A novel low shrinkage dimethacrylate monomer as an alternative to BisGMA for adhesive and resin-based composite applications

Abstract The aim of this study was to develop a mixture of dimethacrylate isomers (PG6EMA) as a potential monomer for dental adhesives and composites. PG6EMA was synthesized de novo and characterized in the presence of ethanol (3%, 6% or 9%). BisGMA/TEGDMA (BTEG, 50/50 wt.%) was used as the resin control. Composites were formulated with 60 wt.% of either PG6EMA or BisGMA (40 wt.% TEGDMA and 70 wt.% filler). DMPA (0.2 wt.%) and DPI-PF6 (0.4 wt.%) were added as photoinitiators, irradiated with a mercury arc lamp (320-500 nm, 500 mW/cm2; Acticure). All materials were tested for polymerization kinetics (near-infrared), viscosity (η) and storage modulus (G', oscillatory rheometry). The composites were further characterized for water sorption/solubility, wet/dry flexural strength/modulus and polymerization stress. Data were analyzed with one-way ANOVA/Tukey's test (α = 0.05). The PG6EMA resins showed lower rates of polymerization compared with BTEG (p = 0.001) but high degrees of conversion (p = 0.002). Solvent concentration did not affect RPMAX but the 6% and 9% mixtures showed higher final DC, likely due to reduced viscosity. PG6EMA had much higher viscosity than BTEG (p <0.001) and lower G' (p = 0.003). Composites modified with PG6EMA have slower polymerization rates (p = 0.001) but higher final DC (p = 0.04) than the control. PG6EMA/TEGDMA showed lower dry/wet flexural strength and comparable dry modulus. The PG6EMA/TEGDMA composite showed a 18.4% polymerization stress reduction compared to the BTEG composite. Both base monomers had similar WS/SL and G'. Within its limitations, this study demonstrated that the newly synthesized PG6EMA was a viable alternative to BisGMA in dental composites.

Ex vivo tooth discoloration induced by calcium silicate-based materials: analysis of an experimental cement / Descoloração dentária ex vivo induzida por materiais à base de silicato de cálcio: análise de um cimento experimental

Objective: This study aimed to investigate of bioactive materials with specific properties, particularly highly plastic bioceramic cements. These materials are being studied extensively due to their potential to maintain pulp vitality and promote tissue regeneration. Material and Methods: Tooth discoloration induced by an experimental tricalcium silicate-based cement (EC) was evaluated and compared with that of Biodentine (BD) and white MTA-Angelus (MTA). Cavities were prepared on the lingual surfaces of thirty-two blocks of healthy bovine incisors. The blocks were chemically cleaned and then subjected to an initial color evaluation (CIELab values) using a spectrophotometer and randomly divided into three experimental groups (n=10); two additional blocks served as controls. After manipulation, the cements were placed in the cavities, which were subsequently restored with composite restorations. After another color measurement (baseline), they were immersed in bottles of distilled water; they were stored at 37 °C and 100% humidity for the entire test period. The color change (ΔE) was measured after 14, 30, 120 and 150 days. ANOVA and Tukey tests showed significant differences after 14 days (EC vs. MTA), 30 days (EC vs. BD) and 120/150 days (EC vs. BD/MTA) (p < 0.05). Results: All tested materials induced ΔE changes, with the EC group showing the least change at the end of the experiment (ΔE=4.08). Conclusion: EC induced less color change over a 5-month period and thus showed color stability over the entire period, whereas BD and MTA showed progressive discoloration. (AU)

