Simplified and quantitative saliva buffer capacity test using a hand-held pH meter.
OBJECTIVE
To evaluate and compare saliva buffer capacity using a hand-held pH meter and a commercial buffer strip in patients at risk of caries.


METHODS
To obtain stimulated saliva, 109 patients were given a paraffin wax to chew for 5 minutes. After reading the pH value of 0.5 ml of tested saliva using a portable hand-held pH meter (B-212), 10 microl of 0.1N HCl was titrated into the obtained saliva up to a total titration of 160 microl, and then the pH value read each time. The commercial buffer strip (CRT) was also evaluated. The correlation in ranking results (high, medium, low) between the B-212 pH meter and CRT buffer were statistically analyzed by the Bartlett's test (P < 0.001).


RESULTS
At the point of 50 microd of titrated HCl, the individual saliva buffer capacities were ranked into one of the following three categories; high (above pH 5.5), medium (pH from 5.5 to 4.5) and low (below pH 4.5). The percentages of the tested patients for the different ranks (high, medium, low) of buffer capacity were 50%, 17% and 33% respectively for the B-212 pH meter, and 56%, 17% and 27% respectively for the CRT. For the CRT buffer, 23 out of 109 cases showed inconclusive color change under the colorimetric test. There was significant correlation between ranking buffer capacity measured by the B-212 pH meter and the CRT buffer (P < 0.001).
Kitasako
Yuichi
Y
Cariology and Operative Dentistry, Department of Restorative Sciences, Graduate School, Tokyo Medical and Dental University, 5-45 Yushima 1-chome, Bunkyo-ku, Tokyo 113-8549, Japan. kitasako.ope@tmd.ac.jp
Moritsuka
Michiyo
M
Foxton
Richard M
RM
Ikeda
Masaomi
M
Tagami
Junji
J
Nomura
Satoshi
S
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002021:Buffers; D003124:Colorimetry; D003732:Dental Caries Activity Tests / Q000295:instrumentation*; D003733:Dental Caries Susceptibility; D004566:Electrodes; D006801:Humans; D006851:Hydrochloric Acid; D006863:Hydrogen-Ion Concentration; D008875:Middle Aged; D011934:Reagent Strips; D015203:Reproducibility of Results; D012463:Saliva / Q000737:chemistry*; D017186:Titrimetry / Q000295:instrumentation
D002021:Buffers; D011934:Reagent Strips; D006851:Hydrochloric Acid