Printer Friendly

Human Chorionic Membrane: A Novel and Efficient Alternative to Conventional Collagen Membrane.

Introduction

The human amniotic membrane (HAM) is composed of two layers, the amnion and the non-placental chorion. HAM has been used as a biomaterial for surgical reconstruction for almost a hundred years. There has been increasing interest in studying the biology of HAM because it could eventually aid in the treatment of tissue defects and improve the quality of human life. HAM exhibits tremendous potential for therapeutic purposes due to its property of absorption, high biocompatibility, regenerative capacity and ease of implementation [1]. Since these tissues are discarded after birth, they are easily accessible and do not raise ethical concerns [2].

The use of amnion originated in the early twentieth century, when it was used as surgical material for skin transplantation [3]. In 1940, De Rotth described the transplantation of HAM for the first time in the repair of conjunctival defects [4]. Amnion is currently used in the management of ophthalmic disorders [5], reconstruction and management of wounds of the oral cavity [6-9], arthroplasty [10], vaginoplasty [11] and in many other areas of medicine [1]. Amnion has also been used as a barrier membrane for guided tissue regeneration in oral surgeries [12]. However, the first commercially available placental allografts composed of dehydrated amnion--chorion laminate for the use in dentistry was released in 2008 [13].

The Tata Memorial Hospital (TMH) Tissue Bank supplied processed, lyophilized, irradiated dura mater, which was used effectively as a barrier membrane in guided oral tissue regeneration. However, due to non-availability of dura mater tissues the processing of dura mater was discontinued creating a lacuna with regard to a good barrier membrane. Initially, amnion was used as a substitute but was found to be too thin and fragile. This led us to explore the possibility of using human chorionic membrane (HCM).

The TMH Tissue Bank like most tissue banks the world over routinely discarded HCM since the primary interest was in amnion, which is a proven biological wound dressing. The aim of this study was to find an efficient, natural and cost effective alternative to commercially available barrier membranes, which was suitable for guided oral tissue regeneration. In 2008, the TMH Tissue Bank started providing processed, lyophilized, irradiated HCM as a barrier membrane for use in oral surgeries. This paper describes the processing of HCM allografts and discusses its clinical use and the many advantages of these allografts. As per the knowledge of the authors, the TMH Tissue Bank is the first tissue bank to process and supply HCM and this is the first report to document the processing of HCM.

Materials and Methods

The procurement, processing and sterilization of the amniotic membrane was done in compliance with the recommendations of the International Atomic Energy Agency (IAEA) and the Standards of the Asia Pacific Association of Surgical Tissue Banking (APASTB) [14, 15]. The TMH Tissue Bank is registered with the Directorate of Health Services, Government of Maharashtra.

The placentae were procured from healthy donors from a maternity hospital near the TMH Tissue Bank. The donors were informed about the possibility of donating amniotic membrane and its clinical use, and their written consent was obtained for donation and screening to rule out presence of any transmissible diseases. The placentae were procured from both caesarean sections and normal deliveries. The donors' blood samples were tested for HIV1 and 2, Hepatitis B, Hepatitis C and Syphilis. The placentae were stored at 4[degrees]C in normal saline and quarantined until receipt of the blood reports. Human placentae that met the selection criteria were considered safe for handling and use and were then processed further.

The amniotic membrane was separated from the placenta. The chorion layer was then separated from the amnion. The tissues were washed free of the blood and blood clots and placed in beakers. The tissues were processed in batches. Both amnion and chorion from a single donor were pooled and pasteurized with normal saline at 60nC for 1 hour. The tissues were then treated with 70% alcohol (Merck, Ph Eur) for 0.5 hour, and washed with normal saline until free of alcohol. The processed tissues were spread on gauze, placed on stainless steel trays and kept frozen at 80 CC until a batch was ready for lyophilisation.

