Bone plasty of the alveolar processes of the jaw

The alveolar ridge is the part of the jaw that holds the teeth. After a tooth is lost it gradually thins, and there may not be enough bone for an implant. Ridge augmentation restores bone height and width so the implant is secure and correctly positioned. At UKRMED Maxillofacial Surgery, augmentation is performed by implant surgeon Anna Kravchenko.

What the alveolar ridge is

The alveolar ridge is the crest of the jaw that contains the tooth sockets. In the upper jaw it is thinner and less dense, with the maxillary sinus above. In the lower jaw it is denser, but the mandibular nerve runs through it. This determines the choice of method.

Why bone is lacking

• After an extraction, unloaded bone resorbs, fastest in the first year.
• Periodontitis destroys bone around teeth — see periodontal treatment.
• Cysts, injuries and difficult extractions.
• A low maxillary sinus floor in the upper jaw.

Augmentation methods

• Guided bone regeneration (GBR) — graft material is covered with a membrane that stops gum tissue growing into the defect. Suited to small defects, often at the same time as the implant.
• Ridge splitting — a narrow ridge is widened by spreading its cortical plates.
• Block grafting — for large defects; the block is fixed with screws.
• Sinus lift — raising the sinus floor in the upper jaw: closed, through the implant site, or open, through a side window.

Large defects of the whole jaw after cysts or injuries are treated with jaw bone grafting.

When grafting can be avoided

A Cochrane review found that with moderate lack of bone height, short implants may be an alternative to vertical augmentation with fewer complications. So the surgeon first checks whether a shorter implant will do, and only then suggests grafting.

Simultaneous or staged

If the implant is stable in the existing bone, the defect is filled during placement. If bone is scarce, grafting comes first and the implant is placed 4–6 months later.

The procedure

1. CT and planning.
2. Anaesthesia — local or sedation.
3. Gum incision and site preparation.
4. Placing the material and fixing the membrane or block.
5. Watertight closure.

Aftercare

Swelling lasts three to five days. Do not chew on that side, do not smoke and rinse as prescribed. Do not wear a removable denture over the area until the doctor allows it. Complications after GBR are rare: in a retrospective study, wound opening occurred in 1.7% of cases and infection in 2%.

Contraindications

• Active periodontitis — the gums are treated first, otherwise infection threatens the graft.
• Acute or chronic sinusitis — before a sinus lift, an ENT consultation and treatment of the sinus are needed.
• Uncontrolled diabetes.
• Antiresorptive therapy for cancer or jaw radiotherapy — a risk of bone necrosis.
• Pregnancy — planned grafting is postponed.

Smoking is not a bar, but it noticeably worsens the result, so it is best stopped before surgery and during healing.

Risks and complications

The risk depends on the method. In a retrospective study of 223 patients, wound opening occurred in 1.7% after GBR, but in 25.9% after staged horizontal and 18.2% after staged vertical block grafting. After staged horizontal augmentation, 37% of patients needed additional grafting at implant placement. So large defects are sometimes rebuilt in two stages, and this is a normal part of treatment.

Other possible complications:

• Sinus membrane perforation during a sinus lift — a small tear is closed with a membrane during surgery; sometimes the stage is postponed.
• Infection — increasing pain, swelling or pus after day three or four.
• Partial resorption of the material — volume is added at implant placement.
• Temporary lip numbness when working on the lower jaw.

How to preserve bone after an extraction

• Do not delay replacing the tooth for long: without load, bone is lost fastest in the first year.
• Treat periodontitis early — it destroys bone even before the tooth is lost.
• A denture that presses on the gum speeds up atrophy, so it is adjusted or replaced.

Prices at UKRMED

Sources

1. Esposito M., Grusovin M. G., Felice P. et al. Interventions for replacing missing teeth: horizontal and vertical bone augmentation techniques for dental implant treatment. Cochrane Database Syst Rev, 2009. https://doi.org/10.1002/14651858.CD003607.pub4
2. Esposito M., Grusovin M. G., Rees J. et al. Effectiveness of sinus lift procedures for dental implant rehabilitation: a Cochrane systematic review. Eur J Oral Implantol, 2010. https://pubmed.ncbi.nlm.nih.gov/20467595/
3. Jensen A. T., Jensen S. S., Worsaae N. Complications related to bone augmentation procedures of localized defects in the alveolar ridge. A retrospective clinical study. Oral Maxillofac Surg, 2016. https://doi.org/10.1007/s10006-016-0551-8