Resumo O objetivo foi avaliar as propriedades físico-químicas e a penetrabilidade nos túbulos dentinários da solução de hipoclorito de cálcio [Ca(OCl)2], com ou sem surfactantes. Os surfactantes cloreto de benzalcônio, cetrimida, Tween 80 e Triton X-100 foram misturados em diferentes concentrações com a solução de hipoclorito de sódio (NaOCl), Ca(OCl)2 e água destilada (controle). Uma vez determinada a concentração micelar crítica (CMC) dos surfactantes em Ca(OCl)2 e NaOCl, foram avaliados o pH, cloro livre, tensão superficial e íons de cálcio livre. A penetrabilidade nos túbulos dentinários de NaOCl e Ca(OCl)2, com ou sem cloreto de benzalcônio e Triton X-100 [surfactantes que promoveram a menor tensão superficial de [Ca(OCl)2] foi avaliada utilizando pré-molares humanos corados com cristal violeta. Os testes estatísticos foram ANOVA de uma via e pós-teste de Tukey, Kruskal-Wallis e pós-teste de Dunn, ANOVA de duas vias e pós-teste de Bonferroni, e teste t; dependendo do ensaio. A adição de surfactantes reduziu a tensão superficial do NaOCl e Ca(OCl)2, e não alterou o pH ou cloro livre das soluções. A adição de todos os surfactantes aumentou a disponibilidade de íons de cálcio livre de Ca(OCl)2, principalmente o cloreto de benzalcônio. Ca(OCl)2 apresentou menor penetrabilidade nos túbulos dentinários do que NaOCl, e a adição de surfactantes não aumentou a penetrabilidade de Ca(OCl)2, mas aumentou a penetrabilidade de NaOCl. Pode-se concluir que a adição de surfactantes no Ca(OCl)2 não aumentou a penetrabilidade nos túbulos dentinários, mas promoveu menor tensão superficial, sem alterar os valores de pH ou cloro livre, e maior disponibilidade de íons de cálcio livre em Ca(OCl)2.

Abstract The aim was to assess the physicochemical properties and the penetration into dentinal tubules of calcium hypochlorite solution [Ca(OCl)2], with or without surfactants. The surfactants benzalkonium chloride, cetrimide, Tween 80 and Triton X-100 were mixed at different concentrations with sodium hypochlorite solution (NaOCl), Ca(OCl)2 and distilled water (control). Once the critical micellar concentration (CMC) of the surfactants in Ca(OCl)2 and NaOCl was determined, pH, free chlorine, surface tension and free calcium ions were evaluated. The penetration into dentinal tubules of NaOCl and Ca(OCl)2, with or without benzalkonium chloride and Triton X-100 [surfactants that promoted the lowest surface tension of Ca(OCl)2], was assessed using human premolars stained with crystal violet. The statistical tests were one-way ANOVA and Tukey’s post-test, Kruskal-Wallis and Dunn’s post-test, two-way ANOVA and Bonferroni’s post-test, and t-test; depending on the assay. The addition of surfactants reduced the surface tension of NaOCl and Ca(OCl)2, and did not alter the pH or the free available chlorine of either solution. The addition of all surfactants increased the availability of free calcium ions in Ca(OCl)2, especially benzalkonium chloride. Ca(OCl)2 exhibited lower penetration into dentinal tubules than NaOCl, and the addition of surfactants did not improve the penetration of Ca(OCl)2, but did increase the penetration of NaOCl. It can be concluded that the addition of surfactants to Ca(OCl)2 did not increase the penetration into dentinal tubules, but it did promote lower surface tension, without changing the pH or free available chlorine values, and higher availability of free calcium ions in Ca(OCl)2.