The tissues were lyophilised (Martin Christ Alpha 1-4 LSC lyophiliser) until residual moisture content of less than 8% was achieved. The lyophilised grafts were aseptically peeled off the gauze base in a laminar airflow cabinet, cut into the required sizes, double packed in polyethylene packets and labelled. HCM was cut into standard sizes of 4-9 [cm.sup.2] or custom made as per the requirements of the surgeons.

The tissues were terminally sterilized by gamma irradiation at a dose of 25 kGy either in the in-house Gamma Chamber 1200 or in the commercial plant of the Government of India.

The processing procedures were validated. The average bioburden was less than 1000 cfu per product unit thereby substantiating a dose of 25kGy for sterilisation [16, 17]. Samples from each batch were tested for sterility. After sterilization, the packages and contents were visually inspected for damage, intact sealing and complete labelling. The radiation indicators were checked for colour change to indicate sterilization. All stages of processing were documented. The products were then released for use in the appropriate surgical procedures against a request by surgeons or other medical professionals.

Results

Processed lyophilised, irradiated chorion produced has a cream colour with a thickness of 0.5-0.6 mms (figure 1). It can be stored at room temperature and has a shelf life of three years. It is thicker than amnion and hence is easier to use and handle.

From the years 2008 to 2018, the TMH Tissue Bank produced 12,597 HCM allografts of which 11,726 grafts were utilized across the country. The year wise production and utilisation of HCM from 2008 to 2018 is shown graphically in figure 2. HCM was used in the treatment of submucosal fibrosis, sinus lift procedures, implant and periodontal surgeries [18-24]. There were no reported incidents of any adverse reactions including disease transmission, graft rejection or immune response during this period.

Discussion

Barrier membranes are used in oral and periodontal surgeries to prevent epithelium from growing into an area where growth of bone is desired. The placement of barrier membranes exclude undesired cells from the wound area and create a wound space into which desired cells are allowed to migrate [25]. This method of preventing epithelial migration into a specific area using a barrier is known as guided tissue regeneration (GTR).

The barrier membranes recommended for use in GTR must be safe, biocompatible, non-toxic, non-antigenic, and induce little or no inflammatory response from the host tissue, and be designed for each clinical application based on a biological rationale. Resorbability may be a very positive quality of a GTR device since a second surgical procedure is avoided. The bioresorption process must be controlled so that the design of the device is maintained during the initial healing period and the barrier function for tissue guidance is maintained for a sufficient length of time. Tissue reactions resulting from the resorption of the membrane should be minimal, reversible, and must not interfere with regeneration of the desired tissues [26]. Certain critical criteria regarding membranes used for GTR have been postulated: tissue integration, cell-occlusivity, clinical manageability, space making and biocompatibility. These criteria may be applied to select appropriate materials and designs for specific GTR applications [27]. Factors critical for success and improved performance of barrier membranes also include the ideal size of membrane perforations, membrane stability, duration of barrier function, enhanced access of bone and bone-marrow-derived cells to the area for regeneration, ample blood fill of the space, and prevention of soft tissue dehiscence [25].

The amnion is the innermost of the two foetal membranes and is in contact with the contents of the amniotic sac, namely the amniotic fluid, the foetus and the umbilical cord. The chorion is the outermost of the two foetal membranes and is in contact with the amnion on its inner aspect and the maternal decidua on its outer aspect. The non-placental chorion consists of four layers. These are, from within outward: cellular layer, reticular layer, pseudo-basement membrane and trophoblast. The cellular layer is frequently imperfect or completely absent from the chorion when examined at term. The reticular network is composed of collagens I, III IV, V, VI and proteoglycans. The basement membrane anchors the trophoblasts to the reticular layer with collagen IV, fibronectin, and laminin. The trophoblast layer is the deepest layer, consisting of 2 to 10 layers of trophoblasts, which contact with the decidua [28, 29]. Chorion is estimated to be 200 [micro]m thick as compared to amnion which is 50 [micro]m thick [30] providing an additional advantage when processed into allografts for use in oral surgeries.

