Matrix metalloproteinase-8 and substance P levels in gingival crevicular fluid during endodontic treatment of painful, nonvital teeth

Objective. The aim of this study was to investigate levels of matrix metalloproteinase-8 (MMP-8) and substance P (SP) in gingival crevicular fluid (GCF) during root canal treatment (RCT) of nonvital teeth. Study design. Patients scheduled for nonsurgical RCT were prospectively selected; all patients provided informed consent. GCF samples were collected from teeth scheduled for RCT and their contralateral teeth across 3 different time periods. MMP-8 and SP levels were measured using enzyme-linked immunosorbent assay (ELISA). Data were analyzed using a mixed model analysis and the Pearson correlation analysis. Results. Patients' subjective pain levels were significantly related to both MMP-8 and SP levels. MMP-8 and SP levels in GCF were decreased during RCT, and they showed a positive correlation with each other (P < .05). Conclusions. This study demonstrated that periradicular inflammation of endodontic origin can elevate SP and MMP-8 levels in GCF. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2011;112:548-554)