Pouyan Razavi - Student Research Committee, Faculty of Dentistry, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran.
Seyed Abdolrahim Rezaee - Immunology Research Center, Inflammation and Inflammatory Diseases Division, Mashhad University of Medical Sciences, Mashhad, Iran.
Salehe Akhondian - Student Research Committee, Faculty of Dentistry, Mashhad University of Medical Science, Mashhad, Iran.
Nastaran Asgari - Student Research Committee, Faculty of Dentistry, Mashhad University of Medical Science, Mashhad, Iran.
Kazem Fatemi - Oral and Maxillofacial Disease Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
Farnaz Mohajertehran* - Oral and Maxillofacial Disease Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.

Background: Periodontal disease is an inflammatory condition affecting the tooth's supporting tissues, resulting in gradual loss of periodontal ligament (PDL), alveolar bone, and gum resorption. Neutrophil and monocyte/macrophage, destructive proteases like matrix metalloproteinase (MMP)-۳ and MMP-۹ play pivotal roles in such lesions in periodontitis. Therefore, this study aims to compare the level of MMP-۳ and MMP-۹ gene expression in patients with or without periodontitis in an Iranian population. Methods: This cross-sectional study was carried out on ۲۲ chronic periodontitis patients and ۱۷ healthy control subjects referred to the department of periodontology, Mashhad Dental School. In both groups, the gingival tissue was removed during surgery and transferred to the Molecular Biology Laboratory for MMP-۳ and MMP-۹ gene expression evaluation. The qRT-PCR, TaqMan method was used for gene expression assessments. Results: The average age of periodontitis patients was ۳۳± ۵ years, and in controls, ۳۴.۷± ۶ with no significant differences. The mean MMP-۳ expression in periodontitis patients was ۱۴۶.۶۷±۳۸.۷, and in controls, ۶۳.۴±۹.۱. The difference was statistically significant (P=۰.۰۴). The mean expression of MMP-۹ in periodontitis patients and controls were ۱۰۳.۸± ۲۱.۶۶ and ۸۷.۵۷± ۱۶.۰۵, respectively. Although the target gene expression in patients was higher, the difference was insignificant. Furthermore, there was not any significant correlation between age or gender with the expression of MMP۳ or MMP۹. Conclusions: The study demonstrated that the MMP۳ seems to have a destructive impact on the gingival tissue in chronic periodontitis, but not MMP۹.

Chronic periodontitis, Matrix metalloproteinase-۳, Matrix metalloproteinase-۹.