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Bone regeneration and soft tissue augmentation

Bone regeneration and soft tissue augmentation with PLLA and PGA scaffolds in tissue engineering for osteointegeration and augmentation of soft tissue

Shohreh Ghasemi ,DDS /MS in restorative dentistry ,AAID Member ,ACOMS  member  in 2015

,advanced program in aesthetic dentistry in NYU,USA

Department of aesthetic dentistry in newyork university (USA)

Member of American association of implant dentistry .

Assistant researcher in craniofacial department of Novauniversity (dental college)

Professor of goohar pajooh skill and labour college

Member of association of surgery in Tehran ,Iran.

International trainer of ZO skinhealth institute .

Dr Marie Odilied Christen .MD the associate education affairs of sinclair pharma college

Headquarter of educational affairs and research faculty of Sinclair college

The appreciation of volume restoration in the aging human face is something that

has arrived in to medicine over the last century ,It has been the bonding of the technology and commercial application for treatment of scar and two dimensional view of the skin’s lines and creases and evolving the challenge of facial volumes, and then the three dimensional view for concept of changing the volume ,what began was using the collagen bovine and silicone to treat the facial volumes and scars .

The first case of soft tissue augmentation was performed on a patient who had tuberculosis in nineteen century .the destruction of soft tissue on his face was predominant, the surgeon was used the patients own fat as a filler of the choice , fat was transferred from the body to the face of the patient ,while the patient did not survive but today the fat is the considered as popular filler for plastic surgery and aesthetic medicine .

But the fact is that the fat was such unpredictable filler in the process of soft tissue augmentation, it is compromised of viable biologically active cellular components, it was important to find an alternative synthetic form that was readily available and stable more

 Bone filler materials are needed to treat patients with many disorders, including bone defects and nonunion resulting from bone tumor excision or trauma, and in procedures such as spinal fusion, the most useful bone filler is the patients own bone, but sometimes the patients bone is too limited or cant be reached with out highly invasive surgery. Consequently artificial bone filler such as PLLA or calcium hydroxyapatite are often used as fillers for bone defects. This material can be bond to the bone tissue in living organism their material can have bond conduction and allow bone tissue to penetrate, and indeed can achieve deeper penetration and bone remodeling

The PLLA is a material that causes new collagen synthesis produced by the a foreign body reaction, the material initially is a powder that needed to be reconstituted, usually with SwFI sterile water for injections. the volume of reconstruction is initially 5 mm but due to the recommendation of the experts ,that was made on 2014,they increase the dilution to decrease the side effect .

It is a first material that has been injected for volume replacement in hIv associated with facial lipoathrophy and we can see lots of research and proof in this indications the main reseon for copolymer such as PLLA/PGA was to modift the duration of the action..the use of PLA with glycolic acid ,causes neocollagenesis ,that does not show the adverse events that’s is greater than PLLA alone, and the result may last up 2 years.

The objective of the study was to evaluate the correlation between the osteointegration of PLLA implants and tissue engineered bone using a nanofibred scaffold ,pure matrix .as with the insufficient soft tissue in the midface and oral cavity ,and the bone defect were prepared with the burs on the bothside of oral cavity .after the placement of PLLA and PGA injection as a blend, in to hard and soft tissue ,we obtain a result that PLA can be useful as a scaffold for bone regeneration and soft tissue augmentation in the the PLLA implants,

The bone regeneration and augmentation of soft tissue for the midface placement are frequently carried out using autografts ,allografts ,xenograft or synthetic materials ,among these materials among these materials ,outogenous are the ideal graft material for aesthetic rejunevation and good standard,but presently any subtitiude such as hydroxyl appetite ,polylactic acid ,are used to provide improvement of the bone development and soft tissue augmentation ,these material need to be researched their safety and effectiveness in clinical practice, and the micro scale environment of this material needs to be serve as an extra cellular in nature . the present study considered the use of the the matrix material and which is synthesized by chemical peptide methods,

Thus so similarity in fluid characteristics.

Thus PLA exhibit good elasticity, absorption,biodegradability , and biocompatibility properties and is devoid of animal pathogens and antigens. Tissue engineering procedures for bone augmentation and PGA effect on skin rejuvenation offer significant advantage ,the PGA is the first practicable tensile ,strength ,lack of toxicity, and minimal tissue reaction ,and it was the first material that has approved .it is the first synthetic absorbable suture material ,it is non proteinous ,polymeric fiber which is predictably absorbed in vivo/

compared with conventential grafts since there is no donor or the site of morbidity.

