Effects of enamel matrix derivative on bioactive glass in rat calvarium defects

Enamel Matrix Derivatives for Periodontal Regeneration: Recent Developments and Future Perspectives

In the era of the growing population, the demand for dental care is increasing at a fast pace for both older and younger people. One of the dental diseases that has attracted significant research is periodontitis. Periodontal therapy aims to regenerate tissues that are injured by periodontal disease. During recent decades, various pioneering strategies and products have been introduced for restoring or regeneration of periodontal deficiencies. One of these involves the regeneration of tissues under guidance using enamel matrix derivatives (EMDs) or combinations of these. EMDs are mainly comprised of amelogenins, which is one of the most common biological agents used in periodontics. Multiple studies have been reported regarding the role of EMD in periodontal tissue regeneration; however, the extensive mechanism remains elusive. The EMDs could promote periodontal regeneration mainly through inducing periodontal attachment during tooth formation. EMD mimics biological processes that occur during periodontal tissue growth. During root development, enamel matrix proteins are formed on the root surface by Hertwig's epithelial root sheath cells, initiating the process of cementogenesis. This article reviews the challenges and recent advances in preclinical and clinical applications of EMDs in periodontal regeneration. Moreover, we discuss the current evidence on the mechanisms of action of EMDs in the regeneration of periodontal tissues.

Amelogenin-Derived Peptides in Bone Regeneration: A Systematic Review

Amelogenins are enamel matrix proteins currently used to treat bone defects in periodontal surgery. Recent studies have highlighted the relevance of amelogenin-derived peptides, named LRAP, TRAP, SP, and C11, in bone tissue engineering. Interestingly, these peptides seem to maintain or even improve the biological activity of the full-length protein, which has received attention in the field of bone regeneration. In this article, the authors combined a systematic and a narrative review. The former is focused on the existing scientific evidence on LRAP, TRAP, SP, and C11's ability to induce the production of mineralized extracellular matrix, while the latter is concentrated on the structure and function of amelogenin and amelogenin-derived peptides. Overall, the collected data suggest that LRAP and SP are able to induce stromal stem cell differentiation towards osteoblastic phenotypes; specifically, SP seems to be more reliable in bone regenerative approaches due to its osteoinduction and the absence of immunogenicity. However, even if some evidence is convincing, the limited number of studies and the scarcity of in vivo studies force us to wait for further investigations before drawing a solid final statement on the real potential of amelogenin-derived peptides in bone tissue engineering.

Healing of two-wall intra-bony defects treated with a novel EMD-liquid-A pre-clinical study in monkeys

AIM

To investigate the effect of a novel enamel matrix derivative formulation (EMD-liquid or Osteogain) combined with an absorbable collagen sponge (ACS) on periodontal wound healing in intra-bony defects in monkeys.

MATERIALS AND METHODS

Chronic two-wall intra-bony defects were created at the distal aspect of eight teeth in three monkeys (Macaca fascicularis). The 24 defects were randomly assigned to one of the following treatments: (i) open flap debridement (OFD) + ACS alone, (ii) OFD + Emdogain + ACS (Emdogain/ACS), (iii) OFD + Osteogain + ACS (Osteogain/ACS) or (iv) OFD alone. At 4 months, the animals were euthanized for histologic evaluation.

RESULTS

Osteogain/ACS resulted in more consistent formation of cementum, periodontal ligament and bone with limited epithelial proliferation compared to OFD alone, Emdogain/ACS and OFD + ACS. Among the four treatment groups, the Osteogain/ACS group demonstrated the highest amount of regenerated tissues. However, complete periodontal regeneration was not observed in any of the defects in the four groups.

CONCLUSIONS

The present findings indicate that in two-wall intra-bony defects, reconstructive surgery with Osteogain/ACS appears to be a promising novel approach for facilitating periodontal wound healing/regeneration, thus warranting further clinical testing.

Guided bone regeneration produced by new mineralized and reticulated collagen membranes in critical-sized rat calvarial defects

The aim of this study was to evaluate the bone regenerative effect of glutaraldehyde (GA) cross-linking on mineralized polyanionic collagen membranes in critical-sized defects on rat calvarias. Bone calvarial defects were induced in Wistar rats, which were then divided into five groups: a sham group; a control group, which received a commercial membrane; and GA, 25GA, and 75GA groups, which received one of three different polyanionic collagen membranes mineralized by 0, 25, or 75 hydroxyapatite cycles and then cross-linked by GA. Bone formation was evaluated based on digital radiography and computerized tomography. Histological analyses were performed 4 and 12 weeks after the surgical procedure to observe bone formation, membrane resorption, and fibrous tissue surrounding the membranes. Measurement of myeloperoxidase activity, tumor necrosis factor alpha, and interleukin 1beta production was performed 24 h after surgery. The percentage of new bone formation in the GA, 25GA, and 75GA groups was higher compared with the control and sham groups. In the GA and 25 GA groups, the membranes were still in place and were contained in a thick fibrous capsule after 12 weeks. No significant difference was found among the groups regarding myeloperoxidase activity and interleukin 1beta levels, although the GA, 25GA, and 75GA groups presented decreased levels of tumor necrosis factor alpha compared with the control group. These new GA cross-linked membranes accelerated bone healing of the calvarium defects and did not induce inflammation. In addition, unlike the control membrane, the experimental membranes were not absorbed during the analyzed period, so they may offer advantages in large bone defects where prolonged membrane barrier functions are desirable.

