| dc.description.abstract | Streptococcus mutans is the dominant bacteria forming dental plaque. Plaque is a collection of microorganisms forming biofilms that accumulate on the surface of teeth or other hard surfaces in the oral cavity. Dental plaque can cause the onset of periodontal disease. Plaque control measures need to be carried out, one of which is by rinsing the mouth. Chlorhexidine is a gold standard mouthwash in inhibiting the formation of dental plaque, but it has the side effect of staining the teeth. Red dragon fruit peel contains flavonoids and chitosan has positive polycation properties that are able to inhibit bacterial growth. The purpose of this study was to evaluate the effectiveness of the inhibitory powers of mouthwashes containing 0,5% chitosan solution and 25% red dragon fruit peel extract against bacterial growth S. mutans. The sample used was S. mutans bacteria ATCC®25175TM which was isolated, incubated and bred on Nutrient Agar media. This study used the Kirby-Bauer diffusion method (disc paper) by measuring the diameter of the clear zone formed around the disc paper using a calipers. The results of this study showed that the mouthwash containing 0,5% chitosan solution and 25% red dragon fruit peel extract had an inhibitory zone diameter of 8,84 mm showing moderate category antibacterial effectiveness. Other groups of mouthwashes, the results of 0,5% chitosan solution mouthwash were obtained by 6,86 mm (medium), red dragon fruit peel extract 25% mouthwash by 8,02 mm (medium) and 0,2% chlorhexidine mouthwash 0f 11,18 mm (strong). Basic mouthwash has no effectiveness in inhibiting bacterial growth because clear zones are not formed. 0,2% chlorhexidine mouthwash has the largest diameter of the inhibitory zone. | en_US |