvements in the quality and quantity of biomaterials, including titanium implants.
Characteristics of the Biomaterials Suited for Human Implants
- The material must not cause harmful changes within the body, whether localized or systemic; though some minimal localized reaction shouldn’t be cause for concern.
- Materials should have physical properties that allow the affected body part to function as normal. Properties such as elasticity, overall and fatigue strength, and wear resistance help determine whether a material can perform effectively.
- Components should be easy to fabricate, and reproductions should consistently meet the individual specifications.
- The material should be physically stable while inside the body, meaning, their rate of degradation and wear needs to be compared to that of their natural counterparts. Titanium is a reliable material, and recycling titanium implants provide an additional benefit.
Materials Used to Construct Implants.
- Nitinol is a nickel-titanium alloy used for bone fixation, stents, and heart valve tools. The elastic strength of Nitinol is near that of natural bone, while its compressive strength is much higher. This newer alloy is one of several alloys characterized by its increased elasticity compared to other metals, so-called shape memory effect.
- PEEK, or polyetheretherketone is a solid and durable plastic used for customized implants such as those for cranial defects or traumatic injury. Implants constructed from PEEK can be manufactured into patient-specific shape and stiffness and allow surgeons to make intraoperative changes to the device. PEEK is an exceptional material for areas where future imaging may be needed. It’s translucent on x-rays and non-magnetic.
- Polyethylene is the most common form of plastic used for implants because it’s inert and doesn’t degrade even though it is porous. Solid, high-density polyethylene has been used for facial reconstruction for several decades. Ultra-high-molecular-weight polyethylene, seen in literature as UHMWPE, is used for artificial hips and knees.
- Silicone is a biomaterial common in breast augmentation but is used in several other devices as well. Silicone tubing is used for diagnostic and medication delivery systems. It’s also found in devices like hydrocephalus shunts, drains, insulation for the pacemaker’s electrical components.
- Titanium has long been used for dental procedures but has more recently replaced stainless steel for orthopedic screws and within artificial hips and pacemakers. Additionally, the possibility of recycling titanium implants appeals to modern patients and their surgeons. Titanium is strong, and readily integrates with bone. It’s also much lighter than other metal alloys.