Mouthwash

How Products are Made, Volume 6 (1998) by Perry Romanowski

Mouthwash

Mouthwash is a liquid oral product designed to freshen breath. Certain varieties may also kill bacteria and/or whiten teeth. Mouthwashes are made by combining the appropriate raw materials in large, stainless steel tanks and then filling the product into individual packages. First used by ancient societies, technological advances in chemistry have resulted in steadily improving formulas. In 1998, Americans spent over $652 million on mouthwash

Background

The need for mouthwash is a result of a condition called halitosis, or bad breath. It is estimated that over half the population occasionally has foul-smelling breath. This typically occurs upon first awakening or after a meal with garlic or onions. It has been found that bad breath is mostly due to bacterial activity in an unclean mouth. Specifically, anaerobic bacteria that grow on the protein-rich food debris stuck between the teeth or on the tongue. As the bacteria breaks down the proteins, those containing sulphur give off foul odor molecules such as methylmercaptan and hydrogen sulphide which result in bad breath.

Mouthwashes are designed to eliminate bad breath in two ways. First, they relieve it by killing the bacteria responsible for producing the foul odor. The best of these products prevent bad breath for as long as eight hours. The second way that mouthwashes help reduce bad breath is by masking the odor. This is a much less effective method which lasts no more than 30 minutes.

History

Products used for freshening breath or cleaning teeth have been in existence for centuries. Many of the ancient societies—including the Egyptians, Chinese, Greeks, and Romans—had recipes for such preparations. They used a variety of ingredients; from edible materials like fruit, honey, or dried flowers to less appealing compounds such as ground lizard, minced mice, or urine. These products were generally ineffective and in some cases were harmful to the sensitive enamel which coats each tooth.

While tooth cleaning preparations steadily improved over the years, it was not until the early 1800s—when the modern toothpaste was developed—that truly effective oral products became available. The first mouthwashes were basically solutions of grain alcohol and were likely developed accidentally during this era. One of the most famous brands, Listerine, was developed during the 1880s and is still sold today.

The antibacterial effect of fluoride was an important discovery for the development of modern mouthwashes. In the early 1900s a dentist named Frederick McKay found that some of his patients had a condition called mottled enamel. He found that this condition was linked to a reduction in tooth decay. In 1931, he tested the drinking water that these patients consumed and found a high level of natural fluoride. By the early 1940s, other workers had determined that fluoride in drinking water at one part per million would reduce tooth decay without causing mottling. Various testing went on during the rest of this decade and by the 1950s it was recommended by the United States federal government that all public water sources be fortified with fluoride. This discovery led to the development of toothpastes and mouthwashes that contained fluoride compounds. During the years that followed, various raw materials have been developed that have an antibacterial effect but do not contain alcohol. Additionally, materials that prevent tartar, whiten teeth, and reduce cavities have also been discovered and added to mouthwash formulas.

Raw Materials

Mouthwashes are generally composed of diluents, antibacterial agents, soaps, flavorings, and colorants. The primary ingredient in most mouthwashes is water, a diluent, making up over 50% of the entire formula. The water is specially treated to remove various particles and ions which might impact flavor. Water treated as such is called deionized water. The sources of water vary, coming from reserves such as underground wells, lakes, and rivers. Alcohol is another diluent typically used in up to 20% of the formula. While early mouthwashes used alcohol extensively; today its use is limited because of governmental regulations and consumer desires.

Numerous antibacterial agents have been employed in mouthwash formulations. These include ingredients like phenols, thymol, salol, tannic acid, hexachloraphene, chlorinated thymols, and quaternary ammonium compounds. Chlorinated phenols like parachlormetacresol have both an antibacterial effect and a desired flavor. Thymol, which is obtained from volatile oils, is used at low concentrations and in conjunction with other ingredients. Hexachloraphene is substantive to the mucous membrane which makes it ideal for longer lasting formulas. Quatemary compounds are often used because of their non-toxic and non-irritant nature. They are effective against plaque.

Color and flavor are added to the formulas to improve the consumer acceptability of the mouthwash ingredients. Flavor is an essential feature of a mouthwash because it has the most consumer perceptible impact. In the United States, flavorants such as peppermint, menthol, methyl salicylate, and eugenol are commonly used. The most common colors, blue and green, are the result of adding governmentally approved and certified FD&C dyes. Some mouthwash formulas also include a synthetic detergent to give extra foaming and cleansing action.