The collagen, imparts the membranes with their strength and elasticity, much as it does in other types of connective tissue [30]. The proteoglycans found in the amniotic basal lamina are thought to perform a barrier function to restrict permeability of amnion and probably account for the biochemical properties of the membrane [31]. This could probably hold true even for chorion. All cellular processes that involve molecular interactions at the cell surface, such as cell--matrix, cell--cell and ligand--receptor interactions, likely involve proteoglycans because these molecules avidly bind proteins and are quite abundant at this site [32]. The fibronectin present is involved in cellular processes including tissue repair, blood clotting, cell migration and adhesion and in the maintenance of normal tissue order [33, 34]. The laminins present are the major non-collagenous component and function as structural components. They are essential for morphogenesis and interact with cell surface receptors. By virtue of their receptor interactions, they initiate intracellular signalling events that regulate cellular organization and differentiation. [35].

The multiple layers of cytotrophoblast cells of the chorion contain stem cell markers, cluster of differentiation (CD) CD34 and CD45, reinforcing the hematopoietic potential of the chorion [36]. The chorion also contains more growth factor and more cytokines per square centimetre as compared to amnion. The chorion shows higher levels of adiponectin, fibroblast growth factor, endocrine gland-derived vascular endothelial growth factor, hepatocyte growth factor, insulin-like growth factor-1, platelet-derived growth factor-AA and -BB, tissue inhibitor of metalloproteinase (TIMP)-2 and 4 [37]. The ability of this membrane to repair tissues occurs through the presence of growth factors and cytokines [1]. Cytokines and growth factors are key signalling molecules that can execute complex cellular processes such as migration, proliferation, differentiation and vascularization [38] and play a critical role in facilitating repair and regeneration in wound healing [39].

In 2004, Dua et al. suggested that the ability of preserved membranes to influence wound healing by changing the local milieu of growth factors and cytokines must be very limited or nonexistent [31]. However, a study done by McQuilling et al. in 2017 suggested that the preserved membranes contained some amounts of growth factors and cytokines [37]. The chorion also acts as an immunological buffer preventing degradation of the amnion and protecting the foetus from the maternal immune system [40]. Amniotic membrane seems to be an immune-privileged tissue. It is generally thought that the immunogenicity of preserved membrane is less than that of fresh membrane [41]. Processing procedures like cleaning off the blood, freezing, lyophilisation and irradiation reduce the immunogenicity of the membranes.

Studies have shown that HCM also has antimicrobial properties. The antimicrobial effect of chorion has been demonstrated against a large number of bacteria, including pathogens: Escherichia coli, Bacillus cereus, Klebsiella pneumonia, Streptococcus pyogenes, Pseudomonas aeruginosa, Staphylococcus aureus, Staphylococcus saprophyticus, Shigella flexneri and one probiotic: Lactobacillus plantarum. The most important finding of the study done by Zare-Bidaki et al. was the superiority observed in antibacterial effects of the chorion compared with the amnion [42, 43].

The presence of higher concentration of cytokines and growth factors in chorion [37], its superior antimicrobial effects [43] and thickness as compared to amnion [30] could be an added advantage when HCM allografts are produced.

Many clinical studies performed using HCM provided by the TMH Tissue Bank have been published. In 2018, Kothiwale and Ajbani studied the anti-inflammatory effect of HCM, which was used as a barrier membrane in periodontal pocket therapy by assessing interleukin-11 (IL-11) level in gingival crevicular fluid. They concluded that an adjunctive use of HCM in flap surgery provides an additive anti-inflammatory effect along with improvement in clinical outcomes enhancing the long-term prognosis. This study confirmed the presence of IL-11 in the HCM allografts [44].

In a study where HCM was incorporated as an innovative step during flap surgery, it resulted in reduction of periodontal pocket depth, increased gingiva thickness, and avoided post-operative recession. Hence, added to the prognostic value of periodontal therapy. The properties of chorionic membrane: anti-inflammatory, adhesion, vascularisation, presence of collagen types with proteoglycans, adhesion with the help of laminins might be responsible in increasing the thickness of gingiva thus making it suitable for periodontal therapy [22].

