Biological and antimicrobial properties of the association Ambroxol and a water-soluble viscous liquid as a vehicle for a tricalcium silicate-based sealer.

This study aimed to investigate the antimicrobial and biological properties of Ambroxol associated with glycerin (GLI), propylene glycol (PG), and polyethylene glycol (PEG) as a possible vehicle for an experimental tricalcium silicate sealer, with the intention of developing a new biomaterial. Mouse undifferentiated dental pulp cells (OD-21) were cultured, and the effects of different association on cell proliferation and inflammatory cytokine production were investigated. Antimicrobial adhesion of Enterococcus faecalis to setting sealers at 2 h was evaluated. Polyethylene tubes containing experimental sealers and empty tubes were implanted into dorsal connective tissues of 12 male 3- to 4-months-old Wistar rats (250-280 g). After 7 and 30 days, the tubes were removed and processed for histological and immunohistochemical analyses. ANOVA followed by Bonferroni correction and ANOVA followed by Tukey test was used for parametric data and Kruskal-Wallis followed by Dunn for nonparametric (p < 0.05). Cell proliferation was dose-dependent, since all association were cytotoxic at higher concentrations; however, Ambroxol-PEG showed significantly higher cytotoxicity than other association (p < 0.05). In addition, irrespective of the association, no cytokine production was observed in vitro. Ambroxol-GLI reduced bacterial viability, whereas Ambroxol-PEG increased (p < 0.05). Histological examination showed no significant difference in the inflammatory response (p > 0.05) and mineralization ability in all association. Additionally, IL-1ß and TNF-α were upregulated on Ambroxol-PEG in relation to Control at 07 days (p < 0.05). Ambroxol-GLI was the best vehicle for experimental tricalcium silicate sealer, as it promoted an increase in antimicrobial activity without altering the inflammatory response or mineralization ability.

Influence of ultrasonic agitation on bond strength, marginal adaptation, and tooth discoloration provided by three coronary barrier endodontic materials.

OBJECTIVES: The effect of ultrasonic agitation (UA) on bond strength and adaptation of cervical plugs prepared with MTA Angelus (MTA), MTA Repair HP (MTAHP), and Biodentine (BIO) was evaluated. Dentin discoloration caused by the materials/treatment was also assessed. MATERIALS AND METHODS: Seventy-two single rooted teeth were divided into six groups depending on the materials/treatment. After cervical plug preparation, dentin discs were excised for the push-out test; additional discs were analyzed under the confocal microscope to determine adaptation (gaps occurrence). For dentin discoloration analysis (ΔE), blocks of bovine incisors had cavities prepared and filled with the materials/treatment (from 7 to 180 days). RESULTS: Both bond strength and adaptation were positively influenced by UA (P < 0.05). Comparison between materials showed an advantage for BIO when compared to MTAHP (P < 0.05). The best and worst results were provided by BIO/UA (12.66 MPa and 1.87%) and MTAHP (2.54 MPa and 28.58%), respectively. For ΔE, significant differences were observed throughout the periods. Just the MTA without UA exhibited noticeable discoloration at 180 days (P < 0.05). CONCLUSIONS: UA favored a better adaptation of the materials to the dentin root, resulting in higher bond strength and adaptation of the materials to the root canal walls. Moreover, UA reduced MTA discoloration, keeping it imperceptible over the period evaluated. CLINICAL RELEVANCE: The better adaptation and higher bond strength provided by UA can be considered clinically relevant due to the importance of maintaining blood clot integrity and the possible esthetic compromise provided by reparative materials when used as coronary barrier in regenerative procedures.

Alveolar mucosa necrosis induced by utilisation of calcium hydroxide as root canal dressing.

This case demonstrates the ability of calcium hydroxide to cause connective tissue necrosis. A patient with a history of trauma exhibited a large area of external inflammatory root resorption affecting the cervical and middle thirds of tooth 12. After root canal cleaning, a calcium hydroxide root canal dressing was applied to control the resorption process. After three days when the patient attended for replacement of the dressing an irregular zone of necrosis was observed on the buccal aspect of the alveolar mucosa. Careful curettage and irrigation was then performed to remove the extruded calcium hydroxide and necrotic tissue. After curettage, the root canal was accessed and irrigated with saline solution for removal of remnants of the dressing. The dressing was than replaced taking care to avoid contact with soft tissue, which might induce further damage, minimising the overflow of material. Improvement in healing was observed at 15-day follow-up, with complete closure of the lesion by soft tissue. At the 120-day follow-up, no scar was detected. At 180-day follow-up, the root canal was filled only with mineral trioxide aggregate (MTA) with aid of K files #20 and #50. At two-year follow-up, there were no symptoms and the resorption process seemed to have ceased. It is important to emphasise the damage that may occur when calcium hydroxide is in close and extended contact with the soft tissues, which could happen when dressing material is extruded through a root resorption.

The Influence of Humidity on Intra-tubular Penetration and Bond Strength of AH Plus and MTA Fillapex: An In Vitro Study.

