Influence of root maturity or periodontal involvement on dentinal collagen changes following NaOCl irrigation: an ex vivo study

Abstract

Aim To refine a FTIR protocol for detection of NaOCl‐induced dentinal collagen changes using an ex vivo irrigation model, and to apply it to determine the collagen change within 0.5 mm of canal or root surfaces, with or without mature roots or periodontal involvement. Methodology The root canals of extracted human roots were irrigated with control saline (n = 3) or 5% NaOCl (n = 3) and sectioned into transverse disks for FTIR analyses, 0.5 mm from both the canal lumen and root surface, before and after surface treatment with 17% EDTA. Amide I/phosphate and amide II/phosphate absorbance ratios were compared using the Wilcoxon sign rank test. Mature roots without periodontal involvement were irrigated with: saline (n = 7), 5% NaOCl (n = 7) or 5% NaOCl + 17% EDTA (n = 7); those with periodontal involvement (n = 7) or immature roots (n = 7) were irrigated with 5% NaOCl. Dentine disks were then prepared for FTIR analyses. The effects of irrigant/root maturity/periodontal involvement were analysed using linear mixed models. Results FTIR analyses of the irrigated samples revealed a significant (P < 0.05) reduction in collagen bands near the canal lumen after NaOCl irrigation using surface EDTA‐treated samples. Irrigation with the test solutions resulted in significant (P < 0.0001) dentinal collagen changes in the mature roots, whilst those in the immature roots were significantly (P < 0.05) greater compared with the mature roots with or without periodontal involvement; but there was no difference between the latter groups. Conclusion EDTA surface treatment of polished dentine surfaces enhanced FTIR detection of NaOCl‐induced collagen changes. Both root maturity and irrigation protocol influenced the ability of NaOCl to alter dentinal collagen up to 0.5 mm from the canal lumen.

Influence of Different Irrigation Solutions on the Push-Out Bond Strength of Fiber Posts to Root Dentin and Root Canal Dentin Microhardness: Methodological Study

“…This finding can be explained by the fact that NaOCl disrupts the collagen structure of dentin in the cervical region, which reveals the PBS. 27 There were no major discrepancies among the PBS amounts of the coronal in CHX, EDTA, and HEBP. This finding suggests that using these solutions as a final irrigant shows no remarkable effect on the PBS of the fiber post.…”

“…NaOCl also removes mineralization inhibitors while dissolving organic tissue while releasing smear tissue. [27][28][29][30] And this may explain the significantly lower microhardness of NaOCl. In addition, it was observed that the use of 2.5% NaOCl as an irrigation solution significantly increased the Ca/P ratio in dentin.…”