Periodontitis is an inflammatory disease that causes pathological alterations in the teeth and their supporting tissues, potentially leading to tooth loss. Despite the remarkably high standards of professional periodontal care, incomplete adult dentitions or edentulism are still evident. Several procedures have been attempted to achieve periodontal regeneration, including root surface conditioning, bone graft placement, guided tissue regeneration (GTR). Tissue engineering is a multidisciplinary field which involves the application of the principles and methods of engineering and life sciences towards the fundamental understanding of structural-functional relationships in normal and pathological mammalian tissues and the development of biological substitutes that restore, maintain or improve tissue function. Advances in tissue engineering life sciences over the past twenty years have lead to various therapies for replacing, repairing, restoring or regenerating human tissues suggesting an important role of tissue engineering in regenerative technology.
Regeneration of the periodontal tissues is a complex phenomenon requiring interplay between various processes in a timely manner.Research strives to attain regeneration in a more predictable, quicker, less invasive ways than allowed by previous techniques. Tissue engineering is a highly promising field of reconstructive biology that draws on recent advances in medicine, surgery, molecular and cellular biology, polymer chemistry and physiology. The objective of using tissue engineering as therapeutic application has been to harness its ability to exploit selected and primed cells together with an appropriate mix of regulatory factors, to allow growth and specialization of cells and matrix. This book is a brief review on the basics of tissue engineering related to Periodontology and also updates the reader with the controlled clinical trials that prove the ability of tissue engineering in achieving new heights in periodontal regeneration.
This book provides an overview of various methods of periodontal osseous regeneration like bone grafts, guided tissue regeneration, biological mediators etc. Information about the properties and important features of various materials used in periodontal regeneration is also discussed. In brief, this book provides the reader a better understanding of regenerative methods and their clinical applications, especially in periodontics .
The prospect of improved regeneration is not only the promise held out by stem cell research, critical studies of unique aspects of early human development are now within reach with the use of embryonic stem cells. Although our understanding of the molecular pathways underlying mesenchymal stem cells differentiation is expanding, translation of this knowledge into tissue engineering strategies remains in its infancy. In the context of orofacial tissue engineering, populations of stem cells that form bone, cementum; dentin and even periodontal ligament have been identified. This has unlocked a new direction of research to restore the form and function of the oral cavity using autologous cells, thereby preventing histocompatibility mismatch and transmission of disease. With the first reports of adult human stem cell populations residing in the periodontal ligament beginning to emerge, the next phase will be to determine the clinical utility of these cells. Accordingly, further studies are now required to determine the efficacy of ex vivo expanded stem cells to repair periodontal defects.
Tissue engineering is the best approach for periodontal regeneration, which utilizes a triad of stem cells, signalling molecules and scaffold. Among the signalling molecules platelet derived growth factor (PDGF) is most commonly used growth factor for regeneration of periodontal defects. Need of a suitable scaffold is must so as to provide support to the signalling molecule, one such scaffold is beta tricalcium phosphate. The present study and review provides the comprehensive data regarding the use of growth factors along with various scaffolds for periodontal regeneration.
Tissue engineering is an emerging interdisciplinary field which applies the principles of biology and engineering to the development of viable substitutes which restore, maintain, or improve the function of human tissues. This form of therapy differs from standard drug therapy in that the engineered tissue becomes integrated within the patient, affording a potentially permanent and specific cure of the disease state. Tissue engineering in periodontology applies the principles of engineering and life sciences towards the development of biological techniques that can restore lost alveolar bone, periodontal ligament, and root cementum. This book is an excellent compilation of the fundamentals of tissue engineering and describes current regenerative procedures for periodontal healing and regeneration. It also explores the progress of tissue engineering in the field of periodontology since its inception, with particular emphasis placed upon current challenges and future possibilities associated with tissue-engineering strategies in periodontal regenerative medicine.
The Periodontium is defined as a connective tissue organ, protected by epithelium, that attaches the teeth to the bone of the jaws and provides a continually adapting apparatus for their support during function. The four connective tissues of the periodontium are the lamina propria of the gingiva, the periodontal ligament, the cementum and the alveolar bone. Periodontal therapy involves two primary components; Removal of bacterial plaque and calculus, and of the anatomic defects produced. There are two primary approaches to eliminate these defects: Resective and Regenerative, both surgical. Regenerative Surgery seeks to eliminate periodontal defects by creating new bone and periodontal ligament and coronally displacing the gingival attachment and margin. The method for the prevention of epithelial migration along the cemental wall of the pocket that has gained wide attention is called Guided Tissue Regeneration.It consists of placing barrier membranes of different types to cover the bone and periodontal ligament.
The healing process is a complex and integrated sequence of events initiated by the stimulus of injury. It requires the well – orchestrated action of many specialized cell types to restore structural and functional integrity. Unlike other wounds in the body, in periodontal wounds, there is a mineralized tissue interface at the junction of epithelium and connective tissue. The understanding of this process is necessary to visualize the outcome of different periodontal procedures, which inhibits the further progression of periodontal disease and restore the lost periodontal structures. Periodontal tissues undergo regeneration or repair according to the response to various periodontal therapies employed. The complex nature of this process can be understood better in the future to develop periodontal procedures resulting in complete regeneration of periodontal tissues.