Abstract Objective: To assess the effects of different peracetic acid (PAA) formulations on smear layer (SL) removal, dentine erosion, cytotoxicity, and antibiofilm activity. Methodology: SL removal and dentine erosion were assessed using 90 premolars, distributed into six groups, according to final irrigation: PAA formulations (1% Sigma, 1% Bacterend OX, 1% Arposept, and 0.09-0.15% Anioxyde), 17% ethylenediaminetetraacetic acid (EDTA), and water (control). Cytotoxicity was assessed by methyl-thiazol-tetrazolium (MTT) and neutral red assays. Antibacterial and antibiofilm effectiveness was evaluated against Enterococcus faecalis. For cytotoxicity and antibiofilm activity assessment, the 2.5% NaOCl was also included. Results: EDTA, Sigma, and Bacterend OX removed more SL than Arposept, Anioxyde, and water (p<0.05). EDTA caused more severe dentine erosion than Sigma and Bacterend OX (p<0.05). Sigma and Bacterend OX had higher cytotoxicity than the other solutions (p<0.05). NaOCl, Bacterend OX, Sigma, and Anioxyde significantly reduced E. faecalis colony-forming units (CFU) (p<0.05). The 2.5% NaOCl solution promoted greater biofilm biomass reduction (p<0.05) than the other solutions. All PAA formulations promoted greater biomass reduction than 17% EDTA (p<0.05). Conclusions: Although Sigma and Bacterend OX had higher cytotoxicity, they had a SL removal capability similar to that of EDTA, were as effective as NaOCl against E. faecalis biofilm, and promoted less dentine erosion than EDTA. Arposept and Anioxyde failed to remove the SL, had lower cytotoxicity, and showed less bacterial activity than NaOCl.

ABSTRACT Two patients attended at the Endodontics Department to evaluate teeth 35 and 46. Both teeth had a history of post placement in a recent endodontic treatment in tooth 46, and 3 months ago in tooth 35, with evident large perforations in the middle third of their roots. In both cases, perforation sealing was recommended. The posts were removed and white MTA Angelus (Angelus, Londrina, PR, Brazil) was placed in the perforations of both cases. Finally, the root canals were obturated using the continuous wave technique. The 6-month, 2-year and 6-years follow-ups (tooth 35), and 3-month, 1-year and 3-year follow-ups (tooth 46) showed a favorable evolution. It can be concluded that the application of MTA in iatrogenic perforations promoted good results, allowing the maintenance of the teeth in function.

RESUMEN Dos pacientes acudieron al departamento de Endodoncia para evaluar las piezas dentarias 35 y 46. Ambas piezas tenían antecedente de colocación de poste en un tratamiento endodóntico reciente en la pieza 46, y hacía 3 meses en la pieza 35, con perforaciones de gran tamaño, evidentes en el tercio medio radicular. En ambos casos se recomendó el sellado de perforaciones. Se retiraron los postes y se colocó MTA Angelus blanco (Angelus, Londrina, PR, Brasil) en las perforaciones de ambos casos. Finalmente, los conductos radiculares se obturaron utilizando la técnica de onda continua. Los controles de 6 meses, 2 años y 6 años (pieza 35) y los controles de 3 meses, 1 año y 3 años (pieza 46) mostraron una evolución favorable. Se puede concluir que la aplicación de MTA en perforaciones iatrogénicas promueve buenos resultados, permitiendo el mantenimiento de los dientes en función dentro de la cavidad oral.

Abstract Bio-C Pulpecto (Bio-CP) was recently developed as the first bioceramic root filling material for primary teeth. Objective To evaluate the physicochemical properties of radiopacity, setting time, pH, cytocompatibility and potential of Bio-CP to induce mineralisation, compared with (1) Calen thickened with zinc oxide (Calen-ZO), and (2) zinc oxide and eugenol (ZOE). Methodology Physicochemical properties were evaluated according to ISO 6876. Saos-2 (human osteoblast-like cell line) exposed to extracts of the materials were subjected to assays of methyl thiazolyl tetrazolium, neutral red, alkaline phosphatase (ALP) activity and mineralised nodule production. The results were analysed using one-way or two-way ANOVA and Tukey’s or Bonferroni’s post-tests (α=0.05). Results All the materials showed radiopacity higher than 3 mm Al. Bio-CP had lower pH than Calen-ZO, but higher pH than ZOE. Calen-ZO and Bio-CP did not set. The setting time for ZOE was 110 min. The cytocompatibility order was Calen-ZO > Bio-CP > ZOE (1:2, 1:4 dilutions) and Calen-ZO > Bio-CP = ZOE (1:12, 1:24 dilutions) and Calen-ZO = Bio-CP > ZOE (1:32 dilution). Bio-CP induced greater ALP activity at 7 days, and greater mineralised nodule production, compared to Calen-ZO (p<0.05). Conclusions Bio-CP showed adequate physicochemical properties, cytocompatibility and potential to induce mineralisation.