Objetivo: O objetivo deste estudo foi investigar materiais bioativos com propriedades específicas, particularmente cimentos biocerâmicos altamente plásticos. Esses materiais estão sendo amplamente estudados devido ao seu potencial para manter a vitalidade da polpa e promover a regeneração dos tecidos. Material e Métodos: A descoloração dentária induzida por um cimento experimental à base de silicato tricálcico (CE) foi avaliada e comparada com a do Biodentine (BD) e do MTA-Angelus branco (MTA). Foram preparadas cavidades nas superfícies linguais de trinta e dois blocos de incisivos bovinos saudáveis. Os blocos foram quimicamente limpos e, em seguida, submetidos a uma avaliação inicial de cor (valores CIELab) usando um espectrofotômetro e divididos aleatoriamente em três grupos experimentais (n=10); dois blocos adicionais serviram como controles. Após a manipulação, os cimentos foram colocados nas cavidades, que foram posteriormente restauradas com compósito. Após outra medição de cor (valor de referência), eles foram imersos em frascos de água destilada; oram armazenados a 37 °C e 100% de umidade durante todo o período de teste. A alteração de cor (ΔE) foi medida após 14, 30, 120 e 150 dias. Os testes ANOVA e Tukey mostraram diferenças significativas após 14 dias (CE vs. MTA), 30 dias (CE vs. BD) e 120/150 dias (CE vs. BD/MTA) (p < 0,05). Resultados: Todos os materiais testados induziram alterações de ΔE, sendo que o grupo EC apresentou a menor alteração no final do experimento (ΔE=4,08). Conclusão: O EC induziu menos alterações de cor em um período de 5 meses e, portanto, apresentou estabilidade de cor durante todo o período, enquanto o BD e o MTA apresentaram descoloração progressiva.(AU)

Are polywave light-emitting diodes more effective than monowave ones in the photoactivation of resin-based materials containing alternative photoinitiators? A systematic review.

OBJECTIVE: This systematic review aimed to analyze if using polywave light-emitting diodes (LED) to photoactivate resin-based materials (resin composites, adhesive systems, and resin cements) containing alternative photoinitiators provide better physicochemical properties than monowave ones. MATERIAL AND METHODS: Inclusion criteria were in vitro studies that evaluated the degree of conversion, microhardness and flexural strength in resin-based materials containing alternative photoinitiators and light-activated with mono and polywave LEDs. Exclusion criteria were studies that evaluated the physicochemical properties of composites through any material interposed between the LED and the resin composite and studies that exclusively compared different modes and/or light activation times. Selection of studies, data extraction, and risk-of-bias analysis was performed. Data from selected studies were qualitatively analyzed. A systematic search was performed in June 2021 using PubMed/Medline, Embase, Scopus, and ISI Web of Science databases and grey literature without language restriction. RESULTS: A total of 18 studies were included in the qualitative analysis. Nine studies used diphenyl (2,4,6-trimethylbenzoyl) phosphine oxide (TPO) as an alternative photoinitiator for resin composite. Polywave LED improved the degree of conversion of resin composite compared to monowave in 9 of the included studies. Polywave LED improved the microhardness of resin composite compared to monowave in 7 of the included studies. Polywave LED improved the degree of conversion for 11 studies and microhardness of resin composite compared to monowave for 7 included studies. No differences in the flexural strength medium between poly and monowave LEDs were observed. The evidence was graded as low quality due to the high risk of bias for 11 studies. CONCLUSION: The existing studies, with their limitations, revealed that the polywave light-emitting diode maximizes activation, resulting in a higher degree of double-bond conversion and microhardness of resin composites containing alternative photoinitiators. However, the flexural strength of these materials is not influenced by the type of light activation device.

Bond strength of composite resin/universal adhesive to dentin submitted to radiotherapy / Fuerza de unión de resina compuesta/adhesivo universal a dentina sometida a radioterapia

Aim: To evaluate the bond strength of a universal adhesive system to dentin submitted to radiotherapy. Materials and Methods: Sixty extracted human teeth were divided into two groups (n = 30): without radiotherapy (control); with radiotherapy, according to the adhesive protocol (n=15): ER-etch-and-rinse (acid + Single Bond Uni-versal); SE-self-etch (Single Bond Universal). The analyzes were shear bond strength (SBS) (n=10), failure pattern (n=10) and scanning electron microscopy (n=5). Data was analyzed by a two-way ANOVA (α =0.05). Results: The radiotherapy decreased SBS of the restorative material to dentin (p<0.0001). The ER protocol provided lower bond strength values (p<0.001). The predominant type of fracture without radiotherapy was mixed (SE), cohesive to the material (ER). Both protocols presented adhesive failures with radiotherapy. Teeth had a hybrid layer and long resin tags (without radiotherapy) and few tags (with radiotherapy). Conclusions: The SE adhesive mode favors the shear bond strength of resin to dentin in teeth submitted to radiotherapy.