OBJECTIVE: The aim of this study was to evaluate the influence of humidity on the intra-tubular penetration, bond strength and failure mode associated with AH Plus (AH) and MTA Fillapex (MTAF) sealers. METHODS: For this analysis, an apparatus was created to maintain the humidity of the specimens. Sixty bovine single-rooted teeth with similar anatomy were used. The teeth were randomly divided into 4 groups (n=15): G1 - AH/moist, G2 - AH/dry, G3 - MTAF/moist and G4 - MTAF/dry. A laser scanning confocal microscope was used to analyse the penetrability of the sealers into the dentinal tubules. A push-out test was performed to examine the diameter and height of the root canal fillings. The failure mode was analysed under a stereomicroscope at 40× magnification. The data were submitted to non-parametric Kruskal-Wallis and Dunn's tests. The significance level was P<0.05. RESULTS: The MTAF sealer exhibited higher intra-tubular penetration values compared to AH Plus (P<0.05) sealer. AH Plus showed the highest bond strength values. Regarding the type of failure mode, a majority of cohesive failures was identified, irrespective of the moisture conditions, which were not statistically significant among the sealers (P<0.05). CONCLUSION: Humidity conditions did not influence the intra-tubular penetration, bond strength and failure mode of AH Plus and MTAF sealers.

Comparisons by microcomputed tomography of the efficiency of different irrigation techniques for removing dentinal debris from artificial grooves.

AIM: The aim of this study was compare the capacity of different irrigation protocols for debris removal from artificial grooves and assess the effectiveness of Easy Clean used in different kinematics by means of micro-CT. METHODOLOGY: Fifty acrylic prototyped maxillary incisors were instrumented and included in a muffle. The specimens were longitudinally sectioned, and a longitudinal groove was made on the inner surface of the root canal in one of hemisections, and the dentin debris was inserted into the grooves. The specimens were divided into five groups (n = 10): G1: Conventional with open-ended needle; G2: Conventional with double side-vented needle; G3: Easy Clean in reciprocating movement; G4: Easy clean in continuous rotation (ECCR); and G5: Passive ultrasonic irrigation (PUI). All specimens were scanned using microcomputed tomography before and after the irrigation technique and calculated the volume (mm3) of dentin debris. The paired t-test and post hoc Tukey test were the statistical tests used, with significance set at 5%. RESULTS: There were no significant difference (P > 0.05) between PUI and ECCR. ECCR was significantly (P < 0.05) more effective than the groups of conventional irrigation techniques. CONCLUSIONS: PUI and ECCR favored the removal of a larger volume of dentin debris from the groove.

Root ZX Electronic Foramen Locator: An Ex Vivo Study of Its Three Models' Precision and Reproducibility.

Although Root ZX is considered the gold standard electronic foramen locator (EFL), two variations of this device were launched, however without different operating mechanisms. This investigation aims to evaluate the precision of Root ZX (RZX), Root ZX II (RII), and Root ZX Mini (RM) EFLs. After access cavity preparation, 32 mandibular single rooted human premolars had their real length measured with the aid of a #15 K-type manual file under magnification (25x). Electronic measurements were performed by the devices in an alternate order until the apical foramen was reached (0.0). Each measurement was performed with adjusted file to the real length of the teeth and verified with a digital caliper. The accuracy of the EFLs was 68.8% (RZX), 65.8% (RII), and 68.8% (RM), considering ±0.5 mm as a margin of tolerance. The mean errors of the devices were 0.37 ± 0.25 mm (RZX), 0.41 ± 0.34 mm (RII), and 0.32 ± 0.28 mm (RM). ANOVA and Tukey test were applied to analyze the obtained data, which showed that there were no statistically significant differences among the locators (P > .05). It can be concluded that the three tested devices demonstrated precise measurements of the real length of the canal without performance differences among them.

Removal of Separated Endodontic K-File with the Aid of Hypodermic Needle and Cyanoacrylate.

A wide range of accidents might happen during the treatment of the root canal system, where the instrument separation is one of the most unpleasant occurrences. Several techniques have been developed to facilitate the removal of the fragments; however, they generally require specific devices that not always are available to the clinician. The aim of this case report is to present a simple alternative technique to remove from the root canals manual instruments fractured during the treatment. The case has its outline based on a 31-year-old patient who sought the clinic to have her maxillary first left premolar rehabilitated. The clinic and radiographic examinations revealed the need of endodontic retreatment and the presence of a fragment of a K-file instrument localized at the apical third of the palatine canal. The retreatment was initiated by the removal of the obturation materials followed by several unsuccessful attempts to take out the fractured instrument. Hence, it was chosen to perform the fragment removal using a hypodermic needle and cyanoacrylate adhesive. The fragment easily came out, which reinforces the technique adopted as a safe, simple, and low cost mean to solve the problem of fractured instruments using only items already present in the endodontic arsenal.

Ex Vivo Evaluation of the Accuracy of Electronic Foramen Locators in Root Canals with an Obstructed Apical Foramen.