Resumo Este estudo teve como objetivo avaliar as propriedades físico-químicas de um material reparador disponível no mercado brasileiro, BioMTA, em comparação com outros dois materiais atualmente em uso (Biodentine e MTA Angelus). O tempo de presa inicial foi avaliado usando a agulha de Gillmore. O pH foi medido com um pH-metro após 24 h, 3, 7, 14 e 21 dias. A radiopacidade foi determinada aplicando a equivalência em milímetros de alumínio (mm Al) de radiografias oclusais digitalizadas. A solubilidade foi determinada após imersão em água por 7 dias. Os dados foram analisados por meio dos testes ANOVA de uma via e Tukey (a=0,05). O tempo de presa inicial do BioMTA (5,2 min) foi menor do que os outros materiais (p<0,05). Todos os materiais apresentaram pH alcalino aos 21 dias. Às 24 h, o BioMTA foi o material mais alcalino (p<0,05); e aos 3, 7, 14 e 21 dias não houve diferença entre BioMTA e Biodentine (p>0,05), sendo ambos mais alcalinos que MTA Angelus (p<0,05). A radiopacidade do BioMTA (4,2 mm Al) foi significativamente maior em comparação ao Biodentine (p<0,05) e menor que o MTA Angelus (p<0,05). A solubilidade dos materiais foi de -4,2%, -1,6% e 4,1% para BioMTA, MTA Angelus e Biodentine, respectivamente, havendo diferença significativa entre eles (p<0,05). Portanto, pode-se concluir que o BioMTA apresentou um menor tempo de presa, pH alcalino, uma alta radiopacidade e um ganho em massa.

Abstract This study aimed to assess the physicochemical properties of a repair material in the Brazilian market, BioMTA, in comparison to other two materials currently in use (Biodentine and MTA Angelus). The initial setting time was evaluated using Gillmore needle. The pH was measured with a pH-meter after 24 h, 3, 7, 14 and 21 days. The radiopacity was determined using the equivalence in millimeters of aluminum (mm Al) from digitized occlusal radiographs. Solubility was determined after immersion in water for 7 days. The data were analyzed by one-way ANOVA and Tukey tests (a=0.05). The BioMTA initial setting time (5.2 min) was lower than the other materials (p<0.05). All materials showed an alkaline pH at 21 days. At 24 h, BioMTA was the most alkaline material (p<0.05); and at 3, 7, 14 and 21 days there was no difference between BioMTA and Biodentine (p>0.05), both being more alkaline than MTA Angelus (p<0.05). The radiopacity of BioMTA (4.2 mm Al) was significantly higher compared to Biodentine (p<0.05) and lower than MTA Angelus (p<0.05). The solubility of the materials was -4.2%, -1.6% and 4.1% for BioMTA, MTA Angelus and Biodentine, respectively, with a significant difference between them (p<0.05). Therefore, it can be concluded that BioMTA displayed a shorter setting time, an alkaline pH, a higher radiopacity, and a gain in mass.

Abstract The aims of the present study were to compare conventional radiography, radiographs digitized with a scanner or photographic camera, and digital radiography, used to evaluate the radiopacity of endodontic materials, and to compare the accuracy of linear and quadratic models used to convert radiopacity values to equivalent millimeters of aluminum (mm Al). Specimens of AH Plus, Endofill, Biodentine and BioMTA materials (n = 8) were radiographed next to an aluminum step-wedge using radiographic films and digital radiography systems (FONA CMOS sensor, Kodak CMOS sensor and photosensitive phosphor plate-PSP). Conventional radiographs were digitized using a scanner or photographic digital camera. Digital images of all the radiographic systems were evaluated using dedicated software. Optical density units (ODU) of the specimens and the aluminum step-wedge were evaluated by a photo-densitometer (PTDM), used in conventional radiographs. The radiopacity in equivalent mm Al of the materials was determined by linear and quadratic models, and the coefficients of determination (R2) values were calculated for each model. Radiopacity of the materials ranged from -9% to 25% for digital systems and digitized radiographs, compared to the PTDM (p < 0.05). The R2 values of the quadratic model were higher than those of the linear model. In conclusion, the FONA CMOS sensor showed the lowest radiopacity variability of the methodologies used, compared with the PTDM, except for the BioMTA group (higher than PTDM). The quadratic model showed higher R2 values than the linear model, thus indicating better accuracy and possible adoption to evaluate the radiopacity of endodontic materials.

