Titanium brackets as an alternative for MRI scans

Magnetic resonance imaging (MRI) scans are a routinely used imaging modality in modern medical practice and can produce very detailed images of the hard and soft tissues. While they can be taken on any region of the body, they are often used for investigations in the head and neck region.

Although comprising a relatively small proportion of orthodontic patients overall, there are an increasing number presenting for treatment with a need to undergo routine MRI scans as part of their ongoing medical care.

MRI scans work by creating a magnetic field around the body and the protons contained within the body's water molecules align with the magnetic field before moving back to resting position.

The extent to which a material gets magnetized in an external magnetic field is known as susceptibility. Diamagnetic substances disperse the magnetic field with no significant field distortion and almost all the body tissues belong to this group. Ferromagnetic materials (such as stainless steel) are strongly susceptible giving rise to inhomogeneity of the magnetic field This can create significant artefacts on the MRI images, appearing as large dark areas around the metal with distortion of the surrounding structures. Paramagnetic substances such as titanium are weakly susceptible to magnetic fields and cause relatively lesser distortion of the magnetic field, thus dramatically reducing susceptibility artefact. The degree of susceptibility artefacts depends on the types of MRI sequence used and field strength of the scanner, being worse on a 3 Tesla (T) MR scanner compared to a 1.5 T.