MRI is a safe and non invasive method to visualise the TM joint. If you are claustrophobic then you can discuss the same with the radiologist and any issue can be addressed.
Next Steps
If your dentist/Specialist has referred you for an MRI, it's better to get it done, rather then delaying.
Health Tips
Symptoms when treated early will help achieve good treatment results, delaying will only lead to further complications.