Implants

Implants are medical devices designed to be placed inside the body to replace missing structures, deliver therapy, or support native tissues. They can be permanent or temporary and may be implanted surgically or via minimally invasive procedures. Common categories include dental implants, orthopedic implants, cardiovascular implants, neural implants, cochlear implants, and ocular implants. In dentistry, a dental implant typically consists of a titanium or zirconia post anchored into the jawbone, supporting a crown, bridge, or denture. Orthopedic implants include joint prostheses (hip, knee), plates, screws, and rods used to stabilize fractures or replace joints. Cardiovascular implants include pacemakers and implantable cardioverter-defibrillators, which regulate heart rhythm, as well as vascular stents to keep arteries open. Neural implants may deliver electrical stimulation to the nervous system, and cochlear implants convert sound to electrical signals for the inner ear. Ocular implants include lenses placed in the eye to restore vision.

Materials used must be biocompatible and durable. Common materials include titanium alloys, stainless steel, cobalt-chromium alloys, ceramics, and medical polymers. The concept of osseointegration is central to some implants, notably dental implants, where the bone grows onto the implant surface for stability.

Regulation and oversight vary by country but typically involve premarket testing, regulatory clearance or approval, and postmarket surveillance. Procedures include evaluation, imaging, placement, and follow-up care; rehabilitation and maintenance are important. Risks include infection, device failure or wear, tissue damage, allergic reactions, and the need for revision surgery. Longevity varies by device but many implants last several years to decades. Ethical and access considerations, including cost and patient selection, are integral to implant use.