Comparative Study Between Demineralized and Mineralized Allogeneic Dentin Grafts for Alveolar Ridge Preservation: A Randomized Controlled Clinical Trial

The alveolar ridge experiences rapid remodeling after tooth extraction, often resulting in significant bone loss if no graft is placed. Clinical observations indicate that an extraction site may lose roughly half of its original width within six to twelve months, severely reducing the bone available for future implants or prosthetic support. This resorption occurs because removal of the tooth and its periodontal ligament eliminates the normal mechanical stimulation that maintains the surrounding bone. Alveolar ridge preservation techniques aim to counteract this remodeling by placing a graft in the extraction socket to maintain bone dimensions and support healing. Preserving the ridge anatomy in this way is critical for subsequent restorative procedures such as dental implant placement or denture support.

In practice, a variety of graft materials have been used to support alveolar ridge preservation. Autogenous bone grafts (harvested from the patient's own body, for example from the iliac crest or intraoral sites) have osteogenic and osteoinductive properties, but require a second surgical site and provide limited graft volume. Alternative materials include allogeneic bone (processed human bone from donors) and xenogeneic bone (such as bovine-derived hydroxyapatite), which are readily available but may integrate more slowly and raise concerns about immune reaction or disease transmission. Synthetic or alloplastic graft materials (calcium phosphates, bioactive glasses, polymers, etc.) are also used, although they typically act only as osteoconductive scaffolds and may not match the biologic activity of natural tissues. Given these limitations, there is ongoing interest in novel graft sources that can offer both safety and biological efficacy.

One promising graft material is dentin, the calcified tissue comprising the bulk of a tooth beneath the enamel. Chemically, dentin closely resembles bone: it is roughly 70% mineral (hydroxyapatite) and 20% organic matrix (predominantly type I collagen) by weight, along with non-collagenous proteins and embedded growth factors. Because dentin is acellular and avascular, it is inherently well-tolerated when used as a graft. Importantly, its organic matrix contains signaling molecules such as bone morphogenetic proteins (BMPs) and other growth factors that are naturally osteoinductive. In clinical practice, an extracted tooth can be cleaned and converted into graft material by grinding it into particulate form or shaping it into a block. Clinical studies have shown that autogenous tooth-derived grafts (using a patient's own extracted tooth) can effectively support socket preservation and guided bone regeneration. However, this approach is limited by the availability of teeth in each patient and by variability in processing methods, which can affect the consistency of the graft material.

Dentin grafts can be prepared in different forms. Demineralized dentin matrix (DDM) is produced by treating the dentin with acid to remove most of the mineral phase, leaving a collagen-rich matrix that retains the dentin's organic proteins and growth factors. DDM is highly osteoinductive: by removing the crystalline mineral, the embedded signaling molecules (such as BMPs and transforming growth factors) are exposed, creating a bioactive scaffold that strongly stimulates new bone formation. In contrast, a fully mineralized dentin graft (for example, ground whole tooth particles that are not demineralized) retains the hydroxyapatite content, which contributes rigidity and initial volume stability. These mineralized grafts act primarily as an osteoconductive scaffold and release bioactive molecules more slowly as they resorb. In practical terms, demineralized dentin grafts are believed to accelerate early bone ingrowth, whereas mineralized dentin grafts may better preserve the initial socket architecture and support gradual long-term remodeling.

Allogeneic dentin grafts are obtained from healthy human donor teeth that have been processed and sterilized under controlled conditions. The use of donated extracted teeth provides a scalable graft source and repurposes material that would otherwise be discarded. Processing typically involves cleaning away any attached soft tissues, removing enamel and cementum, and grinding the remaining tooth structure into particles. Sterilization (for example by freeze-drying, gamma irradiation, or other validated methods) ensures the graft is safe for implantation. For demineralized allografts, an additional acid step is applied to decalcify the particles. These preparation steps remove or inactivate cells and pathogens, minimizing immunogenic components. Preclinical studies suggest that properly processed allogeneic dentin matrix can induce bone formation with minimal immune reaction or rejection. However, standardized clinical evidence on allogeneic dentin grafts remains limited.