Abstract This study aimed to evaluate the tissue repair capacity of four bioceramic endodontic sealers by quantifying type I and III collagen fibers. The following sealers were tested: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, USA), Bio C Sealer (Angelus, Londrina, Brazil), Bioroot RCS (Septodont, Santa Catarina, Brazil), and Sealer Plus BC (MKLife, Porto Alegre, Brazil). Polyethylene tubes 1.5 mm in diameter and 1 cm in length containing the endodontic sealers were implanted in the subcutaneous tissue of five rats (Rattus norvegicus albinus, Wistar lineage). After 14 days, the animals were euthanized, and collagen fibers were quantified from the histological tissue sections. Given a non-normal distribution of the data, a gamma regression with log link function was employed and implemented through the generalized linear models module, was used to test whether there was a significant difference between the sealers. The pairwise comparison was performed using Least significant difference. There were significant differences between the sealers for type I (p=0.001), type III (p=0.023), and total collagen (p=0.002). Overall, Bioroot sealer was statistically superior to the other sealers, except in the analysis of type III collagen, in which there was no difference between the Bioroot sealer and Bio C Sealer sealer and the control group (p>0.05). Bioroot RCS bioceramic endodontic sealer stimulates a greater production of collagen.

Resumo Este estudo visou avaliar a capacidade de reparação de tecidos de quatro cimentos endodônticos biocerâmicos através da quantificação de fibras colágenas de tipo I e III. Foram testados os seguintes cimentos: EndoSequence BC Sealer (Brasseler, Brasseler, Savannah, EUA), Bio C Sealer (Angelus, Londrina, Brasil), Bioroot RCS (Septodont, Santa Catarina, Brasil), e Sealer Plus BC (MKLife, Porto Alegre, Brasil). Foram implantados tubos de polietileno de 1,5 mm de diâmetro e 1 cm de comprimento contendo os cimentos endodônticos no tecido subcutâneo de cinco ratos (Rattus norvegicus albinus, linhagem Wistar). Após 14 dias, os animais foram eutanasiados e as fibras colágenas foram quantificadas a partir de cortes histológicos do tecido. Diante de uma distribuição não-normal dos dados, uma regressão gama com função de ligação log, implementada por meio do módulo de modelos lineares generalizados, foi empregada para testar se havia diferença significativa entre os cimentos. A comparação dois a dois foi realizada utilizando Least significant difference. Houve diferença significativa entre os cimentos para os colágenos tipo I (p=0,001), tipo III (p=0,023) e colágeno total (p=0,002). No geral, o cimento Bioroot foi estatisticamente superior aos demais cimentos, com exceção na análise do colágeno tipo III na qual não houve diferença entre o cimento Bioroot e o cimento Bio C Sealer e o grupo controle (p>0,05). O cimento endodôntico biocerâmico Bioroot RCS foi capaz de estimular uma maior produção de colágeno.

RESUMO Objective: Avaliar a eficácia do XP-endo Finisher (XP) na remoção da smear layer em canais radiculares, comparando diferentes protocolos de irrigação. Métodos: Setenta e dois dentes humanos unirradiculares foram similarmente instrumentados usando limas R25 (VDW, Munich, Germany) aplicadas no modo reciprocrantes em um motor endodôntico VDW GOLD (VDW, Munich, Germany). O comprimento de trabalho foi determinado a 1 mm aquém do forame apical. Os canais foram irrigados com 5 mL de hipoclorito de sódio 2,5% durante a instrumentação. Os dentes foram divididos aleatoriamente em seis grupos (n=12). Um grupo controle, que não foi submetido ao protocolo final de irrigação, e cinco grupos experimentais com diferentes irrigantes e técnicas de agitação: EDTA/Lima, EDTA/XP, EDTA/Irrigação Ultrassônica Passiva (IUP), Água destilada (AD)/XP, e AD/IUP). Os escores de qualidade de remoção da camada de smear layer foram avaliados nos terços apical, médio e cervical do canal radicular com base em imagens obtidas por microscopia eletrônica de varredura. Os dados foram analisados pelo teste de Kruskal-Wallis, seguido de comparações dois a dois pelo teste de Dunn (α = 5%). Resultados: Os grupos EDTA/lima, EDTA/PUI e EDTA/XP demonstraram escores significativamente menores que os outros grupos (P <0,05). Não foi observada diferença entre os grupos que utilizaram água destilada e o grupo controle em todos os terços avaliados (P> 0.05). Conclusão: A lima XP-endo Finisher não aumentou a eficiência do EDTA na remoção da smear layer em canais radiculares.