Objetivo: Evaluar la fuerza de adhesión de un sistema adhesivo universal a la dentina sometida a radioterapia. Materiales y Métodos: Sesenta dientes humanos extraídos se dividieron en dos grupos (n = 30): sin radioterapia (control); con radioterapia, según protocolo adhesivo (n=15): ER-grabado y enjuague (ácido + Single Bond Universal); autograbado SE (Single Bond Universal). Los análisis ejecutados fueron resistencia al cizallamiento (SBS) (n=10), patrón de falla (n=10) y microscopía electrónica de barrido (n=5). Los datos se sometieron al test de ANOVA de dos vías (α =0,05). Resultados: La radioterapia disminuyó la SBS del material restaurador a la dentina (p<0,0001). El protocolo ER proporcionó valores de fuerza de unión más bajos (p<0,001). El tipo de fractura predominante sin radioterapia fue mixta (SE), cohesiva al material (ER). Ambos protocolos presentaron fallas adhesivas con radioterapia. Los dientes tenían una capa híbrida y colas de resina largas (sin radioterapia) o pocas colas de resina (con radioterapia). Conclusión: El modo adhesivo SE favorece la resistencia al corte de la resina a la dentina en dientes sometidos a radioterapia.

Physicochemical properties of a calcium aluminate cement containing nanoparticles of zinc oxide.

Objectives: This study evaluated the effect of different nanoparticulated zinc oxide (nano-ZnO) and conventional-ZnO ratios on the physicochemical properties of calcium aluminate cement (CAC). Materials and Methods: The conventional-ZnO and nano-ZnO were added to the cement powder in the following proportions: G1 (20% conventional-ZnO), G2 (15% conventional-ZnO + 5% nano-ZnO), G3 (12% conventional-ZnO + 3% nano-ZnO) and G4 (10% conventional-ZnO + 5% nano-ZnO). The radiopacity (Rad), setting time (Set), dimensional change (Dc), solubility (Sol), compressive strength (Cst), and pH were evaluated. The nano-ZnO and CAC containing conventional-ZnO were also assessed using scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectroscopy. Radiopacity data were analyzed by the 1-way analysis of variance (ANOVA) and Bonferroni tests (p < 0.05). The data of the other properties were analyzed by the ANOVA, Tukey, and Fisher tests (p < 0.05). Results: The nano-ZnO and CAC containing conventional-ZnO powders presented particles with few impurities and nanometric and micrometric sizes, respectively. G1 had the highest Rad mean value (p < 0.05). When compared to G1, groups containing nano-ZnO had a significant reduction in the Set (p < 0.05) and lower values of Dc at 24 hours (p < 0.05). The Cst was higher for G4, with a significant difference for the other groups (p < 0.05). The Sol did not present significant differences among groups (p > 0.05). Conclusions: The addition of nano-ZnO to CAC improved its dimensional change, setting time, and compressive strength, which may be promising for the clinical performance of this cement.

Effect of aging and cementation systems on the bond strength to root dentin after fiber post cementation

Abstract This study evaluated the effect of aging and cementation of fiber posts using glass ionomer and resin cements on push-out bond strength, failure mode, and resin tag formation. One hundred and twenty bovine incisors were used. After post-space preparation, the specimens were randomly allocated into 12 groups (n = 10) according to the cementation system used: GC - GC Gold Label Luting & Lining); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200 and the aging periods (24 hours, 6 months, and 12 months). Slices from the cervical, middle, and apical thirds were obtained and analyzed by push-out bond strength test and confocal laser scanning microscopy. One-way ANOVA and Tukey's post-hoc test was used at a significance level of 5%. For the push-out bond strength test, no differences among GC, RU, and MC in the cervical and middle thirds were observed, regardless of the period of storage (P > 0.05). In the apical third, GC and RU showed similar bond strength but higher than other groups (P > 0.05). After 12 months, GC showed the highest bond strength (P < 0.05). Bond strength to post-space dentin decreased over time, regardless of the cementation system used. Cohesive failure was the most frequent, regardless of the period of storage, cementation system, and post-space third. Tag formation was similar among all groups. After 12 months, GC showed the highest bond strength values.

