Alkaline EDTANa was slower in removing the smear layer than EDTAHNa , but when mixed with NaOCl during biomechanical canal preparation promoted organic matter dissolution and smear layer removal simultaneously. However, the mixing of NaOCl and EDTANa should be performed immediately before use to prevent the reduction of free available chlorine.

Aim To evaluate the capacity of carbopol gel to maintain the intensity of a LED curing light (blueLED) along the length of prepared root canals in bovine teeth, and to assess the antimicrobial capacity of curcumin photoactivated by a LED curing light in the presence of carbopol gel. Methodology Experiment 1: Eight straight roots of bovine incisors were standardized to a length of 15 mm, and the root canals instrumented up to a size 120 K‐file. The LED curing light was irradiated inside the root canals using an aluminium collimator (1.5 mm in diameter) placed at the orifice (n = 8). Initially, the irradiation was performed in empty root canals and then repeated with the root canals filled with carbopol gel. Simple standardized photographs of the roots were taken with a digital camera in the mesial perspective during the irradiation procedure and the images analysed in OriginLab software to verify the light intensity along the length of the root. Experiment 2: Twenty dentine blocks were obtained from the cervical third of bovine incisors using a trephine bur. Biofilms were induced for 21 days on the blocks using Enterococcus faecalis (ATCC 4083) at 109 cells mL−1. The blocks were treated according to the groups (n = 5): positive control; standard PDT (methylene blue + diode Laser); curcumin; LED curing light; and curcumin + LED curing light. After the treatment, the samples were dyed with Live/Dead BacLight Bacterial Viability solution and fluorescence images were obtained by Confocal Scanning Laser Microscopy (CSLM). Experiment 3: Thirty‐two roots of bovine incisors were prepared as described in experiment 1. Their dentinal tubules were contaminated and the root canals treated according to the groups (n = 8): positive control; standard PDT; curcumin + LED curing light; curcumin + carbopol gel + LED curing light. The specimens were sectioned longitudinally and the split roots were treated with the Live/Dead dye to obtain fluorescence images by CSLM. All images were processed using BioImageL software to measure the percentage of viable bacteria and the data analysed statistically using the nonparametric Kruskal‐Wallis test (α < 0.05). Results In Experiment 1, carbopol gel did not improve the intensity of LED light transmission along the root canal. In Experiment 2, a significant decrease (P < 0.05) in bacterial viability occurred in the following order: positive control < only LED curing light < only curcumin < curcumin + LED curing light = standard PDT; and in Experiment 3 positive control = curcumin + LED curing light ≤ curcumin + gel + LED curing light ≤ standard PDT. Conclusion Similar disinfection effectiveness was obtained using curcumin + LED curing light and methylene blue + 660 nm LASER (standard PDT). The use of carbopol gel did not favour a greater transmission of LED light along the root canal and also resulted in less bacterial killing when used in endodontic PDT.

The purpose of this study was to evaluate the pH, solubility and antimicrobial action of Calcium Hydroxide Paste (CH), Double Antibiotic Paste (metronidazole+ciprofloxacin-DAP), calcium hydroxide added to DAP (CH/DAP) and Triple Antibiotic Paste (metronidazole + ciprofloxacin+minocycline-TAP). pH (n=10) were measured by pHmeter. Root canals of acrylic teeth (n=10) were filled with the above-mentioned intracanal-dressings, immersed in ultrapure water, and solubility was measured by the difference between the initial and final volume (7,15 and 30 days) by using micro-computed tomography. Enterococcus faecalis biofilm was induced on bovine dentin disc surfaces (n=20), and treated with the pastes for 7 days. Percentage bacterial viability was verified by confocal microscope, with LIVE/DEAD dye. CH and CH/DAP presented the highest pH values. Regarding solubility, after 7 days, antibiotic groups presented significant volume loss. CH and CH/DAP showed no statistical difference compared with the Control in antimicrobial action against E. faecalis biofilm. However, TAP and DAP presented a significant percentage reduction in bacterial population. Due to high solubility of the pastes, renewing antibiotic dressings every 7 days, or using the medications for this period in regeneration protocols is recommended. DAP is indicated for killing E. faecalis in biofilm because it has antimicrobial action similar to TAP. Adding Calcium Hydroxide to DAP significantly decreased its antimicrobial action. In spite of its the low solubility and high pH values, the CH paste showed a low level of antimicrobial action against E. faecalis in biofilm.

