Oxymetazoline Versus Sodium Hypochlorite as Hemostatic Agents in MTA Pulpotomy of Primary Molars (OXY - MTA)

The rationale for pulpotomy procedure is based on the healing capacity of the remaining pulp tissue following surgical amputation of the affected or infected coronal pulp. After achieving hemostasis, the exposed pulp stumps are covered either with a pulp-capping agent that promotes healing or with an agent that fixes the underlying tissue. MTA has been established as the gold standard medicament for pulpotomy owing to its several desirable properties such as biocompatibility, bioactivity, hydrophilicity, radiopacity, sealing ability and low solubility.

Besides the type of the pulp dressing material, one of the crucial parameters influencing the success of the pulpotomy procedure is the ability to control bleeding from the amputated pulp tissue. Selection of a hemostatic agent during pulpotomy has been a subject of extensive research and debate with respect to its influence on clinical and radiographic outcomes. The hemostatic agent provides not only hemostasis but also a sterile environment which is essential for pulp healing. Failure to achieve proper hemostasis means that blood will be continuously oozing out resulting in dislodgment of the placed medicament which will form a thick fibro purulent membrane over the pulpal tissue creating a dead space paving way for secondary infection and subsequent failure of the procedure. Furthermore, blood clot formation after hemostasis is undesirable because the fibrin present in the clot can act as a chemoattractant for polymorphonuclear leukocytes leading to prolonged pulpal inflammation.

Sodium hypochlorite (NaOCl) is one of the most popular hemostatic agents. It has tissue dissolution capacity by interfering with the cytoplasmic membrane integrity leading to irreversible enzymatic inhibition, biosynthetic change in cell metabolism, and phospholipid destruction in lipid peroxidation. It also helps in the formation of dentinal bridge. NaOCl has unique properties of simultaneous disinfection of dentine-pulp interface and chemical amputation of necrotic cells and blood clot. This ensures direct contact between pulp tissue and the capping material facilitating wound healing. In spite of its favorable antibacterial and hemostatic properties, NaOCl is considered cytotoxic. A histological study demonstrated that irrigating the tooth with 5.25% NaOCl after access opening resulted in damage to pre-dentine and dissolution of up to 4-5 layers of odontoblasts in the pulp tissue, consequently increasing the risk of internal root resorption after exposure of calcified tissue.

Furthermore, NaOCl was found to be hazardous to dental pulp stem cells (DPSCs) and hence it may theoretically cause a disturbance in pulp healing and negatively influence the outcome of the pulpotomy procedure. Moreover, NaOCl is believed to cause damage to the surrounding tissues, and alter the properties of the remaining tooth structure as it is associated with a significant decrease in dentin elastic modulus and flexural strength. Unpleasant taste and odor could also be added to the list of drawbacks of NaOCl.

Dental pulp tissue is innervated mainly by the autonomic nervous system, and activation of α-1 receptors causes vasoconstriction. Oxymetazoline (OXY) is a highly effective α -1 receptors agonist and can initiate hemostasis by vasoconstricting the smooth muscles associated with arterioles and venules in pulp tissue.

Nasal sprays containing oxymetazoline (NS-OXY) are routinely used during otorhinolaryngology surgical procedures and by anesthesia teams to control nasal bleeding during intubation. OXY has a transient effect and is eventually systemically absorbed via blood circulation. As a selective α-1 receptors agonist, OXY has low activity on beta-adrenergic receptors that increase heart rate. This selectivity adds to the safety profile of NS-OXY in children and adults for use as a nasal decongestant and hemostatic agent in surgery.

In addition to providing effective hemostasis, NS-OXY products contain compounds that help eradicate oral bacteria that may contaminate the blood clot. NS-OXY contains benzalkonium chloride (BKC) and edetate disodium (EDTA), which are antibacterial compounds. BKC and EDTA are preservatives that increase the shelf life of the NS-OXY bottle and reduce bacterial contamination when NS-OXY is used intranasally and comes in contact with nasal bacteria. BKC, a cationic organic quaternary ammonium compound, exhibits broad antimicrobial activity and antimatrix metalloproteinase activity. Furthermore, it was found that BKC exerts a membrane disruption action against S. mutans and R. dentocariosa. EDTA improves the bacterial membrane disruption activity of BKC. Moreover, EDTA is highly biocompatible with dental pulp cells and has the potential to be bio-inductive towards mineralization through the release of transforming growth factor-β1 (TGF1β) from the dentin matrix. According to Jones et al 2026, OXY is biocompatible with dental human pulp stem cells and can be used as a hemostatic agent prior to the placement of MTA.