bioavailability – The degree to which a drug or substance is available to the target tissue following administration.

buffer – Chemical system that confers resistance to a change in the pH of a solution (e.g., saliva) when hydrogen ions (H+) are added or removed.

carbohydrate – Important energy source for the body; a complex molecule made up of one or more simple sugars.

calculus – Calcified plaque: a hard yellowish deposit on the teeth, consisting of organic secretions and food particles deposited in various salts, such as calcium carbonate; also called tartar.

caries – The process of dental decay, beginning with the earliest initiation of tooth demineralization and culminating with the collapse (cavitation) of a specific tooth surface. Dental caries is an infectious disease caused by the complex interaction of certain plaque bacteria with carbohydrates (i.e., sugars), resulting in the generation of acids that can attack and damage both enamel and dentin.

cariogenic – Contributing to the production of caries.

chelate – Action of certain chemical compounds whereby they form several noncovalent bonds to a single metal ion (e.g., Ca2+), sequestering it and preventing it from reacting with its surroundings.

chromogen – Substance that can be converted to a pigment or dye.

compound – In chemistry, a substance that consists of two or more chemical elements in union.

covalent – In chemistry, a chemical bond formed by the sharing of one or more electrons, especially pairs of electrons, between atoms.

crevicular – A fluid produced by epithelium of the gingival crevice; it contains immunoglobulins and has antimicrobial properties.

dental erosion – Irreversible loss of tooth structure resulting from strong acids of non-bacterial origin (e.g. dietary, gastric).

enzyme – Protein that catalyzes, or facilitates, biochemical reactions.

extrinsic stain – Tooth stain on the exterior surface of the tooth that can be removed through routine cleaning procedures. It is generally composed of dietary chromogenic molecules and metal ions which become bound within the salivary pellicle layer that coats exposed tooth surfaces.

gingivitis – Inflammation of the gums that often manifests as bleeding during brushing and flossing; mildest form of periodontal disease that is reversible.

heme – A complex red organic pigment containing iron and other atoms to which oxygen binds.

halitosis – The condition of having stale or foul-smelling breath.

hydrophobic – Water-resisting; refers to a chemical entity that repels water and prefers oily environments.

ions – Atoms or molecules that carry either a positive or a negative electric charge in a solution. For example, sodium chloride (NaCl, common table salt) in water dissociates into Na+ and Cl– ions.

intrinsic stain – Staining caused by the presence of pigment within the enamel or dentine. Intrinsic stain can often be mediated through bleaching procedures.

lysis – The destruction or dissolution of a cell or molecule, generally through the action of a specific agent.

metabolize – The process through which food is broken down to release energy.

molecule – Chemical entity that consists of two or more atoms that have chemically combined to form a single species.

New drug application (NDA) – Application requesting FDA approval to market a new drug, drug formulation, or dose.

noncavitated lesion – Demineralized, subsurface carious lesion without evidence of discontinuity or break in the enamel surface (sometimes called an early lesion, incipient lesion, or white spot lesion).

organic acids – Acid containing at least one carbon atom; also called a carboxylic acid; written chemically as:

Image: carboxylic acid

over-the-counter (OTC) – Drug products that are generally recognized as safe and effective and are available without a prescription; in oral care, many dentifrices and some rinses are OTC products.

OTC Monograph – A document published by the US FDA that includes lists of ingredients that have proven effectiveness and safety for a particular health concern, as well as information about dosing, drug formulations and labeling.

patency – State or quality of being open, expanded, or unblocked.

pharmacology – Study of a drug’s origin, chemistry, effects, and uses.

plaque – An organized community of many different microorganisms that forms itself into a biofilm and is found on the surface of the tongue and all hard surfaces in the oral cavity. Dental plaque is present in all people and can vary from being comprised of totally healthy microorganisms (commensals) to being very harmful (pathogenic), predisposing the patient to dental caries or periodontal diseases. Note: Dental plaque is not food debris, nor does it contain food debris. Dental plaque can only be completely removed by mechanical means, such as toothbrushing or prophylaxis.

subgingival – Located beneath the free margin of gingival tissue.

supragingival – Located on a portion of the tooth that is not surrounded by gingival tissue.

surfactant – Compounds such as detergents, emulsifiers, and foaming agents that provide cleaning or help mix substances that prefer to separate (like oil and water). Surfactants typically have a hydrophilic, polar head that interacts with water and a hydrophobic, nonpolar tail that avoids water.

tartar – Calcified plaque: a hard yellowish deposit on the teeth, consisting of organic secretions and food particles deposited in various salts, such as calcium carbonate; also called calculus.

toxicology – Study of the unwanted and often adverse effects of substances.