Goal of this prospective observational study is determine effect of smoking on periapical healing after NSRCT. Population includes systemically healthy smokers with radiographic evidence of apical periodontitis will be recruited and compared with same type of population of non smokers after non surgical root canal treatment intervention in both the groups. Outcome will be assessed using periapical index scoring system at 6 and 12 months follow up period

The clinical and radiological success of primary non-surgical endodontic treatment in smoker & nonsmoker patients will be compared between both groups and smoking cessation effect on periapical healing will be assessed.

The correlation between the self-reported smoking status & smoking status by urine analysis

Inclusion Criteria:

• systemically healthy patients of age 18 years and above, known current smoker patient , a non-smoker or former smoker patient ,should have at least minimum 8 teeth in oral cavity, requiring periapical radiographs of teeth with periapical pathosis

Exclusion Criteria:

• Pregnant or patient having systemic disorders, those patients who are non-compliant and not maintaining oral hygiene, teeth requiring retreatment and having procedural errors. Teeth that are not suitable for rubber dam isolation, teeth that have advanced periodontal disease and having endo-perio lesions and, patients requiring endocarditis prophylaxis

Smokers of age 18 years (male/female) and above having apical periodontitis with age and gender matched controls will be enrolled in the study.