In an earlier study using HCM it was shown that GTR was more effective than conventional therapy for the periodontal pocket therapy particularly with regard to the amount of bone regeneration. This study found no events of adverse healing or epithelial invasion of the grafted sites. The advantage of bio-absorbable HCM was that the technique did not require a second surgical procedure, thus improving the clinical results. The membrane when placed dry quickly hydrates with blood, became very pliable, and closely adapted to the contours of the underlying surface. It is self-adherent in nature, did not displace easily and did not need to be fixed into place using sutures [19]. HCM has better handling properties when compared to amnion, as it is a thicker membrane [45]. The diverse properties of HCM make it unique, novel and potential biomaterial for use in medicine, tissue engineering, stem cell research, repair, and regeneration. Their use in dentistry is also quickly expanding with a wide range of applications in Periodontics [46]. The unique properties of HCM makes it an interesting new option for application in oral wound healing. Hence, this membrane was used as an alternative to conventional collagen membrane, which results in excellent aesthetics, prevention of tissue loss, and a good biotype postoperatively [20]. Like in the case of other biological material, the choice of HCM too should be decided carefully depending on the desired clinical outcome. As in all surgeries, the clinical outcome would also depend on the skill and experience of the surgeon.

From the tissue banking perspective, HCM although thicker than amnion is less elastic and tears more easily, hence chorion needs to be separated very carefully from the placenta. Numerous blood vessels are present on the HCM, hence it should be washed carefully and gently to prevent the membrane from losing the outer layers and getting too thin. A right balance has to be maintained between processing and obtaining an ideal product suitable for clinical use. Since amnion and chorion are obtained from a single donor, they are pooled and processed thereby reducing operating cost per unit and doubling the output of grafts thereby enabling the TMH Tissue Bank to provide the grafts at cost effective rates as compared to the exorbitantly priced commercially available barrier membranes.

HCM supplied by the TMH Tissue Bank is a biomaterial that can be made available in different sizes as per the requirements of the patients and/or surgeons. It is non-toxic and non-antigenic. Being a bio-resorbable membrane, the technique does not require a second surgical procedure, thereby improving clinical results and cost-effectiveness, and decreasing patient morbidity. The lyophilized HCM does not require special storage conditions and can be stored at room temperature, and easily transported. The TMH Tissue Bank supplies HCM all over the country by post or courier.

Conclusions

HCM supplied by TMH Tissue Bank proved to be an economical, natural, biocompatible, and predictable grafting material. Having demonstrated good results, it can serve as an efficacious alternative to conventional collagen membrane. Most tissue banks the world over process only the amnion and discard the chorion membrane, a valuable biomaterial as a biomedical waste. The HCM obtained from the placental donors can be easily processed into allografts, which could be used to improve the quality of life of patients. In a developing country like India, the biggest advantage of the HCM prepared indigenously is its affordable cost thereby reducing the total cost of the surgery. It is less expensive than the products available commercially. HCM has been successfully used in oral and periodontal surgeries in India. Further research needs to be done on understanding its biological properties as well as widening the scope of its clinical use.

Received 28 October 2019

Accepted 20 December 2019

Published online 30 January 2020

Acknowledgements

The authors would like to thank Nowrosjee Wadia Maternity Hospital, Parel, Mumbai for the valuable support in the procurement of placenta.

References

[1.] J.C. Francisco, R.C. Cunha, R.B. Simeoni, L.C. Guarita-Souza, R.J. Ferreira et al, Amniotic membrane as a potent source of stem cells and a matrix for engineering heart tissue, J. Biomedical Science and Engineering, 6, 1178-1185 (2013).

[2.] A. Lindenmair, T. Hatlapatka, G. Kollwig, S. Hennerbichler, C. Gabriel, S. Wolbank, H. Redl, C. Kasper, Mesenchymal stem or stromal cells from amnion and umbilical cord tissue and their potential for clinical applications, Cells, 1, 1061-1088 (2012).

[3.] J.W. Davis, Skin transplantation with a review of 550 cases at the Johns Hopkins Hospital, Johns Hopkins Medical Journal, 15, 307 (1910).

