Abstract
Background & Aim: sIgA is the prominent immunoglobulin in whole saliva and is considered to be the main specific defense mechanism in the oral cavity. Smoking can alter the level of salivary sIgA. The aim of this study was to investigate the relationship between smoking and sIgA.
Materials & Methods: In this Historical Cohort 40 people which were divided into two groups (20 in smokers group and 20 in control group) were examined.  Data such as age, gender, BOP, Oral lesions, systemic disease, use of medicine, xerostomia, CAL and history of dental treatment in 1 last month were collected and fill out the questionnaire, and clinical examination was done. Then about 1cc of unstimulated saliva was collected by the spitting method from all subjects between 09:00 to12:00 and transferred to the laboratory in the next 2 hours .The Data were analyzed by t-test and Multiple linear regression test.
Results: The results indicated that the salivary secretory IgA concentration was significantly lower in the smoker group (164.23±92.61) than controls (232.48±148.02). (p=0.042).
Conclusion: In this research, smoking was associated with a significant decreased in secretory IgA concentration.
    Key Words: IgA, Smoking, Immune system