Renata Dornelles Morgental

Antibacterial activity of two MTA‐based root canal sealers

AIM To evaluate the pH and antibacterial activity of Endo CPM Sealer and MTA Fillapex by two different methods, using white MTA and Endofill as references for comparison. METHODOLOGY Antibacterial activity was evaluated against Enterococcus faecalis (ATCC 29212). The agar diffusion test (ADT) was performed to evaluate the effect before setting. The materials were placed in four equidistant wells made in ten agar plates. After incubation at 37 °C for 48 h, the inhibition zones were measured using a digital paquimeter. The direct contact test (DCT) was performed to assess the antibacterial effect after setting. Suspensions of crushed materials were prepared and mixed with E. faecalis. After different periods of time (1, 6, 15 and 60 min), the survival of bacteria was assessed by using 10-fold serial dilution and cultivated on agar plates in triplicate. Colony-forming units (CFU) mL(-1) were calculated after incubation. pH values were also measured in triplicate. Comparison between sealers in the ADT and DCT was performed by the Kruskal-Wallis test. RESULTS In the ADT, inhibition zones were found with MTA Fillapex and Endofill. They were similar to each other and greater than the other sealers (P < 0.05). None of the tested sealers demonstrated antibacterial activity in the DCT, and thus, all sealers had similar bacterial counts compared with the negative control group (P > 0.05). White MTA and Endo CPM Sealer suspensions had pH values >11, whilst MTA Fillapex and Endofill had lower values. CONCLUSIONS MTA Fillapex and Endofill had an antibacterial effect against E. faecalis before setting, but none of the sealers maintained antibacterial activity after setting, despite the high pH of the MTA-based materials.

Pulp sensibility test in elderly patients

BACKGROUND The ageing process transforms the histological composition of the dental pulp and may affect the response to pulp sensibility tests. OBJECTIVES The aim of this study was to assess the influence of age on pulp response time and on pain intensity. MATERIAL AND METHODS Fifty elderly patients and 50 young patients were selected. Different classes of teeth were evaluated. The pulp sensibility test was performed with a refrigerant spray. The pulp response time was measured in seconds and the pain intensity was assessed by visual analogue scale. RESULTS The Spearman coefficient was calculated and detect a positive correlation between age and pulp response time for maxillary incisors, premolars, mandibular incisors, and mean (p < 0.05). On the contrary, there was a negative correlation between age and pain intensity for maxillary incisors, mandibular incisors, and mean (p < 0.05). Also, the results of elderly and young groups were compared by Mann-Whitney test. Significant difference was noted regarding the pulp response time for maxillary incisors, premolars, mandibular incisors, and mean (p < 0.05). Significant difference was detected regarding the pain intensity for mandibular incisors only (p < 0.05). CONCLUSIONS Pulp response time increases when people get older while pain intensity decreases. There were variations among the classes of teeth.

Efficacy of four irrigation needles in cleaning the apical third of root canals

This study aimed to evaluate the influence of irrigation needle gauge and design, and the final root canal diameter on the apical cleaning efficacy. Twelve human mandibular incisors were used. At different stages of root canal widening (sizes 20, 30 and 40 K-files), root canals were filled with radiopaque contrast medium. Four different needles were evaluated: 23G with side opening, 22G with apical opening, 30G with side opening and 30G with apical opening. Irrigation was carried out with 2mL distilled water. The same tooth was radiographed with a digital system several times to assess the four types of needle in those three stages of canal widening. Pre-irrigation (canals filled with contrast) and post-irrigation (canals with remaining contrast) images were submitted to digital subtraction using the Adobe Photoshop CS4 program. Pre-irrigation (filled with contrast) and subtracted (cleaned by irrigation) areas were outlined by a trained and blinded operator using the Image Tool 3.0 software. Their ratio was calculated to express the percentage of apical cleaning in each stage of canal widening (sizes 20, 30 and 40 K-files) with each of the four needles. Data obtained were subjected to one-way ANOVA and Tukeys tests. The 30G needles with side and apical opening promoted better apical cleaning at all stages of root canal widening (p<0.05). In conclusion, smaller diameter needles were more efficacious in cleaning the apical third of the root canals, regardless of their design.

