Irwin D. Mandel

The Functions of Saliva

Natures demands on salivary glands are extensive and diverse and range from the reptilian need for a venomous drop to incapacitate its prey to the 100 quarts that ruminants require to digest a days grazing. Other species depend on saliva not for survival, but for improving the quality of life, using the fluid for functions varying from grooming and cleansing to nest-building. Humans can manage without saliva; its loss is not life-threatening in any immediate sense, but it results in a variety of difficulties and miseries. Oral digestion per se is only of marginal importance in humans, but saliva is important in preparing food for mastication, for swallowing, and far normal taste perception. Without saliva, mealtimes are difficult, uncomfortable, and embarrassing. The complex mix of salivary constituents provides an effective set of systems for lubricating and protecting the soft and hard tissues. Protection of soft tissues is afforded against desiccation, penetration, ulceration, and potential carcinogens by mucin and anti-proteases. Saliva can encourage soft tissue repair by reducing clotting time and accelerating wound contraction. A major protective function results from the salivary role in maintenance of the ecological balance in the oral cavity via; (1) debridement/lavage; (2) aggregation and reduced adherence by both immunological and nan-immunological means; and (3) direct antibacterial activity. Saliva also possesses antifungal and anti-viral systems. Saliva is effective in maintaining pH in the oral cavity, contributes to the regulation of plaque pH, and helps neutralize reflux acids in the esophagus. Salivary maintenance of tooth integrity is dependent on: (1) mechanical cleansing and carbohydrate clearance; (2) post-eruptive maturation of enamel; (3) regulation of the ionic environment to provide a remineralizing potential without spontaneous precipitation; and (4) pellicle deposition and limitation of acid diffusion. Saliva also plays a role in water balance, can serve in a limited way in excretion, and has possible hormonal function in the gastro-intestinal tract.

Sialochemistry in Diseases and Clinical Situations Affecting Salivary Glands

AbstractDuring the past few years an increasing number of investigators in a variety of disciplines have become interested in the potential of saliva as a diagnostic tool. The increase in interest reflects (in part at least) the marked proliferation in information on salivary physiology and salivary chemistry. Sialochemistry is being applied to (1) diseases of the salivary glands per se with no evidence of systemic involvement, (2) systemic diseases in which salivary glands are involved, and (3) clinical situations in which salivary flow rate and chemistry are helpful in diagnosis or monitoring patient progress (Tables 1 and 2).

Pilocarpine for the treatment of xerostomia associated with salivary gland dysfunction

A double-blind placebo-controlled study was conducted to evaluate the efficacy of orally administered pilocarpine in treating oral dryness caused by salivary gland hypofunction. At low dosages, pilocarpine increased the production of saliva by parotid and submandibular and/or sublingual glands and relieved the sensation of oral dryness. The quantity and composition of pilocarpine-stimulated secretions were similar to saliva produced in response to gustatory stimulation with citrate. In appropriate patients, pilocarpine is a safe, easily administered, effective therapy to relieve xerostomia by increasing natural salivary function.

Antimicrobial Mouthrinses: Overview and Update

The Seal of Acceptance of the American Dental Associations Council on Dental Therapeutics has been awarded to Listerine and chlorhexidine gluconate (Peridex). The mechanism of action of Listerine involves bacterial cell wall destruction, bacterial enzymatic inhibition, and extraction of bacterial lipopolysaccharides. Chlorhexidine has the property of substantivity, i.e. the ability to bind to hard and soft tissue with slow release. Antibacterial mouthrinses/dentifrices containing triclosan hold promise for the reduction of plaque and gingivitis but are not yet available in the United States. The quaternary ammonium compounds and sanguinarine compounds (Viadent) have some merit, but studies of their efficacy in plaque and gingivitis reduction are mixed. New products containing various fluorides and oxygenating agents may have potential for the future as antiplaque and antigingivitis agents.

