Effect of urea concentration on its utilization, on the pH and the formation of ammonia and carbon dioxide in a human salivary sediment system

Biswas, Shibdas; Kleinberg, I.

doi:10.1016/0003-9969(71)90121-x

Cited by 39 publications

(13 citation statements)

References 15 publications

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“…The results from early studies, which have been confirmed over a 20-year period, indicate that urea is rapidly metabolized in the mouth by resident bacteria expressing urease activities. As a result, ureolysis probably contributes a great deal to the ammonia present in dental plaque (Kleinberg, 1967;Biswas and Kleinberg, 1971;Singer et al, 1983;Singer and Kleinberg, 1983a,b;Cutress, 1987, 1988;Wijeyeweera and Kleinberg, 1989a More recent studies have been conducted in which cells from pH-controlled, steady-state chemostat cultures at pH values of 7.0, 6.0, and 5.5 were used. The results showed that S. salivarius could dramatically regulate the amount of urease it produced.…”

Section: (B) Role Of Salivary Urea In Protecting the Oral Streptococcmentioning

confidence: 99%

Genetics of Acid Adaptation in Oral Streptococci

Quivey

Kuhnert

Hähn

2001

Critical Reviews in Oral Biology & Medicine

116

107

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A growing body of information has provided insights into the mechanisms by which the oral streptococci maintain their niches in the human mouth. In at least one case, Streptococcus mutans, the organism apparently uses a panel of proteins to survive in acidic conditions while it promotes the formation of dental caries. Oral streptococci, which are not as inherently resistant to acidification, use protective schemes to ameliorate acidic plaque pH values. Existing information clearly shows that while the streptococci are highly related, very different strategies have evolved for them to take advantage of their particular location in the oral cavity. The picture that emerges is that the acid-adaptive regulatory mechanisms of the oral streptococci differ markedly from those used by Gram-negative bacteria. What future research must determine is the extent and complexity of the acid-adaptive systems in these organisms and how they permit the organisms to maintain themselves in the face of a low-pH environment and the microbial competition present in their respective niches.

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Section: (B) Role Of Salivary Urea In Protecting the Oral Streptococcmentioning

confidence: 99%

Genetics of Acid Adaptation in Oral Streptococci

Quivey

Kuhnert

Hähn

2001

Critical Reviews in Oral Biology & Medicine

116

107

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“…the method ofFolin-Bell -(5-10), microdiffusion (l, [11][12][13], distijlatipn in vacuo (14) and common distillation (15,16).…”

Section: Introductionmentioning

confidence: 99%

Determination of Ammonia in Saliva Using Indophenol, an Ammonium Electrode and an Enzymatic Method: A Comparative Investigation

Huizenga¹,

Ch²

1982

CCLM

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Summary: Three methods for determination of ammonia in saliva are reported. The indophenol method on diluted saliva has the best precision (coefficient of Variation 0.8%) and the lowest reagent cost. The ammonium electrode method is the quiekest, but it requires simultaneous determination of the potassium content of the specimen. The enzymatic method gives the same result äs the electrode method, but is more expensive. Deproteinisation proved not to be necessary. In one hour 10, 20 or 40 determinations can be performedVith the enzymatic, indophenol-or the electrode method, respectively. Bestimmung von Ammoniak im Speichel mit der Berthelot-Reaktion, einer Ammonium-Elektrode und einer enzymatischen Methode: Eine vergleichende Untersuchung Zusammenfassung: Drei Methoden zur Bestimmung von Ammoniak im Speichel wurden geprüft. Die Methode nachBerthelot für verdünnten Speichel hat die beste Präzision (VK -0,8%) und die geringsten Reagenzienkosten. Die Messung mit der Ammoniak-Elektrode ist die schnellste, erfordert jedoch die gleichzeitige Kalium-Bestimmung. Die enzymatisehe Methode ergibt die gleichen Resultate wie die potentiometrische, ist jedoch teurer. Enteiweißung ist nicht erforderlich. In einer Stunde können mit der enzymatischen Methode 10 ? mit der Berthelot-Reaktion 20 und mit der potentiometrischen Methode 40 Bestimmungen durchgeführt werden.

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“…1943], salivary sediment [Biswas and Kleinberg, 1971;Sis sons et al. 1985], dental plaque [Frostcll.…”

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confidence: 99%

Effect of Urea in Sugar-Free Chewing Gums on pH Recovery in Human Dental Plaque Evaluated with Three Different Methods

1995

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The aim of this investigation was to study the effect of sugar-free chewing gums containing various amounts of urea on the pH recovery in dental plaque. Three plaque-measuring methods were used, i.e., the telemetric, the microtouch, and the sampling methods. The subjects who had refrained from toothbrushing for 3–7 days rinsed with either 10 or 50% (w/v) sucrose solutions and then chewed for 10 min: (1) one piece of chewing gum in a series of six tests in which the urea content increased from 10 to 80 mg per piece of gum; (2) one or two pieces of gum containing 20 mg urea, and (3) one, two, or three pieces of gum, one after the other, containing 20 mg urea. In some of the test series, a conventional sugarless gum was used as a control. A quick rise in plaque pH was found with all urea-containing chewing gums within the first minutes of chewing, and neutralization continued during the whole 10-min chewing periods. Higher concentrations of urea resulted in more pronounced pH recovery. Slightly higher plaque pH values were found when chewing on two pieces at a time of a 20-mg urea gum was compared with only one piece. Significantly higher pH values were recorded when using three pieces of chewing gum, one after the other (10+10+10 min), as compared with two pieces (10+10 min) or just one piece (10 min). In conclusion, all sugar-free chewing gums tested, particularly the urea-containing ones, initiated a pronounced pH recovery in dental plaque when chewed after a sucrose rinse. Variations were seen depending on the amount of urea in the gum and on the number of pieces chewed.

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Effect of urea concentration on its utilization, on the pH and the formation of ammonia and carbon dioxide in a human salivary sediment system

Cited by 39 publications

References 15 publications

Genetics of Acid Adaptation in Oral Streptococci

Genetics of Acid Adaptation in Oral Streptococci

Determination of Ammonia in Saliva Using Indophenol, an Ammonium Electrode and an Enzymatic Method: A Comparative Investigation

Effect of Urea in Sugar-Free Chewing Gums on pH Recovery in Human Dental Plaque Evaluated with Three Different Methods

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