This is a multi-center, randomized, double-blinded, placebo-controlled study to evaluated the efficacy and safety of DKF-306 in patients with periodontal diseases.

Inclusion Criteria:

• Aged 19 years and older
• Periodontal diseases
• Having not less than 16 permanent teeth including at least 4 molars (third molars excluded)
• Having teeth with not less than 2 sites of both probing pocket depth (PPD) ≥ 4 mm and gingival index (GI) ≥ 2 in at least 2 quadrants
• Agrees not to use over-the-counters (oral, ointment, toothpaste, film, etc.) or quasi-drugs (gargle and mouthwash) to alleviate or treat the symptoms of gingivitis or periodontitis during the study
• Voluntarily signed the informed consent form
• Willing to participate in the study

Exclusion Criteria:

• Hypersensitivity to ingredients of investigational products

• Hypersensitivity to Azo dyes, acetylsalicylic acid or other prostaglandin synthase inhibitors

• Following diseases or state in the mouth:

  1. rampant caries or decayed tooth/teeth remained untreated for a long time
  2. multiple restorations which may be related to periodontal inflammation
  3. poor oral hygiene with heavy plaque or calculus deposition
  4. soft or hard tissue tumor
  5. systemic chronic diseases with oral manifestations
  6. fibrotic gingival enlargement

• Use of orthodontic appliances or removable partial denture(s)

• Having teeth or state in need of immediate treatment such as periodontal abscess, a tooth indicated for extraction, etc.

• History of aggressive periodontitis or acute necrotizing ulcerative gingivitis

• Received dental treatments such as endodontic treatments or periodontal therapy (including both nonsurgical and surgical therapy) within 3 months from randomization

• Received the following drugs for more than 2 weeks within 3 months from randomization:

  1. systemic/local antibiotics in the mouth or non-steroidal anti-inflammatory drugs
  2. cyclosporine or corticosteroids
  3. phenytoin, calcium antagonists, anticoagulants or antiplatelets

• Initiated drugs in treatment of chronic diseases within 3 months from randomization

• Received the same drug with investigational products within 3 months from randomization

• Medical conditions or diseases affecting the efficacy and safety of investigational products at the investigator's discretion

• Heavy smoker (20 cigarettes or more a day)

• Pregnant or breast-feeding

• Plans to have a child or unwilling to comply with using medically accepted contraception methods during the study

• Alcohol or drug abuse

• Other investigational products or procedures within 3 months from screening

• Not eligible due to other reasons at the investigator's discretion