# Allogeneicic Demineralized Dentin Matrix Graft for Guided Bone Regeneration in Dental Implants
## 1 Introduction  
Autogenous demineralized dentin matrix (Auto-DDM) has been widely used in implant dentistry in Korea since 2008 for socket preservation, alveolar ridge augmentation, sinus augmentation, and guided bone regeneration (GBR) associated with dental implants [1, 2]. GBR is dental surgical procedure that is predominantly applied to support new hard tissue growth on an alveolar ridge to allow stable placement of dental implants [3]. The rationale for the use of demineralized dentin matrix (DDM) on GBR is based on the structural and biochemical similarities between dentin and bone. DDM is defined as an acid-insoluble, highly cross-linked type I collagen (95%) with collagenous and matrix-binding proteins such as transforming growth factors (TGFs), insulin growth factor (IGF), fibroblast growthfactor (FGF), and bone morphogenetic protein (BMP) [4; 5]. Although fabrication process of DDM removed dental stem cells [6; 7], DDM is an \"inductive substrate\" due to transformation of the fibroblasts of the mesenchymals into cartilage or bone in the extra-skeletal site. Transforming factors in dentin induce the growth of undifferentiated mesenchymal cells, and these cells are converted into chondroblasts and osteoblasts to form new bones [8]. Consequently, Auto-DDM has shown promising clinical and histological results as an alternative to autogenous bone grafts without the limitations of donor availability, risk of infection at the donor site, and marked resorption rates of \(\geq\)50% [9]. [PERSON] et al. [1] reported six cases of GBR using Auto-DDM (AutoBT, Korea Tooth Bank, Seoul, Korea) with simultaneous implant placement. At average 4.5-month after GBR, histologic evaluation of each case highlighted the excellence of AutoBT for bone regeneration with osteoconduction and osteoinduction. A report of a previous case of long-term follow-up (5 years) reported 1 mm of buccal marginal bone resorption around the implant with the formation of cortico-cancellous bone, approximately six years after socket preservation in 2016 [9]. So far, Auto-DDM accelerates bone regeneration in numerous human clinical studies [10; 11]. Recently, a fragmented, partially demineralized tooth matrix was used for maxillary sinus augmentation. Histological analysis revealed neither inflammatory nor infective reactions against the tooth graft. Granules appeared surrounded by newly formed bone and partially resorbed, indicating ongoing remodeling [12]. Another clinical study using autogenous mineralized dentin matrix for socket preservation, to compare the alveolar contractions as well as to analyze the densitometric differences between both post-extraction sockets presented that the dimensional contraction of the post-extraction socket in the study group was lower than that in the control group at 16 weeks after surgery, both vertically and horizontally [13]. The Auto-DDM has some limitations. Primarily, it is time-consuming because of the inevitable surgical extraction and the external manufacturing process required to prepare the material. Following, the amount of Auto-DDM obtained is unpredictable as it depends on several clinical conditions, such as dental caries, restorations, and prostheses in the harvested teeth. Therefore, the application of allogeneic DDM (Allo-DDM) has been proposed to overcome the shortcomings of Auto-DDM. In 1967, [PERSON] and [PERSON] [14] proved that allogeneic, demineralized, and lyophilized dentin induced new bone formation in an in vivo study. Subsequently, Allo-DDM exhibited excellent bone formation capacity without eliciting an immune response or antigenic effect in experimental studies of the early 1970s and 80s [15; 16]. Further, clinical trials revealed that allogeneic freeze-dried dentin matrix demonstrated a high osteoinductive potential in periodontal osseous defects [17]. Allo-DDM in the cystic lesions of the jaw in 33 patients presented excellent bone healing without immunologic complications [18].