James L. McDonald

Comparisons of Various Salivary Parameters in Smokers Before and After the Use of a Nicotine-containing Chewing Gum

This study was designed to compare various salivary parameters between smokers and non-smokers and to determine the influence of a nicotine-containing chewing gum (used to aid in quit-smoking efforts) upon these same parameters. At the baseline examination, subjects were assigned to one of three groups: non-smokers who did not utilize any gum, smokers provided a nicotine-containing gum, and smokers provided a placebo gum. Saliva was collected from all subjects and analyzed for acidogenicity and buffer pH as well as for levels of thiocyanate, lactoperoxidase, lysozyme, lactoferrin, and secretory IgA. After 15 weeks of gum usage, saliva was again collected from each subject and the identical analyses performed. Significant differences were observed between smokers and non-smokers with regard to three parameters: The saliva of smokers contained greater concentrations of thiocyanate and lower concentrations of lactoferrin, at the baseline examination and after the 15-week test period. In addition, the CO content of alveolar air was higher in smokers at both examination periods. In contrast, the use of the nicotine gum per se had no effect on any of the test parameters.

Overreporting of Smokeless Tobacco Use by Adolescent Males

This study evaluates the impact of a pipeline assessment (salivary cotinine determination) on the accuracy of self-reported use of cigarettes and smokeless tobacco by 160 rural seventh-and eighth-grade males ranging in age from 12 to 16. Half of them were randomly assigned to complete a questionnaire on tobacco use prior to revealing the biochemical validation materials and collecting samples. The others had the samples collected prior to receiving and completing the questionnaires. The questionnaire-first group reported significantly greater smokeless tobacco use than did the pipeline-first group. Only for the latter were their self-reports significantly corroborated by the cotinine results. These results suggest that the utilization of a biochemical pipeline not only can improve self-reported tobacco use but also may help identify perceptions about the social desirability of using harmful substances.

Animal Studies Concerning the Cariogenicity of Dry Breakfast Cereals

Four studies were performed in rats and hamsters concerning the cariogenicity of cereals and the role of sucrose in that process. The findings indicate that sucrose content per se does not necessarily reflect the cariogenic potential. Presweetened cereals were more conducive to the formation of smooth surface caries in the hamster than were non-presweetened cereals while no major differences between the cereals were observed in occlusal caries in rats.

Modifying role of trace elements on the mutagenicity of benzo[a]pyrene

Benzo[a]pyrene (BaP) is a polycyclic aromatic hydrocarbon that is found in tobacco smoke and various environmental contaminants and has been shown to be carcinogenic and mutagenic in animal and cell culture studies, respectively. Research studies suggest that various nutritional factors such as the antioxidant vitamins and selenium are very promising as potential anticarcinogenic agents. Moreover, some evidence exists showing that both iron and germanium, at specific dosage levels, may possess antimutagenic potential. This study examined the influence of ferrous sulfate and germanium oxide, independently, upon the mutagenic potential of BaP in the Ames test. Four test strains of Salmonella typhimurium were exposed to BaP (15 micrograms/plate) in the presence of different dosage levels of iron (0-1000 micrograms/plate) and germanium (0-600 micrograms/plate). In the case of iron, it was observed that, depending upon the strain tested, iron reduced BaPs mutagenicity. In strain TA98, this was a significant effect at 100 micrograms/plate and higher. In strains TA97a and TA100, iron concentrations had to reach 250 micrograms/plate or higher to produce significant effects. Iron was much less effective in reducing BaP mutagenicity in strain TA102. In general, germanium was not as effective in reducing the mutagenic potential of BaP. Only in the case of the highest concentrations tested (400 and 600 micrograms/plate) was any effect noted, and this in only three of the four strains evaluated.

The smokeless tobacco ‘time bomb’

All healthcare professionals need to become aware of the extent and seriousness of smokeless tobacco use. In this article, the authors briefly review the current status of smokeless tobacco and describe its usage patterns and practices, pharmacologic (addictive) aspects, and associated health problems. They also suggest ways that primary care physicians can discover or prevent smokeless tobacco use in their patients.

Influence of selected fatty acids upon plaque formation and caries in the rat

Weanling rats were given high-sucrose cariogenic diets containing 2 per cent lauric acid, linoleic acid, nonanoic acid or monolaurin. Plaque accumulation was determined on the incisors of half the animals during only the last 3 days of the study and on the remaining animals at the conclusion of a 21-day test period when both sulcal and smooth-surface caries were assessed. No significant differences between the test groups in food consumption were observed nor were there any differences in body weight gain. The least amount of plaque was observed in the animals given monolaurin; the other fatty acids exerted no significant effect upon plaque accumulation. The smooth-surface caries data indicated that the least number of lesions occurred in the animals on the diet containing monolaurin. Nonanoic acid was significantly more effective in limiting sulcal caries than any of the other fatty acids studied. Thus both monolaurin and nonanoic acid have significant cariostatic activity in the rat.

Influence of Fluoride upon Plaque and Gingivitis in the Beagle Dog

Two studies were conducted to explore the effects of twice daily topical applications of NaF, SnF 2, and an amine fluoride at equivalent fluoride concentrations (0.1%) upon plaque and gingivitis in the dog. Although some trends toward modest benefits were noted in certain instances, none of the agents exerted a significant effect upon either parameter.

Effects of nicotine-containing chewing gum on oral soft and hard tissues: A clinical study

A double-blind clinical trial was conducted to determine whether the use of a chewing gum containing 2.0 mg nicotine (as an adjunct to a stop-smoking program) had any effects upon oral health. A total of 193 adults who smoked cigarettes volunteered with informed consent, were given routine dental prophylaxes, and were examined for the presence of plaque, stained pellicle, gingivitis, calculus, and general oral pathosis. The subjects were then randomly assigned to use either a nicotine-containing or a placebo chewing gum. After 15 weeks the subjects were recalled and re-examined. Smoking cessation was determined through questionnaire and analysis of the carbon monoxide content of alveolar air. At the completion of the study, 79 subjects had used the placebo gum and 78 had used the nicotine gum. Data analysis indicated that the nicotine chewing gum had no significant influence on any of the oral health parameters graded, as compared to the placebo gum. The continuation of smoking, however, was associated with significant increases in gingivitis and calculus rates.

The Use of the Beagle Dog as a Dental Stain Model

Two studies were conducted to assess stain accumulation in beagle dogs following four wk of treatments with water or chlorhexidine. Clinical stain assessments were made by two examiners using different grading procedures. Both scoring methods demonstrated increased stain associated with chlorhexidine usage, and the results for both examiners appeared to be reproducible from one study to the other.

Further Studies of the Cariostatic Properties of Tin (II) and Oat Hulls in the Rat

Two experimental dental caries studies were conducted in rats to investigate further the cariostatic activity of oat hulls and tin (II). The findings confirm the cariostatic activity of oat hulls regardless of the nutritional content of the diet, indicate that tin (II) may exert cariostatic activity depending on the concentration and nutritional content of the diet, and that the two agents are partially additive at tin (II) concentrations of 15 and 75 ppm but are not synergistic.