Resumo Avaliar o efeito do envelhecimento e sistemas de cimentação usando ionômero de vidro e cimentos resinosos na resistência de união à dentina após a cimentação do pino de fibra. Cento e vinte incisivos bovinos foram utilizados. Após o preparo do pós-espaço, os corpos de prova foram distribuídos aleatoriamente em 12 grupos (n = 10) de acordo com o período de envelhecimento (24 horas, 6 meses e 12 meses) e o sistema de cimentação utilizado: GC - cimento de ionômero de vidro (GC Gold Label Cimentação e Revestimento); RL - RelyX Luting 2; MC - MaxCem Elite; RU - RelyX U200. Cortes dos terços cervical, médio e apical foram obtidos e analisados por teste de resistência de união push-out e microscopia confocal de varredura a laser. ANOVA one-way e teste de Tukey foi usado a um nível de significância de 5%. Para o teste de resistência de união, não foram observadas diferenças entre GC, RU e MC nos terços cervical e médio, independentemente do período de armazenamento (P > 0,05). No terço apical, GC e RU apresentaram resistência de união semelhante, porém superior aos demais grupos (P > 0,05). Após 12 meses, o GC apresentou a maior resistência de união (P < 0,05). A resistência de união à dentina no espaço para pino diminuiu ao longo do tempo, independentemente do sistema de cimentação utilizado. A formação de tags foi semelhante entre todos os grupos. Após 12 meses, o GC apresentou os maiores valores de resistência de união.

Effect of thickness of CAD/CAM materials on light transmission and resin cement polymerization using a blue light-emitting diode light-curing unit.

OBJECTIVE: Evaluate the effect of thickness of high-translucency (HT) CAD/CAM materials on irradiance and beam profile from a blue light-emitting diode light-curing unit (LCU) and on the degree of conversion (DC) and maximum polymerization rate (Rpmax ) of a light-cured resin cement (LCC). MATERIAL AND METHODS: The direct output from the LCU, the light transmission and irradiance ratio (IR) through one conventional composite and nine HT CAD/CAM materials (0.5, 1.0, 1.5, or 2.0-mm thick; n = 5) were measured with a integrating sphere coupled to a spectrometer. The light beam was assessed with a beam profiler camera. The DC at 600 s and the Rpmax of one LCC was determined using a Fourier transform infrared spectrometer (n = 5). Data were analyzed by ANOVA followed by Tukey's tests, and Dunnett's test was also used for irradiance data (α = 0.05). RESULTS: A significant decrease in irradiance through all materials occurred as thickness increased. Thin CAD/CAM materials improved light homogeneity, which decreased with the increase in thickness. The DC of the LCC directly exposed to light was the same as when exposed to 45%, 25%, 15%, or 5% IRs. Rpmax decreased with the decrease in IR. CONCLUSIONS: Although the HT CAD/CAM materials reduced the irradiance from the LCU, minor effects were observed in the LCC's DC. CLINICAL SIGNIFICANCE: Despite the light attenuation of blue light through different CAD/CAM materials that were up to 2-mm thick, the degree of conversion of one brand of light-cured resin cement was clinically acceptable when the LCU was used for 30 s.

The effects of TiO2 nanotubes on bond strength and radiopacity of a self-adhesive resin cement in self-curing mode / Os efeitos de nanotubos de TiO2 na resistência de união e radiopacidade de um cimento resinoso auto-adesivo no modo auto-polimerizável

Objective: The aim of this in vitro study w as t o analyze the influence of the titanium dioxide nanotubes i n a self-cure mode polymerization of a dual resin luting agent through push out bond strength and radiopacity tests. Material and Methods: After mixed with a commercial du al self-adhesive resin cement, three concentrations o f tit anium dioxide nanotubes (0.3, 0.6, and 0.9% by weight) we re analyzed in self-curing mode. T he bond strength to bovine root dentin and fi berglass posts was assessed with the push out bond str ength t est and was evaluated in three thirds (cervical, middle and apical) (n=10), followed by failure mode analysis (SEM), and the ISO standard 9917-2 was followed for radiopacity test (n=10). Data were statistically analyzed by one-way ANOVA test, followed by Tukey's test (α=0.05). Results: Reinforced self-adhesive resin cement with 0.6% titanium dioxide nanotubes showed significant difference compared to the control gr oup for push out test (p=0.00158). The modified groups did not s how significant difference among thirds (p=0.782). Radiopacity sh owed higher value for group w ith 0.9% titanium dioxide nanotubes in comparison w ith control group (p<0.001). Conclusion: The addition of titanium dioxide nanotubes to a self-adhesive resin cement increased the bond strength to dentin and radiopacity values in the self-cure polymerization mode (AU)

