Bactericidal Effect of a Novel Alkaline EDTA Root Canal Cleaning Solution.

OBJECTIVES: In this study, we aimed to evaluate the bactericidal effect and cytotoxicity of an ethylenediaminetetra-acetic acid (EDTA)-based root canal irrigant solution capable of efficiently removing both the organic matter and the smear layer. We prepared a strong alkaline EDTA (AE) solution with an acid buffer capacity similar to that of sodium hypochlorite. MATERIALS AND METHODS: AE was used at concentrations of 1%, 2%, and 3%. The bactericidal effect of AE on Enterococcus faecalis was evaluated by determining the colony number and biofilm removal rate. Biofilms were visualized using a Live/Dead BacLight bacterial viability kit. Viability of AE-treated cells were determined using a CCK-8 cell counting assay. STATISTICAL ANALYSIS: One-way analysis of variance followed by a Dunnett's multiple comparison test were used for comparisons among groups. RESULTS: Significant reduction in cell viability and biofilm formation were observed in case of 3% and 2% AE. AE exerted bactericidal effects in a concentration-dependent manner. Damage of normal human fibroblasts was not observed at any of the AE concentrations. CONCLUSIONS: Our results suggest that the AE solution could be used as an effective canal irrigant for the removal of bacterial biofilm.

Effect of salivary secretion with mouthguard use on seasonal allergic rhinitis symptom improvement.

OBJECTIVES: It was shown that mucosal immunity via salivary IgA may be related to the improvement of seasonal allergic rhinitis (SAR) symptoms, and improvement of SAR symptoms through saliva flow increase has been reported in patients using mouthguard (MG) in dental treatment. The purpose of this study was to analyze the effect of MG use on SAR symptom improvement and to clarify the role of saliva on SAR symptom development. METHODS: We recruited patients from the Kanagawa Dental University Hospital including 38 and 8 patients with SAR and non-SAR symptoms during two seasons from March 2017 to April 2018. We analyzed the saliva flow rate pre- and post-MG use and measured the amount of IgA and IgG4 in the saliva. We assessed the correlation between SAR symptoms and MG use. SAR symptoms were examined according to a specific clinical score. RESULTS: It was revealed that salivary IgA concentration was significantly lower in SAR patients than in controls. SAR symptoms significantly improved with MG use. The saliva flow rate and IgA levels significantly increased with MG use, although the IgG4 levels did not change. CONCLUSIONS: MG use may be beneficial for improving the symptoms of SAR patients by increasing the IgA levels. TRIAL REGISTRATION: University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR: UMIN000026428) on 6thMarch 2017.