Thomas M. Graber Award of Special Merit Lecture: Cellular and Matrix Response of the Mandibular Condylar Cartilage to Botulinum Toxin

Injections of botulinum neurotoxin (botox) into the muscles of mastication have been used to alleviate the symptoms related to temporomandibular joint disorders. Studies have shown negative effects of Botox injection into the masseter in the mandibular ramus and condyle, but there are no investigations with the aim of understanding the cellular mechanisms behind the osteopenia caused by this type of treatment. This presentation will reveal the cellular responses and the structural changes of the mandibular condylar cartilage of transgenic mice after injection of Botox into the masseter.

Learning Objectives:

• Show that botox injection into the masseter of transgenic mice decreases cartilage width, cartilage thickness and proteoglycan content of the mandibular condylar cartilage.
• Demonstrate that this treatment reduces chondrocyte differentiation, proliferation and increases cell apoptosis in the mandibular condylar cartilage of mice.
• Illustrate that botox injection into the masseter decreases expression of proteins important for cell differentiation and mineralization at the mandibular condylar cartilage and subchondral bone of mice.