Table 6. Recommendations for the removal of orthodontic appliances based on the type of material.

Appliance type	Magnitude of artifact	Recommendations for appliance removal
Ceramic brackets with metal slot and titanium brackets	Very limited or no artifacts	Removal is only necessary if the area under investigation is close to fixed appliances (i.e., in the oral cavity).
Fixed retainers containing steel	Poor image quality in the area of the oral cavity only	Removal is only necessary ahead of an MRI scan if the area under investigation is within the oral cavity.
Stainless steel brackets	Extensive artifacts in the oral cavity and other areas (TMJ, posterior cerebral fossa, maxillary sinus), images uninterpretable	Removal is always necessary before MRI images of the head and neck area are taken.

MRI, magnetic resonance imaging; TMJ, temporomandibular joint.