Can tmjd (via long-term night and day bruxism) contribute to / cause intermittent non-painful paresthesia in the (one side - left in my case) jawline?

Very unlikely: While not impossible,I think it would be extremely unlikely. Your symptoms could be related to a dental or a medical problem, or perhaps both. Please see your dentist as soon as possible for a complete and thorough examination and evaluation. Based upon the findings, your dentist might refer you to a physician for a consultation.

Unlikely: Numbness of the jaw would involve the inferior alveoral nerve. If you did not have surgery in the lower jaw that precipitated the numbness, you may have a destructive tumor. See an oral surgeon asap this is not something you want to delay. Act now!

Yes, but: Yes, but see an oral surgeon for exam to make sure nothing else causing numbness.