Dental Implants: What They Are and When They Are Considered

The three parts of an implant tooth

An implant tooth is built in three parts:

• The implant. A screw-shaped post, usually made of titanium, placed in the jawbone. Ceramic (zirconia) implants also exist. The implant takes the place of the tooth's root.
• The abutment. A connector that is fixed to the implant and rises through the gum.
• The crown, bridge or denture. The part you see and chew with. One implant can carry a single crown. Two or more can carry a bridge, and several can hold a full-jaw bridge or a denture that clips on.

Because the implant sits in the bone, it does not rest on the neighbouring teeth. A conventional bridge, by contrast, is held by the teeth on either side of the gap, and those teeth are reduced to carry it.

When a dentist considers an implant

An implant is one of several ways to replace a tooth. A dentist usually suggests it in these situations:

• One missing tooth with healthy neighbours. An implant avoids reducing the teeth either side of the gap.
• Several missing teeth. Implants can carry individual crowns, or a bridge can span the gap on fewer implants.
• All the teeth in a jaw. A fixed bridge on four or six implants, or a denture that clips onto implants. The All-on-4 page explains the whole-jaw options.
• A loose denture. Implants can be added to hold a denture more firmly.

Three conditions matter:

• Bone. There has to be enough bone to hold the implant. If there is not, a bone graft or sinus lift may come first, which adds time and has its own risks.
• Healthy gums and mouth. Active gum disease, infection and decay are treated first.
• General health. Some conditions and medicines change the risk or the timing. Bone-strengthening medicines (bisphosphonates), for example, have been linked with implant loss and with jaw osteonecrosis, the death of jaw bone², on very low-certainty evidence. Tell your dentist about any bone-strengthening medicine, tablets or injections, now or in the past, and do not stop one without asking the doctor who prescribed it. Implant treatment waits until the jaw has stopped growing.

The decision is made after an examination, a 3D scan and a look at your medical history.

What treatment involves

Treatment has two main stages, the surgery and the crown or bridge, with healing in between. The full steps are on our dental implants page.

1. Examination and 3D scan: Bone, gums and medical history are assessed, and the plan is given in writing.
2. Preparation: Decay and gum disease are treated first. If a tooth comes out, the implant may go in at the same session or later.
3. Surgery: The implant is placed under local anaesthetic, with sedation if you want it and it suits you.
4. Healing: The implant fuses with the bone over months. Your dentist estimates your healing time after the examination.
5. The crown or bridge: Once healing is confirmed, a scan or impression is taken and the crown or bridge is fitted.
6. Baseline record and reviews: An X-ray and gum measurements are taken when the crown or bridge is complete. Regular reviews follow.

Can the tooth go on straight away?

Sometimes, for selected patients. Research names three timings for fitting the tooth: immediate (within a week), early (one week to two months) and conventional (after two months)³. A Cochrane review of 26 randomised trials, with follow-up of four months to a year, found no convincing difference in implant failure between immediate and conventional loading, but its result was imprecise and most of its trials were at high or unclear risk of bias, so it does not show that the two are equally safe. Its evidence does not reach beyond the first year. A review of 39 randomised trials reported slightly lower implant survival⁴ with immediate loading.

Placing the implant at the same session as the extraction is a separate choice. In one review, about 95 in 100 implants placed straight into the socket⁵ survived, against about 98 in 100 in healed bone. The authors advise caution. A tooth fitted on the day is usually temporary; ask which yours would be.

How long implants last

The figures come from a review of 46 studies of implants carrying a single crown. Of every 100 implants, about 97 were still in the mouth after five years and about 95 after ten. The crown on the implant is a separate part. In the same review, about 96 in 100 crowns were still in use after five years and about 89 after ten¹. A crown can be replaced while the implant stays.

These are averages pooled from studies in different countries and groups of patients. They are not the result of one clinic, dentist or implant brand, and they are not your personal risk. The ten-year values are model estimates from studies with a mean follow-up of at least five years, not counts of people followed for ten years. The reviews used here give no pooled figures beyond ten years. An offer that promises an implant for life is not based on evidence.

