Ar. Loescher et al., CHARACTERISTICS OF PERIODONTAL MECHANORECEPTORS SUPPLYING CAT CANINE TEETH WHICH HAVE SUSTAINED ORTHODONTIC FORCES, Archives of oral biology, 38(8), 1993, pp. 663-669
The characteristics of these mechanoreceptors were investigated after
orthodontic forces had been applied for either 3 days or 12 weeks, and
also 8 weeks after the tooth had been moved into a new position and t
he tissues allowed to recover. Electrophysiological recordings were ma
de from single mechanosensitive units dissected from the inferior alve
olar nerve and each was characterized by applying forces to the tooth
crown. The characteristics were compared with those of receptors inner
vating normal teeth. Three days after the onset of tooth movement, the
periodontal mechanoreceptors had higher thresholds to forces applied
at slow rates and lower discharge frequencies. Twelve weeks after the
onset of tooth movement, the mechanoreceptors again had higher force t
hresholds and lower discharge frequencies but also responded to applie
d forces over a narrower range of directions and adapted more rapidly
than the controls. After the tooth had been moved into a new position
and the tissues allowed to recover, the mechanoreceptor characteristic
s were nearer to normal but they still had raised thresholds to forces
applied at slow rates, lower discharge frequencies, and responded to
applied forces over a narrower range of directions. It seems likely th
at the altered receptor characteristics would have resulted from a com
bination of disorganization of the collagen matrix and direct injury t
o the nerve terminals.