ABSTRACT Objective: The aim of this study was to evaluate the effectiveness of XP-endo Finisher (XP) on removal of the smear layer in root canals by comparing different irrigation protocols. Methods: Seventy-two human single-rooted teeth were similarly instrumented using R25 Reciproc files (VDW, Munich, Germany) applied in reciprocating mode with a VDW GOLD endo motor (VDW, Munich, Germany). The working length was determined at 1 mm short of the apical foramen. The canals were irrigated with 5 mL of 2.5% sodium hypochlorite during instrumentation. The teeth were divided at random into six groups (n=12). A control group, which was not submitted to the final irrigation protocol, and five experimental groups with different irrigants and agitation techniques: EDTA/File, EDTA/XP, EDTA/Passive Ultrasonic Irrigation (PUI), Distilled Water (DW)/XP, and DW/PUI). Smear layer removal quality scores were assessed in the apical, middle, and cervical thirds of the root canal based on images obtained by scanning electron microscopy. Data were analyzed using the Kruskal-Wallis test, followed by two-by-two comparisons with the Dunn test (α=5%). Results: EDTA/File, EDTA/PUI, and EDTA/XP groups demonstrated significantly lower scores than the other groups (P<0.05) in all thirds evaluated. No significant difference was observed between the groups in which distilled water was used and the control group in all thirds evaluated (P> 0.05). Conclusion: The XP-endo Finisher file did not increase the efficiency of EDTA in removal of the smear layer in root canals.

Abstract To evaluate the influence of rewetting solutions on bond strength to root dentin of conventional gutta-percha (GP) or niobium phosphate glass-based gutta-percha (GNb) associated with a bioceramic sealer. The root canals of 80 human mandibular premolars were prepared using nickel-titanium instruments and irrigation with sodium hypochlorite and EDTA. The teeth were randomly divided into four groups according to the gutta-percha used: GNb or GP associated with EndoSequence BC Sealer (BC) and the solution for rewetting dentin before filling (distilled water; phosphate buffer saline solution - PBS; simulated body fluid – SBF; or no solution). The root canals were filled with a single cone using warm vertical condensation. Micropush-out bond strengths associated with the filling materials in slices from middle root thirds was determined 30 days after root filling. The failure mode was analyzed with stereoscopic lens. The data were statistically analyzed by two-way ANOVA and Holm-Sidak test (p < 0.05). There was significant difference in the types of gutta-percha (p < 0.001) and in the different rewetting solutions (p = 0.003). The interaction between gutta-percha and rewetting solutions was not significant (p = 0.53). The SBF solution provided an increase in bond strength for both gutta-percha solutions. The GNb+BC (3.42 MPa) association increased bond strength when compared with GP+BC (2.0 MPa). The use of SBF as a dentin rewetting solution increased bond strength in the groups studied. Association of GNb with bioceramic sealer was beneficial, increasing the bond strength to dentin when compared with the association with GP.