Resumo Para a seleção do irrigante endodôntico deve-se considerar os possíveis efeitos citotóxicos. O objetivo foi avaliar os efeitos do hipoclorito de cálcio [Ca(OCl)2] e do cloridrato de octenidina (OCT) em células L929 e do ligamento periodontal humano (hPDL). As células foram expostas a diferentes doses das soluções: Ca(OCl)2 2,5% e 5%, OCT 0,1%, hipoclorito de sódio (NaOCl) 2,5% e clorexidina (CHX) 2%. A viabilidade celular foi avaliada pelos ensaios de metil-tiazol-tetrazólio (MTT) e vermelho neutro (NR), e a proliferação/migração pelo teste de cicatrização. Os resultados foram analisados por ANOVA de duas vias e Bonferroni (α=0,05). Os ensaios MTT e NR mostraram que OCT 0,1% foi menos citotóxico nas células do hPDL (p<0,05), seguido da CHX 2% e Ca(OCl)2 2,5% (p<0,05). Não houve diferença entre NaOCl 2,5% e Ca(OCl)2 5% (p>0,05). No entanto, estas soluções foram mais citotóxicas que as demais. O resultado foi o mesmo nas células L929, exceto que não houve diferença significativa entre CHX 2% e Ca(OCl)2 2,5% (p>0,05). A proliferação/migração das células L929 e do hPDL às 24 h nos grupos OCT 0,1%, CHX 2%, e Ca(OCl)2 2,5% foi maior que nos grupos Ca(OCl)2 5% e NaOCl 2,5% (p<0,05). Concluiu-se que OCT foi menos citotóxico que CHX, Ca(OCl)2 e NaOCl. Ca(OCl)2 2,5 e 5% apresentaram citotoxicidade menor ou similar ao NaOCl 2,5%, respectivamente. Os grupos OCT, CHX e Ca(OCl)2 2,5% apresentaram maior proliferação/migração celular do que os grupos do Ca(OCl)2 5% e NaOCl 2,5%. Portanto, OCT e Ca(OCl)2 têm potencial para serem utilizados como irrigantes endodônticos.

Abstract The aim of this study was to assess cytotoxicity and cell migration of calcium hypochlorite [Ca(OCl)2] and octenidine hydrochloride - OCT (Octenisept®, Schülke & Mayr, Norderstedt, Germany) in L929 and human periodontal ligament (hPDL) cells. The cells were exposed to different doses of different solutions: 2.5% and 5% Ca(OCl)2, 0.1% OCT, 2.5% NaOCl and 2% CHX for 10 min. Cell viability was assessed by methyl-thiazol-tetrazolium (MTT) and neutral red (NR) assays, and cell migration was determined by wound-healing assay. Statistical analysis was performed by two-way ANOVA and Bonferroni tests (α=0.05). The MTT and NR assays revealed that 0.1% OCT was less cytotoxic in hPDL cells (p<0.05), followed by 2% CHX and 2.5% Ca(OCl)2 (p<0.05). There was no significant difference between 2.5% NaOCl and 5% Ca(OCl)2 (p>0.05), but these solutions showed greater cytotoxicity than the others. The result was the same for L929 cells, except that there was no significant difference between 2% CHX and 2.5% Ca(OCl)2 (p>0.05). Wound-healing assay in L929 and hPDL cells showed that cell migration of 0.1% OCT, 2% CHX and 2.5% Ca(OCl)2 groups was higher than 5% Ca(OCl)2 and 2.5% NaOCl groups at 24 h (p<0.05). In conclusion, 0.1% OCT had lower cytotoxicity in tested cell lines than CHX, Ca(OCl)2 and NaOCl. Cell migration was higher for 0.1% OCT, 2% CHX and 2.5% Ca(OCl)2. Therefore, in terms of cytotoxicity, OCT and Ca(OCl)2 have the potential to be used as root canal irrigants.

