Jassim, S. and Ibrahim, L. 2016. Correlation between Periodontal Health Status and Salivary Matrix Metalloproteinase-9 Levels in Smoker and Non-Smoker Chronic Periodontitis Patients (A Comparative Study) . Journal of Baghdad College of Dentistry. 28, 4 (Dec. 2016), 128-133. DOI:https://doi.org/10.12816/0033223.