[4.] A. De Rotth, Plastic repair of conjunctival defects with fetal membrane. Arch. Ophthalmol., 23(3), 522-525 (1940).

[5.] V.S. Sangwan, S. Burman, S. Tejwani, S.P. Mahesh, R. Murthy, Amniotic membrane transplantation: A review of current indications in the management of ophthalmic disorders, Indian J. Ophthalmol., 55, 251-260 (2007).

[6.] Gurinsky Brian, A novel dehydrated amnion allograft for use in the treatment of gingival recession: An observational case series, The Journal of Implant & Advanced Clinical Dentistry, 1(1), 65-73, (2009).

[7.] M.E. Sham, N. Sultana, Biological wound dressing--role of amniotic membrane, International Journal of Dental Clinics, 3(3), 71-72 (2011).

[8.] T.N. Mehta, M. Mittal, R. Mehta, B.S. Hora, A Novel Dehydrated Amnion Allograft for Use in the Treatment of Gingival Recession: A Case Report, J. Res. Adv. Dent., 3(2), 176-181 (2014).

[9.] S. Mishra, S. Singh, Human Amniotic Membrane: Can it be a Ray of Hope in Periodontal Regeneration?, Paripex--Indian Journal of Research, 3(9), 118-121 (2014).

[10.] G.K. Vishwakarma, A.K. Khare, Amniotic arthroplasty for tuberculosis of the hip: A preliminary clinical study, J. Bone. Joint. Surg. Br. 68B (1), 68-74 (1986).

[11.] M. Zafar, S. Saeed, B. Kant, B. Murtaza, M.F. Dar, N.A. Khan, Use Of Amnion In Vaginoplasty For Vaginal Atresia, J.C.P.S.P., 17 (2), 107-109 (2007).

[12.] S.V. Kothiwale, P. Anuroopa, A.L. Gajiwala, A clinical and radiological evaluation of DFDBA with amniotic membrane versus bovine derived xenograft with amniotic membrane in human periodontal grade II furcation defects, Cell Tissue Bank, 10, 317-326 (2009).

[13.] D.J. Holtzclaw, N.J. Toscano, Amnion--Chorion Allograft Barrier Used For Guided Tissue Regeneration Treatment of Periodontal Intrabony Defects: A Retrospective Observational Report, Clinical Advances in Periodontics, 3(3), 131-137 (2013).

[14.] APASTB Standards of Tissue Banking, 1st Edition, in Radiation in Tissue Banking, Basic Sciences and Clinical Applications of Irradiated Tissue Allografts, World Scientific, Singapore, 383-442, (2007).

[15.] APASTB Standards of Tissue Banking, 2nd Edition, Asia Pacific Association of Surgical Tissue Banking, (2016).

[16.] ISO Sterilisation of Health Care Products-Radiation-Part 2: Establishing the Sterilisation Dose, ISO 11137:2013, International Organisation for Standardisation, Switzerland (2013).

[17.] N. Hilmy, N. Yusof, "Procurement and Processing of Amniotic Membrane" in Human Amniotic Membrane Basic Science and Clinical Application, World Scientific, Singapore 157-176 (2017).

[18.] D.K. Suresh, A. Gupta, Gingival Biotype Enhancement and Root Coverage Using Human Placental Chorion Membrane, Clinical Advances in Periodontics, 3(4), 237-242 (2013).

[19.] S.V. Kothiwale, The evaluation of chorionic membrane in guided tissue regeneration for periodontal pocket therapy: a clinical and radiographic study, Cell Tissue Bank, 15, 145-152 (2014).

[20.] R. Shah, R. Thomas, D.S. Mehta, Ridge preservation using demineralized freeze-dried bone allograft and chorion membrane, Int. J. Oral Health Sci. 4, 89-92 (2014).

