DuqueJA, Fernandes SL, Bubola JP, Duarte MAH, Camilleri J, Marciano MA. The effect of mixing method on tricalcium silicate-based cement.International Endodontic Journal, 51, 69-78, 2018. Aim To evaluate the effect of three methods of mixing on the physical and chemical properties of tricalcium silicate-based cements. Methodology The materials evaluated were MTA Angelus and Portland cement with 20% zirconium oxide (PC-20-Zr). The cements were mixed using a 3 : 1 powder-to-liquid ratio. The mixing methods were manual (m), trituration (tr) and ultrasonic (us) activation. The materials were characterized by means of scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy. Flowability was analysed according to ANSI/ADA 57/2012. Initial and final setting times were assessed following ASTM C266/08. Volume change was evaluated using a micro-CT volumetric method. Solubility was analysed according to ADA 57/2012. pH and calcium ion release were measured after 3, 24, 72 and 168 h. Statistical analysis was performed using two-way analysis of variance. The level of significance was set at P = 0.05. Results The SEM analysis revealed that ultrasonic activation was associated with a homogeneous distribution of particles. Flowability, volume change and initial setting time were not influenced by the mixing method (P > 0.05). Solubility was influenced by the mixing method (P < 0.05). For pH, at 168 h, significant differences were found between MTA-m and PC-20-Zr-m (P < 0.05). For calcium ion release, PC-20-Zr-tr had higher values than MTA-m at 3 h, and MTA-tr had higher values than PC-20-Zr-m at 168 h (P < 0.05). Conclusions The ultrasonic and trituration methods led to higher calcium ion release and pH compared with manual mixing for all cements, whilst the ultrasonic method produced smaller particles for the PC-20-Zr cement. Flow, setting times and volume change were not influenced by the mixing method used; however, it did have an impact on solubility.

This study showed that titanium tetrafluoride (TiF 4 ) varnish and solution were less effective than sodium fluoride (NaF) varnish and potassium oxalate gel in reducing dentin hydraulic conductance. Therefore, TiF 4 might be not successful against dentin hypersensitivity (DH), whereas NaF varnish or potassium oxalate gel could benefit patients with DH. SUMMARYDentin hypersensitivity (DH) is related to an increase in dentin permeability. This study tested the effect of titanium tetrafluoride (TiF 4 ) compared with sodium fluoride (NaF) and potassium oxalate gel on reducing hydraulic conductance (Lp) from the perspective of diminishing dentin permeability. The Lp of the dentin disks (1.0 6 0.2 mm) was evaluated using Flodec. The maximum Lp values of each disk were taken after phosphoric acid etching (15 seconds) and randomly allocated to seven groups (n=8) according to the treatments. The minimum (smear layer) and the maximum (after acid etching) Lp values were recorded. Treatments were performed for 4 minutes as follows: 1) NaF varnish 2) and solution (2.45% F, pH 5.0), 3) TiF 4 varnish and 4) solution (2.45% F, pH 1.0), 5) 3% potassium oxalate gel, 6) free fluoride varnish (placebo, pH 5.0), 7) and no treatment (control). The Lp after each treatment was assessed. Samples were exposed to an erosive challenge (6% citric acid, pH 2.1, 1 minute), and the final Lp was recorded. The data were statistically analyzed using repeat-

