Antimicrobial activities of forty traditional Chinese medicines on oral bacteria: A experimental study

Abstract

Dental caries and periodontal disease are common human diseases that affect a large majority of subjects, in particular, orthodontic patients with fi xed appliances which prove to be more susceptible to both of them (Geiger et al., 1992). Microorganisms in oral biofi lm are the major aetiological agents of dental caries. The ‘pioneer species’ of oral biofi lm are Streptococcus oralis, S. mitis and S. sanguis. There are also specifi c bacteria that are closely related to specifi c dental diseases, for example, S. mutans and Porphyromonas gingivalis are associated with dental caries and periodontal disease, respectively (Samaranayake, 2006). Traditional Chinese medicines (TCM) have been used in China to treat various infectious diseases for more than 4000 years. Different from western medicine, TCM works as a formula of herbs that is tailored to individual patients under their specifi c condition (Eisenberg, 1998). Recently the mechanism of one of these formulae has been investigated at the molecular, cellular and organism levels (Wang et al., 2008). Certain TCM have been shown to have antibacterial properties (Seneviratne et al., 2008) but so far none has shown to have any known resistance. Currently, a number of TCM herbs are used in oral healthcare products such as toothpaste according to their effects. Yet few studies have been performed to screen these TCM and evaluate their effectiveness against oral bacteria forming oral biofi lm. Forty TCM herbs were selected for investigation as they are used to treat infections and diseases in different parts of body. The aim of this study was to evaluate in vitro 40 TCM herbs that are currently used to treat infectious diseases for their antimicrobial activity against bacteria in oral biofi lm that cause caries and periodontal disease. The null hypothesis is the TCMs investigated have no effect against the four common oral bacteria.