Dental implants and jaw bone reconstruction

What is an implant?

A dental implant, in the words of Guy’s and St Thomas’ hospital, is an artificial replacement for a tooth root. It is a screw-like post made of titanium that is placed in the jawbone, and a crown, a bridge or a firm denture is fixed on top of it. The American Association of Oral and Maxillofacial Surgeons (AAOMS) writes that titanium fuses with the bone over several months, and this fusing cannot be hurried. This is what makes an implant more stable than a removable denture and, according to the same association, bone loss under it is usually not a problem. Even so, gum disease around an implant can lead to bone loss.

There are two other options, and the sources set them alongside implants: a bridge or crowns on the neighboring teeth, or a denture. Each has its own advantages and cost, and an implant is not the only right way.

Who might be able to have an implant?

Cambridge University Hospitals writes that suitability depends on general health, oral hygiene and how stable the remaining teeth are. The teeth should not have active decay or infection, and the height and volume of bone must be enough. Guy’s and St Thomas’ reminds patients to tell the treatment team about their conditions and medicines, because some of them change the advice.

Three things raise the risk of failure: smoking, gum disease and teeth grinding. Cambridge University Hospitals names all three.

A few other situations change the plan. AAOMS writes that implants in children are usually put off until jaw growth is complete. If you take an osteoporosis medicine or a similar cancer medicine, or have had radiotherapy to the head and neck, tell the surgeon before any decision, because surgery in the jaw of these patients can lead to serious damage to the jawbone. A review in the International Journal of Implant Dentistry advises against implant surgery for cancer patients who receive these medicines in high doses. See Medicines you should tell your surgeon about for details.

The steps

UK hospitals usually describe the treatment as three or four stages:

• Assessment and imaging. Cambridge University Hospitals says an ordinary dental X-ray is always taken and sometimes a 3D CT scan is requested. Impressions of the teeth are also taken to plan the surgery. To learn about the images, see the guide to jaw imaging.
• Bone graft, only if needed.
• Placing the implant. The surgeon either leaves part of the implant above the gum the same day (one-stage), or covers it under the gum and uncovers it in a second small operation later (two-stage).
• Making and fitting the crown, bridge or denture once it has fused.

You must sign a consent form before starting. The type of anesthetic, whether local, sedation or general, depends on how complex the work is and should be explained to you before the operation.

If there is not enough bone

Cambridge University Hospitals states plainly that an implant needs enough bone at the site. When there is too little, a bone graft can help. According to this hospital, the material placed acts as a scaffold and the patient’s own bone grows into it, a process that may take four to twelve months.

There are several types of graft material:

• the patient’s own bone, from elsewhere in the jaw or from the chin, hip or skull,
• human bone from another person, from a bone bank,
• material made from cow bone that has been sterilized and prepared,
• synthetic material.

A membrane that the body absorbs is often placed over the graft to keep gum cells from growing into it, and Cambridge University Hospitals says the usual membrane comes from pigs. If you have a religious or personal objection to animal-derived materials, raise it with the surgeon before the operation.

A small graft is sometimes done at the same appointment as the implant. A larger graft is placed at least four months before the implant. Guy’s and St Thomas’ writes that they usually wait three to six months. If bone is taken from the hip, Cambridge University Hospitals notes that you may stay in hospital for a night and be left with a scar of about eight centimeters, and Guy’s and St Thomas’ writes that walking may be uncomfortable for two to four weeks.

Sinus lift. In the upper jaw, toward the back of the mouth, bone becomes thin after teeth are lost and the sinus drops lower. AAOMS writes that the surgeon decides by examination and imaging, lifts the lining of the sinus, and places graft material in the space. This is usually done with local anesthetic and, if needed, sedation, and the implant is placed either at the same time or after the graft has healed.

How long does it take?

Cambridge University Hospitals says fusing of the implant usually takes three to six months and sometimes longer, and the whole treatment “at least a year” from start to finish. Guy’s and St Thomas’ writes the whole journey as six to twelve months. This range depends on the state of the bone, the number of implants and whether a graft is needed. A figure that is right for you alone becomes clear after an examination.

Complications and risks

The sources list these honestly:

• The implant may not fuse with the bone and may need to be removed. Most implants fuse, but not all. The risk is higher in some people, including smokers. After a healing period it is sometimes possible to place an implant again.
• Sometimes the site turns out to be unsuitable for an unexpected reason and another option has to be considered.
• Swelling, bruising and discomfort after surgery are normal. Cambridge University Hospitals says discomfort usually lasts about a week. For grafting, the same hospital says swelling peaks around the second day.
• A little bleeding is normal, and heavy bleeding is “very rare”.
• Numbness or tingling of the lip, chin or tongue, mainly after implants in the lower jaw. Cambridge University Hospitals calls it very rare, but reports differ widely and one meta-analysis considers the risk with lower jaw implants to be considerable. A large share of patients recover on their own, and sometimes the problem is permanent. If the lip or chin is still numb after the anesthetic has worn off, or you have new pain, tell the surgeon the same day. A few case reports suggest that attention within the first 36 hours helped feeling return.
• Infection, if the after-surgery instructions are not followed. Infection is also possible with a graft, and sometimes the graft has to be removed.
• After a graft, not enough bone may form and the graft may need to be repeated. Cambridge University Hospitals says that with grafting, minor problems are common and a serious problem is less so. In the upper jaw, a connection between the sinus and the mouth is a rare complication that needs another operation.
• Years later, the crown, bridge or denture wears and may need repair or replacement.

Care after placement

Cambridge University Hospitals stresses that cleaning the implant carefully is “vital” for long-term success. Poor cleaning can lead to gum inflammation and then to loss of the bone around the implant, called peri-implantitis, which usually needs further treatment. This hospital suggests a check-up and scale and polish every three to six months. If you grind your teeth, tell the surgeon.

Before you decide

Ask the surgeon these questions: Do I have enough bone or will I need a graft? What type of anesthetic? How many months does the whole process take? What happens if the implant does not fuse? What are the non-surgical alternatives? How much will later maintenance cost? If a material of animal origin is suggested, is there an alternative? The surgeon should give clear answers.

When to act urgently

For implants, the sources do not give a separate list of urgent signs. The signs that are worrying after any mouth surgery are the ones the NHS lists for tooth extraction: bleeding that does not stop with pressure, severe or worsening pain and swelling, and pain with a bad taste in the mouth, fever or feeling unwell. In that case, contact your surgeon the same day. Numbness that remains after the anesthetic has worn off also needs a call the same day. Difficulty breathing or swallowing, and swelling or bruising of the floor of the mouth or neck that is spreading, is an emergency, especially after an implant in the front of the lower jaw, because it can narrow the airway. Call 115 and look at the list of urgent signs.

This page is for general information and does not replace an examination.