[21.] J. Esteves, K.M. Bhat, B. Thomas, J.M. Varghese, T. Jadhav, Efficacy of Human Chorion Membrane Allograft for Recession Coverage- A Case Series, J. Periodontal., 86(8), 941-944 (2015), doi: 10.1902/jop.2014.140025c.

[22.] S. Kothiwale, A. Rathore, V. Panjwani, Enhancing gingival biotype through chorion membrane with innovative step in periodontal pocket therapy, Cell Tissue Bank 17, 33-38 (2016).

[23.] C.P. Joshi, C.B. D'Lima, U.C. Samant, P.A. Karde, A.G. Patil, N.H. Dani, Comparative alveolar ridge preservation using allogenous tooth graft versus freeze-dried bone allograft: A randomized, controlled, prospective, clinical pilot study, Contemp. Clin. Dent., 8(2), 211-217 (2017).

[24.] C.P. Joshi, A. A. Panjwani, C.B. D'Lima, N.H. Dani, Comparative Evaluation of Amnion-Chorion Membrane and Chorion Membrane for Root Coverage and Gingival Biotype Enhancement: A Case Report, EC Dental Science, 14(6), 255-259 (2017).

[25.] C.H.F. Hammerle, R.E. Jung, Bone augmentation by means of barrier membranes, Periodontology, 33, 36-53 (2000).

[26.] J. Gottlow, Guided tissue regeneration using bioresorbable and nonresorbable devices: Initial healing and long-term results, J. Periodontal, 64 (11), 1157-1165 (1993).

[27.] T.V. Scantlebury, 1982-1992: A decade of technology development for guided tissue regeneration, J. Periodontol., 64 (11), 1129-1137 (1993).

[28.] G. Bourne, The Foetal Membranes A Review of the Anatomy of Normal Amnion and Chorion and Some Aspects of Their Function, Postgrad. Med. J., 38, 193-201 (1962).

[29.] H. Niknejad, H. Peirovi, M. Jorjani, A. Ahmadiani, J. Ghanavi, A.M. Seifalian, Properties Of The Amniotic Membrane For Potential Use In Tissue Engineering, Europeon Cells and Materials, 15, 88-99 (2008).

[30.] WK. Chua, M.L. Oyen, Do we know the strength of the chorioamnion? A critical review and analysis, European Journal of Obstetrics & Gynecology and Reproductive Biology, 144, 128-133 (2009).

[31.] H.S. Dua, J.A.P. Gomes, A.J. King, V.S. Maharajan, The amniotic membrane in ophthalmology, Survey of Ophthalmology, 49 (1), 51-77 (2004).

[32.] N. Perrimon, M. Bernfield, Cellular functions of proteoglycans-an overview, Seminars in Cell & Developmental Biology, 12, 65-67 (2001).

[33.] E. Rouslahti, Fibronectin, Journal of Oral Pathology, 10, 3-13 (1981).

[34.] B.J. Baum, W.E. Wright, Demonstration of Fibronectin as a Major Extracellular Protein of Human Gingival Fibroblasts, J. Dent. Res., 59(3), 631-637 (1980).

[35.] P. Tunggal, N. Smyth, M. Paulsson et al, Laminins: Structure and Genetic Regulation, Microscopy Res. Technique, 51, 214-227 (2000).

[36.] L.F. Martin, L. Richardson, R. Menon, "Characteristics, Properties, and Functionality of Fetal Membranes: An Overlooked Area in the Field of Parturition" in Encyclopedia of Reproduction, 2nd edn, Volume 3, 387-398 (2018). https://doi.org/10.1016/B978-0-12-801238-3.64498-7

[37.] J.P. McQuilling, J.B. Vines, K.A. Kimmerling, K.C. Mowry, Proteomic Comparison of Amnion and Chorion and Evaluation of the Effects of Processing on Placental Membranes, Wounds, 29(6), 38-42 (2017).

[38.] M.S. Sane, N. Misra, N.M. Quintanar, C.D. Jones, S.B. Mustafi, Biochemical characterization of pure dehydrated binate amniotic membrane: role of cytokines in the spotlight, Regen. Med. 13(6), 689-703 (2018).

