Can you tell me docs, is chewing gum helps to make the sharp jawline?

Possible BUT..: Just like everything else in your body, it all depends: 1)do you have a squared jaw- bone? 2)are you obese? 3)Is there any significant Class II skeletal malocclusion? Giving you a yes/no answer, without the complete picture, would be a disservice to you. Get an evaluation done with a Dentist to be sure! (It IS possible , IF you have the correct anatomy !-)