To evaluate the efficacy of locally delivered ozone gel as an adjunct to conventional periodontal therapy on selected clinical parameters as well as alveolar bone density (BD) and superoxide dismutase (SOD) activity in patient with chronic periodontitis.

In this study, the investigators tested the effect of ozone gel as a local delivery system in treatment of chronic periodontitis in term of probing pocket depth reduction, mean gain in clinical attachment level, a more rise in BD values as well as greater reduction in SOD activity compared to scaling and root planing (SRP) alone.

Inclusion Criteria:

1. The participant's age ranged between 30 and 60 years.
2. All of the patients suffered from chronic periodontitis with attachment loss ≥ 5mm.
3. Willingness to participate and sign the informed consent.

Exclusion Criteria:

1. Any systemic disease that affect the periodontium.
2. Pregnancy, lactation, postmenopausal women
3. People who take anti-inflammatory drugs, antibiotics or vitamins within the previous 3 month.
4. People who use mouth washes regularly
5. Heavy smoking (> 10 cigarettes/day)
6. History of alcohol abuse.
7. Participation in other clinical trials.