Objetivo: O objetivo deste estudo in vitro foi analisar a influência de nanotubos de dióxido de titânio na polimerização química de um agente cimentante resinoso dual através de testes de resistência à união e radiopacidade. Material e Métodos: Após misturado com um cimento resinoso auto-adesivo comercial, três concentrações de nanotubos de dióxido de titânio (0,3, 0,6 e 0,9% em peso) foram analisadas. A resistência da união para a dentina da raiz bovina e os pinos de fibra de vidro foi avaliada pelo teste de push-out e avaliada em três terços (cervical, médio e apical) (n = 10), seguido pelo análise de modo de falha (MEV) e a norma ISO 9917-2 foi seguido para teste de radiopacidade (n = 10). Os dados foram analisados estatisticamente pelo teste ANOVA um fator seguido do teste de Tukey (α = 0,05). Resultados: O cimento resinoso auto-adesivo reforçado com nanotubos de dióxido de titânio a 0,6% mostrou diferença significativa em comparação com o grupo controle para teste de push-out (p=0,00158). Os grupos modificados não mostraram diferença significativa entre os terços (p=0,782). A radiopacidade mostrou maior valor para o grupo com nanotubos de dióxido de titânio 0,9% em comparação com o grupo controle (p<0,001). Conclusão: A adição de nanotubos de dióxido de titânio a um cimento resinoso auto-adesivo aumentou a os valores de resistência de união à dentina e radiopacidade no modo de polimerização química do agente cimentante (AU)

Pulp chamber temperature rise in light-cure bonding of brackets with and without primer, in intact versus restored teeth

ABSTRACT Objective: To evaluate the pulp chamber temperature rise (PCTR) in light-cure bonding of brackets with and without primer, in intact and restored mandibular central incisors (M1), maxillary first premolars (Mx4), and mandibular third molars (M8). Material and Methods: Ninety human teeth were included: M1 (n=30), Mx4 (n=30), and M8 (n=30). Light-cure bonding of brackets was performed in intact (n=60) and restored (n=30) teeth, with primer (n=60) or without (n=30) primer. PCTR was defined as the difference between initial (T0) and peak temperatures (T1), recorded with a thermocouple during light-cure bonding. Differences on PCTR between bonding techniques (primer vs. no primer), teeth types (M1 vs. Mx4 vs. M8), and teeth condition (intact vs. restored) were estimated by ANCOVA, with α=5%. Results: PCTR was significantly higher with the use of primer (2.05 ± 0.08oC) than without primer (1.65 ± 0.14oC) (p=0.02), and in M1 (2.23 ± 0.22oC) compared to Mx4 (1.56 ± 0.14oC) (p<0.01). There was no difference in the PCTR in M8 (1.77 ± 0.28oC) compared to M1 or Mx4 (p>0.05), and no difference between intact (1.78 ± 0.14oC) and restored (1.92 ± 0.08oC) teeth (p=0.38). There was no influence of dentin enamel thickness in the PCTR (p=0.19). Conclusion: PCTR was higher in light-cure bonding of brackets with primer, especially in M1. Light-cure bonding seems less invasive without primer.

RESUMO Objetivo: Comparar o aumento na temperatura da câmara pulpar (ATCP) na colagem de braquetes com fotoativação usando ou não primer, em dentes hígidos versus dentes restaurados, em incisivos centrais inferiores (ICI), primeiros pré-molares superiores (1PMS) e terceiros molares inferiores (3MI). Métodos: Foram incluídos noventa dentes humanos: ICI (n=30), 1PMS (n=30) e 3MI (n=30). A colagem de braquetes com fotoativação foi realizada em dentes hígidos (n=60) ou dentes restaurados (n=30), com primer (n=60) ou sem (n=30) primer. O ATCP foi definido como a diferença entre as temperaturas inicial (T0) e máxima (T1) registradas com um termômetro durante a colagem com fotoativação. As diferenças no ATCP entre as técnicas de colagem (com primer vs. sem primer), diferentes dentes (ICIvs.1PMSvs.3MI) e condição dos dentes (hígidos vs. restaurados) foram estimadas por ANCOVA, com α=5%. Resultados: O ATCP foi significativamente maior com o uso de primer (2,05 ± 0,08oC) do que sem primer (1,65 ± 0,14oC) (p=0,02), e no ICI (2,23 ± 0,22oC) do que no 1PMS (1,56 ± 0,14oC) (p<0,01). Não houve diferença no ATCP do 3MI (1,77 ± 0,28oC) em comparação com ICI ou 1PMS (p>0,05), e não houve diferença entre dentes hígidos (1,78 ± 0,14oC) e restaurados (1,92 ± 0,08oC) (p=0,38). Não houve influência da espessura da dentina e do esmalte no ATCP (p=0,19). Conclusão: O ATCP foi maior na colagem de braquetes com fotoativação usando primer, principalmente no ICI. A colagem com fotoativação parece ser menos invasiva sem primer.

