METHODS: We applied a multiplex serology assay to simultaneously measure antibody responses to 11 F. nucleatum antigens in prediagnostic serum samples from 485 colorectal cancer cases and 485 matched controls. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CI).
RESULTS: We observed neither a statistically significant colorectal cancer risk association for antibodies to individual F. nucleatum proteins nor for combined positivity to any of the 11 proteins (OR, 0.81; 95% CI, 0.62-1.06).
CONCLUSIONS: Antibody responses to F. nucleatum proteins in prediagnostic serum samples from a subset of colorectal cancer cases and matched controls within the EPIC study were not associated with colorectal cancer risk.
IMPACT: Our findings in prospectively ascertained serum samples contradict the existing literature on the association of F. nucleatum with colorectal cancer risk. Future prospective studies, specifically detecting F. nucleatum in stool or tissue biopsies, are needed to complement our findings.
Materials and Methods: Sixty freshly extracted maxillary incisors teeth collected in saline. Access cavity prepared and canals were made free of bacterial and pulp. The teeth were mounted on the bacteria collecting apparatus. Root canals were contaminated with the Fusobacterium Nucleatum (ATCC25586) and dried at 37°C for 24 h. In Group 1 (Control group): No instrumentation was done and biomechanical preparation done in all other groups with Group 2: Hand K-files, Group 3: Protaper gold, Group 4: K3XF, Group 5: Edge taper platinum, and Group 6: Hyflex CM rotary file systems. Then, the extrude was collected, and it is incubated in Mueller-Hinton agar for 24 h and the number of colony forming units were counted and statistical comparison was done using Kruskal-Wallis test and Mann-Whitney U test.
Results: Hand K-files extruded more bacteria when compared to other four rotary systems, K3XF file system extruded least number of bacteria.
Conclusion: All instrumentation techniques extruded intracanal bacteria apically. However, engine-driven nickel-titanium instruments extruded less bacteria than the manual technique. The K3XF rotary file system comparatively extruded less bacteria than other rotary file systems.