The effect of a 2% zinc citrate, 0.3% Triclosan dentifrice on plaque acid production following consumption of a snackfood

The role of Triclosan in dentifrice formulations, with particular reference to a new 0.3% Triclosan calcium carbonate-based system

AIM

To discuss the role of Triclosan in dentifrice systems and demonstrate the enhanced efficacy of Triclosan in calcium carbonate-based systems when the level of the antimicrobial agent is raised from 0.2% to 0.3%. Triclosan is the most commonly used antimicrobial agent in oral care products, being compatible with a wide range of ingredients found in toothpaste formulations, whilst having no negative sensory features (e.g. taste, staining) that are associated with some other antimicrobial/anti-plaque agents. Triclosan is a broad spectrum antimicrobial agent, with additional anti-metabolic and anti-inflammatory properties. When delivered to the mouth in oral care products, Triclosan can selectively inhibit Gram negative anaerobic bacteria implicated in gingivitis and periodontal diseases, while leaving species associated with oral health relatively unaffected. Worldwide, attempts have been made to boost delivery/activity of Triclosan, either by use of copolymers or by combination with other agents such as zinc citrate. However, Triclosan has also been shown to maintain clinical efficacy against plaque and gingivitis when present as the sole antimicrobial in toothpaste formulations.

The oral environment: the challenge for antimicrobials in oral care products

For any antibacterial/ anti-plaque system from an oral care product to be effective, it must firstly be delivered and retained at relevant sites in the oral cavity and secondly, remain active within the chosen formulation to successfully target the biofilm cells within dental plaque. This must include inhibition of the growth and metabolism of relevant organisms associated with disease. This review will concentrate on understanding the environmental conditions in which such oral care products must work and summarise the activity within the oral cavity of the main antibacterial and anti-plaque agents in common oral care products, namely chlorhexidine, essential oils, metal salts and Triclosan. Routes to further enhance the activity of these products, together with the use of relatively novel formats such as confectionery products to provide added consumer oral health benefits will be considered.

Plaque antibacterial levels following controlled food intake and use of a toothpaste containing 2% zinc citrate and 0.3% Triclosan

OBJECTIVES

To measure the levels of zinc and Triclosan present in plaque 12 hours post-brushing and following two weeks home use of a toothpaste formulation containing 2% zinc citrate and 0.3% Triclosan. To measure the levels of zinc and Triclosan in plaque following two weeks home use of the test toothpaste formulation together with a further morning's brushing and a day of controlled food intake.

METHODS

A total of 104 subjects completed the study. Plaque samples were taken before use of the test toothpaste and again after a specified regime of product use and food intake. The samples were analysed for zinc or Triclosan.

RESULTS

Levels of zinc and Triclosan in plaque 12 hours after last brushing and following a 2-week home usage of product, were 149.1 microg/g and 8.6 microg/g respectively. Following a morning brushing and a day of controlled food intake zinc and Triclosan levels were 94.7 microg/g and 4.1 microg/g respectively. These levels of agents were found to reduce pH drop in vitro.

CONCLUSIONS

Regular use of a toothpaste containing 2% zinc citrate and 0.3% Triclosan can lead to a build-up of antibacterial agents in plaque that continue to work even after controlled food intake.

The effect of a toothpaste containing 2% zinc citrate/0.3% Triclosan on the glycolysis of plaque bacteria ex vivo after food intake

OBJECTIVE

To develop an ex vivo plaque pH method to assess the efficacy of a new zinc citrate/Triclosan formulation.

METHODS

Study (1) focussed on method development. Study (2) examined the effect of a toothpaste containing 2% zinc citrate/0.3% Triclosan on the pH of plaque after product use and consumption of pizza. Study (3) investigated the effect of the same formulation and a fluoride toothpaste on the pH of plaque without an 'eating occasion'. The pH of plaque samples was measured over 10 minutes in the presence of glucose.

RESULTS

The test product significantly reduced the amount of acid produced 30 minutes (p = 0.0035) and 3 hours (p = 0.0018) after brushing (study (2)). In study (3) use of the test product significantly reduced the amount of acid produced 3 hours after brushing (p = 0.0023). No significant benefit was found for the fluoride toothpaste.

CONCLUSION

An ex vivo plaque pH method has been developed which can detect changes in acid produced following brushing with different toothpastes. A toothpaste containing 2% zinc citrate/0.3% Triclosan significantly reduced the total acid produced for at least 3 hours after product use. Moreover it has been demonstrated that this effect is detectable even after eating.

Anti-microbial efficacy and mode of action studies on a new zinc/Triclosan formulation

OBJECTIVE

To test in vitro the anti-plaque/ antimicrobial efficacy of a new toothpaste formulation containing a 2% zinc citrate/ 0.3% Triclosan anti-microbial system compared with a 0.75% zinc citrate/ 0.3% Triclosan system and where appropriate, against controls of a standard fluoride paste and a 0.3% Triclosan/ 2% copolymer product.

METHODS

The anti-metabolic activity was assessed using a range of assays measuring the ability of the active systems to inhibit bacterial glycolysis. The antibacterial/ anti-plaque activity was assessed in an in vitro multispecies biofilm assay.

RESULTS

Both zinc formulations were shown to have significantly superior activity at inhibiting glycolysis compared with the 0.3% Triclosan/ 2% copolymer formulation and the standard fluoride paste, particularly in reducing the pH drop after sugar challenge, the new formulation having the greatest activity. Likewise, in the antibacterial assay, both zinc formulations were found to have significantly superior activity over a standard fluoride paste and the 2% zinc citrate/ 0.3% Triclosan formulation was shown to be significantly better than 0.75% zinc citrate/ 0.3% Triclosan formulation.

CONCLUSION

These data provide support for the enhanced performance of the 2% zinc citrate/ 0.3% Triclosan formulation.

The effect of a toothpaste containing 2% zinc citrate and 0.3% Triclosan on bacterial viability and plaque growth in vivo compared to a toothpaste containing 0.3% Triclosan and 2% copolymer

OBJECTIVE

To compare the antimicrobial efficacy and effect on plaque growth of a new silica-based fluoride toothpaste containing 2% zinc citrate/ 0.3% Triclosan with a silica-based fluoride toothpaste containing 0.3% Triclosan/2% copolymer.

METHODS

In Study 1, plaque was collected after one week's use of each toothpaste and assessed for bacterial viability, live/ dead ratio and microbial membrane integrity. In study 2, plaque was measured immediately and 18 hours after a single brushing with the specified toothpastes.

RESULTS

The 2% zinc citrate/0.3% Triclosan formulation significantly reduced the total number of viable aerobic and anaerobic bacteria (p = 0.0223 and p = 0.0443 respectively) compared to the 0.3% Triclosan/2% copolymer formulation. Both toothpastes increased the bacterial membrane permeability significantly. However, the proportion of live bacteria for the 2% zinc citrate/0.3% Triclosan product was significantly reduced (p < 0.05). Study 2 showed significantly less plaque growth 18 hours after using the 2% zinc citrate/0.3% Triclosan toothpaste compared to the 0.3% Triclosan/2% copolymer toothpaste (p < 0.01).

CONCLUSION

Regular use of a fluoride toothpaste containing 2% zinc citrate and 0.3% Triclosan, significantly reduced the viability of plaque bacteria compared to a fluoride toothpaste containing 0.3% Triclosan/ 2% copolymer 12 hours after brushing. In addition, a clinical plaque growth study confirmed that this anti-microbial efficacy leads to a significant reduction in plaque growth.