The Effect of Saliva on Plaque pH in vivo

The impact of saliva on plaque pH in vivo, following exposure to a sucrose substrate, was measured in ten caries-resistant (CR) and ten caries-susceptible (CS) subjects under varying conditions of salivary access. When the plaque was denied access to saliva, the pH minima reached by the CR and CS groups were comparable. As the access to saliva was increased, the observed pH minima increased to a significantly greater degree in the CR subjects than in the CS subjects. This demonstrates the major role that saliva plays in modifying plaque pH, especially in caries-resistant people.

Tooth surface-pellicle lipids and their role in the protection of dental enamel against lactic-acid diffusion in man

The lipid content and composition of the enamel pellicle from caries-resistant (CR) and caries-susceptible (CS) subjects and their effect on its ability to retard the diffusion of lactic acid were investigated. Lipids accounted for 22.2 per cent of the dry weight of CR pellicle and 23.7 per cent of CS pellicle. The content of glycolipids in both groups was similar but CR pellicle contained 42 per cent less neutral lipids and 31 per cent less phospholipids. CR lipids had a higher content of cholesterol, cholesterol esters and sphingomyelin, whereas CS pellicle was richer in free fatty acids and phosphatidylethanolamine. Retardation of lactic-acid diffusion by CR pellicle was 45 per cent higher than by CS. Removal of lipids caused 50 per cent reduction in retardation by CR pellicle and 35 per cent by CS pellicle.

Sialochemistry in Sjögren's syndrome

The value of sialochemistry in the study of Sjögrens syndrome was explored by comparative examination of a spectrum of parotid components in twelve subjects with a positive diagnosis of the disease and twelve control subjects with normal gland function. The subjects with Sjögrens syndrome all exhibited a marked reduction in flow rate and phosphate concentration and a marked elevation in sodium and chloride concentration. The concentration of IgA was somewhat elevated (commensurate with reduced flow rate); the levels of IgG, IgM, and albumin were normal. The major functional abnormality in the parotid gland in Sjögrens syndrome appears to be luminal transport in the ductal region; leakage of serum components is minimal. Sialochemistry can be helpful in differentiating Sjögrens disease from other diseases of the salivary gland and in assessing degree of pathologic change.

Characterization of salivary components separated by paper electrophoresis

Abstract Using a standardized procedure of paper electrophoresis, seven fractions were consistently separated from parotid saliva. These components were eluted from the paper strips and analysed chemically and immunochemically. Serum proteins (albumin, α, β and γ-globulins) comprised 25 per cent of the total. The specific salivary proteins included amylase, two non-antigenic glycoproteins, and an unidentified antigenic cationic protein. The two glycoproteins (accounting for 35 per cent of the total protein) were cationic, contained hexoses, fucose and hexosamine in a ratio of 1:1 and little if any sialic acid.

Properties of Cysteine-containing Phosphoproteins from Human Submandibular-sublingual Saliva

Cysteine-containing phosphoproteins (CCP) similar to those found in human submandibular-sublingual saliva have also been detected in parotid saliva and tears suggesting a serous origin. No appreciable difference was found in salivary CCP concentrations between caries-susceptible and caries-resistant individuals. CCPadsorbed to hydroxyapatite, and this binding was due in part to phosphate residues. In addition, these molecules inhibited the transformation of dicalcium phosphate dihydrate, albeit to a lesser extent than statherin.

Studies on the mucoproteins of human parotid saliva

Abstract Two cationic mucoprotein fractions from parotid saliva were separated by paper electrophoresis and analysed for amino acids. The two fractions had a similar composition. The major amino acids were proline, glycine and glutamic acid in a molar ratio of about 3:2:2. The tyrosine content was very low. When the FolindashCiocalteu and the biuret reaction were compared for protein estimation of total parotid saliva and separated fractions the biuret values were usually about 1.4 times as high for the total saliva, 2 times as high for the mucoprotein fractions and about the same for the amylase fraction. Studies of the relation of the various nondialysable carbohydrate components of parotid saliva to total protein content and to rate of flow disclosed that: (a) there was a high correlation between changes in amounts of nondashdialysable carbohydrates and changes in total protein content and (b) there was a very low correlation between changes in amounts of carbohydrates and protein and changes in flow rate.