Bone tissue engineering scaffolding: computer-aided scaffolding techniques

Tissue engineering is essentially a technique for imitating nature. Natural tissues consist of three components: cells, signalling systems (e.g. growth factors) and extracellular matrix (ECM). The ECM forms a scaffold for its cells. Hence, the engineered tissue construct is an artificial scaffold populated with living cells and signalling molecules. A huge effort has been invested in bone tissue engineering, in which a highly porous scaffold plays a critical role in guiding bone and vascular tissue growth and regeneration in three dimensions. In the last two decades, numerous scaffolding techniques have been developed to fabricate highly interconnective, porous scaffolds for bone tissue engineering applications. This review provides an update on the progress of foaming technology of biomaterials, with a special attention being focused on computer-aided manufacturing (Andrade et al. 2002) techniques. This article starts with a brief introduction of tissue engineering (Bone tissue engineering and scaffolds) and scaffolding materials (Biomaterials used in bone tissue engineering). After a brief reviews on conventional scaffolding techniques (Conventional scaffolding techniques), a number of CAM techniques are reviewed in great detail. For each technique, the structure and mechanical integrity of fabricated scaffolds are discussed in detail. Finally, the advantaged and disadvantage of these techniques are compared (Comparison of scaffolding techniques) and summarised (Summary).

Effects of enamel matrix proteins in combination with a bovine-derived natural bone mineral for the repair of bone defects

OBJECTIVES

Previously, the use of enamel matrix derivative (EMD) in combination with a natural bone mineral (NBM) was able to stimulate periodontal ligament cell and osteoblast proliferation and differentiation. Despite widespread use of EMD for periodontal applications, the effects of EMD on bone regeneration are not well understood. The aim of the present study was to test the ability of EMD on bone regeneration in a rat femur defect model in combination with NBM.

MATERIALS AND METHODS

Twenty-seven rats were treated with either NBM or NBM + EMD and assigned to histological analysis at 2, 4, and 8 weeks. Defect morphology and mineralized bone were assessed by μCT. For descriptive histology, hematoxylin and eosin staining and Safranin O staining were performed.

RESULTS

Significantly more newly formed trabecular bone was observed at 4 weeks around the NBM particles precoated with EMD when compared with NBM particles alone. The drilled control group, in contrast, achieved minimal bone regeneration at all three time points (P < 0.05).

CONCLUSIONS

The present results may suggest that EMD has the ability to enhance the speed of new bone formation when combined with NBM particles in rat osseous defects.

CLINICAL RELEVANCE

These findings may provide additional clinical support for the combination of EMD with bone graft for the repair of osseous and periodontal intrabony defects.

The effect of an enamel matrix derivative (Emdogain) combined with bone ceramic on bone formation in mandibular defects: a histomorphometric and immunohistochemical study in the canine

Background. The purpose of this study was to evaluate the combination of an enamel matrix derivative (EMD) and an osteoconductive bone ceramic (BC) in improving bone regeneration. Materials and Methods. Four cylindrical cavities (6 × 6 mm) were prepared bilaterally in the mandible in three dogs. The defects were randomly assigned to four different treatments—filled with EMD/BC and covered with a nonresorbable membrane, filled with EMD/BC without membrane, membrane coverage only, or control (left untreated)—and healed for 2, 4, or 6 weeks. Harvested specimens were prepared for histologic, histomorphometric, and immunohistochemical analyses. Results. Sites treated with EMD/BC with or without membrane showed more total bone formation and lamellar bone formation than membrane-only and control defects. There were no statistically significant differences in total bone formation between EMD/BC with or without membrane. Conclusion. EMD with BC might improve bone formation in osseous defects more than membrane coverage alone; the use of a membrane had no significant additive effect on total bone formation.

Prevention of hemorrhagic complications after dental extractions into open heart surgery patients under anticoagulant therapy: the use of leukocyte- and platelet-rich fibrin

Leukocyte- and platelet-rich fibrin (L-PRF) is a biomaterial commonly used in periodontology and implant dentistry to improve healing and tissue regeneration, particularly as filling material in alveolar sockets to regenerate bone for optimal dental implant placement. The objective of this work was to evaluate the use of L-PRF as a safe filling and hemostatic material after dental extractions (or avulsions) for the prevention of hemorrhagic complications in heart surgery patients without modification of the anticoagulant oral therapy. Fifty heart surgery patients under oral anticoagulant therapy who needed dental extractions were selected for the study. Patients were treated with L-PRF clots placed into 168 postextraction sockets without modification of anticoagulant therapy (mean international normalized ratio  =  3.16 ± 0.39). Only 2 patients reported hemorrhagic complications (4%), all of which resolved a few hours after the surgery by compression and hemostatic topical agents. Ten patients (20%) showed mild bleeding, which spontaneously resolved or was resolved by minimal compression less than 2 hours after surgery. No case of delayed bleeding was reported. The remaining 38 patients (76%) showed an adequate hemostasis after the dental extractions. In all cases, no alveolitis or painful events were reported, soft tissue healing was quick, and wound closure was always complete at the time of suture removal one week after surgery. The proposed protocol is a reliable therapeutic option to avoid significant bleeding after dental extractions without the suspension of the continuous oral anticoagulant therapy in heart surgery patients. Other applications of the hemostatic and healing properties of L-PRF should be investigated in oral implantology.