Abstract
Magnetic resonance imaging (MRI) is a widely used diagnostic technique. Patients wearing orthodontic appliances are often requested to remove their appliances, even when the MRI exam involves anatomical areas far from mouth, in order to avoid heating of the metal and detachment of the appliance. The purpose of the present investigation was to measure and compare temperature changes and orthodontic appliances’ adhesion to enamel after different MRIs. A total of 220 orthodontic brackets were bonded on bovine incisors and wires with different materials (stainless steel and nickel titanium). Moreover, various sizes (0.014″ and 0.019″ × 0.025″) were engaged. Appliances were submitted to MRI at two different powers (1.5 T and 3 T). The temperatures of brackets and wires were measured before and after MRI. Subsequently, the shear bond strength (SBS) and adhesive remnant index (ARI) scores were recorded. Statistical analysis was performed. After MRI, a significant increase in the temperature was found for both the brackets and wires in some groups, even if the mean temperature increase was clinically insignificant, as the temperature ranged between 0.05 °C and 2.4 °C for brackets and between 0.42 °C and 1.74 °C for wires. The MRI did not condition bracket adhesion in any group. No differences were reported when comparing the 1.5 T with 3 T groups. The ARI Scores were also significantly lower after MRI. The results of the present report show that, under MRI, orthodontic appliances present a low temperature rise and no debonding risk. Therefore, the removal of orthodontic appliance is not recommended routinely, but is suggested only in the case of a void risk or potential interference in image quality.
Highlights
Magnetic resonance imaging (MRI) is a non-invasive radiologic diagnostic technique that is widely used to assess lesions, those involving soft tissues [1]
The second null hypothesis of the investigation is that there is no significant difference in the shear bond strength values among different groups
The normality of distribution was calculated with the Kolmogorov and Smirnov test
Summary
Magnetic resonance imaging (MRI) is a non-invasive radiologic diagnostic technique that is widely used to assess lesions, those involving soft tissues [1] As this procedure does not involve the use of ionizing radiation, its applicability is wide and common, for both young and aged patients [2]. The magnetic field attracts metal objects that patients could accidentally wear during examination, resulting in patient injury and damage to the radiographic device [4]. The removal of orthodontic appliance, even for only a few days or hours, is time consuming, costly, and uncomfortable for both the patient and the clinician [9] This procedure could damage the enamel structure or lengthen treatment time [10]
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