Abstract Objectives: To evaluate the radiopacity of Biodentine (BD) and BD associated with 15% calcium tungstate (BDCaWO4) or zirconium oxide (BDZrO2), by using conventional and digital radiography systems, and their physicochemical and biological properties. Materials and Methods: Radiopacity was evaluated by taking radiographs of cement specimens (n=8) using occlusal film, photostimulable phosphor plates or digital sensors. Solubility, setting time, pH, cytocompatibility and osteogenic potential were also evaluated. Data were analyzed using one-way ANOVA and Tukey post-test or two-way ANOVA and Bonferroni post-test (α=0.05). Results: BD radiopacity was lower than 3 mm Al, while BD ZrO2 and BD CaWO4 radiopacity was higher than 3 mm Al in all radiography systems. The cements showed low solubility, except for BDCaWO4. All cements showed alkaline pH and setting time lower than 34 minutes. MTT and NR assays revealed that cements had greater or similar cytocompatibility in comparison with control. The ALP activity in all groups was similar or greater than the control. All cements induced greater production of mineralized nodules than control. Conclusions: Addition of 15% ZrO2 or CaWO4 was sufficient to increase the radiopacity of BD to values higher than 3 mm Al. BD associated with radiopacifiers showed suitable properties of setting time, pH and solubility, except for BDCaWO4, which showed the highest solubility. All cements had cytocompatibility and potential to induce mineralization in Saos-2 cells. The results showed that adding 15% ZrO2 increases the radiopacity of BD, allowing its radiography detection without altering its physicochemical and biological properties.

Abstract The aim of this study was to evaluate the effect of peracetic acid (PAA) as a single irrigant on the smear layer, on the intraradicular dentinal bond strength, and on the penetrability of an epoxy-based resin sealer into the dentinal tubules. A total of 120 roots were distributed into 4 groups according to the irrigant used in root canal preparation: 1% PAA (PAA); 2.5% NaOCl followed by final irrigation with 17% EDTA and 2.5% NaOCl (NaOCl-EDTA-NaOCl); 2.5% NaOCl (NaOCl); and saline solution (SS). The smear layer was evaluated using scanning electron microscopy. The bond strength of an epoxy-based resin sealer (AH Plus) to root dentin was evaluated by the push-out test and penetrability of the sealer into dentinal tubules was observed by confocal laser microscopy. The results were analyzed by the Kruskal-Wallis and the Dunn post-test (α = 0.05). The use of 1% PAA as single root canal irrigant provided smear layer removal and improved the penetrability and bond strength of AH Plus to root dentin in a manner similar to that of the NaOCl-EDTA-NaOCl group (p > 0.05). The NaOCl and SS groups had higher values of smear layer and lower values of sealer penetrability and dentin bond strength than the PAA and NaOCl-EDTA-NaOCl groups (p < 0.05). Thus, 1% PAA has the potential to be used as a single irrigant in root canals.

Abstract Decalcification of enamel during fixed orthodontic appliance treatment remains a problem. White spot lesions are observed in nearly 50% of patients undergoing orthodontic treatment. The use of fluoride-containing orthodontic materials has shown inconclusive results on their ability to reduce decalcification. The aims of this investigation were to compare the levels of Streptococcus mutans (SM) in saliva and biofilm adjacent to orthodontic brackets retained with a resin-modified glass ionomer cement (RMGIC) (Fuji ORTHO LC) and a light cured composite resin (Transbond XT), and to analyze the influence of topical application of the 1.23% acidulated phosphate fluoride (APF) on SM counts. In a parallel study design, two groups (n=14/15) were used with random allocation and high salivary SM counts before treatment. Biofilm was collected from areas adjacent to the brackets on teeth 13, 22, 33, and 41. Both saliva and biofilm were collected on the 7th, 21st, 35th, and 49th days after appliance placement. Topical fluoride application was carried out on the 35th day. Bonding with RMGIC did not alter SM counts in saliva or biofilm adjacent to the brackets. On the other hand, the biofilm adjacent to brackets retained with composite resin showed a significant increase in SM counts along the trial period. Topical application of 1.23% APF did not reduce salivary or biofilm SM counts regardless of the bonding material. In conclusion, fluoride topical application did not show efficacy in reducing SM. The use of RMGIC as bonding materials allowed a better control of SM cfu counts in dental biofilm hindering the significant increase of these microorganisms along the trial period, which was observed in the biofilm adjacent to the composite material.

