Autograft dan allograft punya persamaan, yaitu sama-sama diambil dari manusia. Perbedaan di antara keduanya adalah autograf diambil dari tubuh pasien itu sendiri, sementara allograft diambil dari orang lain lalu dipasangkan pada pasien. Orang lain yang dimaksud bisa orang yang masih hidup atau orang yang sudah meninggal (kadaver). 

Alograft ada 3 jenis, yaitu:

1. Tulang segar atau segar beku
2. FDBA
3. DFDBA

The use of allografts for bone repair often requires sterilization and deactivation of proteins normally found in healthy bone. Contained in the extracellular matrix of bone tissue are the full cocktail of bone growth factors, proteins, and other bioactive materials necessary for osteoinduction and successful bone healing; the desired factors and proteins are removed from the mineralized tissue by using a demineralizing agent such as hydrochloric acid. The mineral content of the bone is degraded, and the osteoinductive agents remain in a demineralized bone matrix (DBM).

The allograft can be derived from cadavers or living donors (tissue harvested from hip replacement surgery). It has natural bone composition and structure. This tissue is osteoinductive as well as osteoconductive but lacks osteogenic properties because of the absence of viable cells.12

A controversy exists as to the association of allogenic material and the risk of transmission of infections such as HIV, hepatitis B and C, prions, malignancies, systemic disorders or toxins.
Aggressive allograft processing gives it a less intense immunologic response, but reduces the osteoinductive properties. Frozen allografts induce stronger immune responses than freeze dried allografts, hence they are no longer used.12

The donor tissue is cleaned and then undergoes ultrasonics to remove blood and tissue components and to eliminate fat from the cancellous bone structure; this improves penetration of the surrounding tissues into the graft material.

Then chemical treatment denatures non-collagenic proteins, inactivates viruses and destroys bacteria. Further oxidative treatment denatures persisting soluble proteins and eliminates potential antigenicity. Dehydration preserves the structural integrity of the material. Final sterilization by gamma radiation ensures sterility.

Allografts are available in different shapes from demineralized bone matrix granules to complete bone segments. Granules can be used in socket preservation for future implant placement, ridge reconstruction for prosthetic therapy, filling osseous defects and maxillary sinus floor elevation.

Allograft bone segment blocks are a predictable and effective alternative to traditional autogenous block grafting and ridge augmentation.13 When very large areas need to be grafted, a shell of autogenous bone is often used as a biologic container; this creates the necessary space for the incorporation of the particulated bone graft material. The bone cells in the autogenous bone die within a few days and then the boneplate functions as a stable, avital, slowly resorbable membrane.14 Allogenic bone blocks can also be used for this shell technique as a substitute for autogenous bone. This avoids the time consuming harvesting and splitting of the autogenous bone blocks.

The space between the local bone and surrounding shell can be filled with a variety of different particulated bone grafting materials (autogenous, allogenic, xenogenic or alloplastic).
Histologic studies have shown no difference in the final stage of incorporation between allografts and autografts.15

Referensi

Prasanna Kumar, Belliappa Vinitha, and Ghousia Fathima. Bone grafts in dentistry. J Pharm Bioallied Sci. 2013 Jun; 5(Suppl 1): S125–S127. doi:  10.4103/0975-7406.113312 PMCID: PMC3722694

Dr. Fay Goldstep, DDS. FACD, FADFE. Bone Grafts For Implant Dentistry: The Basics. https://www.oralhealthgroup.com/features/1003918360/ ; akses 15 November 2016