Journal of Clinical and Diagnostic Research. 2023 Feb, Vol-17(2): ZE10-ZE13 10 10 DOI: 10.7860/JCDR/2023/59632.17485 Dentistry Section Hyaluronic Acid in Periodontal Regeneration and Implant Dentistry-A Review Review Article INTRODUCTION Hyaluronate also identified as hyaluronan or “HA”, is a non sulphated, higher molecular mass linear polysaccharide present in connective tissue, synovial fluid, the extracellular matrix and other tissues. It has a variety of biological and physical functions, including extracellular, cellular, growth factor interactions, osmotic pressure regulation, and lubrication of tissue [1]. All of these roles contribute to the tissue’s structural and homeostatic integrity. On periodontal tissues invaded by submicrobial flora, HA have anti-oedematous and anti- inflammatory properties [1]. Structure The HA is a non sulphated glycosaminoglycan having naturally occurring 4,000 to 20,000,000 daltons molecular weight. The HA structure is made up of alternating 1-3 and 1-4 bonds connecting “polyanionic disaccharide units of glucouronic acid and N-acetyl glucosamine” [Table/Fig-1] [2]. It is a straight chain of polysaccharide found in synovial fluid, connective tissue, embryonic mesenchyma, skin, vitreous humour and a variety of other body organs and tissues. HA can be synthesised by almost all cells in the body, and the process occurs in cell membrane [1]. between Reactive Oxygen Species (ROS) and antioxidants has been discovered to be the most important requirement for healthy periodontal tissue which is provided by HA. REVIEW Mechanism of action Most cells in the body can synthesise HA, which is a major polysaccharide component of connective tissue’s extracellular matrix [5]. It helps with tissue hydrodynamics, cell migration, and proliferation, as well as improving the tissue’s healing properties [6]. HA helps in chemotaxis, proliferation, and effective differentiation of mesenchymal cells speed up regeneration of bone [7]. Source, body reservoir and uptake of Hyaluronic Acid (HA) The quantity of HA in human skin is estimated to be 5 grams. HA can be found in majority of periodontal tissues like gingiva and Periodontal Ligament (PDL). Hyaluronan Synthase (HAS) enzymes (HAS1, HAS2, and HAS3) synthesise high molecular weight Hyaluronan (HY) in gingiva and PDL, cementoblasts in cementum, and osteoblasts in alveolar bone, as well as in smaller amounts in mineralised tissues like alveolar bone and cementum [8]. Properties of Hyaluronic Acid (HA) The HA is hygroscopic in nature, Viscoelastic, has a bacteriostatic effect and is biocompatible, non anti-genic having anti-inflammatory, anti-oedematous and anti-oxidant properties [8]. Use of HA in Periodontal Regeneration such as in infrabony defects, gingival recession and papilla reconstruction: Topical application of HA in subgingival regions has been found to minimise microbial activity, aid in bone regeneration in deep periodontal bony defects, and is useful in directed bone regeneration, non surgical treatment of peri-implantitis pockets, peri-implant maintenance of immediately inserted implants, and gingival augmentation in mucogingival surgery. Other molecules used in directed bone regeneration techniques and tissue engineering study, such as bone morphogenic protein-2 and platelet derived growth factor-BB, can serve as scaffolds for HA as was shown in study by Park JK et al. [9]. Keywords: Anti-inflammatory, Connective tissue, Hyaluronate, Peri-implantitis, Periodontal wound healing DEEPIKA AJIT MASURKAR 1 , PRIYANKA JAISWAL 2 , BHAIRAVI KALE 3 , AISHWARYA RATHOD 4 ABSTRACT The glycosaminoglycan Hyaluronic Acid (HA) is present in the connective tissue of vertebrates. In the extracellular matrix of soft periodontal tissues, it is the most prevalent glycosaminoglycan with a higher molecular weight. In medical fields such as orthopaedics, dermatology, and ophthalmology, the use of HA in the treatment of inflammatory processes is well established. The extracellular matrix of various tissues, including connective tissue, synovial fluid, and other tissues, contains HA, a naturally occurring linear polysaccharide. Its efficacy in the treatment of inflammatory conditions has been proven. It has anti-inflammatory and anti-bacterial effects in the treatment of gingivitis and periodontitis in dentistry. It could be used as an adjunct to mechanical therapy in the treatment of periodontitis because of its tissue healing properties. Use of HA for implant surface modification has also been extensively studied. HA has proven to be effective in peri-implantitis. The purpose of this review paper is to explain HA’s involvement in periodontal therapy. [Table/Fig-1]: Diagram of HA molecule based on information given by Dahiya P and Kamal R [2]. Image hand drawn by authors History Vedamurthy M mentioned in the study that Scientists John Palmer discovered HA in 1934 at Columbia University in New York, from the glassy jelly from eyes of cows, they isolated a chemical substance [3]. The initials HA were chosen because they were derived from the Greek word “hyalos,” which means “glass.” Preliminary clinical trials have been carried out in the field of dentistry by Vangelisti R et al., [4]. Peri-implantitis is initiated primarily by bacteria similarly as periodontitis, and HA has been proven to have anti-oedematous, anti-inflammatory, and anti-bacterial properties. The balance