Experimental Gingivitis in Man

Role of Streptococcus mutans in human dental decay.

An adequate supply of saliva is critical to the preservation and maintenance of oral tissue. Clinicians often do not value the many benefits of saliva until quantities are decreased. Much is written on the subject of salivary hypofunction, but little attention is paid to normal salivary flow and function. This article is a brief, up-to-date overview of the literature on the basics of normal salivary composition, flow, and function. A review of the literature was conducted using MEDLINE and Healthstar (1944 through 1999); articles were selected for inclusion on the basis of relevance and significance to the clinician.

A review of saliva: Normal composition, flow, and function

Wearable biosensors are garnering substantial interest due to their potential to provide continuous, real-time physiological information via dynamic, noninvasive measurements of biochemical markers in biofluids, such as sweat, tears, saliva and interstitial fluid. Recent developments have focused on electrochemical and optical biosensors, together with advances in the noninvasive monitoring of biomarkers including metabolites, bacteria and hormones. A combination of multiplexed biosensing, microfluidic sampling and transport systems have been integrated, miniaturized and combined with flexible materials for improved wearability and ease of operation. Although wearable biosensors hold promise, a better understanding of the correlations between analyte concentrations in the blood and noninvasive biofluids is needed to improve reliability. An expanded set of on-body bioaffinity assays and more sensing strategies are needed to make more biomarkers accessible to monitoring. Large-cohort validation studies of wearable biosensor performance will be needed to underpin clinical acceptance. Accurate and reliable real-time sensing of physiological information using wearable biosensor technologies would have a broad impact on our daily lives.

Wearable biosensors for healthcare monitoring.

The cloning of a G protein-coupled extracellular Ca(2+) (Ca(o)(2+))-sensing receptor (CaR) has elucidated the molecular basis for many of the previously recognized effects of Ca(o)(2+) on tissues that maintain systemic Ca(o)(2+) homeostasis, especially parathyroid chief cells and several cells in the kidney. The availability of the cloned CaR enabled the development of DNA and antibody probes for identifying the CaR's mRNA and protein, respectively, within these and other tissues. It also permitted the identification of human diseases resulting from inactivating or activating mutations of the CaR gene and the subsequent generation of mice with targeted disruption of the CaR gene. The characteristic alterations in parathyroid and renal function in these patients and in the mice with "knockout" of the CaR gene have provided valuable information on the CaR's physiological roles in these tissues participating in mineral ion homeostasis. Nevertheless, relatively little is known about how the CaR regulates other tissues involved in systemic Ca(o)(2+) homeostasis, particularly bone and intestine. Moreover, there is evidence that additional Ca(o)(2+) sensors may exist in bone cells that mediate some or even all of the known effects of Ca(o)(2+) on these cells. Even more remains to be learned about the CaR's function in the rapidly growing list of cells that express it but are uninvolved in systemic Ca(o)(2+) metabolism. Available data suggest that the receptor serves numerous roles outside of systemic mineral ion homeostasis, ranging from the regulation of hormonal secretion and the activities of various ion channels to the longer term control of gene expression, programmed cell death (apoptosis), and cellular proliferation. In some cases, the CaR on these "nonhomeostatic" cells responds to local changes in Ca(o)(2+) taking place within compartments of the extracellular fluid (ECF) that communicate with the outside environment (e.g., the gastrointestinal tract). In others, localized changes in Ca(o)(2+) within the ECF can originate from several mechanisms, including fluxes of calcium ions into or out of cellular or extracellular stores or across epithelium that absorb or secrete Ca(2+). In any event, the CaR and other receptors/sensors for Ca(o)(2+) and probably for other extracellular ions represent versatile regulators of numerous cellular functions and may serve as important therapeutic targets.

Extracellular Calcium Sensing and Extracellular Calcium Signaling

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.

Role of salivary mucins in the protection of the oral cavity

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 carcinoge...

The Functions of Saliva

Dental practitioners are becoming more cognizant of the importance of saliva as they treat a greater number of older patients, especially those with medical problems requiring a variety of medications that have xerostomia as a side effect. This article discusses salivary composition and function in a broad perspective, relating them to clinical concerns and current research. Understanding the role of saliva in maintaining health, as well as its relation to oral disease, is vital to the competent dental practitioner.

The role of saliva in maintaining oral homeostasis

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.

Chemotherapeutic agents for controlling plaque and gingivitis

It is becoming increasingly apparent to investigators and clinicians in a variety of disciplines that saliva has many diagnostic uses and is especially valuable in the young, the old and infirm and in large scale screening and epidemiologic studies. The highly sensitive test procedures that are now commonplace makes it practical to quantitate, despite very low concentrations, a large number of hormones and drugs in saliva. Indeed, all steroids of diagnostic significance in routine clinical endocrinology can now be readily measured in saliva. Drug monitoring can include abusive as well as therapeutic agents. The concordance between anti HIV antibodies in saliva and serum has stimulated application to various other antiviral antibodies as well as to viral antigens per se. Saliva has found use as a diagnostic aid in an increasing number of clinical situations and in systemic diseases that can affect salivary gland function and composition such as Sjogren's syndrome, cystic fibrosis and diseases of the adrenal cortex. The list keeps growing.

Irwin D. Mandel

Papers

Role of salivary mucins in the protection of the oral cavity

The Functions of Saliva

The role of saliva in maintaining oral homeostasis

Chemotherapeutic agents for controlling plaque and gingivitis

The diagnostic uses of saliva