Tehran University of Medical Sciences Iranian Journal of Microbiology 2008-3289 11 2 2019 05 30 177 180 EN Latief Mooduto Department of Conservative Dentistry, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia Dian Wahjuningrum Department of Conservative Dentistry, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia Agatha Prita A Department of Conservative Dentistry, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia Cecilia Lunardhi Department of Conservative Dentistry, Faculty of Dental Medicine, Universitas Airlangga, Surabaya, Indonesia 2018 09 23 2019 03 22 Background and Objectives: Chitosan, a polysaccharide derived from squid pens – the squid waste, is gaining considerable interests in biomedical engineering due to the biodegradability, biocompatibility, nontoxicity, and antibacterial activity. It is necessary to eradicate the bacteria from root canal in endodontic treatment, including Porphyromonas gingivalis. P. gingivalis is one of the most prevalently found bacteria in root canals and its presence can cause endodontic treatment failure. This study was conducted to find the antibacterial effect of chitosan from squid pen against P. gingivalis at a certain concentration. Materials and Methods: Chitosan 1.5% (w/v) was diluted in several tubes. The lowest concentration with no bacterial growth was considered to have antibacterial activity against P. gingivalis. Results: There was no bacterial growth in nutrient agar media at the concentration of 10.75%. Conclusion: Chitosan that was made from squid pens has antibacterial activity against P. gingivalis. https://ijm.tums.ac.ir/index.php/ijm/article/view/1893 https://ijm.tums.ac.ir/index.php/ijm/article/download/1893/1133