Evaluating changes in the color and luminosity of dental enamel after orthodontic treatment: A clinical study

Abstract The aims of this clinical study were to evaluate the Color change - ΔE (based on spectrophotometry and visual analysis) and luminosity - L* (based on spectrophotometry) of dental enamel surface (after orthodontic treatment) around the area where orthodontic brackets were fixed, based on different cementing materials such as a resin (R group) and resin-modified glass ionomer cement (RMGIC group). The split-mouth study initially comprised 14 patients. Orthodontic brackets were fixed to the upper central incisors with resin or RMGIC. The color of the buccal surface of each tooth was measured through spectrophotometry and visual examination before the bracket-fixation process. Four individuals were excluded during the follow-up; thus 10 patients were evaluated (n=10). Brackets were removed after 12 months of orthodontic treatment, tooth color measurement and visual examination were performed again, and Adhesive Remaining Index (ARI) was also measured. ΔE and L* results were subjected to Student's t-test and by repeated-measures analysis of variance, respectively (α=0.05). ARI data were analyzed in percentages. There was statistically significant difference in ΔE between groups; the R group showed statistically higher values of L* after orthodontic treatment. ARI of 2 and 3 prevailed in the RMGIC group, whereas the R group presented 0 and 1. After orthodontic treatment, the RMGIC group presented smaller changes in ΔE, and the increase in the white scale was observed on the enamel surface around the area where brackets were fixed in the R group. The visual analysis did not show color change on the evaluated teeth.

Resumo Os objetivos deste estudo clínico foram avaliar a alteração de cor - ΔE (baseada em espectrofotometria e análise visual) e luminosidade - L* (baseada em espectrofotometria) da superfície do esmalte dentário (após tratamento ortodôntico) ao redor da área onde os braquetes ortodônticos foram fixados, com base em diferentes materiais de cimentação, como resina (grupo R) e cimento de ionômero de vidro modificado por resina (grupo RMGIC). Estudo boca dividida foi inicialmente composto por 14 pacientes. Os braquetes ortodônticos foram fixados nos incisivos centrais superiores com resina ou RMGIC. A cor da superfície vestibular de cada dente foi mensurada por espectrofotometria e avaliada por exame visual antes do processo de fixação dos braquetes. Quatro indivíduos foram excluídos durante o acompanhamento; assim, 10 pacientes foram avaliados (n=10). Os braquetes foram removidos após 12 meses de tratamento ortodôntico, a mensuração da cor do dente e o exame visual foram realizados novamente, e o Índice de Remanescente do Adesivo (IRA) também foi mensurado. Os resultados ΔE e L* foram submetidos ao teste t de Student e à análise de variância para medidas repetidas, respectivamente (α=0.05). Os dados do ARI foram analisados em porcentagens. Houve diferença estatisticamente significativa no ΔE entre os grupos; o grupo R apresentou valores estatisticamente maiores de L* após o tratamento ortodôntico. O IRA 2 e 3 prevaleceu no grupo RMGIC, enquanto o grupo R apresentou 0 e 1. Após o tratamento ortodôntico, o grupo RMGIC apresentou menores alterações no ΔE e o aumento da escala branca foi observado na superfície do esmalte ao redor da área onde os braquetes foram fixados no grupo R. A análise visual não mostrou mudança de cor nos dentes avaliados.

