Hydrogen peroxide is a bleaching agent with antimicrobial effects [Gaffar, 1997] that has been used historically, at high concentrations, for the treatment of severe gingivitis. It is an effective bleaching agent that can penetrate enamel to bleach intrinsic stains. Papain is a naturally occurring enzyme that dissolves protein. There is some evidence to show that the combination of papain and citrate can remove superficial tooth staining.
Sodium tripolyphosphate (STP) slows the growth of crystals and so inhibits the formation and growth of hard deposits of mineralized plaque (calculus). [Kohut et al., 1997] At higher concentrations, STP breaks down the stain matrix. It does this by removing calcium bridges between the stain molecules and surface proteins on the teeth, making the stain easier to remove.
Abrasives in toothpaste help remove stains and plaque as well as polish teeth. Common abrasives include silica and calcium carbonate. Toothpaste should be abrasive enough to remove plaque and stains, but not so abrasive as to damage tooth enamel.
TOOTH DESENSITISING INGREDIENTS
Potassium nitrate is used in products to reduce hypersensitivity from exposed dentinal surfaces. Strontium – agents based on strontium reduce the pain from sensitive teeth by blocking the tubules in the exposed dentine.
FLAVOURS AND GUMS
Flavours – the natural oils and flavours used in oral healthcare products include wintergreen, eucalyptus oil, menthol and thymol. It has been suggested that natural oils may work by reducing the levels of bacterial toxins in the plaque. [Mandel 1988] Gums – various gums are used to thicken toothpaste, but also to retain moisture, so the toothpaste does not dry out if the top is not replaced.
CARIES PREVENTIVE INGREDIENTS
Fluoride may be included in oral health products in many forms, including sodium fluoride (NaF), sodium monofluorophosphate, amine fluoride and
stannous fluoride. Fluoride strengthens the teeth against caries by making the enamel less soluble and by promoting remineralization. [Manson & Eley, 1995]
At the same time, it interferes with the metabolism of plaque bacteria and so may help inhibit plaque acid production. [Slots & Taubman, 1992] Calcium glycerophosphate (CaGP) has been reported to increase the amount of fluoride that is taken up into tooth enamel. [Forward et al., 1979] CaGP present in the toothpaste has also been reported to increase the amount of calcium and phosphate available for the remineralization of enamel. [Duke et al., 1979]
ANTIBACTERIAL AND pH-MODIFYING INGREDIENTS
Chlorhexidine salts are antimicrobial agents that are effective against a wide variety of bacteria. [Collins & Walsh, 1992] They have been reported to inhibit plaque acid production. [Manson & Eley, 1995; Marsh, 1992]
Triclosan is a broad-spectrum antibacterial agent in toothpaste and mouthwash. At low concentrations it interferes with the uptake of nutrients into bacterial cells and inhibits their growth. At higher concentrations, triclosan is bactericidal. [Zuckerbraum et al., 1998] Zinc salts exert an antimicrobial effect by inhibiting a variety of bacterial enzyme reactions, [Mandel, 1988] including the breakdown of sugar into plaque acid. Zinc, used in combination with other substances, has been shown to reduce calculus.
It is also reported to be effective against halitosis as zinc ions have an affinity for sulfur compounds, reported to be primary components of bad breath, and convert offensive sulfur compounds to non-volatile substances. [Waler, 1997] Baking soda (bicarbonate of soda) has the potential to modify the pH of plaque, and possibly the activity of the bacteria that cause tooth decay. It may also interfere with plaque metabolism and so reduce acid production. [Legier-Vargas et al., 1995] Sodium lauryl sulfate is a foaming, cleaning and dispersing agent with antibacterial properties.