Dental implants and bone surgery: the pathway, and who it is for

Why is a tooth lost, and when is an implant indicated?

In adults, the causes of tooth loss are few. Periodontitis, a chronic infection of the tissues that hold the tooth, progressively destroys bone and ligament: the tooth loosens, becomes mobile and eventually cannot be kept. A root fracture, deep decay that has destroyed too much tooth, a failed root canal treatment or trauma also lead to extraction. More rarely, a tooth has been missing since birth.

The decision to extract is never taken lightly. A tooth with weakened support can often be treated, stabilised and kept for years: periodontitis treatment, periodontal regeneration or splinting are considered before an implant is discussed. An implant becomes an indication when the tooth is already missing, or when its prognosis is judged too poor to justify keeping it, and a replacement is wanted for chewing, appearance or the stability of the neighbouring teeth.

Replacing a tooth: what an implant is

A dental implant is an artificial root, usually made of titanium, placed in the jawbone. During healing, the bone bonds to its surface: this is called osseointegration. The implant can then support a crown or a bridge, or stabilise a removable denture.

An implant is not the only option. A bridge bonded or cemented to the neighbouring teeth, a removable denture, or sometimes leaving the gap are also discussed. The choice depends on the condition of the adjacent teeth, the amount of bone, your general health and your expectations.

What happens when a tooth is not replaced?

After an extraction, the bone that surrounded the root resorbs. A systematic review of human studies reports, six months after extraction, an average loss of about 3.8 mm in width and 1.2 mm in height, most of it occurring in the first three to six months ^[1].

The opposing tooth may also drift into the gap (supra-eruption). In a retrospective study of 65 patients, supra-eruption was measured in 78% of them, averaging 0.9 mm over about seven months ^[2]. These movements are often modest, but they can complicate the future restoration. They are not a reason to rush: they are a reason to plan.

Three requirements before placing an implant

• Enough bone in height and width, assessed in three dimensions with a cone beam CT (a dental scanner using a cone-shaped X-ray beam). If bone is lacking, a bone graft may be offered before or at the same time as implant placement.
• Healthy gums around the future implant and the neighbouring teeth, with daily cleaning that is achievable.
• Stable periodontal tissues. The periodontium is the set of tissues that hold the tooth (gum, bone, ligament). Active periodontitis must be treated before an implant is placed.

This last point is central to a periodontist’s approach. A 2024 meta-analysis shows that patients with a history of periodontitis, even treated, have more peri-implantitis (inflammation with bone loss around the implant) and slightly lower implant survival than patients without such a history ^[3]. These are observational studies: they show an association, not an inevitability. The authors conclude that an implant remains possible if the disease is controlled and stable.

The European (EFP) guideline for stage IV periodontitis includes tooth replacement, with tooth- or implant-supported prostheses, within an overall treatment plan, after the phase that treats the infection ^[4]. The 2023 EFP guideline on peri-implant diseases states that prevention starts when the implant is planned and continues with regular follow-up ^[5].

The pathway, step by step

• Full periodontal assessment and examination of the area to be restored.
• Treatment of periodontitis if needed, followed by re-evaluation.
• 3D imaging (cone beam CT) and software planning, starting from the future tooth.
• Bone grafting if the bone volume is insufficient (sometimes at the same time as the implant).
• Implant placement, possibly with a surgical guide.
• Healing, then fitting of the crown.
• Lifelong periodontal and peri-implant maintenance.

The surgical procedures (graft, implant placement) are carried out under local anaesthetic in the practice’s operating room. The crown is then made in coordination with your own dentist when they provide the prosthetic part. The principle of implant placement is described on the page Placing an implant and guided surgery.

Which page should you read?

Limitations, relative contraindications and possible failures

There are few absolute contraindications to implants, but several situations raise the risk of failure and are discussed before a decision is made. Smoking is associated with more failures and more bone loss around implants. Poorly controlled diabetes is associated with more peri-implantitis, whereas well-controlled diabetes gives results comparable to those of people without diabetes. Unstable periodontitis means placement is postponed. Certain treatments (high-dose antiresorptive bone medication, head and neck radiotherapy) and an unstable general condition call for a joint opinion with your doctor. These factors, and the studies that document them, are detailed on the page about implant placement.

An implant can fail in two ways. Early failure occurs in the first months: the bone does not bond to the implant, which becomes mobile and must be removed; a new placement is often possible after healing. Late failure occurs years later, most often through peri-implantitis: an infection of the tissues around the implant, comparable to periodontitis, that destroys the supporting bone. It is more common in people who have had periodontitis, in smokers and when regular follow-up is lacking. It is not always noticeable: an implant can lose bone without pain, which is why check-ups matter.

Lifespan and follow-up: the gums decide

A meta-analysis of 18 studies estimates ten-year implant survival at 96.4%; a more conservative sensitivity analysis gives 93.2%, with lower survival in people aged 65 and over ^[6]. Survival does not mean freedom from complications: an implant that is still in place can develop peri-implantitis. This is why follow-up matters as much as surgery.

This follow-up takes the form of periodontal maintenance visits whose frequency depends on your level of risk: checking the gums around teeth and implants, measuring pocket depth, professional cleaning, and X-rays at regular intervals to monitor the bone. Between visits, daily cleaning around the implants (interdental brushes, careful brushing at the neck of the crown) is the first line of protection. The article Gum care around implants details these habits and explains mucositis and peri-implantitis.

Frequently asked questions