Dental implants: how they work and how long they last

What an implant is

A dental implant replaces the root of a missing tooth. It is a small screw, usually made of titanium, placed in the jawbone. Over the following weeks and months the bone grows tightly against its surface, and the implant becomes firm. An abutment and a crown are then fixed on top. One implant can carry one crown; several implants can carry a bridge or a full arch of teeth.

How the treatment goes

It starts with imaging — usually a CT scan — to measure how much bone there is and where the nerves and sinuses lie. The surgeon plans the position of each implant, places it under local anaesthesia, and the bone is left to heal. The final crown follows once the implant is stable. Where there is not enough bone, a bone graft or a sinus lift may be needed first, or a different kind of implant (see the summary on advanced implants).

What the research shows

Howe and colleagues (2019) pooled 18 prospective studies of modern implants followed for ten years. The summary estimate of survival was 96.4% at implant level (95% confidence interval 95.2–97.5%).

The same authors then repeated the analysis allowing for the patients who were lost to follow-up — people who stop attending are not always people whose implants are fine. That more cautious estimate was 93.2%, and 91.5% for patients aged 65 and over.

What raises the risk

Smoking is the best-documented risk. A review of 107 studies (Chrcanovic and colleagues, 2015) counted 6.35% failed implants among smokers against 3.18% among non-smokers, and found smoking also linked to more infection after surgery and more bone loss around the implant. The authors caution that other factors in those studies could not all be controlled.

Your general health, your gums and how you look after your teeth also matter, and are assessed before a plan is made.