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Biomedical subjects

I L Shannon

Publications and source records attributed to I L Shannon.

At least 19 recordsLinked to original sources
PubMed1979

Fluoride treatment and microhardness of dentin.

Effects of various fluoride treatments on the microhardness of human dentin were determined. Treatment with acidulated phosphate-fluoride at pH 3.0 induced a significant (p less than .05) softening when compared to treatment with water. APF at pH 4.0 did not bring about a significant change. Response to treatment with 0.4% SnF2 did not differ significantly from water treatment. Sequential treatment with APF (pH 4.0) followed by SnF2 produced significant (p less than .05) hardening of dentin. This hardening with APF-SnF2 differed at a high level of significance (p less than .001) from the softening produced by the pH 3.0 APF. A similarly significant difference was found between this single APF treatment and the single SnF2 treatment. When hardening of exposed dentin surfaces is desired, the sequential treatment method should be employed.

Acidulated Phosphate Fluoride↗
PubMed1979

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).

Animals↗
PubMed1978

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.

Head and Neck Neoplasms↗
PubMed1978

Enamel solubility reduction by acidulated phosphate-fluoride (APF) treatment.

The enamel solubility reducing (ESR) potential of acidulated phosphate-fluoride (APF) solutions containing varying amounts of F was studied. Commercial APF (1.23% F, pH 3.0) reduced solubility by about 80%. Fivefold dilutions of this APF were made with either phosphoric acid or water without significant effect on ESR potential. Further dilution to 0.12% F significantly decreased effectiveness. Commercially available APF products (1.23%) can be diluted several-fold with distilled water in the dental office without significant loss of ability to reduce the solubility of enamel.

Acidulated Phosphate Fluoride↗
PubMed1978

Alterations in whole saliva flow rate induced by fractionated radiotherapy.

Sequential changes in flow rate of whole saliva are detailed in 13 patients. Samples were collected without exogneous stimulation during a course of fractionated radiotherapy involving major portions of the salivary glands. Flow rate decreased markedly during the initial 3 treatment days and gradually thereafter until a minimal flow rate was reached. Early in the treatment, variable degrees of recovery were seen on Mondays following a weekend (Friday-Sunday) without treatment. After a minimal flow rate was reached, no such recovery was observed. Radiation needed to produce minimal flow varied from 450 to 4,050 rad. Patients with higher initial flow rates required higher dosages to reach the minimum. No return of secretory function was noted after extended periods of time.

Aged↗
PubMed1978

Effect of fluoride concentration on rehardening of enamel by a saliva substitute.

An evaluation was made of the effect of different concentrations of F on the ability of OraLube, a saliva substitute developed by the Veterans Administration designed for use by xerostomic patients, to reharden enamel surfaces. Test preparations contained either 0, 1.0, 2.0, 3.0, 4.0 or 5.0 ppm and groups of softened enamel surfaces were treated with these solutions for 30 minutes. Treatment with saliva substitute containing no F did not significantly alter the hardness of enamel surfaces. Including 1.0 ppm F in the formula induced a rehardening of about 5 per cent; 2.0 ppm F solution rehardened at a 12.5 per cent rate. Additional F up to 5.0 ppm did not increase rehardening significantly. The inclusion of 2.0 ppm F in OraLube assures that, in addition to its ability to relieve intraoral soft tissue problems associated with xerostomia, an optimal rehardening potential is provided.

Calcium↗