Caries Research

doi: 10.1159/000259819pmid: N/A

Shannon, Ira L.; Suddick, R.P.; Edmonds, Eleanor J.

doi: 10.1159/000259818pmid: 4509044

A series of experiments were carried out to determine the effect of the rate of gland function on parotid saliva fluoride levels in the human. Means for fluoride for stimulated parotid saliva ranged from 0.012 to 0.02 ppm. These are much lower levels than those previously reported for whole saliva and support other electrode analyses recently reported. In a 3-hour experiment involving continuous exogenous stimulation, salivary fluoride levels showed no alterations suggestive of depletion. Significantly higher levels of fluoride were found in parotid saliva collected without exogenous stimulation. It is suggested that the glandular mechanisms responsible for these observations are purely passive in nature with the fluoride ion probably moving in bulk flow with the fluid of secretion as it is generated by the secretory cells. However, the exact mechanisms which govern absolute saliva fluoride levels remain obscure.

Birkeland, J.M.

doi: 10.1159/000259820pmid: 4509042

The interaction between fluoride and some plaque components has indicated that fluoride binds to norganic salivary substances which are ultrafiltrable. The ffect of pH on the affinity of fluoride to these salivary sub stances was investigated in whole saliva, ultrafiltrated saliva, and ‘synthetic saliva’. When the pH was maintained above 7, an initial fluoride ion concentration of 10^-5m (0.2 ppm) decreased to 10^-6M (0.02 ppm). Addition of sucrose to incubated whole saliva or of hydrochloric acid to the inorganic solution prevented the decrease in fluoride ion concentration. In the absence of substances which decreased pH, the fluoride ion concentration decreased from the initial 10^-5M to 10^-6M. This bound fluoride was released when the pH was decreased by means of sucrose or acid. Upon storage of the ‘synthetic saliva’, the calcium concentration decreased from 2 × 10^-3M to 2 × 10^-4M. Fluoride per se seemed to have no measurable effect upon this decrease in calcium concentration. The decrease in fluoride and calcium concentrations was inhibited by citrate. These observations indicate that fluoride in plaque may be bound to a calcium phosphate precipitate, and that the binding is affected by the pH.

Ferguson, D.B.; Fort, A.

doi: 10.1159/000259821pmid: 4509043

A study of circadian variation in unstimulated submandibular and stimulated parotid saliva has shown that concentrations of calcium and phosphate in saliva show well-defined and opposite variation during the 24 h. Individual variation exists in the amplitude and phasing of these rhythms. This factor must be considered in evaluating results of calcium and phosphate estimations and in the use of figures calculated from these concentrations. Circadian variations may explain some of the discrepancies in previous reports on salivary calcium and phosphate. Since Ca×P products show circadian variation, the composition of the oral environment varies at different times of day. It may be, therefore, that the progress of oral disease varies as a consequence.

Sönju, T.; Rölla, G.

doi: 10.1159/000259822pmid: 4509045

A method for the collection of the proteins film formed on pumiced teeth in vivo is described. The amount of adsorbed protein increased during the first 1.5 h. No differences were detected in amino acid composition of protein collected from upper molars, upper incisors, and lower anteriors. Muramic acid and diaminopimelic acid were not detected. The content of acidic amino acids in the material may support the view that acidic proteins are selectively adsorbed to tooth surfaces.

Birkeland, J.M.

doi: 10.1159/000259823pmid: 4509046

2-min mouth rinses with 7 and 10 ml 0.05% NaF were carried out by 9 adults and 24 children (10–11 years old). Each person rinsed 5 times with , fluoride each volume. The oral expectorate with the rinsing solu tion was then weighed. The fluoride ion activity of the expectorates was determined, and retention of fluoride (μg and %) was calculated. Significantly higher fluoride ion activity with 10 than with 7 ml was obtained both by the adults (14.7 ± 6.5 ppm F^-) and the children (9.0 ± 5.7 ppm F^-). The differences in retention with 10 vs. 7 ml rinses were significant: 64 ± 30μg (n = 9) and 89 ± 81 μg (n = 24). The percentage retention with 7 ml was 15.4 ± 2.6 (n = 9) and 14.1 ± 4.8 (n = 24), the corresponding values with 10ml were 13.6 ± 2.2 and 13.8 + 3.6. Each subject seemed to have a pattern in the amount of expectorated fluid and fluoride ion activity with the 7- and 10-ml volumes, whereas no retention pattern was indicated. The findings indicate that in programs using fluoride mouth rinses, 7 ml are preferable to 10 ml, as (1) reduced amounts of swallowed fluid probably cause decreased retention and (2) the anti-caries effect seems to be equal.

Ericsson, Y.

doi: 10.1159/000259824pmid: 4509047

Shed deciduous canines and molars were obtained from 9-to 10-year-old schoolchildren in Uppsala (about 1.2 ppm water F) who, during their first year of life, had been either typically breast-fed or formula-fed and in the latter case had received a much greater F supply. While cervical enamel and dentine practically always had higher F contents than the occlusal counterparts, the formula-fed children had about a 2–3 times higher F content in both occlusal and cervical tissues than the breast-fed children.

Matthews, R.W.; Jenkins, G.N.

doi: 10.1159/000259825pmid: 4509048

The effect of fluoride in lowering the pH during 30 days standing of the supernatant when calciumdroxide solution is added to 0.01m orthophosphoric acid to the point of precipition is confirmed. Other trace elements which influence the solubility of apatite or which have been implicated in the prevention of caries do not exert this effect. Theeffects of phytate and fluoride on this system are antagonistic.

Duff, E.J.

doi: 10.1159/000259826pmid: 4509049

The phase relationships under aqueous conditions along the fluoroapatite-hydroxyapatite join of the system CaF-CaO-P₂O₅-H₂O have been examined theoretically in relation to the activities of H⁺, F^-, Ca²⁺ and orthophosphate ions. The results obtained from these calculations have been used to suggest a possible mechanism for the prophylactic action of fluoride in the inhibition of dentalcaries.

Duff, E.J.

doi: 10.1159/000259827pmid: 4509050

Recent suggestions concerning the incorporation F-into dental enamel during remineralisation, and the exchange of PO₃F₂-ions for HPO₄^- ions on the surface of dentalenamel have been correlated to formulate a possible mechanism or the action of PO₃F^2- in the reduction of dental caries.