This clinical trial is designed to evaluate two locally delivered gels, metformin and chlorhexidine, as adjunctive therapies to scaling and root planing (SRP) in patients with Stage II, Grade B periodontitis. Periodontitis is a chronic inflammatory condition that damages the supporting tissues of the teeth. Although SRP is the standard non-surgical treatment, it may not fully eliminate harmful bacteria or prevent disease recurrence.

Chlorhexidine is a widely used antimicrobial gel, while metformin, a medication commonly prescribed for diabetes, has shown anti-inflammatory and bone-supportive effects when used locally in the gums. This study will directly compare the effectiveness of 1% metformin gel and 0.2% chlorhexidine gel, both applied subgingivally after SRP, against SRP alone.

Sixty adult participants diagnosed with Stage II, Grade B periodontitis will be randomly assigned into three groups: SRP only (control), SRP plus metformin gel, and SRP plus chlorhexidine gel. Clinical outcomes (plaque index, gingival index, probing pocket depth, and clinical attachment level), inflammatory markers (MMP-8 in gingival crevicular fluid), and radiographic bone density will be measured at baseline, 1 month, 3 months, and 6 months.

The goal is to determine whether metformin gel or chlorhexidine gel provides superior improvements in periodontal healing when compared with SRP alone. Findings from this trial may guide evidence-based decisions on optimizing non-surgical periodontal therapy.

This is a randomized, controlled, single-blind clinical trial conducted at the Department of Oral Medicine, Periodontology, Oral Diagnosis, and Oral Radiology, Faculty of Dentistry, Kafrelsheikh University, Egypt. Sixty participants aged 18-60 years with Stage II, Grade B periodontitis will be enrolled. Participants will be randomly allocated (1:1:1) into three groups:

Group A (Control): SRP only

Group B (Test 1): SRP + 1% Metformin Gel

Group C (Test 2): SRP + 0.2% Chlorhexidine Gel

Subgingival gels will be applied after SRP using sterile syringes, followed by periodontal pack placement for one week. All patients will receive standardized oral hygiene instructions.

Outcome Measures:

Primary Outcomes: Clinical attachment level (CAL) changes, reduction in inflammatory markers (MMP-8), and radiographic bone density gain.

Secondary Outcomes: Probing pocket depth (PPD), plaque index (PI), and gingival index (GI).

Follow-up assessments will be performed at 1, 3, and 6 months. Data will be statistically analyzed using ANOVA and paired t-tests, with significance at p < 0.05.

The trial has been reviewed and approved by the Scientific Research Ethics Committee, Faculty of Dentistry, Kafrelsheikh University (Approval No. KFSIRB200-564, dated 24 February 2025).

Inclusion Criteria:

Adults aged 18-60 years.

Diagnosis of Stage II, Grade B periodontitis.

Probing pocket depths ≤ 5 mm with clinical attachment loss of 3-4 mm in selected sites.

Generally healthy individuals without systemic conditions affecting periodontal health.

Exclusion Criteria:

Current smokers or users of tobacco products.

Pregnant or lactating women.

Known allergy to metformin or chlorhexidine.

Use of antibiotics or anti-inflammatory drugs within the past 3 months.

History of periodontal therapy within the past 6 months.

Single-blind design: participants are blinded to intervention allocation; clinicians applying treatment are aware of the group assignment.