Exposure to lipopolysaccharide and calcium silicate-based materials affects the behavior of dental pulp cells

Abstract This study assessed the cell viability, cytokine production, and mineralization potential of human dental pulp cells (hDPCs) after exposure to lipopolysaccharide (LPS) and application of calcium silicate-based materials (CSBM). Characterization of the CSBM was performed by infrared spectroscopy (n = 3). Extracts of Bio-C Repair, Biodentine, Cimmo HD, and MTA Repair HP were prepared and diluted (1:1, 1:4, and 1:16). Culture of hDPCs was established and treated or not with 1 µg/mL of LPS from Escherichia coli for 7 days. MTT assay was used to assess cell viability at 24, 48, and 72 h (n = 6). Alkaline phosphatase (ALP) activity was assayed on day 7 (n = 4). Il-10 and TNF-α were quantified by ELISA at 24 h (n = 6). Data were analyzed by ANOVA and Tukey's test (α = 0.05). Cell viability of LPS-activated hPDCs was higher than untreated control in 48 and 72 h (p < 0.05). Differences between non-treated and LPS-activated hPDCs were observed for Biodentine and Cimmo HP (p < 0.05). The CSBM influenced the cell viability (p < 0.05). ALP activity was higher in LPS-activated hDPCs (p < 0.05). No changes in the concentration of TNF-α were observed between groups (p > 0.05). The CSBM increased the Il-10 production (p < 0.05). LPS-activated hDPCs presented increased cell viability and ALP activity. The CSBM showed mild toxicity and was able to enhance the cell viability and mineralization potential of untreated and LPS-activated hDPCs. The CSBM also induced anti-inflammatory mechanisms without compromising pro-inflammatory ones.

Resumo Este estudo avaliou a viabilidade celular, produção de citocinas e potencial de mineralização de células da polpa dentária humana (hDPCs) após exposição a lipopolissacarídeo (LPS) e aplicação de materiais à base de silicato de cálcio (CSBM). A caracterização do CSBM foi realizada por espectroscopia (n = 3). Extratos de Bio-C Repair, Biodentine, Cimmo HD e MTA Repair HP foram preparados e diluídos (1: 1, 1: 4 e 1:16). A cultura de hDPCs foi estabelecida e tratada ou não com 1 µg / mL de LPS de Escherichia coli por 7 dias. O ensaio de MTT foi usado para avaliar a viabilidade celular em 24, 48 e 72 h (n = 6). A atividade da fosfatase alcalina (ALP) foi avaliada no dia 7 (n = 4). Il-10 e TNF-α foram quantificados por ELISA em 24 h (n = 6). Os dados foram analisados ​​por ANOVA e teste de Tukey (α = 0,05). A viabilidade celular das hPDCs ativados por LPS foi maior do que o controle não tratado em 48 e 72 h (p <0,05). Diferenças entre hPDCs não tratados e ativados por LPS foram observados para Biodentine e Cimmo HP (p < 0,05). Os CSBM influenciaram na viabilidade celular (p <0,05). A atividade de ALP foi maior em hDPCs ativadas por LPS (p <0,05). Não foram observadas alterações na concentração de TNF-α entre os grupos (p> 0,05). Os CSBM aumentaram a produção de Il-10 (p < 0,05). Os hDPCs ativados por LPS apresentaram um aumento na viabilidade celular e atividade ALP. Os CSBM apresentaram toxicidade moderada e foram capazes de aumentar a viabilidade celular e o potencial de mineralização de hDPCs não tratados e ativados por LPS. Os CSBM também induziram mecanismos anti-inflamatórios sem comprometer os pró-inflamatórios.

Response of periodontal ligament stem cells to lipopolysaccharide and calcium silicate-based materials