[39.] T.J. Koob, J.J. Lim, N. Zabek, M. Massee, Cytokines in single layer amnion allografts compared to multilayer amnion/chorion allografts for wound healing, J. Biomed. Mater. Res. Part B, 103B, 1133-1140 (2015).

[40.] M.L. Oyen, S.E. Calvin, D.V. Landers, Premature rupture of the fetal membranes: Is the amnion the major determinant?, American Journal of Obstetrics and Gynecology, 195, 510-515 (2006).

[41.] M. Kubo, Y Sonoda, R. Muramatsu, M. Usui, Immunogenicity of Human Amniotic Membrane in Experimental Xenotransplantation, Investigative Ophthalmology & Visual Science, 42(7), 1539-1546 (2001).

[42.] N. Kjaergaard, M. Hein, L. Hyttel, R.B. Helmig, H.C. Schonheyder, N. Uldbjerg, H. Madsen, Antibacterial properties of human amnion and chorion in vitro, European Journal of Obstetrics & Gynecology and Reproductive Biology, 94, 224-229 (2001).

[43.] M. Zare-Bidaki, S. Sadrinia, S. Erfani, E. Afkar, N. Ghanbarzade, Antimicrobial Properties of Amniotic and Chorionic Membranes: A Comparative Study of Two Human Fetal Sacs, J. Reprod. Infertil. 18(2), 218-224 (2017).

[44.] S. Kothiwale, J. Ajbani, Evaluation of anti-inflammatory effect of chorion membrane in periodontal pocket therapy: A clinical and biochemical study, J. Indian Soc. Periodontol. 22, 433-437 (2018).

[45.] S. Chakraborthy, S. Sambashivaiah, R. Kulal, S. Bilchodmath, Amnion and Chorion Allografts in Combination with Coronally Advanced Flap in the Treatment of Gingival Recession: A Clinical Study, Journal of Clinical and Diagnostic Research, 9(9), 98-101 (2015).

[46.] A. Gupta, S.D. Kedige, K. Jain, Amnion and Chorion Membranes: Potential Stem Cell Reservoir with Wide Applications in Periodontics, Hindawi Publishing Corporation International Journal of Biomaterials, Article ID 274082, 9 pages. http://dx.doi.org /10.1155/2015/274082 (2015).

Cynthia D'Lima (1), Urmila Samant (1), Astrid Lobo Gajiwala (1), Ajay Puri (1,2,3)

(1) Tissue Bank, (2) Department of Surgery, Tata Memorial Hospital, Tata Memorial Centre, Parel, Mumbai 400012, India

(3) Homi Bhabha National Institute (HBNI), Anushaktinagar, Mumbai 400094, India

* Coresponding author.

E-mail address: cynthiadhma@rediffmail.com (Cynthia D'Lima, Scientific Officer, Tissue Bank, Tata Memorial Hospital, Mumbai India)

Figure 1: Human chorionic membrane
Figure 2: Production and Utilization of HCM: 2008-2018

       Production   Utilisation

2008   2            2
2009   36           25
2010   99           83
2011   405          307
2012   937          877
2013   1377         782
2014   2604         1646
2015   1108         1993
2016   1848         1951
2017   1517         2051
2018   2664         2009

Note: Table made from bar graph.
COPYRIGHT 2020 Society for Biomaterials and Artificial Organs
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 2020 Gale, Cengage Learning. All rights reserved.

Article Details
Printer friendly Cite/link Email Feedback
Title Annotation:Original Article
Author:D'Lima, Cynthia; Samant, Urmila; Gajiwala, Astrid Lobo; Puri, Ajay
Publication:Trends in Biomaterials and Artificial Organs
Geographic Code:9INDI
Date:Jan 1, 2020
Words:4263
Previous Article:A Developed Meta-model for Biomaterials Selection.
Next Article:Hip Implant: CAD Modelling and Static Analysis.
Topics:

Terms of use | Privacy policy | Copyright © 2021 Farlex, Inc. | Feedback | For webmasters |