‘Molto al dente’ means very al dente, and is similar to blanching. It is used when the pasta is intended to be cooked twice, either during service, but also for pasta bakes that will go in the oven. When the pasta is ‘molto al dente', again, the only way to tell is to bite it. You can drain and run the pasta under cold water to stop the cooking process, although be aware that washing the pasta will rinse off the starch, so it affects the nutritional value of the pasta, and some Italians might take offence if they catch you doing this.
Can I par-boil or blanch al dente pasta?
You can blanch (cook it for half the time) pasta ahead, so that when you want to prepare your meal, you only have to plunge the pasta into boiling water for 2-3 minutes. Many chefs use this technique when working busy service.