Archives of oral biology vol:28 issue:8 pages:659-63
In seven volunteers, controlled small forces were applied in an axial direction to a maxillary central incisor. The forces were generated by a stimulating device supported by the maxillary molars. The stimuli had a symmetrical triangular shape; force-application rates were varied from 1.88 to 960 mN/s. Threshold levels of sensation were determined at the various force-application rates. The relation between force-application rate and threshold level was negative, using 1.88, 3.75 and 7.5 mN/s stimuli. This trend was interrupted as threshold levels were higher at 15 than at 7.5 mN/s. In the range of more rapidly applied forces, 15-960 mN/s, the relationship was also negative, consistently, with a slope of -0.22 of the linear regression line after logarithmic transformation. It was concluded that the periodontal mechanoreceptive unit, as far as conscious functioning is concerned, may be described as a relatively inaccurate static force-detector when small magnitude forces are applied at low rates. Some rate sensitivity appears with more rapidly-applied stimuli.