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Home » Dental Bone Grafting: Autograft, Allograft, Xenograft

Dental Bone Grafting: Autograft, Allograft, Xenograft

Dental bone grafts are a standard outpatient dental procedure. They add bone to places on your jaw where the bone has receded or suffered damage.

There are several different dental bone graft methods; the most common are autografts, allografts, and xenografts. We will talk about them in detail in this post.

Dentists, periodontists, and oral surgeons are qualified to perform the necessary surgeries. Although they can be stressful and have long recovery times, these surgeries are safe and successful.

Why Get a Dental Bone Graft?

Dentists recommend dental bone grafts to patients who have lost, or are going to lose, significant bone in their jaw. These patients often try to rebuild and strengthen their jawbones before installing dentures.

Sometimes, they have suffered bone loss from gum disease. Finally, the most common reason for a dental bone graft is to prepare for a dental implant.

5 Types of Dental Bone Grafts

1. Socket Preservation

This graft fills in the hole left by an extracted or missing tooth. It prevents the teeth on both sides of the socket from collapsing into it and the jawbone from receding.

2. Creation of a Healthy Base

Dentists use ridge augmentations to increase the width of the jawbone. A wider jawbone helps provide a solid foundation for implants.

3. Sinus Lift

Sometimes the sinuses move down and occupy the space left behind by a missing upper back tooth. A periodontist or oral surgeon can lift the sinuses back to their proper place. In addition, a dental bone graft will keep the sinuses from coming back down.

4. Supporting Loose Teeth

Gum disease causes infections that erode the jawbone and loosen teeth. Dentists will perform bone grafts to reduce tooth movement and provide support.

5. Nerve Removal

Sometimes dentists must remove nerves to make room for a dental implant. After removing the nerve, they fill the space with a bone graft.

What is an Autograft?

An autograft uses the patient’s tissue to repair damage to the mouth. This type of grafting has the highest success rate and quick recovery time.

A patient’s immune system will not reject tissue from their body, and there is a lower risk of infection. To graft gums, a dentist may take tissue from the roof of the mouth.

Or they may take a piece of bone from the chin or hip to fix a damaged socket.

Several factors limit the effectiveness of autografting. First, there will always be at least two surgical sites. Two surgeries mean increased discomfort and require more post-graft care.

In addition, because of the two surgical sites, dentists will only autograft one small area at a time. Finally, suppose the patient does not have fitting tissue to graft onto the injured area. In that case, an autograft will not be the best choice.

Autograft: Main Features

The pros of an autograft are:

  • No chance of rejecting the graft
  • No medical reason not to perform the graft
  • The fastest healing time of all grafting techniques
  • Minimal risk of infection

The cons of an autograft are:

  • The patient must have quality tissue to use for the graft
  • More than one surgical site
  • Increased pain
  • Limited grafting area at one time

What is an Allograft?

Allografts use tissue from another human being. For example, dentists will use living soft tissues from donors, but they source bone tissue from cadavers.

Since there is only one surgical site, the pain and discomfort are less than in an autograft. Therefore, dentists can graft a larger area at one time. Allografts are frequent choices for people who do not have enough quality tissue of their own available.

Although it is very uncommon, there is a slight risk that the patient’s immune system could reject the graft. Furthermore, the patient’s body will not take to another person’s tissue as quickly as it would their own. The mismatched tissues lead to longer recovery times for allografts.

Finally, some patients do not want to use cadaver bones for ethical reasons and may seek another alternative.

Allograft: Main Features

The pros of an allograft are:

  • Only one surgical site
  • Less painful healing process
  • It is possible to graft larger areas than autografts
  • A great alternative to autograft if the patient does not have quality tissue

The cons of an allograft are:

  • Significantly longer healing period
  • Slight risk the immune system will reject foreign tissue

What is a Xenograft?

A xenograft uses tissue from another species, usually cows and pigs. In addition, surgeons will often use horse bones for bone grafts since they have similar qualities to human bones.

Since animal tissue is widely available, there is no limit on how much grafting a dentist performs at one time. Also, a xenograft requires only one surgical site, causing less pain during recovery than an allograft.

Xenografting tissues are not living and do not match the patient’s tissues. Therefore, there is a slightly higher risk of rejection or failure to incorporate the graft. Even without rejection, there is a significantly longer recovery time for xenografts.

Like allografts, xenografts may be the best option for people who do not have sufficient quality tissue for an autograft. Patients who do not want to use human cadaver bones are often more open to using animal bones.

Xenograft: Main Features

The pros of a xenograft are:

  • Unlimited supply of usable animal tissue
  • Only one surgical site
  • It is possible to graft larger areas than autografts
  • A great alternative to autograft if the patient does not have quality tissue
  • A safe alternative to human cadaver bones

The cons of a xenograft are:

  • Higher risk of rejection than either an autograft or allograft
  • Longer recovery period than either an autograft or allograft

What is the Best Bone Graft for Dental Implants?

Every patient’s needs are unique, and a good dentist will consider all the medical factors when they suggest a graft. Patients need to consider three things when they choose a grafting method.

First, do they have enough high-quality tissue to support an autograft? Second, how much concern do they have about the success rate of each type of graft? Finally, would they prefer a quicker yet more painful recovery or a slower but less uncomfortable one?

Suppose a patient has sufficient tissue, prefers the highest success rate, and wants the quickest recovery. In that case, an autograft is the best choice. However, patients who cannot have an autograft or are concerned about discomfort might want an allograft or xenograft. Both are safe alternatives but come at the expense of longer recovery times and higher failure rates.

There is no best bone graft for dental implants. The decision comes down to the situation and preferences of the patient.

Do dental bone grafts smell?

