A two-component system for the preparation of a hydrogel for preventing and/or treating a periodontal disease, selected from the group consisting of periimplantitis, gingivitis, periodontitis and peri-implant mucositis. The two-component system comprises as a first component an aqueous suspension having a pH value of less than 7 comprising a pH-sensitive gelling agent, and as a second component a sodium hypochlorite (NaOCl) solution at a pH in the range of 10 to 13. The first component is physically separated from the second component.