Chronic periodontitis is inflammation caused by periodontopathogenic microorganisms characterized by alveolar bone resorption, loss of attachment and apical migration of junctional epithelium. Non-surgical and surgical periodontitis treatments including curettage are performed to reduce inflammation and form new attachments before flap surgery. The purpose of this writing is to treat periodontitis before flap surgical treatment is carried out. Case report: Female, 39 years old, came to RSGM UMY with complaints of loose lower front teeth and gums that bleed easily when brushing her teeth. The patient had no history of systemic disease. Intra-oral examination at the first visit revealed that the gingiva of the mandibular anterior teeth was reddish, unstippling and loose texture grade 2, OHI 7.3 (poor), PD 8 mm, PI score 30%, CAL 8 mm, and 3 tooth loss due to periodontitis. X-ray results showed resorption of the alveolar bone horizontally in the apical 1/3. DHE treatment plan, scaling and root planning, occlusal adjustment, splinting, curettage, flap surgery. Results: Control 2 weeks after curettage, gingiva was coral pink and PD was reduced. Conclusion: Curettage treatment in periodontitis cases reduces the depth of periodontal pockets and there are changes in clinical attachment levels (CAL) in mandibular anterior teeth. Surgical flap treatment is required in this case after curettage