Cocoa (Theobroma cacao L.) is one of the Indonesian export commodities of the country with an adequately high sale value. The Ministry of Agriculture reported that in 2010, Indonesia ranks as the third largest cocoa producer country in the world with total exports amounting to 900 thousand tons. The accumulation of dental plaque can cause caries. The biggest problem is the cause of periodontal disease in which the incidence of dental caries. It is caused by the accumulation of dental plaque. Cocoa beans contain antibacterial compounds; namely flavonoids and tannins which can inhibit the growth of bacteria. The study aims to determine the bioactivity of cocoa beans extracts between the growth of dental plaque bacteria isolated in vitro by using the disc diffusion method and Mueller hinton media in order to isolate dental plaque bacteria. This study shows that there is an
inhibition zone of growth of dental plaque bacteria isolates of the cocoa seed extract when the researcher gives it (the cocoa extraxt) in 10%, 20%, 30% and 40%. Kruskal-Wallis test result showed that there are differences of treatment outcomes between cocoa beans extracts and dental plaque bacteria isolated. Mann-Whitneyy test result showed that there were significant differences in the effectiveness of antibacterial compounds toward the dental plaque bacteria isolate. The conclusion is an extract of cocoa beans has bioactivity in inhibiting the growth of dental plaque bacteria isolate.