INTRODUCTION: The objective of the present study was to evaluate the accuracy of electronic foramen locators (EFLs), Root ZX II (RZX; J. Morita, Tokyo, Japan), Propex II (Dentsply Maillefer, Ballaigues, Switzerland), and Apex ID (AID; SybronEndo, Glendora, CA), in root canals with an obstructed apical foramen (OAF) and to compare them with those 1.0 mm short of the apical foramen (AF; -1.0) and at the AF (0.0). METHODS: Thirty human mandibular molars had their coronal and cervical preparations accessed. Then, the AFs were standardized (250 µm). Electronic root canal measurements were performed for the -1.0 and 0.0 working lengths, and the canals were obstructed with dentinal debris. The distance to the AF displayed by the EFLs was then recorded. The last instrument used was fixed with a cyanoacrylate-based adhesive; the apical portions of the roots were scraped, allowing for the determination of the distance between the tips of the instruments and the AFs. RESULTS: The precision rates at 0.0, -1.0, and the OAF were 94.7%, 43.9%, and 1.8% (RZX); 93.0%, 54.4%, and 54.4% (Propex II); and 93.0%, 68.5%, and 75.4% (AID), respectively (±0.5 mm). No significant differences were found between the devices at 0.0; however, for the measurements at -1.0 and the OAF, the AID offered significantly better results than RZX (P < .05). CONCLUSIONS: The absence of foraminal patency caused by dentin debris obstruction affects the accuracy of the EFLs differently, suggesting distinctive interactions with their operating mechanisms.

An ex vivo comparison of root canal length determination by three electronic apex locators at positions short of the apical foramen.

OBJECTIVE: The aim of this study was to evaluate the precision of working length determination of 3 electronic apex locators (EALs): Root ZX, RomiApex D-30, and Ipex at 0.0 mm, at the apical foramen (AF), and at 1.0 mm short of the AF. METHODOLOGY: Thirty-eight mandibular premolars had their real lengths previously determined. Electronic measurements were determined at 1.0 mm, followed by measurements at 0.0 mm, performed in triplicate. RESULTS: Precision of devices at 1.0 mm and 0.0 mm were: 94.7% and 97.4%, respectively (Root ZX); 78.9% and 97.4% (RomiApex D-30); and 76.3% and 97.4% (Ipex). Although no statistical differences were observed between the EALs at 0.0, at 1.0 mm Root ZX performed significantly better than the others. CONCLUSION: The EALs had acceptable precision when measuring the working length at the AF. However, when used at levels short of the AF, only Root ZX did not suffer a significant negative effect on precision.

Evaluation of pH and calcium ion release of new root-end filling materials.

OBJECTIVE: The purpose of this study was to evaluate the pH and calcium ion release of 6 materials used for root-end filling and perforation repair. STUDY DESIGN: Gray ProRoot MTA, gray MTA-Angelus, white MTA-Angelus, and CPM were compared to 2 experimental ones: MTA-exp, also based in Portland cement with a modified mixing liquid, and MBPc, an epoxy-resin based cement containing calcium hydroxide. After 3, 24, 72, and 168 hours the water in which each sample had been immersed was tested to determine the ph and calcium ion release. RESULTS: All the analyzed materials showed alkaline pH and capacity to release calcium ions; however, a tendency of reduction of these characteristics was noted for all the analyzed materials, except for the MBPc, which showed a slight increase of pH among the 3 initial periods. CONCLUSION: The results suggest that all materials investigated presented alkaline pH and ability of release of calcium ions.

Cleaning ability of chlorhexidine gel and sodium hypochlorite associated or not with EDTA as root canal irrigants: a scanning electron microscopy study.

The aim of this study was to evaluate the cleaning efficacy of 2% chlorhexidine gluconate gel (CHX) compared to 2.5% sodium hypochlorite solution (NaOCl) associated or not with 17% EDTA used as irrigants during the biomechanical preparation. Fifty freshly extracted single-rooted human teeth with complete apex formation were randomly divided into five groups: G1 - sterile saline, G2 - 2.5% NaOCl, G3 - 2% CHX, G4 - 2.5% NaOCl + EDTA and G5 - 2% CHX + EDTA. The specimens of G1 were subdivided into two control groups. The teeth were decoronated and the coronal and middle root thirds were prepared with Gates-Glidden burs, and the apical third was reserved to manual instrumentation. All procedures were performed by a single operator. In all groups, 2 mL of irrigant was delivered between each file change. The teeth were sectioned and prepared for analyses under scanning electron microscopy (SEM). SEM micrographs were graded according to a score scale by two examiners. Data were analyzed statistically by Kruskal-Wallis and Dunn tests at 1% significance level. The best results were obtained in the groups in which the irrigant was used followed by the chelating agent. No statistically significant difference was observed among G4, G5 and the positive control group (p<0.01). The groups G2 and G3 were significantly different from the others, presenting the worst cleaning capacity. In conclusion, the use of the chelating agent is necessary to obtain clean canal walls, with open tubules and no heavy debris. The use of 2% chlorhexidine gluconate gel alone is not able to remove the smear layer.