the ultimate goal of periodontal therapy is to arrest the progress of periodontal disease and regenerate the lost periodontal support .
hyaluronic acid ( ha ) is a high molecular weight , nonsulphated glycosaminoglycan component which is produced during various phases of cell 's life cycle .
it contributes in tissue hydrodynamics , cell migration , and proliferation , and improves healing properties of the tissue .
its physiological , structural , and biochemical properties prove that it provides elasticity and stability to tissues and is critically beneficial in tissue regeneration .
pharmacologically , the content of ha in the tissues is often broken down by the blood stream or by lymphatic drainage and its turnover rate is found to be 2030% . after being broken down ,
ha was discovered in 1934 from cow 's eye by karl meyer and john plamer and was first used in 1942 by endre balazs as a substitute for egg white in bakery products .
the chemical structure of ha shows alternate units of n - acetyl glucosamine and d - glucorounic acid , both of the components linked through glycosidic bonds .
ha acts as an antioxidant by scavenging reactive oxygen species , which helps in the regulation of immune response implying its anti - inflammatory properties .
it has also been reported that ha shows osteoinductive properties , which is useful for treatment of periodontal disease .
other beneficial effects have also been seen for the treatment of recurrent apthous ulcer , for treating gingival lesions , and promote healing in extraction socket .
ha has also reported as a diagnostic biomarker of inflammation in gingival crevicular fluid and repair of tissues .
recent investigations have indicated that ha induces mineralization of dental pulp cells through cd44 cell surface glycoprotein and is considered to be a principle ligand for receptor cd44 .
hyaluronic acid was found to have extensive actions in various periodontal therapies such as topically applied in subgingival regions reduces microbial activity , bone regeneration in deep periodontal bony defects , guided bone regeneration , nonsurgical treatment of peri - implantitis pockets , peri - implant maintenance of immediately placed implants , and gingival augmentation in mucogingival surgery .
ha may act as a scaffold for other molecules such as bone morphogenic protien-2 and platelet derived growth factor - bb , used in guided bone regeneration techniques and tissue engineering research .
ha when applied to patients with chronic periodontitis showed reduction in bleeding on probing ( bop ) , probing pocket depth ( ppd ) , and clinical attachment level , and hence , can be used as an adjunct to scaling and root planning .
ha gel , injections , or oral ( by mouth ) should not be used in patients with allergies .
a 24-year - old female reported to the department of periodontics with her esthetic concern and complaint regarding the loss of interdental papilla , i.e. black triangle , in the anterior maxillary region [ figure 1 ] .
patient was concerned for esthetics ; class ii type of interproximal tissue loss without any bone loss and no extra oral deformities were detected .
a written informed consent was taken from the patient before the procedure , and ethical clearance certificate was obtained from the institution .
preoperative : black triangle between maxillary right central incisor and lateral incisor nordland and tarnow proposed a classification using three reference points , i.e. , contact point , facial and apical extent of cementoenamel junction ( cej ) , and interproximal extent of cej ( icej ) , and was classified into the following four classes : normal : interdental papilla occupies embrasure space to the apical part of the interdental contact point .
class i : tip of interdental papilla occupies space between the interdental contact point and the most coronal part of cej .
class ii : tip of interdental papilla lies at / or the apical to the icej but coronal to the apical most part of the cej on facial aspect .
class iii : tip of interdental papilla lies at level with or apical to the facial cej .
the loss of interdental papillae can be due to many reasons such as gingivitis , oral hygiene procedures with trauma , tooth shape with abnormal anatomy , or improper contours of the restoration .
inclusion criterion for the study were : 
 age range : 2075 yearsmaxillary anterior teethplaque index less than 20%teeth should not have caries and no fixed prosthesis or orthodontic appliancenonsmoker individualsno systemic disease that may affect the periodontal statusavoid consumption of drugs causing gingival overgrowth . 
