Evaluation of NIPSA Using Alloplastic Bone Graft and Cross-Linked Hyaluronic Acid in theTreatment of Intrabony Defects (RCT)

Periodontitis comprises a group of diseases that are inflammatory in origin and generally affect the connective tissue attachment and the teeth- supporting bone. It results from interactions between periodontal microflora and the host defense response. If left untreated, periodontitis may progress to tooth mobility and eventual tooth loss, which can adversely affect oral function and esthetics, thereby influencing patients' daily activities, social behavior and overall quality of life. The main goal of comprehensive periodontal treatment is to eliminate inflammation and prevent further destruction of the periodontium, as well as to achieve a sustainable condition in the long term. Over the past decades, significant efforts have been made to develop both materials and surgical techniques that can predictably contribute to periodontal regeneration. Among the various periodontal defects associated with periodontitis, intraosseous defects represent one of the most challenging clinical conditions due to their complex morphology and limited potential for spontaneous healing, thereby necessitating a regenerative therapeutic approach. The morphology of the intraosseous defects must be carefully considered when selecting an appropriate regenerative approach. Intrabony defect morphology is commonly classified based on the number of remaining bony walls (one-wall, two-wall, or three-wall defects, or combined configurations). Defect morphology plays a critical role in periodontal regeneration by influencing the availability of essential cellular and vascular elements. Additionally, the remaining bony walls contribute to clot stability and space maintenance, both of which are essential for successful regenerative outcomes. Deep and narrow three-wall intrabony defects provide a favorable spatial architecture and are therefore associated with the highest potential for predictable periodontal regeneration. The regeneration of intrabony defects remains a significant clinical challenge in periodontal therapy. Consequently, numerous regenerative techniques and a wide range of biomaterials have been developed to enhance biological processes and improve both the quality and quantity of newly formed periodontal tissues. Regenerative procedures include the use of bone grafts, barrier membranes, biological mediators, or combinations thereof, with the aim of facilitating true periodontal regeneration, which is histologically characterized by the formation of new root cementum, periodontal ligament, and alveolar bone. The Non-Incised Papillae Surgical Approach (NIPSA), introduced in 2018 by Moreno Rodríguez and Caffesse, is a microsurgical technique designed for the treatment of isolated, deep periodontal defects. The technique is based on a single buccal horizontal incision placed apically to the periodontal defect,while preserving the marginal and lingual tissues intact, in order to create optimal conditions for periodontal regeneration and soft-tissue preservation. .

EthOss is a bioactive synthetic alloplastic bone graft composed of 65% beta-tricalcium phosphate and 35% calcium sulfate that can be easily manipulated and adapted to intrabony defects after mixing with saline or the patient's own plasma to provide a scaffold for newly formed bones.

Hyaluronic acid has specific physical and biochemical properties in normal tissues that make it an ideal structural compound. It is detectable in all vertebrate animals and within bacterial biofilms.There is no antigenic specificity for species or tissues; thus, hyaluronic acid has a low potential for allergic or immunogenic reactions. Cross-linked hyaluronic acid represents a chemically modified form of native hyaluronic acid in which individual polymer chains are covalently interconnected, forming a three-dimensional network. This structural modification significantly enhances the mechanical stability of the material, increases its resistance to enzymatic degradation, and prolongs its persistence within the tissues compared with non-cross-linked hyaluronic acid. Consequently, cross-linked hyaluronic acid demonstrates prolonged bioavailability and sustained biological activity, making it particularly suitable for periodontal and soft-tissue regenerative procedures.Minimally invasive surgical techniques have gained increasing attention in periodontal regenerative therapy, particularly for the management of intrabony defects. The Non-Incised Papillae Surgical Approach (NIPSA) has been proposed as a treatment modality aimed at preserving soft tissues and enhancing regenerative outcomes. NIPSA involves a single incision in the mucosa apical to the bone margin delimiting the periodontal defect, maintaining the marginal and interproximal soft-tissue architecture intact. This preserved tissue acts as a "dome," protecting the regenerative space within the vertical component of the defect and preventing collapse of the interproximal soft tissues into the underlying defect. Clinical studies evaluating NIPSA have demonstrated favorable outcomes, including periodontal pocket resolution, clinical attachment level (CAL) gain, and enhanced soft-tissue preservation, with particular improvements in interproximal soft-tissue stability. However, since bone substitute materials were used in conjunction with NIPSA in all reported studies, it remains difficult to isolate the specific contribution of the bone substitutes in supporting soft tissues, preventing their collapse, and enhancing papilla preservation. In addition, regenerative biomaterials such as alloplastic bone substitutes and cross-linked hyaluronic acid have been used with NIPSA to support periodontal wound healing and tissue regeneration. However, clinical evidence, comparing the regenerative effectiveness of these biomaterials when used individually or in combination with NIPSA remains limited. Therefore, further randomized clinical and radiographic studies are required to evaluate and compare their effectiveness in the treatment of periodontal intrabony defects.