Generally ,in tissue engineering ,the cells are typically seeded in a three dimensional  scaffold, which not only provides the anchorage for cell adhesion ,but also creates a suitable cellular microenvironment through adhesions that regulate cell differentiation and cell-cell signaling.

METHODS AND MATERIALS

All animal experiments undertaken were performed in strict accordance with protocols approved by the institutional animal care committee,  after a acclimation hybrid dogs with a mean age of 2 years were operated under the anesthesia.the molars and soft tissue of the oral cavity was extracted and the extraction site were allowed to heal for 4 weeks, bone defect and soft tissue loss were prepared for a 10 mm bur.the defects receive the PLLA and PGA injection as  blend graft material, the first group, is pure matrix, group 2 is PLLA, group 3 PLA and PGA group 4, control (just defect only). with out any differences between the various sites in terms of bone healing ,three defects preside of the mandible of oral cavity were prepared ,and the four groups of materials were implanted in a random and non site specification ,after 8 weeks ,bone and soft tissue biopsies were taken using a 2mm diameter bur ,were placed into the hard tissue for regeneration  of the sutures and soft tissue..

Nowadays ,a concept of isolation cells ,signal molecules, and scaffolds are necessary in cell biology and tissue engineering ,successful tissue engineering involves the implantations of vital cells along with synthetic materials and results in new tissue regeneration ,tissue engineering shows significant advantage compared to the former or conventional  method .which there is no donor or risk of morbidity.

Cell cultivation

PLLA is a synthetic sequence peptide consisting of a sequence of 16 amino acids, PLLA peptide hydrogel was sonicated for 30 minutes using a sonic machine, it was layered over the top of the hydrogel ,allowed to sit at room temperature for 1 minute, and then mixed gently, and the PGA was prepared according to previous methods.

RESULTS:

PLA is an injectable scaffold and show the good elasticity bar around 5 mm.

PLA is a gel with improved tissue retention and it can be injected into bone defects, in histological observations, the cavities or resorption invaded by fibrous tissue ,PM /dmscs sites showed new partial bone formation ,there fore when the silhouette sutures, were inserted in to the facial areas, the exposure of the thread implants in the control and PM/dmsc grouped was observed ,but the exposure of thread insertion was only minimally observed in the group, it was labeled by green and after the thread insertion ,we can see an new collagen synthesis and formation of volume of face can observed ,and the regeneration of bone marrow ,the regenerated bone marrow showed the highest level of maturity around the thread implant .

In addition  ,,regenerated bone showed the highest level of maturity around thread implant in PLA SITES.

and 8 weeks after the insertion placement the BIC of the PLA group, showed a significant increase in the implant surface compared with the control ,

Discussion

Tissue engineering for bone regeneration and skin rejuvenation has shown to be an attractive and charming alternative to autogenesis bone subsitiude

And nowadays that we have seen lots of approaches in tissue engineering, scaffolds of PLLA having the ability to induce bone formation and skin rejuvenation at insufficient bone and soft tissue , be safer for the host and harmonize with the soft tissue of the face, and with the timing we can observe the tissue healing and tissue repair, in this study he new PLLA with poly glycolic acid which forms a unique gel that is absorbable and Nano fibered for tissue engineering was investigated.

The study has confirmed the synthetic peptide with sequence of 16 amino acids ,the repeats in the sequence of PLLA are so similar to the extracellular matrix of structure in the bone and soft tissue of the face. Both in the terms of chemical and biological and physical structure ,in this reports ,as we can see  the bone formation ,the PLLA  ,to achieve the better result ,it is advisable to use PGA ,as a signal molecules.PLLA alone might not be able to stimulate sufficient bone formation for any implant even soft or hard tissue .

CONCLUSION

The results suggest that tissue engineered bone can integrate well around PLLA and we can see the soft tissue augmentation with PGA ,PLLA is a 3D structure that may have a potential to be scaffold applicable in bone tissue engineering ,in the future ,we can see the bone regeneration for using the PLLA and PGA using tissue engineering technology,as we can see the blend of PLLA /PGA ,corresponded to the sutures.

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