 
age range : 2075 years maxillary anterior teeth plaque index less than 20% teeth should not have caries and no fixed prosthesis or orthodontic appliance nonsmoker individuals no systemic disease that may affect the periodontal status avoid consumption of drugs causing gingival overgrowth .
patient was completely informed about the study . after introducing a local anesthetic agent , less than 0.2 ml of the ha gel
was injected at the sites 23 mm apical to the coronal tip of the papilla [ figure 2 ] .
the patient was instructed not to brush on the day of treatment but maintain oral hygiene , and after 24 hours , using a soft bristle toothbrush at the anterior teeth to start their routine oral hygiene measures and avoid using dental floss at the sites of treatment .
the patient was on follow - up for 3 weeks and was recalled for a total of 4 times .
after first follow - up , 3 weeks later , the treatment patient did not show any improvement , therefore ; another shot of 0.2% ha injection was given .
measurements of the black triangle were done using photography . injecting 2% hyaluronic acid into interdental papilla after 3 months , photographs were taken and comparison was done using these images .
this technique resulted in significant gain in papillary volume and esthetic improvements were notable [ figure 3 ] .
because using 0.2% ha for the reconstruction of lost interproximal tissue gave significant changes , it can be used as a noninvasive method , which will reduce the use of surgical procedures for regenerating soft tissues in upcoming years .
this study can be limited by the amount of the interproximal tissue loss , depending upon the size of the black triangle , which might require surgical intervention to gain complete coverage .
the main advantage of this study is that it is nontoxic to the patient and there is reduced discomfort after the procedure as compared to surgical procedure done .
furthermore , this study can be elaborated by more number of patients depending upon the size and type of the black triangle .
becker et al . concluded that ha gel is a synthetic material and can be used with no drug interference and is a safe material , which significantly decreases the interdental black triangle in the esthetic zone .
vedamurthy reported ha to be a dermal filler and applied it for soft tissue augmentation , observing significant improvements .
monheit et al . discussed the inherent properties of ha that make them ideal for cosmetic surgeries .
studied gingival augmentation with an autologous cell ha and reported significant results with the complete coverage .
found that antioxidant capacity of ha is inversely proportional to the severity of inflammation and can be used as a biomarker in periodontitis .
it is acceptable that injecting ha to periodontal wound sites had shown significant effects in periodontal tissue regeneration .
engstrm et al . reported bone regenerative effects of ha in nonsurgical and surgical groups and showed no statistical difference when evaluated on radiographs in the nonsurgical group ; however , there was remarkable decrease in the height of alveolar bone after oral prophylaxis in both the nonsurgical and surgical group .
ha when involved with soft and hard tissues showed negligible effect on the immune system of the patient .
stated enhanced accelerating capacity of new bone formation in the infrabone defects when combined with autologous bone graft .
this study indicates possible improvements in regenerating lost interdental papilla and removal of black triangle by injecting ha into the lost papilla using a nonsurgical approach . because of its property of modulating periodontal wounds ,
this nonsurgical approach limits the use of surgical procedures for regenerating lost papilla , and hence , it is a noninvasive method and also reduces patient discomfort .
therefore , this study demonstrates ha to be a nonsurgical approach for regenerating lost papilla and gave significant and satisfactory results . to overcome the limitations of using of ha for regenerating lost papilla , this study need to be elaborated with more number of patients depending upon the size of the black triangle .
 interdental papilla construction , especially in the esthetic area , is one of the most challenging tasks . 
 interdental papilla loss might occur due to several reasons as a consequence of periodontal surgery or trauma . 
 the purpose of this study is to report the reconstruction of lost interdental papilla using hyaluronic acid gel . 
 hyaluronic acid is a glycosaminoglycan molecule with anti - inflammatory , anti - edematous properties on periodontal tissues invaded by submicrobial flora . 
 it enhances wound healing and accelerates periodontal repair and regeneration . 
 in addition to the field of dentistry , it has been used in other fields such as orthopedics , ophthalmology , and dermatology . 
 it shows growth factor interaction , regulates osmotic pressure , and enhances tissue lubrication , which helps in maintaining the structural and homeostatic integrity of tissues , hence resulting in beneficial effect on lost interdental papilla . 
 this study was aimed to reconstruct the lost interdental papilla by injecting 0.2% hyaluronic acid via nonsurgical approach . 
 it is a noninvasive approach which reduces patient 's postoperative discomfort with marked variations in the volume of interdental papilla before and after the procedure . 
 as sufficient information is not available regarding the effectiveness of hyaluronic acid in interdental papilla construction , this study was conducted . 