[Organic fluoride].

The purpose of this methodological study was to compare methods used to assess reliability for gingival inflammation and plaque. Duplicate examinations were conducted by one examiner on 17 subjects (506 scoring sites), using the gingival index (GI), bleeding points index (BPI), and plaque index (PI). The percentage of agreement, the weighted and unweighted kappa coefficients, and Pearson correlation coefficients were calculated as statistics of reliability for mesial buccal site scores and whole mouth mean scores when appropriate. For mesial buccal sites the respective values of the GI, BPI, and PI for weighted kappas were: 0.47, 0.49, and 0.75; for the correlation coefficients: 0.47, 0.49, and 0.76; for unweighted kappas, 0.39, 0.49, and 0.39; and for percentage of agreement 66.2%, 76.1%, and 51.2%. For whole mouth means the correlation coefficients for the GI, BPI, and PI were 0.87, 0.59, and 0.87, respectively. In conclusion, the most useful statistics in assessing the intraexaminer reliability of a solo examiner in descending order were the weighted kappa coefficient, Pearson correlation coefficient, the unweighted kappa coefficient, and percentage of agreement.

Dental Plaque↗

PubMed1995

A comparative study of glucose and galactose uptake in pure cultures of human oral bacteria, salivary sediment and dental plaque.

The ability to utilize glucose and the weaker sugar acidogen, galactose, was surveyed in salivary sediment, pooled dental plaque, and in pure cultures of the bacteria that numerically comprise most of the bacteria in these mixed microbial systems. Except for a veillonella isolate, which showed no uptake of either sugar, glucose was utilized more rapidly than galactose by the 27 pure cultures tested and by both sediment and plaque. This sugar difference was also seen for two other measures of glycolysis, formation of acid and previously studied ability to produce an acidic pH. Rates of uptake of the two sugars by individual pure cultures varied considerably. Generally, the Gram-positive bacteria utilized glucose and galactose at rates similar to those seen with salivary sediment and dental plaque, whereas the Gram-negative cultures tested showed much slower uptakes. Bacteria previously identified as arginolytic had lower glucose and galactose uptake rates than similar non-arginolytic micro-organisms. This, together with the ability to produce base from arginine, would explain their tendency to produce a less acidic pH. In pure culture mixtures, uptakes were generally predictable and indicated an averaging effect. When the microbial compositions of salivary sediment or dental plaque were altered by mixing with pure cultures of high glucolytic activity, such as many of the Gram-positives, glucose uptake was enhanced. The opposite was observed when the less glucolytic Gram-negative bacteria were similarly incorporated. As well as determining the glucose and galactose uptake rates of the various bacteria that collectively comprise the bulk of the salivary sediment and supragingival plaque microfloras, this study has shown how variation in microbial composition affects sugar uptake rates and has indicated how microbial composition could be manipulated to produce dental plaques with different capacities to ferment sugars and presumably different cariogenicities.

Dental Plaque↗