Resumo O objetivo deste estudo foi avaliar a citotoxicidade e bioatividade de cimentos à base de silicato de cálcio associados com óxido de nióbio (Nb2O5) micro e nanoparticulados, e comparar a resposta em diferentes linhagens celulares. Foram utilizadas quatro linhagens celulares: duas culturas primárias (células da polpa dentária humana - hDPCs e células do folículo dentário humano - hDFCs) e duas culturas imortalizadas (células osteoblásticas humanas - Saos-2 e células do ligamento periodontal de ratos - mPDL). Os materiais analisados foram: Cimento Portland branco (PC); Agregado trióxido mineral (MTA); PC associado com micropartículas (PC/Nb2O5µ) ou nanopartículas (PC/Nb2O5n) de óxido de nióbio (Nb2O5). A citotoxicidade foi avaliada pelos ensaios de brometo de metil-tiazolil-difeniltetrazólio (MTT) e azul de tripan, e a bioatividade pela atividade da enzima fosfatase alcalina (ALP). Os resultados foram analisados por ANOVA e teste de Tukey (a=0,05). O grupo do PC/Nb2O5n apresentou viabilidade celular semelhante ou maior do que o grupo do PC/Nb2O5μ em todas as linhagens celulares. Além disso, ambos os grupos apresentaram viabilidade celular semelhante ou maior do que o MTA. Saos-2 apresentaram maior atividade de ALP, com destaque para o material PC/Nb2O5μ aos 7 dias de exposição. Concluiu-se que cimentos de silicato de cálcio associados com Nb2O5 micro ou nanoparticulado apresentaram citocompatibilidade e bioatividade, demonstrando potencial do Nb2O5 como agente radiopacificador alternativo para estes cimentos. As linhagens celulares estudadas apresentaram resposta semelhante na avaliação da citotoxicidade de cimentos de silicato de cálcio. No entanto, a bioatividade é melhor detectada na linhagem de células osteoblásticas humanas, Saos-2.

Abstract The aim of this study was to evaluate the cytotoxicity and bioactivity of calcium silicate-based cements combined with niobium oxide (Nb2O5) micro and nanoparticles, comparing the response in different cell lines. This evaluation used four cell lines: two primary cultures (human dental pulp cells - hDPCs and human dental follicle cells - hDFCs) and two immortalized cultures (human osteoblast-like cells - Saos-2 and mouse periodontal ligament cells - mPDL). The tested materials were: White Portland Cement (PC), mineral trioxide aggregate (MTA), white Portland cement combined with microparticles (PC/Nb2O5µ) or nanoparticles (PC/Nb2O5n) of niobium oxide (Nb2O5). Cytotoxicity was evaluated by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) and trypan blue exclusion assays and bioactivity by alkaline phosphatase (ALP) enzyme activity. Results were analyzed by ANOVA and Tukey test (a=0.05). PC/Nb2O5n presented similar or higher cell viability than PC/Nb2O5µ in all cell lines. Moreover, the materials presented similar or higher cell viability than MTA. Saos-2 exhibited high ALP activity, highlighting PC/Nb2O5µ material at 7 days of exposure. In conclusion, calcium silicate cements combined with micro and nanoparticles of Nb2O5 presented cytocompatibility and bioactivity, demonstrating the potential of Nb2O5 as an alternative radiopacifier agent for these cements. The different cell lines had similar response to cytotoxicity evaluation of calcium silicate cements. However, bioactivity was more accurately detected in human osteoblast-like cell line, Saos-2.

Objectives: To describe the macroscopic, microscopic characteristics and material characterization of nickel titanium (NiTi) ProTaper Universal system scompared to similar instruments of dubious origin. Material and methods: Macroscopic analysis was performed using macro photography of the boxes and files. For microscopic analysis, S1 and F1 files were used, which were sectioned and analyzed by scanning electron microscopy comparing active parts and cross-sections at 300-550X magnification. Additionally, the characterization of fragments was performed by energy dispersive x-ray microanalysis (EDX). Results: Macroscopic analysis showed that boxes differed in design and specifications. File shanks showed differences in shape, color, finish. The active part of some files showed differences in diameter, shape and finish. Microscopic analysis indicated that adulterated files showed less sharp cutting angles and absence of triangular convexities. By EDX, comparing the chemical composition of the instruments, it was shown that both instruments have a composition Ni-Ti like. Conclusions: The major differences between ProTaper Universal system and its counterpart adulterated, were presented in macroscopic analysis. Microscopic analysis showed differences mainly in cross-section configuration.