Are Premixed Calcium Silicate–based Endodontic Sealers Comparable to Conventional Materials? A Systematic Review of In Vitro Studies

Introduction This study aimed to compare the physicochemical and biological properties of premixed calcium silicate–based endodontic sealers with other conventional root canal filling materials by systematically reviewing laboratory studies. Methods The search was conducted in 3 databases (Medline via PubMed, Scopus, and Web of Science) following the Preferred Reporting Items for Systematic Reviews and Meta‐Analyses. Two reviewers independently selected the studies and extracted the data. The properties of interest were bond strength, radiopacity, pH, solubility, setting and working time, dimensional change, flow, calcium ion release, antimicrobial activity, biocompatibility, and cytotoxicity. Results From 2636 potentially eligible studies, 31 were selected for full‐text analysis, and 27 were included in the review. Premixed calcium silicate–based endodontic sealers followed the ISO 6876:2012 requirements for most physicochemical properties except for solubility. The target sealers also presented favorable biological findings when compared with conventional sealers. Conclusions Despite the lack of well‐designed long‐term clinical trials, the target premixed calcium silicate–based sealers show good physicochemical and biological properties in vitro. In general, the results were similar or better than conventional endodontic sealers as observed in in vitro and in vivo animal studies. HighlightsCalcium silicate‐based sealers showed proper physicochemical properties.Calcium silicate‐based sealers presented optimal biological properties.

Effect of Superoxidized Water and Sodium Hypochlorite, Associated or Not with EDTA, on Organic and Inorganic Components of Bovine Root Dentin

INTRODUCTION This study aimed to evaluate the effects of Sterilox (Sx), a superoxidized water, 5% and 2% sodium hypochlorite (5NaOCl and 2NaOCl), and 17% EDTA (E) on the organic and inorganic components of bovine dentin. METHODS Eighty bovine incisors were randomly divided into 8 groups (n = 10): 5NaOCl, 5NaOCl + E, 2NaOCl, 2NaOCl + E, Sx, Sx + E, E alone, and distilled water (H2O). Root canal instrumentation was performed by using the corresponding irrigant. The apical 15 mm was longitudinally sectioned into 2 fragments, one for light microscopy analysis in slides stained with picrosirius red (organic component) and the other for scanning electron microscopy analysis (inorganic component). Scores data obtained in the light microscopy analysis were submitted to the Kruskal-Wallis test, followed by multiple comparisons test (P < .05). Scanning electron microscopy images were analyzed descriptively. RESULTS The chemical solution 5NaOCl had a greater effect on the organic component of dentin in area and depth than 2NaOCl. The chemical solutions 5NaOCl + E, 5NaOCl and 2NaOCl + E caused the greatest change in the collagenous organic matrix near the root canal lumen. The chemical solution 2NaOCl showed similar behavior to Sx, associated or not with E, promoting more superficial disorganization of collagen in a smaller area. Demineralization was observed in all groups in which E was used. However, areas of erosion and open dentinal tubules were detected only when it was combined with NaOCl. CONCLUSIONS Five percent NaOCl promoted the most extensive damage to the organic component of dentin, and when associated to EDTA, dentinal erosion could be seen. Considering these specific aspects, 2% NaOCl and Sx had milder effects on bovine root dentin.

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.

Effect of Super-Oxidized Water, Sodium Hypochlorite and EDTA on Dentin Microhardness

The present study aimed to evaluate the influence of the following irrigating solutions on the microhardness of root canal dentin: 2% sodium hypochlorite (2NaOCl), 5% sodium hypochlorite (5NaOCl), super-oxidized water (400 ppm Sterilox - Sx) and 17% EDTA (E). Eighty roots from bovine incisors were randomly divided into 8 groups (n=10): 2NaOCl, 5NaOCl, Sx, and 2NaOCl + E, 5NaOCl + E, Sx + E (associated with E as final irrigant for 5 min), E solely and distilled water (dH2O) as the negative control. Root canal preparation was performed by hand instruments, using one of the irrigation protocols for 30 min. Then, 5 mm of the cervical root third were cut out from each sample and subjected to the Vickers microhardness test, at two points, one at approximately 500-1000 µm from the root canal lumen (distance 1), and the other at approximately 500-1000 µm from the external root surface (distance 2). Data were analyzed by Wilcoxon and Kruskal-Wallis tests at 5% significance level. Microhardness values at distance 1 were significantly lower than those at distance 2 for all groups, except 5NaOCl and 5NaOCl + E groups (p>0.05). EDTA showed the lowest microhardness values. However, no statistically significant difference was detected among groups at distance 1 and EDTA was significantly different only from Sx at distance 2. In conclusion, all tested solutions showed lower microhardness at the most superficial root canal dentin layer compared to the one found near the external root surface, except 5NaOCl and 5NaOCl + E; EDTA promoted lower microhardness values in comparison to Sterilox at this site.

