Dentin tooth can be classified into three groups according to the degree of demineralization undemineralized dentin (UDD), partially demineralized dentin matrix (PDDM) (70% decalcified) and demineralized dentin matrix (DDM). Some authors have shown that UDD is less effective in bone formation whereas other studies have shown that DDM is biocompatible and also osteoinductive, similar to demineralized bone matrix. Valdes concluded in their in vitro study that PDDM with large particle (1000µm) has much more bone regenerative activity in comparison to UDD. This could be explained because demineralization enhances the osteoinduction capacity of tooth material by exposing organic substances within the teeth to the surface, increasing porosity and surface area, and decreasing crystallinity . Nevertheless, some authors have reported successful bone regeneration applying UDD. UDD can be easily obtained from a dentin grinder, after disinfection and cleaning process. PDDM can be only obtained from the tooth after a partial demineralization process of the dentin. In any case, teeth must be free of restorations and caries, and endodontic teeth must be excluded.

However, several animal studies showed that demineralized dentin matrix (DDM) is not only biocompatible but also osteoinductive, similar to demineralized bone matrix. Dentin also contains some growth factors common to a bone, namely, insulin-like growth factor-II, bone morphogenetic protein (BMP), and transforming growth factor-beta. While APDDM has limited osteogenic potential but could be a suitable scaffold for osteoblastic cells. Furthermore, APDDM resists the rapid resorption of graft material. Complete resorption of DDM and remodeling into host bone has been reported to require \>6 months. APDDM appears to resorb more slowly because it contains approximately 70% of original dentin matrix mineral. This partial demineralization of dentin matrix may affect the long-term stability of regenerated bone. While DDM may constitute an excellent BMP-2 carrier, APDDM could be a suitable substrate for cell attachment and differentiation. Notably, partial demineralization of dentin exposes collagen fiber, which enables cells to easily attach to substrate; the growth factors released from APDDM might concurrently stimulate osteoblastic differentiation. Furthermore, residual mineral in APDDM could enhance osteoclastic activity, thereby promoting bone remodeling. These factors may have contributed to the rapid and sufficient bone formation for dental implant placement with primary fixation.

To date, no other trial has been published that has used autogenous dentin as a graft material to resolve the periodontal defects on the distal aspect of the second molar derived from LTM extraction with post-operative clinical and CBCT monitoring. This present study was conducted to compare Early implant placement with Simultaneous Contour Augmentation using Partially demineralized dentin graft covered with a collagen membrane versus Early implant placement with Simultaneous Contour Augmentation using bovine xenograft covered with a collagen membrane in terms of esthetic and bone level changes during the first year of functional loading.