Ira L. Shannon

Chemical protection against postirradiation dental caries

Experience with dental caries in twenty-four patients receiving irradiation for malignant lesions of the head and neck demonstrates the critical importance of cooperation by the patient, a program of strict oral hygiene, and daily self-treatment with 0.4 per cent stannous fluoride gel. The ravaging form of dental caries associated with the postirradiation period can be essentially eliminated in cooperating patients. In nine patients who were uncooperative, fifty-seven crowns were amputated and an additional seventy-five carious surfaces were found 3.75 years after irradiation. In six patients who cooperated and used the gel on a daily basis, no crowns were amputated and only one carious area was found over the same time period.

The Crystalline Components of Dental Calculi: Human vs. Dog

Dental calculus from the dog was found to consist principally of the calcite form of calcium carbonate mixed with small amounts of apatite; other calcium phosphates, consistently present in human calculus, were not present in dog calculus. Precipitable calcium salts from human saliva were mainly apatite; for the dog the principal precipitated salt was calcium carbonate (calcite form).

Remineralization of enamel by a saliva substitute designed for use by irradiated patients

A saliva substitute, VA‐OraLube, was evaluated for ability to reharden dental enamel and to relieve intraoral soft tissue symptoms in patients receiving radiotherapy for malignancies of the head and neck. Treatments of 15, 30 and 60 minutes rehardened enamel by 3.1%, 4.0%, and 5.5%, respectively. In the second experiment, treatment for 60 minutes with the complete solution rehardened enamel by 5.2%. Omitting calcium, phosphorus and/or fluoride from the formulation greatly decreased this rehardening potential. Treatment of enamel with fresh whole saliva induced rehardening at a 7.3% level in comparison to the 5.5% and 5.2% derived by using the saliva substitute. Since the xerostomic patient usually uses the product very frequently, there is a remineralization potential of significant consequence. A total of 125 xerostomic patients used the saliva substitute on an ad lib basis over a period of 4 months. Patient responses indicated a very high level of acceptance and the virtual elimination of troublesome problems previously associated with the dry mouth state.

Effect of fluoride dosage on human parotid saliva fluoride levels

Abstract Parotid fluid and urine F levels were studied in healthy young adult males receiving either 0, 1.0, 3.0, 5.0 or 10.0 mg of F by mouth. Urinary F excretion rates were virtually a linear function of size of dose. For the different doses of F, urine F recovery rates ranged from 20.0 to 31.3 per cent (mean = 25.3 per cent). For saliva F, dosage with 1.0 mg did not significantly change the placebo pattern. The 3.0 mg dose increased saliva F significantly in the 20–30 min sample. The 5.0 mg dose produced this change in the 10–20 min sample, and the 10 mg dose was effective in the 0–10 min specimen. Peak salivary F concentrations occurred at about 40–50 min after dosage and declines, with slopes a function of dose level, ensued thereafter. Even after 4 hr, saliva F levels for the 3 higher dose groups remained significantly elevated. There was a suggestion of carry-over effect in that pre-dose control saliva F levels each morning were significantly higher when subjects were receiving 3.0, 5.0 or 10.0 mg than when the dosage level was 1.0 mg.

Hyperhydration and Parotid Flow in Man

It has been stated that the most important systemic condition affecting salivation is undoubtedly the degree of hydration of the tissues. Although dehydration has been correlated with decreased salivary flow,1-6 reports dealing with the effect of hyperhydration are sparse.7 8 The question of whether hyperhydration affects salivary flow has not received proper experimental attention. This study explores the effect of graded degrees of forced water ingestion on the rate of function of the unstimulated parotid gland.

Evidence for absence of ascorbic acid in human saliva.

Abstract l -Ascorbic acid was sought in parotid and whole saliva utilizing the standard 2,4-dinitrophenylhydrazine colourimetric technique and a quantitative procedure involving paper chromatographic separation and gas-liquid chromatographic analysis. The colourimetric technique indicated the presence of measurable levels. However, no ascorbic acid was found after chromatographic separation from interfering substances. The absence of ascorbic acid persisted unfailingly even with supplemental ascorbic acid dosage. The findings indicate that ascorbic acid is not present in saliva in measureable amounts.

Effects of arterial and venous occlusion on submaxillary gland secretion in rats

Abstract Experiments were conducted with rats to test the possibility that blood flow and pressure may play a role in salivary secretion. Ligation of the main arterial supply of the submaxillary glands produced an immediate and marked depression of secretion which ceased entirely within 2–3 min when the ligation was placed on the submaxillary artery was ligated. Results of ligation of the venous drainage of the gland differed from arterial ligation in several respects: the decline in rate of secretion was not nearly as marked nor as abrupt, and secretion continued at a reduced but steady rate for at least 10 min. The differential effects of venous vs . arterial ligation were also demonstrated in experiments wherein both ligations were performed sequentially. These differences between venous ligation and arterial ligation, the abruptness and severity of the arterial effects, and the ability of the gland very quickly to regain secretory capacity on untying the ligatures, all argue against anoxia as the sole cause of the severe depression of secretion following arterial ligation. Conclusions were that intraglandular vascular flow and/or pressure is intimately associated with the secretory process.

Comparison of orthodontic cements containing sodium fluoride or stannous flouride

A laboratory study was carried out to evaluate the effectiveness of NaF and SnF2, when incorporated into zinc oxyphosphate cement, in reducing the solubility and increasing the microhardness of human enamel. The control cement contained no added fluoride, and the test cements were prepared to contain fluoride concentrations of either 1,000, 2,000, or 4,000 ppm from each of the two test fluorides. SnF2-containing cement provided significantly (P < .01) greater solubility reduction at all three concentrations than did NaF cement. SnF2 was also more effective than NaF in rehardening enamel surfaces. SnF2 is thus much more effective than NaF when added to orthodontic cement. Current topical treatment literature, both laboratory and clinical, is in accord with this conclusion.