Resumo Avaliar o efeito da incorporação de vidro niobofosfato bioativo (NbG, 40% em peso) em dois sistemas adesivos simplificados convencionais (One Step [OS] e Prime & Bond {PB}) com e sem silano, no grau de conversão (%) e resistência de união (RU) após 6 meses. Os seguintes grupos foram testados: Controle OS: sem adição de partículas; OS e adição de NbG sem silano (OSNbG); OS e adição de partículas silanizadas NbG (OSNbGS); Controle PB: sem adição de partículas; PB e adição de partículas de NbG sem silano (PBNbG); PB e adição de partículas silanizadas NbG (PBNbGS). O grau de conversão (GC) foi determinado utilizando espectroscopia de Fourier (FTIR/ATR). Para RU, 48 terceiros molares humanos (n=8) foram restaurados e cortados para obter corpos-de-prova (0,8 mm2) e, em seguida, testados em dois momentos: imediato e após seis meses. O padrão de fratura foi avaliado com lupa estereoscópica (40×) e microscópio eletrônico de varredura (MEV). Os dados foram submetidos à análise de variância e Tukey (a=0,05). NbG não comprometeu valores de GC dos sistemas adesivos (p>0,05). Além disso, a adição de NbG aos sistemas adesivos não afetou os valores de RU (p>0,05). O padrão de fratura ocorreu predominantemente na interface dentina-adesivo. NbG não afetou os resultados de GC e RU.

Abstract To evaluate the effect of incorporating niobium phosphate bioactive glass (NbG) into commercial etch-and-rinse adhesive systems, with and without silane, on their degree of conversion (DC) (%) and microtensile bond strength (μTBS). The NbG micro-filler was added to two etch-and-rinse adhesive systems: One Step (OS) and Prime & Bond (PB) at 40% concentration. The following groups were formed: control without glass addition OS; addition of unsilanized NbG (OSNbG); addition of silanized NbG (OSNbGS); control without glass PB; addition of unsilanized NbG (PBNbG); addition of silanized NbG (PBNbGS). The DC was determined using total Fourier spectroscopy reflection (FTIR/ATR). For μTBS testing, 48 human third molars (n=8) were restored and sliced to obtain specimens (0.8 mm2) and they were tested at two different time intervals: immediately and after 6 months. The fracture mode was evaluated with a stereoscopic loupe (40×) and by scanning electron microscopy (SEM). The data were subjected to ANOVA and Tukey tests (a=0.05). NbG addition did not compromise the adhesive system DC values (p>0.05). Furthermore, the NbG added to the adhesive systems did not affect μTBS values (p>0.05). Fracture occurred predominantly at the dentin-adhesive interface. NbG bioactive glass did not affect the DC or microtensile bond strength results.

Resumo Este estudo avaliou o pH e a liberação de íons cálcio, sódio e fosfato de diferentes medicamentos em dentina humana. Cinquenta pré-molares foram preparados e divididos aleatoriamente em grupos: (CHX) - clorexidina gel 2%; (CHX + CH) - CHX + hidróxido de cálcio PA; (CH) - CH + propilenoglicol 600; (NPBG) - vidro experimental nióbio fosfato bioativo + água destilada; (BG) - vidro bioativo (Bio-Gran) + água destilada. Os espécimes foram submersos em água deionizada e as variações de pH foram mensuradas. A quantificação dos íons nas soluções foi feita por espectrometria de emissão atômica com plasma indutivamente acoplado (ICP - AES) nos tempos de 10 min, 24 h, 7, 14, 21 e 30 dias. Os resultados foram analisados por ANOVA e teste Tukey, com um nível de significância de 5%. Verificou-se que CH a teve a maior liberação íons de cálcio ao final de 30 dias, enquanto CHX e BG liberaram mais íons de sódio. BG, NPBG e CHX apresentaram a maior liberação de íons fosfato. O pH de CH foi significativamente maior em comparação com os outros grupos testados. O grupo CH aumentou o pH e a liberação de íons cálcio. Os vidros bioativos obtiveram uma maior liberação de íons sódio e fosfato e apresentaram pH alcalino imediato e ao final de 30 dias.

