Matrix metalloproteinase 8 production of cariously-exposed irreversible pulpitis

Matrix metalloproteinase 8 (MMP-8) is a major enzyme released by neutrophils and may serve as a potential biomarker for pulpal inflammation. This study aimed to compare MMP-8 levels in normal pulp and cariously-exposed pulp diagnosed with irreversible pulpitis, including both asymptomatic irreversible pulpitis (AIP) and symptomatic irreversible pulpitis (SIP) and to assess the association between clinical factors and MMP-8 concentrations in the pulpitis group. Pulpal blood samples were collected following caries removal in pulpitis cases or intentional pulp exposure in the normal pulp group. Both active and total forms of MMP-8 were measured. Clinical factors that might affect the concentrations of MMP-8 in the pulpitis group (AIP and SIP), were included to determine theircorrelations. Fifteen teeth diagnosed with irreversible pulpitis (AIP and SIP) and five sound premolars (normal pulp) were included. Higher concentrations of MMP-8 were observed in both AIP and SIP groups (AIP: active = 18.40 ± 3.04 ng/mL, total = 36.79 ± 7.88 ng/mL; SIP: active = 16.06 ± 3.10 ng/mL, total = 32.02 ± 6.12 ng/mL) compared to normal pulps (active = 4.63 ± 0.96 ng/mL, total = 7.17 ± 1.41 ng/mL). No significant difference was found between AIP and SIP. The presence of radiographic periapical pathology was significantly associated with increased MMP-8 concentrations in the pulpitis group. Irreversible pulpitis exhibited elevated MMP-8 levels regardless of pulpal pain symptoms. MMP-8 concentrations were significantly higher in cases with periapical pathology, supporting its potential role as a bioactive marker for pulpal inflammation.