Some patients complain of a foul smell or taste in their mouth after a dental bone graft. Usually, dental bone grafts do not smell or taste foul. However, dentists use antibiotics during the surgery that can leak out of the socket and have a very unpleasant taste.

Moreover, if the patient does not follow aftercare instructions, a smell may arise from decaying food debris and blood products. Finally, a bad smell could be a sign of infection.

Infections are uncommon but not too rare. If new pain and swelling accompany the smell, the patient should return to the dentist immediately. Patients should follow aftercare instructions to the letter to reduce infection risk.

Can your body reject a dental bone graft?

Your body cannot reject an autograft since it is your tissue. There is a low rejection rate for allografts and xenografts, but it can occur. Dental bone grafts fail more often because of human error.

For example, the dentist could forget to sterilize grafting material or tools. Dirty tools could lead to an infection, as could poor aftercare.

To minimize the chances of bone graft failure, patients should follow the aftercare instructions their dentists provide. Poor health increases infection rates. Patients can help by observing good hygiene before and after the bone graft procedure.

They should also see their dentist immediately if there is any sign of infection or graft failure.

Where do dental offices get the human bone material for grafting?

For autograft patients, dentists use the patient’s bone material. The most common bones used for autografting are the jaw, hip, and tibia. Dentists receive human bones for allografting from tissue banks. A tissue bank collects, processes, and stores human tissues for transplant. In the case of bone, the tissue banks collect bones from cadavers.

Some patients do not want to use bones from cadavers, and other options are available. For example, a xenograft uses animal bones to perform the grafting procedure. Synthetic grafts use proteins, collagen, and growth factors to accelerate a patient’s bone growth.

Can dental bone grafts cause cancer?

Scientists have conducted several studies on oral cancers in bone graft patients. However, the studies failed to link dental bone grafts to increased cancer rates.

Can a dental bone graft be removed?

Dental bone grafts can be removed if necessary, although it is uncommon.

However, removal may be required in cases of terrible infection when bacteria prevent the healing process.

In addition, a dentist may remove a bone graft if the patient’s body rejects it or if there is an allergic reaction to a synthetic graft. Finally, poor hygiene and refusal to follow aftercare instructions can limit recovery. Either factor can cause an infection or failure that requires removal.

Can a dental bone graft fall out?

Some dental bone grafts can fall out, though it is very uncommon. It is usual for small particles of synthetic bone grafts to come loose after the procedure. These particles sometimes pass through a membrane the dentist puts over the graft to protect it.

After several days, the membrane falls off naturally after the healing process starts. However, synthetic graft materials can fall out entirely if it comes off early. An exposed socket is very painful, and patients who lose their synthetic graft should return to the dentist immediately.

Is alloplastic bone grafting equally effective as autograft in dental implant fitting?

Alloplast bone grafts have a very high success rate and are proven safe. They provide effective and sturdy bases for implants and have grown in popularity in recent years.

However, autografts use the patient’s tissue, and there is no chance the patient’s immune system will respond negatively. Therefore, autografts have the highest success rate of all the grafting methods.

Alloplast bone grafts use natural and synthetic components to form the graft. Although it is infrequent, some patients may be allergic to one or more of the compounds in the graft.

Patients are more likely to be allergic to the titanium posts that the dentist anchors in the jawbone. Patients can test for a titanium allergy before the procedure to avoid a reaction.

How long after a bone graft can I delay the actual dental implant?

After about 8 to 12 months, the dental bone graft will dissolve. Your body will sense no pressure on the bone and stop reinforcing it. Instead, it will take minerals out of the bone for use elsewhere. Some treatments support bone grafts with materials that do not dissolve, but the costs increase.

Therefore, scheduling a bone graft when you are ready to install an implant within a reasonable time is best.

On average, the recovery time from a bone graft is between 6 and 9 months. The recovery time depends partially on the overall health of the patient.

The dental team should observe the recovery closely. Once the patient has incorporated the graft fully, they should schedule the implant procedure.

How can I speed up dental bone graft healing?

You cannot speed up dental bone graft healing directly. However, you can arrange conditions that allow your body to focus on healing and not get distracted. Here are some quick tips to avoid damaging the graft site and promote a faster recovery.

  • Right after the procedure, use ice to reduce inflammation.
  • Change your diet to prevent too much chewing.
  • Raise your head slightly to reduce pressure on the graft site when sleeping on your back.
  • Make sure to avoid physically demanding activities and brush your teeth very gently.
  • See that you follow all the aftercare instructions fully.
  • No smoking!
Can a dental bone graft get infected?

A dental bone graft can get infected just like any other surgical procedure. A dentist can introduce bacteria by not sterilizing tools properly. In addition, if the tissue bank provides grafting material that they did not process correctly, it could start an infection. Poor aftercare could also damage the graft site and introduce bacteria after the procedure. Finally, the patient’s overall health determines their ability to fight infection. So, patients with weaker immune systems are much more likely to have problems.

Who approves alloplastic bone graft products?

In the USA, it is the FDA. From 1996 to December 2020, the FDA approved as many as 87 alloplastic bone graft products. In Japan, the Japanese Ministry of Health, Labor, and Welfare. They have approved 10 products from 2004 to December 2020. In Korea, it is The Korean MOHW. They approved 36 products from 1980 to December 2020. Ref: Multidisciplinary Digital Publishing Institute (MDPI), 2021 Mar; 14(5): 1096.


Sources:

  • Cleveland Clinic. ‘Dental Bone Graft.’
  • The Johns Hopkins University (Johns Hopkins Medicine). ‘Bone Grafting.’
  • Journal of Oral & Maxillofacial Research. ‘Oral Cancer around Dental Implants Appearing in Patients with\without a History of Oral or Systemic Malignancy: a Systematic Review.’ 2017 Jul-Sep; 8(3): e1.

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