Jassim, S. . . D.; Ibrahim, L. . . M. Correlation Between Periodontal Health Status and Salivary Matrix Metalloproteinase-9 Levels in Smoker and Non-Smoker Chronic Periodontitis Patients (A Comparative Study) . J Bagh Coll Dent 2016, 28 (4), 128-133. https://doi.org/10.12816/0033223.