What can go wrong

Problems with the parts on top. Over five years the same review reported screw loosening in 8.8 per cent and soft-tissue problems in 7.1 per cent¹. Chipped porcelain was 3.5 per cent. A loose screw can be tightened and a damaged crown repaired or replaced.

Inflammation around the implant. Peri-implantitis is inflammation of the gum around an implant with loss of the bone that supports it. A 57-study review found it in about 20 in 100 patients and about 12 in 100 implants⁶; the rate depends on the definition used. If it is not controlled, the implant can be lost.

Surgery. Bleeding, swelling, bruising and infection can occur. Sometimes an implant does not fuse with the bone and has to be removed; your dentist then explains the options. In the lower jaw, because the nerve canal is close, the lip and chin can go numb; this is usually temporary and rarely permanent. In the back of the upper jaw the sinus is close: its membrane can tear, sinusitis can develop, or an opening can form between the mouth and the sinus. A 3D scan and careful planning reduce these risks; they do not remove them.

What raises the risk. In people smoking more than 20 cigarettes a day, implant loss was about 2.5 times as likely per implant⁷ as in non-smokers, and about 4 times as likely per patient; the risk rose with the number of cigarettes, and no safe number has been shown. People treated in the past for gum disease that had damaged the bone (periodontitis) lost implants at about 1.75 times the rate⁸ of people without that history. In people likely to clench or grind, the odds of failure were about 2.2 times higher⁹. For diabetes the findings on implant loss are mixed. Two of three reviews found no significant difference (2021 review¹⁰; 2016 review¹¹), and the third found higher odds of implant loss¹² in people with diabetes than in people without. All three found more bone loss around implants, so blood-sugar control, daily cleaning and regular reviews matter. These are associations from observational studies, not proven cause and effect. Who should not have an implant is covered in a separate article.

Looking after an implant

An implant cannot decay, but the gum and bone around it can become inflamed. It needs cleaning every day, around the crown and between the teeth, as your dentist shows you.

When the crown or bridge is complete, an X-ray and gum measurements should be taken as a baseline record¹³. Later changes are compared with it. After that, implants need a structured programme of regular checks¹⁴, set for your risk. A routine check-up interval is not automatically enough for an implant.

If an implant is not for you

There are other ways to deal with a missing tooth:

• Leaving the gap. For a single missing back tooth this is a reasonable choice for some people. Over time the neighbouring teeth can drift and the bone in the gap shrinks.
• A removable partial denture. No surgery is needed. You take it out to clean it, and getting used to it takes time.
• A resin-bonded bridge. For suitable single gaps, a false tooth with a wing bonded to the back of a neighbouring tooth. It needs little or no grinding and no surgery, but it can come loose.
• A conventional bridge. The teeth either side of the gap are reduced and crowned to carry it. No surgery is needed, but the tooth tissue removed does not grow back.
• A full denture. For a whole jaw, without surgery.

Which option suits you depends on the gap, the neighbouring teeth, the bone, your bite and your health. The figures above are for implants only. They do not show that an implant is better than a bridge or a denture for you.

When to see a dentist

See a dentist for an examination if you have a missing tooth, a tooth that may need to come out, or a denture that no longer fits. Bring a list of the medicines you take, and mention smoking, diabetes, gum disease and clenching.

If you already have an implant, contact your dentist if you notice any of these:

• The implant or crown moves, a screw feels loose, or a piece breaks
• Bleeding, a bad smell, pus or receding gum around the implant
• Pain or swelling that increases after the third day following surgery
• Numbness of the lip, tongue or chin that lasts beyond the anaesthetic (tell your dentist promptly; do not wait for a review)

Emergencies. Difficulty breathing or swallowing, rapidly spreading swelling of the face or neck, or high fever are serious signs. Go to the nearest emergency department or call 112.

Frequently asked questions