the Peri-implant Tissue Changes Around Implants in the Esthetic Zone Using Demineralized Dentin Graft vs Xenograft

Dentin grafts are categorized into mineralized dentin, partially demineralized dentin matrix (PDDM), and demineralized dentin matrix (DDM). Mineralized dentin can be obtained from a dentin grinder and was found to be less effective in bone formation, while DDM is biocompatible and osteoinductive. Thus, PDDM which requires a partial demineralization process is an interesting point of research to be studied for its ability for contour augmentation in the esthetic zone.

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.

Eligibility Criteria:
Inclusion Criteria:

1. Adults aged ≥20 years.
2. Mild smokers \<1 pack of cigarettes a day
3. Capable of understanding or signing the informed consent form before surgery and capable of meeting oral cleaning requirements for implant placement
4. Healthy individuals with no systemic disease
5. Patients who have a single non-restorable tooth in the esthetic zone
6. Thin buccal plate of bone \< 1mm prior to tooth extraction indicated for early implant placement with the ability to place a bone level implant able to achieve 35 N cm stability after placement.

Exclusion Criteria:

* 1) A habit of bruxism or inability to achieve requirements for oral cleaning 2) The presence of acute or chronic infection at the site of tooth extraction with lack of treatment for periodontal disease, or x-rays showing loss of alveolar bone on the adjacent teeth 3) Subjects who have a systemic disease which affects bone healing as diabetes and Paget's disease 4) Use of steroid therapy or under current treatment by chemotherapy or radiation therapy to the head and neck (as Bisphosphonates) 5) Pregnant or breastfeeding women