Objetivos: Describir las características macroscópicas, microscópicas y la caracterización del material de instrumentos rotatorios de Níquel-Titanio (NiTi), ProTaper Universal, en comparación con instrumentos similares de dudosa procedencia. Material y métodos: El análisis macroscópico se realizó por medio de fotografía macro de las cajas e instrumentos. Para el análisis microscópico, se utilizaron los instrumentos S1 y F1, los cuales fueron seccionados y analizados a través de Microscopía electrónica de barrido comparando las partes activas y las secciones transversales con una magnificación de 300 a 550X. Adicionalmente, se realizó la caracterización de los fragmentos, a través de microanálisis por dispersión de energías de rayos-X (EDX). Resultados: Al análisis macroscópico, las cajas de los sistemas presentaron diferencias en el diseño y especificaciones, los vástagos de los instrumentos presentaron diferencias de forma, color y acabado, y las partes activas de algunos instrumentos, presentaron diferencias de diámetro, forma y acabado. Al análisis microscópico, los instrumentos adulterados presentaron ángulos de corte menos afilados y ausencia de convexidades triangulares. Al comparar la composición química de los instrumentos, el análisis EDX mostró que ambos instrumentos tienen una composición Ni-Ti similar. Conclusiones: Las mayores diferencias entre el sistema ProTaper Universal y su homólogo adulterado se presentaron en el análisis macroscópico. El análisis microscópico presentó diferencias principalmente en el formato de la sección transversal.

ABSTRACT Objective Mineral Trioxide Aggregate (MTA) is a calcium silicate cement composed of Portland cement (PC) and bismuth oxide. Hydroxyapatite has been incorporated to enhance mechanical and biological properties of dental materials. This study evaluated physicochemical and mechanical properties and antibiofilm activity of MTA and PC associated with zirconium oxide (ZrO2) and hydroxyapatite nanoparticles (HAn). Material and Methods White MTA (Angelus, Brazil); PC (70%)+ZrO2 (30%); PC (60%)+ZrO2 (30%)+HAn (10%); PC (50%)+ZrO2 (30%)+HAn (20%) were evaluated. The pH was assessed by a digital pH-meter and solubility by mass loss. Setting time was evaluated by using Gilmore needles. Compressive strength was analyzed by mechanical test. Samples were radiographed alongside an aluminum step wedge to evaluate radiopacity. For the antibiofilm evaluation, materials were placed in direct contact with E. faecalis biofilm induced on dentine blocks. The number of colony-forming units (CFU mL-1) in the remaining biolfilm was evaluated. The results were submitted to ANOVA and the Tukey test, with 5% significance. Results There was no difference in pH levels of PC+ZrO2, PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p>0.05) and these cements presented higher pH levels than MTA (p<0.05). The highest solubility was observed in PC+ZrO2+HAn (10%) and PC+ZrO2+HAn (20%) (p<0.05). MTA had the shortest initial setting time (p<0.05). All the materials showed radiopacity higher than 3 mmAl. PC+ZrO2 and MTA had the highest compressive strength (p<0.05). Materials did not completely neutralize the bacterial biofilm, but the association with HAn provided greater bacterial reduction than MTA and PC+ZrO2 (p<0.05) after the post-manipulation period of 2 days. Conclusions The addition of HAn to PC associated with ZrO2 harmed the compressive strength and solubility. On the other hand, HAn did not change the pH and the initial setting time, but improved the radiopacity (HAn 10%), the final setting time and the E. faecalis antibiofilm activity of the cement.