Background and aims. Increasing the temperature of sodium hypochlorite (NaOCl) enhances its dissolution and antibacterial properties. However, the high resistance of multi-species biofilms could restrict the effect of the solution regardless of its temperature, enabling the long-term recovery of the surviving bacteria. The aim of this study was to investigate if the increase of temperature of NaOCl improves its antibacterial and dissolution ability on oral biofilms and if the post-treatment remaining bacteria were capable of growing in a nutrient-rich medium.Materials and methods. Forty dentin blocks were infected intra-orally for 48 hours. Then, the specimens were treated with 1% and 2.5% NaOCl at room temperature (22ºC) and body temperature (37ºC) for 5 and 20 min. The percentage of live cells and the biovolume were measured pre- (control) and post-treatment and after the biofilm revitalization. Four confocal ‘stacks’ were chosen from random areas of each sample. Statistical analysis was performed using Kruskal-Wallis and Dunn tests. Statistical significance was defined at P <0.05.Results. All the NaOCl groups were effective in dissolving the biofilm at any temperature, concentration and contact time without statistical differences among them (P >0.05). The 1%-NaOCl for 5min was not able to significantly kill the bacteria, regardless of its temperature and contact time (P >0.05).Conclusion. The temperature variation of the NaOCl was not relevant in killing or dissolving bacterial biofilms. Twenty-four hours of reactivation did not appear to be enough time to induce a significant bacterial growth.

Descrita em 1836 como sendo uma celulite tóxica por Wilhelm Frederick Von Ludwig, a Angina de Ludwig pode ser uma celulite extremamente fatal se não houver um diagnóstico preciso e precoce. Tendo vários fatores causal sendo o principal às infecções odontológicas dentre outras como: traumatismos e lacerações dos tecidos bucais, infecções das glândulas salivares, picada de insetos no queixo, neoplasias bucais infectadas, linfadenites, osteonecrose da mandíbula relacionada com o uso de bisfosfonatos. Afetando os espaços fasciais do pescoço, espaço submandibular, espaço submentoniano assim tendo o comprometimento principal as vias aéreas, pacientes imunossuprimidos e com comprometimento na condição sistêmica tendem a ser mais suscetível a Angina de Ludwig. Tendo tratamento a internação imediata e em seguida a prescrição de antibióticos para o controle da infecção e a drenagem cirúrgica para a remoção do material purulento e em seguida a remoção da causa da infecção como extrações e tratamento endodôntico, devido ao comprometimento das vias aéreas em alguns casos mais graves deve se realizar uma traqueostomia ou intubação endotraqueal. Este trabalho visa o melhor entendimento sobre o manejo de pacientes com Angina de Ludwig oferecendo ao leitor um conhecimento sobre a etiologia, diagnóstico e tratamento, bem como o prognostico relativo ao tratamento estabelecido.

Context:Postoperative pain control after endodontic treatment is important to maintain patient comfort.Aim:The aim of this prospective clinical study was to evaluate the postoperative symptomatology of endodontic treatments performed in a single session, with or without photodynamic therapy (PDT), using Reciproc #40 file in necrotic unirradicular anterior teeth.Materials and Methods:In a prospective clinical study, 40 teeth indicated for endodontic treatment were treated by a single endodontist according to a preestablished protocol. The teeth were randomly divided into two groups (n = 20): control group (CG) and laser group (LG). After 24 h, 72 h, and 1 week of endodontic treatment, patients' pain symptomatology was evaluated through a Visual Analog Scale (VAS) ranging from 0 to 10, in which 0 corresponds to no pain and 10 indicates extreme pain. In both workgroups, similar protocols were used for instrumentation with the Reciproc system (R40), irrigation with 2.5% sodium hypochlorite, and filling by the gutta-percha plastification technique, in which the CG did not use PDT, and the LG used PDT after the instrumentation sequence. After the visit, the patients were given a prescription for ibuprofen 400 mg to be taken every 6 h if they experienced pain.Results:The results of the study, analyzing the VAS, did not show any difference in pain symptoms between the groups at 24 h, 72 h, and 1 week (P > 0.05).Conclusions:It was concluded that there was no statistical difference between the groups.

