How much local anesthetic is contained in a cartridge of 4% articaine (1.7 ml solution)?

To determine the amount of local anesthetic contained in a cartridge of 4% articaine that has a volume of 1.7 ml, the calculation is based on the concentration of the solution.

A 4% solution means there are 4 grams of articaine per 100 mL of solution. To convert this to milligrams, we remember that 1 gram is equal to 1000 milligrams. Therefore, 4 grams is equivalent to 4000 mg.

Now, we need to find out how much is in 1.7 ml. Since 100 mL contains 4000 mg of articaine, we can set up a proportion:

4000 mg / 100 mL = X mg / 1.7 mL.

By cross-multiplying, we obtain:

X = (4000 mg * 1.7 mL) / 100 mL = 68 mg.

Thus, a cartridge of 4% articaine containing 1.7 mL of solution has 68 mg of articaine. This reasoning confirms that option A is the correct choice.