Cone-beam Computed Tomography Analysis of the Root Canal Morphology of Mandibular Incisors Using Two Classification Systems in a Spanish Subpopulation: A Cross-Sectional Study.

OBJECTIVE: This study evaluated the root and canal morphology in permanent mandibular incisors teeth using cone-beam computer tomography imaging in a Spanish subpopulation, and compared these findings with ipsilateral (similarity) and contralateral (symmetry) incisors. In addition, the position of canal splitting was measured. METHODS: A total of 229 datasets comprising four mandibular teeth each (n=916 incisors) were analysed using Vertucci and Ahmed et al. classifications, and, the similarity and symmetry were calculated. The distance from the cemento-enamel junction (CEJ), and the most coronal canal divergence was measured (if present). The role of sex was also assessed. The Cochran Q Test, LOGIS PROC in SUDAAN, Chi-square, and Kappa were used for the different comparisons. A p-value of less than 0.05 was considered significant. RESULTS: All incisors were single-rooted and no significant differences regarding root canal morphology were found according to the sex of the subjects included in the database. The most common morphology was Vertucci type I/Ahmed et al. 1MI1(65.3% for central and 66.8% for lateral incisors respectively), followed by type III/1MI1-2-1 (31% for central and 30.6% for lateral incisors). 1.8% of the samples were considered as non-classifiable with Vertucci but were classified with codes using the Ahmed et al. system. Similarity values were 74.7% for the left side, and 74.2% for the right side, whereas symmetry values were 90% for central and 84.3% for lateral incisors. In the presence of divergences, the main (SD) distances from the CEJ were for type II/1MI1-2-1 3.8+-0.8 (centrals) 4.0+-0.7 mm (laterals); for type V/1MI1-2 this value ranged between 6.0+-1.8 and 5.5+-1.5 mm, whereas values for 1MI1-2-3-2-1 were 1.8 and 2.1 mm. No significant differences were found when the position of the most coronal divergence was compared between lateral and central incisors for the different morphologies. CONCLUSION: A high prevalence of Vertucci I/Ahmed et al. 1MI1 configuration was present in mandibular incisors from Spanish individuals. Similarity and symmetry were common, particularly for central incisors. The position of the coronal splitting of the canals varied according to the root canal morphology.

The effect of a preparation containing glycocholic acid on the biocidal efficacy of sodium hypochlorite in a biofilm laboratory model.

This study assessed the antimicrobial effect of sodium hypochlorite (NaOCl) mixtures combined with Keratobacter (KB) using an engineered biofilm root canal model. Clinical and reagent grade NaOCl were mixed with KB (9:1-vol/vol) to assess pH values over 1 min to select the ideal solution with a pH just below the pKa of hypochlorous acid. The samples were randomly divided into five groups: 1% and 4% NaOCl reagents, a mixture of NaOCl:KB using 1% and 4% NaOCl reagents and distilled water. Outcome measures were colony-forming units (CFUs/mL) and positive/negative cultures. No significant differences were observed in the pairwise comparisons between 1%, 4% NaOCl and 4% NaOCl+KB for the outcome CFUs/mL. Only 4% NaOCl presented with negative cultures in all samples, whereas 1% NaOCl and 4% NaOCl+KB had similar results (54% vs. 40%). The addition of KB has a limited effect on the antimicrobial efficacy of 4% NaOCl in this laboratory model.