Which preservative is used in dental cartridges?

Sodium bisulfite is the preservative commonly used in dental cartridges, particularly in local anesthetic formulations that contain a vasoconstrictor, such as epinephrine. Its primary role is to prevent the oxidation of the vasoconstrictor, thus maintaining its efficacy and prolonging the shelf life of the anesthetic solution. By inhibiting this oxidative process, sodium bisulfite ensures that the local anesthetic will provide the expected numbing effect when administered.

In contrast, sodium chloride is typically included in anesthetic formulations to make the solution isotonic with body tissues, but it does not serve as a preservative. Sodium bisulfate is chemically distinct and is not commonly used as a preservative in dental cartridges. Methylparaben, while a preservative in some pharmaceutical products, is not used in dental anesthesia due to potential allergic reactions in some patients. Thus, sodium bisulfite stands out as the appropriate choice for maintaining the integrity of local anesthetics in dental practice.