Botox for TMJ Disorders May Not Lead to Bone Loss in the Short Term
Low-Dose Botox Injections for Jaw and Facial Pain Not Linked to Bone Changes, But NYU Dentistry Researchers Observe Reduced Bone Density at Higher Doses.
Botox injections to manage jaw and facial pain do not result in clinically significant changes in jaw bone when used short term and in low doses, according to researchers at NYU College of Dentistry. However, they found evidence of bone loss when higher doses were used.
The researchers, whose findings are published in the Journal of Oral Health Rehabilitation, call for further clinical studies to track bone- and muscle-related changes with long-term use of Botox for TMJD, or temporomandibular muscle and joint disorders.
Botox (or botulinum toxin), an FDA-approved injectable drug, is approved to treat certain muscle and pain disorders, including migraines. It works in part by temporarily paralyzing or weakening muscles. In the U.S., a Phase 3 clinical trial is currently underway to study the use of Botox to treat TMJD, but in the meantime, it is increasingly being used off-label.
Thus far, small studies using Botox to treat TMJD in humans have had mixed results. In animal studies, Botox injections in jaw muscles have led to major bone loss in the jaw. This is thought to be due to the muscles not being used to exert force needed for bone remodeling, but Botox may also have a direct effect on bone resorption, the process of breaking down bone tissue.
The NYU study included 79 women with TMJD affecting their facial muscles: 35 of whom received Botox injections (between two and five rounds in the past year) and 44 who were not treated with Botox but may have used other TMJD treatments. Using specialized CT scans, the researchers measured participants’ jaw bone density and volume.
The researchers found that jaw bone density and volume were similar between women who had Botox injections to treat their TMJD and those who did not. While most study participants were given relatively low doses of Botox—smaller than in most clinical trials for TMJD—individuals who received higher doses of Botox were more likely to have lower bone density.
The team recommends that more human studies be conducted to better understand the impact of the long-term use of Botox on jaw muscles and bones—and whether it just reduces muscle force on bone or also plays a direct role in altering bone resorption.
