Cholesterol esterase-like (CE) activity from saliva and esterase from cariogenic bacteria hydrolyze ester linkages of dental methacrylate resins. Collagenolytic, matrix metalloproteinase-like (MMP) activities from dentin and bacteria degrade collagen in demineralized tooth dentin. Human neutrophils in the oral cavity contain factors that are hypothesized to have CE and MMP activities that could contribute to the degradation of methacrylate resins and dentinal collagen. Objectives: To measure the CE and MMP activities from human neutrophils and their ability to degrade dental methacrylate resin composite and dentinal collagen.

Aim To measure collagenolytic protease activity from Enterococcus faecalis and Micrococcus luteus and their ability to degrade human dentinal collagen. Methodology Proteases activity of E. faecalis ATCC 29212, ATCC 47077 and M. luteus towards generic and specific human matrix metalloproteinase (MMP) substrates was measured using a fluorimetric assay. The ability of the bacteria to degrade dentinal collagen was tested by quantifying the amount of hydroxyproline released into the media following incubation of the bacteria or heat‐inactivated bacteria (HIN) with demineralized human dentine samples for 24 h and by scanning electron microscopy (SEM). Multifactorial anova and Tukey's post hoc test were used to analyse the data (P < 0.05). Results All strains had MMP‐like activities, but with different substrate affinity; E. faecalis ATCC 29212, ATCC 47077 and M. luteus had the greatest affinity towards MMP‐8 (7.75 ± 0.88 μmol L−1/3 × 106 CFU), MMP‐9 (33.86 ± 5.16 μmol L−1/3 × 106 CFU) and generic MMP (26.08 ± 4.48 μmol L−1/3 × 106 CFU), respectively. The amount of hydroxyproline released from demineralized dentine was similar (P > 0.05) for the three strains (range 1.8 ± 0.17 to 2.38 ± 0.39 μg 50 μL−1) and was significantly higher (P < 0.001) compared to their HIN counterparts (0.61 ± 0.22 μg 50 μL−1). SEM revealed increased collagen network degradation after incubation with bacteria versus HIN. Conclusions Endodontic pathogens possess collagenolytic protease properties that enable them to degrade dentinal collagen, potentially compromising the restoration‐tooth and sealer‐tooth interfaces. These collagenolytic protease properties could facilitate the migration of pathogenic bacteria into the root canal system and explain in part their role in root canal infections.

E. faecalis possesses esterase-like degradative activity toward dental methacrylate resin restoration materials, which could accelerate the degradation of the dentin-methacrylate resin interface, increasing bacterial biofilm proliferation and penetration into the root canal system.

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