Background: Periodontitis is the most common form of periodontal disease, greatly affecting the aesthetics, function as well as patient’s quality of life. In the periodontal disease treatment strategy, nonsurgical treatment is considered as the initial phase for anti-infection and soft-tissue management.

Objective: This study aims to compare the effect of two nonsurgical periodontal modalities: one-stage full-mouth and partial-mouth protocols for periodontitis. Materials and Methods: 60 patients with chronic periodontitis were randomly allocated to 2 groups. Group I (n = 30) was treated according to partial-mouth therapy. Group II (n = 30) was treated according to full-mouth disinfection therapy. Periodontal parameters were assessed at baseline and 1, 3, and 6 months, including plaque index, gingival index, periodontal probing depth, clinical attachment loss, and bleeding on probing.

Results: Both two treatment modalities resulted in significant improvements in all clinical parameters over the entire duration of the study (p < 0.05). Full-mouth disinfection therapy showed significantly better improvements than the partial-mouth one during follow-up times (p < 0.05).

Conclusion: Nonsurgical periodontal treatment has positive effects on controlling periodontitis. Full-mouth therapy shows clinical benefits over partial-mouth therapy in improving periodontal conditions.