SIGNIFICANCE OF SALIVARY ANALYSES UPON SMALL GROUPS OF SUBJECTS

¹ The Division of Dental Research, School of Medicine and Dentistry, University of Rochester Rochester, N.Y.

Eighteen different chemical and bacteriological studies were made on 20 samples of stimulated, whole saliva taken from different subjects (Table I) and the results treated by the usual statistical methods.

When the group was considered as a whole, no definite correlation could be found between any constituent studied and the rate of flow, either on an amount-per-cc. basis or on an amount-per-cc.-per-minute basis (fig. 1). The range of any constituent was just as great on either basis; in fact, it was greater when the values were expressed on the rate-of-flow basis (Table II).

When divided into "fast" and "slow" groups of 8 cases each, throwing out the 4 cases nearest the mean for the group of 20, there was a significant difference between the rates of flow of total nitrogen, protein nitrogen, acid-neutralizing power, base-neutralizing power, total buffer capacity, total solids, total bacteria, and volume (Table III).

When divided into "old" and "young" age groups, 2 of the 8 significantly different constituents just mentioned were still significantly different and 3 others were on the verge of significance (D/D > 2, < 3).

When calculated on an amount-per-cc. basis, no correlation could be found between any constituent and either the rate of flow or age.

The work emphasizes the difficulty of interpreting the results of salivary analyses from small groups, no matter how they are calculated.