Simone Bonato Luisi

Microflora associated with primary endodontic infections: Correlations among sem evaluation, clinical features, and radiographic findings

The aim of the present study was to characterize, by means of SEM, primary endodontic infections and to correlate with clinical and radiographic findings. Twelve (12) human extracted teeth (19 roots) presenting primary endodontic infection were examined. SEM qualitative observations of bacterial and defense cells, their features and distribution within the root canal lumen and root dentine were recorded for association with clinical and radiographic tabled data. Although a direct correlation between biofilm composition and clinical/radiographic findings was not established, structural organization and distribution of the biofilm, as well as the characteristics of host response, could be easily related to those features. Bacterial biofilm was predominant at the apical third. Symptomatic apical periodontitis was related to presence of bacterial biofilm all thirds. Defense cells could be seen in the apical third of some samples. These cells were present in all thirds in some of the cases with open cavities. The correlations performed in this study allowed a better understanding of the picture of primary endodontic infection, host response and relevant clinical features. The combined use of scanning electron microscopy with clinical and radiographic evaluation has the potential to overcome some limits of the current knowledge related to pulpal and periapical diseases, providing important insights for improving treatment strategies. Microsc. Res. Tech., 2012.

Preflaring effects on the accuracy of three electronic apex locators

PURPOSE: To compare the accuracy of three electronic apex locators (EALs) and evaluate the influence of cervical preflaring in them. METHODS: The working length (WL) of thirty extracted human mandibular incisors was determined visually. All teeth were mounted in conducting medium and tested with: Novapex, Mini Apex Locator and Propex II. The electronic WL was determined before and after preflaring with LA Axxess burs. Differences between the electronic and visual WL were calculated and analyzed by Friedman and Wilcoxon tests. Radiographs were taken using the electronic WL of each EAL and the distance between the instrument tip and the radiographic apical vertex was measured. This value was compared to a reference or ideal value (1 mm) by one-sample t test. RESULTS: The Novapex was the most accurate EAL before and after the preflaring procedure, which was confirmed by the radiographic analysis. All EALs tested increased their accuracy after preflaring, but no significant difference was noted for the Novapex. CONCLUSION: The Novapex was more accurate compared to the Mini Apex and Propex II. Preflaring procedure was advantageous for all EALs.

Calcium Hypochlorite Solutions: Evaluation of Surface Tension and Effect of Different Storage Conditions and Time Periods over pH and Available Chlorine Content

INTRODUCTIONnThe aim of this study was to evaluate the pH and the available chlorine content from sodium hypochlorite (NaOCl) and calcium hypochlorite (Ca[OCl]2) solutions stored in different conditions and time periods and the surface tension of Ca(OCl)2 solutions in comparison with NaOCl.nnnMETHODSnSolutions at 0.5%, 1%, 2.5%, and 5.25% concentrations were prepared. The pH level and the available chlorine content of freshly prepared solutions and solutions stored for 30, 60, and 90 days at 25°C, 4°C, or 37°C were evaluated in a digital pH meter and by titration, respectively. Surface tension was tested using a Du Nouy tensiometer (Sigma 702, Force Tensiometer; Attension, Espoo, Finland). Descriptive and inferential statistical analyses were performed.nnnRESULTSnA precipitate formed by 2.5% and 5.25% Ca(OCl)2 solutions was observed. Ca(OCl)2 showed a higher concentration of available chlorine than NaOCl. Both 2.5% and 5.25% NaOCl and Ca(OCl)2 had a decrease in the available chlorine content when compared with freshly prepared solutions; 0.5% and 1% NaOCl tend to have a lower pH compared with 0.5% and 1% Ca(OCl)2. NaOCl, 5.25%, showed higher pH compared with 5.25% Ca(OCl)2. NaOCl and Ca(OCl)2 in 0.5% and 1% concentrations tend to show a reduced pH level, whereas 2.5% and 5.25% solutions showed an increase in pH. The heat contributed to the instability of the solutions. NaOCl showed lower surface tension values than Ca(OCl)2.nnnCONCLUSIONSnCa(OCl)2 solutions are extremely alkaline and tend to have more available chlorine content than NaOCl but have a higher surface tension than NaOCl. Regarding the available chlorine content, these solutions tend to be stable to 30 days of storage when kept at 4°C or at 25°C.