ORAL SENSORY THRESHOLDS OF PERSONS WITH NATURAL AND ARTIFICIAL DENTITIONS

¹ Laboratory for Oral Physiology, Tufts College Dental School, Boston, Mass., and Department of Psychology, Brown University, Providence, R. I.

Judgment of thickness of disks between anterior teeth is similarly acute among denture wearers and persons with a natural dentition. The minimal threshold is 0.18 mm. or 3.3 per cent of disks about 5 mm. thick.

The acuteness of hardness judgments by natural and artificial dentition cases is similar when tested on soft rubber disks between anterior teeth. With hard rubber disks the denture wearers are less sensitive.

The tactile thresholds on biting surfaces of teeth of natural dentition cases ranged from an average of 1 Gm. on anterior teeth to 10 Gm. on molar teeth. The median threshold for eight denture cases was over 125 Gm. at the first premolar position on the denture.

Nine out of ten natural dentition cases were able to detect 2.9 per cent or less CaCO₃ in bland pudding, whereas six out of ten denture wearers required over 9 per cent.

In general it appears that the sensory discrimination of denture patients is not impaired when the forces and movements involved are of the magnitude used in mastication. When very small forces or movement are encountered as in judgments of texture, the denture patients seem to possess considerable handicap.