THE RELIABILITY AND VALIDITY OF TOOTH PULP ALGESIMETRY

¹ Department of Physiology and Pharmacology, Northwestern University Dental School, Chicago, Illinois

An effort has been made to evaluate quantitatively the reliability and validity of electrical excitation of the human tooth pulp as an algesimetric method.

Mechanical variations were rigorously controlled and the influence of suggestion was carefully evaluated and found to he significant after oral medication.

Evidence of reliability was obtained by finding that a) no significant differences occurred between the thresholds of experimentally induced pain when measured in 28 teeth, three times in immediate succession; and b) when 2 teeth were studied in each of 9 men, the changes in threshold which occurred after injection of 65 mgm. of codeine correlated very significantly in 4 of the subjects. The stability of the threshold was studied and found to decline significantly over two-hour's time.

The effects of A. P. C. and aspirin, 0.63 gm. each, orally, did not differ from each other or from the effects of placebos, though all three elevated the threshold significantly.

The validity of the method is partially attested by finding that 65 mgm. of codeine significantly elevated the threshold above the average pre-medication level, above the average threshold when no treatment is given and above the average threshold after placebos.