-has it been a while since your last cleaning?
-is this a new dental office for you?
-have you been neglecting your routine oral care of brushing and flossing at home?
-is it genetic /runs in your family?
All of these contribute to the amount of tartar and the tenaciousness of it.
As tartar calcifies over time it becomes more difficult to remove. Similar to a barnacle.
More stubborn tartar will require more time to remove.
Tartar isn’t always where you can see it above the gum line. Often it hides below the gum line causing damage. In both situations it needs to be removed for your oral health to improve.
If tartar can be seen on your X-rays in multiple places the odds are very high you will require additional appointment(s). There has to be a significant amount to be seen on X-rays.