Mucins are the principal organic constituents of mucus, the slimy visco‐elastic material that coats all mucosal surfaces. Compelling evidence suggests that they play an integral role in non‐immune protection of the oral cavity. Specific protective functions include: 1) protection against desiccation and environmental insult, 2) lubrication, and 3) antimicrobial effects against potential pathogens. Biosynthesis of mucin is regulated by both intrinsic (“cooperative sequential specificity”) and extrinsic (“structural modulation”) controls. These controls form the basis by which mucin's structure can be modified to meet a dynamically changing biological need.

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Nature's 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 day's 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 non-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: (I) 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.

There has been a vigorous search for many years for chemical agents that could supplement or even supplant patient-dependent mechanical plaque control and thus reduce or prevent oral disease. 5 categories of agents or approaches have been considered: (1) broad spectrum antiseptics, (2) antibiotics aimed at specific bacteria, (3) single or combinations of enzymes that could modify plaque structure or activity, (4) non-enzymatic dispersing or modifying agents and (5) agents that could affect bacterial attachment. The success of these approaches can be evaluated clinically by the use of standard scoring methods for measuring plaque and gingivitis and their safety established by soft tissue and microbiologic examination. Antiseptic agents have received the bulk of the attention over the years. At present, only 2 antiseptics, the bis-biguanide, chlorhexidine gluconate (Peridex) and a combination of phenol related essential oils (Listerine), have developed sufficient supporting data in 6-month (or longer) studies to gain the approval of the Council On Dental Therapeutics of the American Dental Association. On the basis of short-term studies, cetylpyridinium chloride, zinc and copper salts, sanguinarine and octenidine warrant continued study as does stannous fluoride at an appropriate concentration. On the basis of current research, a new generation of more specific antibacterial agents that interfere with attachment to pellicle can be developed. It is hard to predict, however, that they will affect gingivitis, at least until there is more information on what specific organisms should be targeted.