Objetivo: Avaliar a resistência à fratura de dentes tratados endodonticamente após tratamento clareador usando peroxido de hidrogênio a 15% com nanopartículas de dióxido de titânio (15HPTiO2) fotoativado por LED-laser, em comparação aos protocolos usando peróxido de hidrogênio 35% (35HP), peróxido de carbamida 37% (37CP) ou perborato de sódio (SP).Material e método:Após tratamento endodôntico, 50 incisivos bovinos extraídos foram divididos em 5 grupos (n = 10): G1- sem clareamento; G2- 35HP; G3- 37CP; G4- 15HPTiO2fotoativado por LED-laser e G5- SP. Nos grupos G2 e G4, o protocolo de clareamento foi aplicado em 4 sessões, com 7 dias de intervalo entre cada sessão. Nos grupos G3 e G5, os materiais foram inseridos na câmara pulpar por 21 dias e trocados a cada 7 dias. Após 21 dias, as coroas foram submetidas à força de compressão com velocidade de 0,5 mm/min, aplicada a 135º em relação ao longo eixo da raiz. empregando máquina de ensaios mecânicos, até a fratura. Os dados foram submetidos aos testes de ANOVA e Tukey (p = 0.05).Resultado:O tratamento clareador em dentes tratados endodonticamente com 15HP e nanopartículas de TiO2fotoativado por LED-laser proporcionou redução da resistência à fratura semelhante ao 35HP, 37CP ou SP (p>0,05). Todos os tratamentos clareadores reduziram a resistência coronária à fratura quando comparados aos dentes sem tratamento (p<0,05).Conclusão:Todos os protocolos de clareamento reduziram a resistência à fratura dos dentes tratados endodonticamente, sem diferenças estatisticamente significantes entre os grupos.

Objective: The aim of this study was evaluate the fracture resistance of endodontically-treated teeth after bleaching treatment using 15% hydrogen peroxide plus titanium dioxide nanoparticles (15HPTiO2) photoactivated by LED-laser, in comparison with protocols using 35% hydrogen peroxide (35HP), 37% carbamide peroxide (37CP) or sodium perborate (SP).Material and method: After endodontic treatment, fifty bovine extracted incisors were divided into five groups (n =10): G1- without bleaching; G2- 35HP; G3- 37CP; G4- 15HPTiO2 photoactivated by LED-laser and G5- SP. In G2 and G4, the bleaching protocol was applied in 4 sessions, with a 7 day interval between each session. In G3 and G5, the materials were kept in the pulp chamber for 21 days, but replaced every 7 days. After 21 days, the crowns were subjected to compressive load at a cross head speed of 0.5 mm/min, applied at 135° to the long axis of the root using an eletromechanical testing machine, until fracture. The data were submitted to ANOVA and Tukey tests (p = 0.05).Result:The bleaching treatment in endodontically-treated teeth with 15HP plus TiO2 nanoparticles and photoactivated by LED-laser caused reduction of the fracture resistance similarly provided by 35HP, 37CP or SP (p>0.05). All bleaching treatments reduced the fracture resistance compared to unbleached teeth (p<0.05).Conclusion: All bleaching protocols reduced the fracture resistance of endodontically-treated teeth, but there were no differences between each other.

Recently, various calcium silicate-based sealers have been introduced for use in root canal filling. The MTA Fillapex is one of these sealers, but some of its physicochemical properties are not in accordance with the ISO requirements. Objective: The aim of this study was to evaluate the flowability, pH level and calcium release of pure MTA Fillapex (MTAF) or containing 5% (MTAF5) or 10% (MTAF10) calcium hydroxide (CH), in weight, in comparison with AH Plus sealer. Material and Methods: The flowability test was performed according to the ISO 6876:2001 requirements. For the pH level and calcium ion release analyses, the sealers were placed individually (n=10) in plastic tubes and immersed in deionized water. After 24 hours, 7 and 14 days, the water in which each specimen had been immersed was evaluated to determine the pH level changes and calcium released. Flowability, pH level and calcium release data were analyzed statistically by the ANOVA test (α=5%). Results: In relation to flowability: MTAF>AH Plus>MTAF5>MTAF10. In relation to the pH level, for 24 h: MTAF5=MTAF10=MTAF>AH Plus; for 7 and 14 days: MTAF5=MTAF10>MTAF>AH Plus. For the calcium release, for all periods: MTAF>MTAF5=MTAF10>AH Plus. Conclusions: The addition of 5% CH to the MTA Fillapex (in weight) is an alternative to reduce the high flowability presented by the sealer, without interfering in its alkalization potential.