Types of bone grafting: your own bone, donor bone, animal-derived or synthetic material?

What types of bone grafting are there, by origin of the material?

By the origin of the material, four types of bone graft are distinguished: your own bone (autogenous), bone from human donors (allograft), processed animal bone (xenograft) and synthetic material (alloplast). Cleveland Clinic explains that human and animal material comes from licensed donor banks, and that bovine (cow) and porcine (pig) bone are the common animal sources.

This guide compares only the materials and techniques. What a bone graft is and when it is needed is covered in our guide bone graft before implants; how healing goes and what applies to the flight home in healing after a bone graft.

The materials also differ in how they contribute to new bone. According to the review by Zhao and colleagues in Molecules (2021), your own bone is the only material with all four biological properties needed for bone formation, because it contains living cells. Animal-derived materials, according to Fukuba and colleagues in Materials (2021), act only as a scaffold for new bone.

When is your own bone used?

Your own bone is described by Zhao and colleagues as the gold standard of grafting materials. The NHS trusts describe three levels:

• Small defects can be filled at implant placement with a small amount of bone taken near the implant site, often mixed with a bone substitute and covered with a membrane; Cambridge University Hospitals says this is usually done without extra healing time.
• Larger defects are closed with bone from your own jaw. According to Guy’s and St Thomas’, minor bone grafting takes bone from the back of the jaw or the chin under local anaesthetic and takes about 1 to 1.5 hours.
• Very large defects may need bone from the hip. Guy’s and St Thomas’ says this is done under general anaesthetic with a short hospital stay, and that the hip can be uncomfortable for 2 to 4 weeks afterwards.

The drawback is the second surgical site. Zhao and colleagues list pain, bleeding, infection and scarring at the donor site, and the limited amount available.

Where does donor bone come from, and how is it processed?

Donor bone (allograft) comes from people who have donated their tissue after death and is processed in tissue banks. The patient information of the American Academy of Orthopaedic Surgeons and the American Association of Tissue Banks describes the safety steps:

1. The donor’s medical and social history is reviewed; people at higher risk are excluded.
2. The tissue stays in quarantine until tests for HIV, hepatitis B, hepatitis C and syphilis are complete.
3. The bone is cleaned of debris and organic matter, soaked in solutions against bacteria and viruses, processed under sterile conditions and, where needed, sterilised with low-dose radiation.
4. The final product is tested microbiologically and released only after review by the tissue bank’s medical director.

These steps have reduced the risk of disease transmission significantly, although a theoretical residual risk remains. Zhao and colleagues add that freeze-drying can reduce the material’s ability to stimulate bone formation.

How is animal-derived material made?

The most widely used animal-derived material comes from cattle. According to Zhao and colleagues, it is heated and chemically treated to remove all organic components, leaving a porous mineral scaffold that closely resembles human bone and has low immunogenicity. In a six-month sinus lift comparison cited in the review, bovine material produced 39 percent new bone compared with 40 percent for the patient’s own bone. Fukuba and colleagues note that the literature discusses a transmission risk for infections such as BSE; the review gives no figure for it.

The membranes that cover the material are also often of animal origin. According to Cambridge University Hospitals, the most commonly used membrane is porcine and dissolves over time. Anyone who does not want animal-derived material should therefore ask about both the graft and the membrane.

When is synthetic material an option?

Synthetic materials are made in the laboratory; the best known are hydroxyapatite, beta-tricalcium phosphate and bioactive glass. According to Fukuba and colleagues, their advantages are consistent quality, no infection risk from donor tissue and no ethical or religious objections. Their drawback is a lower capacity for bone regeneration, which is why they are often combined with membranes or other materials. Zhao and colleagues also point to the low mechanical strength of hydroxyapatite.

How do the types compare at a glance?

No material is superior in every situation: the 2021 Cochrane review on preserving the socket after extraction found no clinically significant difference between animal-derived, human and synthetic material, with very low certainty of evidence.

Which techniques are there besides the material?

The technique depends on the size and shape of the defect:

• Filling with bone chips or granules during implant placement for small defects (Cambridge University Hospitals).
• Guided bone regeneration: the material is covered with a membrane so that bone, not gum, fills the space (Cambridge University Hospitals, Guy’s and St Thomas’).
• Block graft: a piece of your own bone is fixed with small pins or screws when more height or width is needed (Guy’s and St Thomas’).
• Ridge augmentation: the gum is lifted and the missing part of the ridge is filled; the American Academy of Periodontology says the bone then usually needs about 4 to 12 months before implants are placed.
• Sinus lift: in the back of the upper jaw the sinus floor is raised and the space filled; see our guide sinus lift.
• Socket preservation: the socket is filled straight after extraction to slow bone loss; see our guide socket preservation after tooth extraction.

What if you do not want animal-derived material?

If you decline animal-derived material for religious, dietary or other personal reasons, say so at the examination; other options are then considered. According to Guy’s and St Thomas’, the team explains which material will be used and where it comes from, and you can talk to them about the choice of material.

Such concerns are not rare. In a survey of 330 patients at five university clinics in Portugal, France, Italy, Spain and Chile (Bucchi and colleagues, 2019), the following were declined:

• donor bone: 40.4 percent
• own bone from a site outside the mouth: 34 percent
• animal-derived material: 32.7 percent
• own bone from inside the mouth: 24.5 percent
• synthetic material: 6.3 percent

Reasons given against animal-derived material were fear of disease transmission, objections to the use of animals and religious beliefs. Fernández and colleagues in BMC Medical Ethics (2015) stress that clinicians should explain technique and origin, inform without steering and obtain consent for each product. Questions you can ask:

• Where do the graft material and the membrane come from?
• Is an option without animal-derived material possible in my case?
• Does that option mean a second surgical site or a longer wait, and therefore possibly an extra stay?

How is the material decided at Rönesans?

At our clinic in Serdivan, the need for and extent of a bone graft are assessed at the examination and on a cone-beam CT (CBCT) scan. We carry out bone grafting and sinus lifts at the clinic, under general anaesthesia if needed, and work to a written sterilisation and hygiene protocol.

Our dentists discuss your case together, and one dentist accompanies you throughout. If you have a preference or concern about the material, raise it at the examination; the options that suit you are considered there. Before treatment starts you receive a written treatment and cost plan with the procedures for each tooth, and when you leave, a summary of your treatment and copies of your X-rays for your dentist at home. We answer questions beforehand in English or German on WhatsApp at +90 532 363 49 54; the treatment is described on our dental implants page.