Abstract This study evaluated pH and release of calcium, sodium and phosphate ions from different medications in human dentin. Fifty premolars were prepared and randomly divided into groups: (CHX) - 2% chlorhexidine gel; (CHX + CH) - CHX + calcium hydroxide PA; (CH) - CH + propylene glycol 600; (NPBG) - experimental niobium phosphate bioactive glass + distilled water; (BG) - bioactive glass (Bio-Gran) + distilled water. The specimens were immersed in deionized water and the pH variations were measured. The quantification of ions in the solutions was made by inductively coupled plasma - atomic emission spectroscopy (ICP/AES) at 10 min, 24 h, 7, 14, 21 and 30 days. The results were analyzed by ANOVA and Tukey`s test, with a significance level of 5%. CH had the highest level of calcium ions release at 30 days, while CHX and BG released more sodium ions. BG, NPBG and CHX released a higher amount of phosphate ions. The pH of CH was significantly higher compared with the other groups. CH favored the greatest increase of pH and calcium ions release. The bioactive glasses released more sodium and phosphate ions and presented an alkaline pH immediately and after 30 days.

The purpose of this study was to evaluate the effects of long-term storage on the microtensile bond strength (µTBS) to dentin of two self-adhesive and three multi-step resin cements. Two self-adhesive cements RelyX U100 (U100) and seT PP (SET), and 3 multi-step resin cements, one using 2-step etch-and-rinse adhesive AllCem (ALC), and two conventional resin cements with self-etching primer Panavia F (PAN) and Multilink (MULT) were used. Human molars were restored (n=5), sectioned and subjected to the μTBS test after 24 h and 6 months. Fractured specimens were examined by stereomicroscope and SEM. The µTBS were analyzed by one-way ANOVA and Tukey test (α=0.05). ANOVA revealed a difference between groups (p<0.0001). All multi-step resin cements ALC, MULT and PAN showed statistically similar bond strength values that were higher than those of the U100 and SET groups. The bond strength value of ALC, MULT and PAN decreases significantly after 6 months. The majority of the failures were adhesive for all the groups. The µTBS produced by the self-adhesive cements were significantly lower than those observed for multi-step luting agents. Regardless of the numbers of steps of resin cements, the storage time reduces µTBS values to dentin only to multi-step luting agents.

O objetivo desse estudo foi avaliar a resistência ao cisalhamento no esmalte, resistência flexural, módulo flexural, tensão de contração de polimerização de duas resinas flow e uma resina ortodôntica. Os bráquetes ortodônticos foram colados em 45 pré-molares humanos e divididos: Transbond XT, Filtek Z-350 flow, Opallis flow e testado para resistência ao cisalhamento (n=15). Para a resistência e módulo flexural espécimes foram confeccionados e testados sob flexão. Para o teste de tensão de contração de polimerização, espécimes cilíndricos foram confeccionados e monitorados com um extensômetro (Instron). Os dados foram submetidos aos testes ANOVA a um critério e Tukey (α=0,05) para contraste de média. (n=15). A resistência de união das resinas flow foram significantemente menos que o da resina ortodôntica (p>0,05). A resistência flexural não demonstrou diferença significante entre os grupos testados (p>0,05). O módulo flexural da resina ortodôntica foi significantemente maior que o grupo das resinas flow (p<0,05). A tensão de contração de polimerização da resina ortodôntica foi significantemente menor (p<0,05). A resina ortodôntica obteve os maiores valores de resistência de união ao cisalhamento, resistência flexural e a menor tensão de contração de polimerização quando comparada as resinas flow testadas.

