RESUMO
Abstract Objective: To evaluate the relationship between the mRNA transcription level of Matrix Metalloproteinase-9 (MMP-9) and the selected clinical periodontal healing at one month of scaling and root planing. Material and Methods: A total of six chronic periodontitis patients and one periodontally healthy subject were recruited. The gingival crevicular fluid was collected from all subjects, and the expression level of MMP-9 mRNA was measured by quantitative real-time PCR. Pocket depth, papilla bleeding index, and clinical attachment loss were measured on day 1 at baseline and day 30. Scaling and root planing was performed on day 1. Data were analyzed using SPSS 22.0 software Results: In comparison to the control, periodontal clinical parameters in the treatment group were significantly reduced after scaling and root planing. MMP-9 mRNA expression did not show a significant change after the 30th day. A weak correlation was noted between the MMP-9 mRNA transcription level and the changed PBI measurement Conclusion: Scaling and root planing is clinically effective for chronic periodontitis with a 4-6 mm pocket, whereas the expression of MMP-9 mRNA was not altered. Further studies with a more extended observation period are needed to confirm or reject the present findings.