A Level Teaspoon in a Cup of Water: The Actual Salt Concentration of the Standard Aftercare Rinse and a More Repeatable Recipe

Patients recovering from a tooth extraction are told to rinse with a teaspoon of salt in a cup of warm water, an instruction whose terms are undefined. This study computes the concentration of six common versions using stated spoon masses (half teaspoon 3.0 g, level teaspoon 6.0 g, heaped teaspoon 9.0 g) and vessel volumes of 200, 250, and 350 mL, against the isotonic reference of 0.9 percent and a stated tolerable band of 0.7 to 1.2 percent. The six versions produce 1.2, 2.4, 3.0, 3.6, 1.71, and 1.5 percent; only one, the half teaspoon in 250 mL at 1.2 percent, falls inside the band. A proposed recipe, one level teaspoon in a standard 500 mL bottle, gives 1.2 percent with the volume fixed by the bottle. This study is simulated, not measured. SIMULATED, NOT MEASURED.