This randomized clinical trial aims to evaluation the clinical and radiographic outcomes of hyaluronic acid, TheraCal, and Mineral Trioxide Aggregate (MTA) when used as pulpotomy agents in primary molars.

The main question it aims to answer is:

In children with restorable mandibular second primary molars requiring pulpotomy, does the use of hyaluronic acid or TheraCal LC, compared to MTA, result in improved clinical and radiographic success rates over a 12-month follow-up period?

Premature loss of primary teeth can affect occlusion development and lead to complications such as space loss and malalignment of permanent teeth. To prevent this, effective pulpotomy treatment is essential. Therefore, identifying the most suitable pulpotomy agent is crucial to retain primary teeth until their natural exfoliation.

According to MTA research, it has a high success rate as a pulpotomy agent and favors tissue regeneration while also having a good long-term prognosis, good biocompatibility, and strong sealing capacity . Among its many applications are direct pulp capping, pulpotomy, root end filling, apexification, apexogenesis, and root perforation . Low compressive strength, high pH (approximately 10.2 after setting which take 3 hours, pH increase to 12,5), high cost, short shelf life, manipulation challenges, lengthy setting time, and discoloration are some disadvantages.

TheraCal LC (Bisco, Schaumburg, IL, USA) is a novel calcium silicate-based resin-modified material designed as a liner under restorative materials to protect and stimulate the pulp in both direct and indirect pulp capping. It contains polyethylene-glycol dimethacrylate monomers, barium zirconate, and tri-calcium silicate particles. According to earlier research, the TheraCal LC material stimulated the production of secondary dentin and apatite by releasing calcium.

TheraCal provides a number of advantages over other silicate-based materials, including low solubility, easy application, good mechanical properties, setting time, adequate bonding ability, and prevention of microleakage. Commercially available as a syringe, TheraCal is user-friendly. TheraCal is a good option for kids who can't handle long visits and might eventually stop cooperating because of all these benefits.

Hyaluronic Acid (HA) is made up of polyanionic disaccharide units of N-acetyl glucosamine and glucuronic acid joined by alternating β-(1ــــ3) and β-(1ــــ4) linkages. It is a naturally occurring non-sulfated glycosaminoglycan with a high molecular weight of 4000-20,000,000 Da. It is a linear polysaccharide found in the extracellular matrix of skin, vitreous humor, embryonic mesenchyme, connective tissue, synovial fluid, and several other human tissues and organs . It is an appealing material for use in several dental operations due to its biocompatibility, regenerative qualities, and antibacterial properties .

It is used in dentistry to treat alveolar osteitis, peri-implantitis, chronic periodontitis, and gingivitis; manage wound healing following free gingival graft; control symptoms like pain, swelling, and trismus that may arise following tooth extraction; heal recurrent oral ulcers; and to manage teething symptoms. Additionally, HA is employed in research utilizing human dental pulp stem cells (hDPSCs) in an effort to offer a novel method of regenerative endodontic therapy.

So the present study will be conducted for evaluation of Hyaluronic Acid, TheraCal, and Mineral Trioxide Aggregate as Pulpotomy Agents in Primary Molars.

Inclusion Criteria:

• Age 4-8 years,
• Co-operative patient
• At least one restorable mandibular second primary molars with deep carious lesions requiring pulpotomy.
• Absence of gingival swelling or sinus tract.
• Absence of spontaneous pain.
• Absence of pain on percussion.
• Controlled bleeding.
• First treatment the tooth.
• Possibility of restoring the tooth with a stainless steel crown.
• No Radiographic evidence of changes associated with pulp degeneration, such as widening of PDL space, internal root resorption, external root resorption, inter-radicular or periapical bone destruction (radiolucency).

Exclusion Criteria:

• Swelling, sinus tract, or fistula.
• Spontaneous pain.
• Necrotic pulp, pathological mobility.
• Cases require for general anesthesia.
• A history of repeated need for analgesics.
• Patients with any systemic diseases.
• Uncontrolled bleeding.
• Selected deciduous teeth without a permanent successor

Operator Blinding: The operator performing the procedure will not be blinded due to the differences in handling and appearance of the materials.

Patient and Parent Blinding: Participants and their parents/legal guardians will be blinded to the type of pulpotomy agent used. All materials will be applied under rubber dam isolation, and the clinical procedure will be standardized to avoid revealing the material identity.

Outcome Assessor Blinding: The clinical and radiographic evaluations will be performed by a blinded, calibrated examiner who is unaware of the group assignments. The radiographs will be coded and assessed using standardized criteria to prevent bias.