The purpose of this study was to evaluate in vitro the shear bond strength to enamel, flexural strength, flexural modulus, and contraction stress of one orthodontic composite and two flowable composites. Orthodontic brackets were bonded to 45 human maxillary premolars with the composites Transbond XT, Filtek Z-350 flow and Opallis flow and tested for shear bond strength. For measurement of flexural strength and flexural modulus, specimens were fabricated and tested under flexion. For the contraction stress test, cylindrical specimens were tested and an extensometer determined the height of the specimens. The data were subjected to one-way ANOVA and Tukey's test (α=0.05). The shear bond strength values were significantly lower (p<0.05) for the flowable composites compared with the orthodontic composite. For the flexural strength, no statistically significant difference was found among the composites (p>0.05) while the flexural modulus was significantly higher (p<0.05) for Transbond XT than for Filtek Z-350 flow and Opallis flow. The orthodontic composite presented significantly lower contraction stress values than the flowable composites (p<0.05). The light-activated orthodontic composite material presented higher flexural modulus and shear bond strength and lower contraction stress than both flowable composites.

O objetivo deste estudo foi avaliar a influência da microestrutura e da composição de ligas básicas quanto à resistência de união (RU) a um agente cimentante resinoso. Foram usadas as seguintes ligas: Supreme Cast-V (SC), Tilite Star (TS), Wiron 99 (W9), VeraBond II (VBII), VeraBond (VB), Remanium (RM) and IPS d.SIGN 30 (IPS). Cinco padrões em cera (13 mm de diâmetro e 4 mm de altura) para cada uma das ligas básicas foram incluídos e fundidos em uma máquina de fundição. As amostras foram então embutidas em resina, polidas com lixas e jateadas. Após a limpeza das superfícies, seis cilindros de tygon tube (0,5 mm de altura e 0,75 mm de diâmetro) foram colocados sobre a superficie da liga e preenchida com cimento resinoso (Panavia F), o excesso foi removido antes da fotoativação. Após armazenagem (24 h/37ºC), cada amostra foi ensaiada por microcisalhamento a 0,5 mm/min. Os dados foram tratados por análise de variância para e medidas repetidas e teste Tukey (α=0,05). Para avaliar a microesturutura, as mesmas amostras foram polidas e condicionadas com solução específica. Os valores mais altos da RU (média/desvio padrão em MPa) foram encontrados para as ligas com estrutura dendrítica, formação eutética e precipitados: VB (30,6/1,7), TS (29,8/0,9), SC (30,6/1,7), com exceção da IPS (31,1/0,9) que apresentou alto valor de RU, mas sem formação eutética. As ligas W9 (28,1/1,5), VBII (25,9/2,0) and RM (25,9/0,9) apresentaram os menores valores de RU e ausência de formação eutética. Pode-se inferir que os valores mais elevados de resistência de união ao cimento resinoso fotoativado ocorre com as ligas que apresentam formação de eutético.

The aim of this study was to evaluate the influence of microstructure and composition of basic alloys on their microshear bond strength (µSBS) to resin luting cement. The alloys used were: Supreme Cast-V (SC), Tilite Star (TS), Wiron 99 (W9), VeraBond II (VBII), VeraBond (VB), Remanium (RM) and IPS d.SIGN 30 (IPS). Five wax patterns (13mm in diameter and 4mm height) were invested, and cast in a centrifugal casting machine for each basic alloy. The specimens were embedded in resin, polished with a SiC paper and sandblasted. After cleaning the metal surfaces, six tygon tubes (0.5 mm height and 0.75 mm in diameter) were placed on each alloy surface, the resin cement (Panavia F) was inserted, and the excess was removed before light-curing. After storage (24 h/37°C), the specimens were subjected to µSBS testing (0.5 mm/min). The data were subjected to a one-way repeated measures analysis of variance and Turkey's test (α=0.05). After polishing, their microstructures were revealed with specific conditioners. The highest µSBS (mean/standard deviation in MPa) were observed in the alloys with dendritic structure, eutectic formation or precipitation: VB (30.6/1.7), TS (29.8/0.9), SC (30.6/1.7), with the exception of IPS (31.1/0.9) which showed high µSBS but no eutectic formation. The W9 (28.1/1.5), VBII (25.9/2.0) and RM (25.9/0.9) showed the lowest µSBS and no eutectic formation. It seems that alloys with eutectic formation provide the highest µSBS values when bonded to a light-cured resin luting cement.