The ultimate goal in the treatment of destructive periodontal disease is the regeneration of the lost attachment apparatus i.e. the formation of new cementum, a new periodontal ligament and new alveolar bone. Tetracycline hydrochloride as a root conditioner was evaluated in vivo studies. Various techniques for application of tetracycline hydrochloride were experimented. Burnishing technique was found to be the best technique among them. It was found that there was lesser tissue destruction and better regeneration of periodontal tissues if tetracycline hydrochloride is used as a root conditioner during periodontal regeneration procedures.
Regeneration of periodontal tissues is perhaps one of the most complex process to occur in the body. A number of new methods have been used to achieve periodontal regeneration.The latest among them is use of growth factors. The aim of this book is to provide a review of periodontal repair and regeneration,features and functions of growth factors,mechanism of action and clinical application of growth factors in periodontal healing. This book will be of interest to researchers,under and post graduates having a keen interest in cellular & molecular biology and periodontal regeneration.
The trend for the future of Root Canal Therapy is leaning towards dental pulp tissue regeneration using tissue engineering principles, stem cells, growth factors and scaffolds. Ideally, Root Canal Therapy would involve the removal of diseased pulp tissue and its permanent replacement with healthy pulp to revitalize teeth. Traditionally, during a Root Canal Therapy, the diseased pulp has been removed and replaced by a biocompatible synthetic material. This book presents the concepts and foundations of this new trend. It also presents the results of an in vitro tissue constructs study and the results of pre-clinical trials of dental pulp tissue regeneration in teeth of non-human primates. This study tested the fundamental principles of dental pulp tissue regeneration, as it is now envisioned, using stem cells, growth factors and scaffolds. The aim is to develop a reliable and reproducible protocol that will always give the same result, the revitalization of teeth by the regeneration of dental pulp tissue.
The management of periodontal defects, including destruction of the periodontal ligament, cementum and the formation of intrabony defects, has always been a challenge in clinical periodontics. During the 1950’s and into the 60’s, resective surgical therapy, with or without osseous recontouring, was considered the norm, in the belief that attainment of shallow pocket depths was a worthwhile goal. Surgeries are always traumatic for patients and thus there is always a look out for treatment modality that may suffice the needs without any invasive procedure. In this look out has emerged the periodontal regenerative concept. Hereby thus presenting a detailed elaboration on the concept, the trends and the scope.
Molecular biology is the study of biology at a molecular level. Writing in Nature in 1961, William Astbury described molecular biology as: "not so much a technique as an approach, an approach from the viewpoint of the so-called basic sciences with the leading idea of searching below the large-scale manifestations of classical biology for the corresponding molecular plan. The term “tissue engineering” was coined at a National Science Foundation (N.S.F.) bioengineering meeting in Washington D.C., in 1987. At a subsequent N.S.F. sponsored workshop, it was formally defined as “ the application of principles and methods of engineering and life sciences, to obtain a fundamental understanding of structural and functional relationships in novel and pathological mammalian tissues, and the development of biological substitutes to restore, maintain or improve tissue function”In Endodontics, that is, regenerative endodontic procedure refers to the regeneration of dentin pulp complex and even whole tooth structure. Murray PE, Gracia- Godoy F, Hargreaves KM in 2007 (85) defined it as “biologically based procedure designed to replace damaged structures including dentin and root structures as w
Since antiquity, wounds of all varieties have been the result of trauma, infection and vascular or autoimmune disorders. The intentional surgical wounding of a tissue is a dynamic process which elicits a complex and dynamic response in the tissue that has been injured.The healing of a wound includes the various phases of blood clotting, wound cleansing, tissue formation, tissue modeling and remodeling. These phases occur in an orderly sequence but, in a given site, may overlap in such a way that in some areas of the wound, tissue formation may be in progress while in other areas tissue modeling is the dominating event. Current scientific evidence points to the presence of cells originating from the periodontal ligament, wound stability, space provision, and primary intention healing, as fundamental biologic and clinical factors that must be met to obtain periodontal regeneration. Only a profound understanding of biological and clinical variables affecting the outcome of periodontal- regenerative procedures will allow clinicians to manipulate biological and clinical factors effectively in order to optimize the clinical result and increase the predictability of periodontal surgery.
Growth factors are a class of natural biologic mediators which regulate key cellular events in tissue repair i.e. cell proliferation, chemotaxis (directed migration), differentiation and matrix synthesis via binding to specific cell surface receptors. The expression of various growth and differentiation factors following bone and soft tissue injury like what happens in a periodontal disease may regulate the repair and regeneration process. The capacity of these mitogenic growth factors to initiate a programmed cellular cascade that results in the induction of bone in a functionally conserved process utilized in embryonic development recapitulated in post fetal osteogenesis and can be re-exploited for the therapeutic initiation of periodontal tissue regeneration.
Healing of periodontal wounds is a more complex process. Melcher established that if PDL cells are given preference, regeneration may consistently occur. Current regenerative therapies include bone grafts, allogenic and xenograft bone matrix, root conditioning agents and cell-occlusive barrier membranes and, most recently, recombinant growth/differentiation factors. Bone grafts, though considered “gold standard”, bone regeneration after grafting is quite variable. Growth/differentiation factors in spite of their promise of revolutionizing field of bone regeneration must be used at very high concentrations to be effective and also they do not induce long-term changes in the diseased tissue. The novel approach would include changes at a genetic level to modify the disease process for long-term beneficial effects of regenerative molecules. 21st century appears to represent a time in history when there is a convergence between clinical dentistry and medicine, human genetics, developmental and molecular biology, biotechnology, bioengineering and bioinformatics, resulting in emergence of novel regenerative therapeutic approaches viz. nanotechnology, gene therapy, RNAi & stem cells.