An implant cannot decay, but it can lose the bone anchoring it. The inflammatory process responsible behaves differently from disease around a natural tooth, and the difference matters clinically.
Inflammation begins in the soft tissue
Bacterial biofilm accumulates on implant components just as it does on teeth. The gum tissue around the implant responds with inflammation, bleeding and swelling.
At this stage the condition is confined to soft tissue and the supporting bone is intact. Clinicians distinguish this reversible phase from the later bone-losing one.
The distinction is made with probing and radiographs rather than appearance, because the surface signs of the two stages overlap considerably.
Bone loss follows a different pattern than around teeth
A natural tooth is attached to bone through a ligament with its own blood supply and fiber bundles that run into the surrounding tissue.
An implant is in direct contact with bone, with no ligament and no fibers inserting into the fixture surface. The tissue seal around it is weaker.
Because that barrier is less robust, inflammation reaching the bone can advance further before it is contained. Defects around implants often appear as a bowl-shaped crater in radiographs.
The implant surface complicates the process
Fixture surfaces are deliberately roughened to encourage bone attachment during healing. That texture works against cleaning once it is exposed to the mouth.
Biofilm adheres more readily to a rough surface and is harder to disrupt mechanically. The feature that helps integration hinders decontamination later.
Exposed threads compound the problem by creating undercuts that instruments cannot easily reach. Access difficulty is a real constraint on treatment.
Why it is often noticed late
Implants have no pulp and therefore no toothache. Loss of supporting bone frequently produces no pain until it is substantial.
The crown remains firm while the bone recedes, because a partly integrated fixture can still feel stable. Mobility appears only near the end of the process.
These features mean the condition is typically identified at scheduled reviews rather than by symptoms. That is the reason recall visits are part of implant care.
Where professional assessment is required
Diagnosis relies on probing depths and radiographs compared with a baseline taken when the restoration was placed. Without that baseline, change is difficult to establish.
Risk is also influenced by oral hygiene, smoking, existing gum disease and how the restoration is contoured. Those factors are evaluated individually.
Anyone with an implant who notices bleeding, swelling or a changed gum margin should have it examined promptly rather than waiting for discomfort.