Effect of scaling and root planing based on MMP-8 mRNA expression and clinical parameters in periodontitis patients

Matrix metalloproteinase-8 (MMP-8) is an important host factor involved in the pathogenesis of periodontal diseases, which is the main collagenase detected in gingival tissues. Collagenases destruct periodontal tissue and result in pocket depth (PD), clinical attachment loss (CAL) and bleeding papilla for slight provocation. This study aims to evaluate the correlation between MMP-8 mRNA expression and clinical parameters in periodontitis patient after scaling and root planning (SRP). GCF from periodontitis patients and healthy subject were sampled and assessed for the MMP-8 mRNA expression by quantitative polymerase chain reaction (q-PCR). The clinical parameters which were PD, papillary bleeding index (PBI), and CAL were assessed 1 month before and after SRP and they were further analyzed for their correlation to MMP-8 mRNA expression. Wilcoxon test and paired t-test were used to compare the mRNA transcription level, PD, CAL and PBI before and after SRP. Furthermore, the relationship between the clinical parameters and the MMP-8 mRNA expression was also evaluated by Spearman test. A significant reduction in the clinical parameters was noted after SRP than before it, although the difference of MMP-8 mRNA expression was not significant. This result indicated a weak positive correlation between the reduction in MMP-8 expression and altered clinical parameters. SRP resulted in the improvement of clinical conditions of periodontal tissues, but not MMP-8 mRNA expression.