The concern with the polymerization shrinkage of restorative resin composites also applies to resin cements. The aim of this study was to evaluate the influence of volume and polymerization mode on forces generated during polymerization shrinkage (FGPS) of resin cements. Two light-cured resin cements--Variolink II (VL; Ivoclar Vivadent) and Nexus 3 (NX; Kerr)--and two self-cured resin cements - Multilink (ML; Ivoclar Vivadent) and Cement Post (CP; Angelus) - were inserted between two rectangular steel bases (6x2 mm) with distance set at 0.1, 0.3 and 0.5 mm, establishing a variation of volume. These steel bases were attached to a universal test machine with 50 kg load cell and forces (N) were registered for 10 min. Values of maximum forces generated by each material were subjected to two-way ANOVA and Tukey's test for individual comparisons (α=0.05). VL, NX and CP developed increasing FGPS as the volume of material increased, while ML presented the opposite behavior. It may be concluded that higher volume increases FGPS even with a concomitant decrease of C-factor, unless the resin cements present lower force generation rates as a function of time in combination with a low C-factor, resulting in stress relief and consequently lower values of FGPS.

Introduction: The use of a protective cervical barrier (PCB) is very well established to perform a safe internal bleaching; however, there is still no consensus on which material has the best sealing ability. Objective: This in vitro study aimed to evaluate the apical and linear sealing of different PCB materials placed during internal bleaching. Material and methods: This study had two study factors: PCB positioning, divided at two levels (cement-enamel junction [CEJ] Response variables were apical and linear sealing obtained through dye penetration and analyzed with a digital microscope. Data were subjected to two-way analysis of variance followed by Tukey test (p<0.05). Results: The main factor for both apical and linear sealing was the type of material (p<0.01), regardless of their position. RC and ZPC presented the worst sealing values (p<0.05). The Spearman

Primeiramente, agradeço a Deus, por iluminar meu caminho, minhas escolhas e por permitir que pessoas admiráveis cruzassem o meu caminho. Agradeço aos meus pais, Nelson Mamoru Oda e Rosana de Lourdes Ferracioli Oda, por toda confiança, dedicação e amor incondicional que recebi, além de todo suporte e apoio em minhas decisões. Agradeço aos meus irmãos, Eduardo Ferracioli Oda e Cristiane Ferracioli Oda, pela eterna amizade e companheirismo. Ao meu querido orientador Prof. Dr. Ivaldo Gomes de Moraes, obrigada por toda a amizade e pelo enorme conhecimento transmitido a mim, sempre com muita paciência e atenção. Agradeço ao Prof. Dr. Marco Antonio Hungaro Duarte pelo auxílio no desenvolvimento e aquisição de equipamento para o desenvolvimento deste trabalho, além das ajudas em sempre esclarecer dúvidas clínicas e sobre estatística. Agradeço à Profa. Dra. Flaviana Bombarda Andrade por me auxiliar nos procedimentos de microbiologia, bem como esclarecer dúvidas e disponibilizar materiais para a sua execução. Agradeço também aos demais professores do Departamento de Endodontia: Prof.

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The use of a protective cervical barrier (PCB) is very well established to perform a safe internal bleaching; however, there is still no consensus on which material has the best sealing ability. Objective: This in vitro study aimed to evaluate the apical and linear sealing of different PCB materials placed during internal bleaching. Material and methods: This study had two study factors: PCB positioning, divided at two levels (cement-enamel junction [CEJ] and 1mm above the cement enamel junction [CEJ+1]); and PCB material, divided at eight levels (resin composite [RC], glass ionomer cement [GIC], resin-modified glass ionomer cement liner [LRGIC], restorative resin-modified glass ionomer cement [RRGIC], zinc phosphate cement [ZPC], eugenol-free zinc oxide cement [ZOC], provisional filling resin [PFR] and gutta-percha as control [GUT]). Response variables were apical and linear sealing obtained through dye penetration and analyzed with a digital microscope. Data were subjected to two-way analysis of variance followed by Tukey test (p<0.05). Results: The main factor for both apical and linear sealing was the type of material (p<0.01) regardless of their position. RC and ZPC presented the worst sealing values (p<0.05). The Spearman rank correlation coefficient revealed a positive correlation between the apical and linear leakage. Conclusion: The results suggest that RC and ZPC must be avoided as a PCB during internal bleaching procedures.