A manually controlled new device for punctuate mechanical stimulation of teeth during functional magnetic resonance imaging studies.

AIM

To design a simple and affordable device that could apply standardized mechanical punctuate stimuli to trigger the periodontal mechanoreceptors during functional magnetic resonance imaging (fMRI).

MATERIAL AND METHODS

A new manually controlled device using von Frey monofilaments was tested on a phantom and on eight volunteers. Four block design paradigms with different timing were compared. Teeth 11, 12, 13, 21, 22, 23 and the thumb were stimulated.

RESULTS

The device did not induce any artefacts in MR images. The most efficient protocol included an epoch duration of 24 s and stimuli delivered at 1 Hz. When stimulating the teeth, activations of the primary (S1) and secondary (S2) somatosensory areas were consistently obtained, either on the ipsilateral, contra-lateral or both sides. Stimulation of the thumb led to activations of the contra-lateral S1 area and either ipsilateral or contra-lateral S2 area.

CONCLUSION

The use of this innovative tool should allow to perform fMRI studies aimed to unveil the neural correlates of periodontal neural receptors, and to understand their plasticity induced by tooth loss and their eventual replacement by endosseous oral implants.