Jaw is out of line because of teeth grinding. will a night time teeth guard help my jaw re-align?

Out of line jaw: What do you mean by this? A teeth guard helps simply to prevent the long term issues from teeth grinding but it alone should not result in any jaw displacement.

Night guard: Is the most effective appliance for tmj. Intraoral occlusal appliance therapy may offer a noninvasive adjunctive method of managing teeth grinding. It is designed to provide a stable occlusal posture by creating contacts between the occlusal surface of the appliance and opposing teeth. Rec.: see a dentist for thorough evaluation.