Interference of partial visual analysis of root filling quality and apical status on retreatment decisions

Objective The presence of periapical radiolucency has been used as a criterion for endodontic treatment failure. However, in addition to the inherent limitations of radiographic examinations, radiographic interpretations are extremely subjective. Thus, this study investigated the effect of partial analysis of root filling quality and periapical status on retreatment decisions by general dentists. Material and Methods Twelve digitalized periapical radiographs were analyzed by 10 observers. The study was conducted at three time points at 1-week intervals. Radiographs edited with the Adobe Photoshop CS4 software were analyzed at three time points: first, only root filling quality was analyzed; second, only the periapical areas of the teeth under study were visualized; finally, observers analyzed the unedited radiographic image. Spearmans coefficient was used to analyze the correlations between the scores assigned when the periapical area was not visible and when the unedited radiograph was analyzed, as well as between the scores assigned when root fillings where not visible and when the unedited radiograph was analyzed. Sensitivity, specificity, positive and negative predictive values between partial images and unedited radiographs were also used to analyze retreatment decisions. The level of significance was set at 5%. Results The visualization of the root filling on the unedited radiograph affected the interpretation of the periapical status and the technical quality of the fillings has a greater influence on the general dentists decision to prescribe endodontic retreatment than the periapical condition. Conclusion In order to make endodontic diagnosis, radiographic interpretation process should not only emphasize technical aspects, but also consider biological factors.

Synthesis of silver-containing calcium aluminate particles and their effects on a MTA-based endodontic sealer

OBJECTIVE To synthetize calcium aluminate (C3A) and silver-containing C3A particles (C3A+Ag) testing their effects on the properties of a MTA-based endodontic sealer in comparison to an epoxy resin- and a calcium silicate-based sealer. METHODS Pure C3A and C3A+Ag particles were synthesized by a chemical method and characterized using XRD to identify crystalline phases. SEM/EDS analysis investigated morphology, particle size, and elemental composition of particles. Setting time, flow, radiopacity, water sorption and solubility of commercial and modified sealers were evaluated according to ISO 6876/2012. The pH and ions release were measured using a pHmeter and a microwave induced plasma optical emission spectrometer. The inhibition of biofilm growth was evaluated by confocal laser scanning microscopy (CLSM). Data were rank transformed and analyzed by ANOVA and Tukey test (P<0.05). RESULTS The C3A particles showed an irregular grain agglomerated structure with voids and pores. In C3A+Ag particles, Ag modified the material morphology, confirming the deposition of Ag. The physicochemical properties of the modified MTA-based sealer were similar to the commercial material, except for the significant increase in Ca+2 release. However, there was no Ag release. Setting time, flow, radiopacity, water sorption and solubility were adequate for all materials. All the materials showed alkaline pH. Antibiofilm effect was improved in the presence of C3A particles, while the biofilm inhibition was lower in the presence of Ag. SIGNIFICANCE The modified sealer presented improved antibiofilm properties and calcium release, without dramatic effects on the other characteristics. It is expected a positive effect in its antimicrobial behavior.

In vitro antibacterial activity of a silicone-based endodontic sealer and two conventional sealers

The aim of this study was to evaluate whether the modification in the silver component is capable of providing GuttaFlow 2 with antibacterial activity against Enterococcus faecalis compared with epoxy resin-based (AH Plus) and zinc oxide and eugenol-based (Endofill) sealers. The antibacterial activity was evaluated using a reference strain of E. faecalis (ATCC 29212). Freshly mixed sealers were subjected to the agar diffusion test (ADT), while the direct contact test (DCT) was performed after materials setting. ADT results were obtained through measurements, in millimeters, of the inhibition zones promoted by the materials, using a digital caliper. In DCT, values of CFU/mL promoted by the three sealers were compared in three experimental periods (1 min, 1 h, and 24 h). The data were analyzed using Kruskal-Wallis and Dunn post-hoc tests (p < 0.05). In both ADT and DCT, GuttaFlow 2 presented no effect against E. faecalis, while Endofill and AH Plus showed similar inhibition zones. Endofill was the only material capable of reducing bacterial growth in DCT. In conclusion, modifications in the silver particle of GuttaFlow 2 did not result in a sealer with antibacterial effect against E. faecalis.