Sue Herring was trained at the University of Chicago (B.S. Zoology, Ph.D. Anatomy) where she studied the comparative cranial anatomy of pigs and their close relatives. Feeling the need to work with live animals, she moved to the College of Dentistry, University of Illinois at Chicago as an NIH postdoctoral fellow, where she developed techniques to record masticatory muscle activity and jaw movement from unrestrained animals. She remained at UIC until 1990, rising to Professor of Oral Anatomy and Anatomy. In 1990 she took up her current position in Seattle as Professor of Orthodontics and Oral Biology (now Oral Health Sciences) at the University of Washington. Her work on the biology of the craniofacial musculoskeletal system has been continuously funded by NIH for over 35 years. She has served on the editorial boards of multiple journals and held office in several societies, including the Society for Integrative and Comparative Biology (chair, Vertebrate Morphology, 1983-4), International Association of Dental Research (Craniofacial Biology Group, president 1997-8), International Society of Vertebrate Morphology (president, 1994-7), and AAAS (member-at-large, Section R, 2008-12). She became a fellow of AAAS in 1992 and of AADR in 2018. She is the recipient of the Craniofacial Biology Research Award from IADR (1999) and the Rothwell Lifetime Achievement Award from UW Dentistry (2015). Her work on the effects of botulinum neurotoxin injection into the muscles of mastication received the Watson Award from the Am. J. Orthod. Dentofac. Orthop. in 2016.

The use of paralytic botulinum toxins in muscles of mastication has vastly expanded in recent years. In addition to cosmetic facial shaping, these toxins are intended to relieve spasm and reduce pain. However, such treatment removes the major forces applied to the jaw, which like other bones requires loading for maintenance. The functional effects on muscle are temporary, but evidence on structural changes is lacking. This presentation will center on a comprehensive series of rabbit studies which reveal severe bone loss in the TMJ and show further that return of muscle force is due to compensation rather than recovery.

Learning objectives:
1. Understand the mechanism by which botulinum toxins (Botox, Dysport, Xeomin, Myobloc etc.) affect muscle.
2. Explore the time course of functional recovery after single and multiple injections of toxin into the masseter muscle.
3. Learn how botulinum toxin changes the structure of the masseter muscle and how it affects bone in the mandible.
4. Evaluate whether the effects of botulinum toxins are truly temporary.