The aim of this study was to evaluate, by stereomicroscopy and confocal laser microscopy, the influence of different lateral compaction methods for the obturation quality, as well as the time spent for the procedure. Thirty root canals of freshly extracted single-rooted human teeth were prepared with the ProTaper system up to F5 instrument and filled with gutta-percha and AH Plus sealer by the lateral compaction technique. The teeth were divided into 3 groups (n=10) in accordance with the method used for the lateral compaction, as follows: Manual, Mechanical and Ultrasonic. The sealers were stained with rhodamine B dye in a proportion of 0.1% per gram in weight to allow for the analysis under a confocal microscope. During the root filling procedure, the time spent was recorded with a stopwatch. The specimens were stored at 37 °C for 48 h, and then sectioned at 2, 4 and 6 mm from the apex. The percentage of gutta-percha, sealer and void areas were evaluated using a stereomicroscope and sealer penetration perimeter by confocal laser microscope. Statistical analyses were performed using the Kruskall-Wallis and Dunn tests (p<0.05). The mechanical method required a shorter time for the lateral compaction than the manual method (p<0.05). There were no significant differences (p>0.05) for the perimeter of the dentin with sealer penetration among all groups. The mechanical method showed a higher (p<0.05) percentage of gutta-percha and less sealer at the 4 mm section in comparison with the manual method. The ultrasonic group showed intermediate values. The void areas found in the root filling were similar (p>0.05) between the three methods. In conclusion, the fastest lateral compaction was achieved with the mechanical method, and all the methods showed void areas in the root filling.

The aim of this study was to assess the effect of time and the ultrasonic activation of ethylenediaminetetraacetic acid (EDTA) in removing the smear layer of at root canal. A total of 60 bovine inferior incisors were transversely sectioned and instrumented; A smear layer was added in the root dentin surface. The specimen were then divided into six groups according to the following final irrigation protocols: Group (G) 1: conventional irrigation with sodium hypochlorite (NaOCl); G2: conventional irrigation with NaOCl + EDTA for 20 s; G3: conventional irrigation with NaOCl + EDTA for 60 s; G4: passive ultrasonic irrigation (PUI) with NaOCl; G5: PUI with NaOCl + PUI with EDTA for 20 s; G6: PUI + NaOCl and PUI with EDTA for 60 s. Samples were analyzed by scanning electron microscope (SEM) at ×500 increase. The images were measured by three blinded evaluators and classified in scores ranging from 1 to 5. The results were analyzed by the Pearson correlation test and the ANOVA nonparametric Kruskal-Wallis and Dunn's tests were used for the comparisons. Irrigated samples only with NaOCl (G1 and G4) had higher scores when compared with other groups. G5 and G6, irrigated with 17% EDTA and ultrasonic irrigation had lower scores. However, there was no statistically significant difference in G2 and G3, where there was no irrigation. It was concluded that irrigation with 17% EDTA for 20 s promoted the effective removal of smear layer, regardless of ultrasonic irrigation.

ObjectivesThis study evaluated the effect of ultrasonic agitation of mineral trioxide aggregate (MTA), calcium silicate-based cement (CSC), and Sealer 26 (S26) on adaptation at the cement/dentin interface and push-out bond strength.Materials and MethodsSixty maxillary canines were divided into 6 groups (n = 10): MTA, S26, and CSC, with or without ultrasonic activation (US). After obturation, the apical portions of the teeth were sectioned, and retrograde cavities were prepared and filled with cement by hand condensation. In the US groups, the cement was activated for 60 seconds: 30 seconds in the mesio-distal direction and 30 seconds in the buccal-lingual direction, using a mini Irrisonic insert coupled with the ultrasound transducer. After the materials set, 1.5-mm thick sections were obtained from the apexes. The presence of gaps and the bond between cement and dentin were analyzed using low-vacuum scanning electron microscopy. Push-out bond strength was measured using a universal testing machine.ResultsUltrasonic agitation increased the interfacial adaptation of the cements. The S26 US group showed a higher adaptation value than MTA (p < 0.05). US improved the push-out bond strength for all the cements (p < 0.05).ConclusionsThe US of retrograde filling cements enhanced the bond to the dentin wall of the root-end filling materials tested.