obsolete chronic primary myofascial orofacial pain 2025-06-30T18:39:42Z true PMID:32103673 OBSOLETE. Mild to moderate levels of deep aching or pressing pain in the masticatory muscles, occurring episodically or unremittingly, often associated with functional impairment such as perceived difficulties in moving the lower jaw, chewing and/or yawning, etc., and with onset more than 3 months ago. It is often associated with psychosocial distress. chronic primary myofascial orofacial pain obsolete class term imported Ava E. Cunningham