Underbite is a form of malocclusion. It can be a result of dental alignment, or due to a jaw bone issue.
To determine whether it is of dental origin or jaw bone, your dentist will need to do a thorough examination, including an X-ray to analyze the situation. This diagnostic step is important because it determines the course of treatment.
Braces can effectively resolve underbite problems if it is due to dental alignment. However, if the problem arises from your skeletal bone, braces alone may not resolve the issue.
Is the pain that you are experiencing coming from the joint? It is common for any form of malocclusion to eventually lead to jaw joint pain.
It is unfortunately a worrying sign - you should seek advise from your dentist as soon as possible. Hope this helps in your decision making!
