JASSIM, S.; IBRAHIM, L. 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, v. 28, n. 4, p. 128-133, 14 dez. 2016.