Abstract This study was conducted to assess the in vitro response of human periodontal ligament stem cells (hPDLSCs) to bacterial lipopolysaccharide (LPS) activation and application of three calcium silicate-based materials (CSBM): Bio-C Sealer, MTA Fillapex and Cimmo HP. Characterization of the CSBM was performed by FTIR (n = 3). Extracts of Bio-C Sealer, MTA Fillapex and Cimmo HP were prepared and diluted (1:1, 1:4 and 1:16). Culture of hPDLSCs was established and treated or not with LPS from Escherichia coli (1 µg/mL) for 7 days. MTT assay was used to assess cell viability at 24, 48 and 72 h (n = 9). Alkaline phosphatase (ALP) activity was indirectly assayed at day 7 (n = 5). TNF-α and Il -1 0 cytokines were quantified by ELISA at 24h-cell supernatants (n = 6). Data were analyzed by ANOVA and Tukey's test (α = 0.05). The cell viability of the LPS-activated hPDLSCs were higher than untreated control (p < 0.05). The application of CSBM affected the cell viability of untreated and LPS-activated cells (p < 0.05). ALP activity was higher for Bio-C Sealer and Cimmo HP in untreated and LPS-activated cells, respectively (p < 0.05). Application of CSBM normalized the TNF-α secretion in the LPS-activated cells (p < 0.05). Only MTA Fillapex in untreated hPDLSCs presented higher values of Il -1 0 (p < 0.05). Taken collectively, the results suggests that the simulation of the inflammatory process by LPS affect the in vitro response the hPDLSCs to the application of the CSBM.

Resumo Este estudo objetivou avaliar a resposta in vitro de células-tronco do ligamento periodontal humano (hPDLSCs) à ativação por lipopolissacarídeo bacteriano (LPS) e aplicação de três materiais à base de silicato de cálcio (CSBM): Bio-C Sealer, MTA Fillapex e Cimmo HP. A caracterização dos CSBM foi realizada por FTIR (n = 3). Extratos de Bio-C Sealer, MTA Fillapex e Cimmo HP foram preparados e diluídos (1:1, 1: 4 e 1:16). A cultura de hPDLSCs foi estabelecida e tratada ou não com 1 µg / mL de LPS de Escherichia coli por 7 dias. O ensaio de MTT foi usado para avaliar a viabilidade celular em 24, 48 e 72 h (n = 9). A atividade de ALP foi avaliada indiretamente no dia 7 (n = 5). As citocinas TNF-α e Il-10 foram quantificadas por ELISA em sobrenadantes de células em 24h (n = 6). Os dados foram analisados por ANOVA e teste de Tukey (α = 0,05). A viabilidade celular das hPDLSCs ativados por LPS foi maior do que o controle (p <0,05). A aplicação dos CSBM afetou a viabilidade celular de células ativadas ou não por LPS (p <0,05). A atividade de ALP foi maior para Bio-C Sealer e Cimmo HP em células não ativadas e ativadas por LPS, respectivamente (p <0,05). A aplicação dos CSBM normalizou a secreção de TNF-α nas células ativadas por LPS (p <0,05). Apenas o MTA Fillapex em hPDLSCs não ativadas apresentou valores mais elevados de Il-10 (p <0,05). Em conclusão, os resultados sugerem que a simulação do processo inflamatório por LPS afetou a resposta in vitro de células-tronco do ligamento periodontal e de materiais à base de silicato de cálcio.

A systematic review and meta-analysis on using preheated resin composites as luting agents for indirect restorations.

OBJECTIVES: This systematic review investigated the hypothesis that preheated resin composites (RCs) used as luting agents improve the mechanical properties, physicochemical performance, and color of indirect ceramic restorations. MATERIALS AND METHODS: Literature search was performed in three databases (Medline/PubMed, Scopus, and Web of Science) and in the grey literature (OpenGrey, ProQuest, and Catalog of Theses & Dissertations from CAPES). Eligibility criteria included only studies comparing at least one preheated RC used as a luting agent with resin cements. RESULTS: Data regarding the mechanical properties, physicochemical characteristics, and color were analyzed qualitatively, and the microtensile bond strength and film thickness were also evaluated by meta-analysis. The search strategy identified 3894 papers, and 28 were full-text screened. Seven studies were included in the review, and 5 were included in the meta-analysis. No significant difference was found for microtensile bond strength (P = 0.14). Preheated RCs showed significantly higher film thickness than resin cements (P = 0.001). CONCLUSION: Overall, the use of preheated RCs as luting agents offers similar to poorer performance than using resin cements for bonding indirect restorations. CLINICAL RELEVANCE: Despite the claim that preheated RC could be used as a luting agent, further studies should investigate the effect of clinically unacceptable film thickness.

Diametral tensile strength of conventional glass ionomer cements with modified powder ratio for uses in atraumatic restorative treatment / Resistência à tração diametral de cimentos de ionômero de vidro convencionais modificados na razão de pó para uso em tratamento restaurador atraumático

ABSTRACT Objective: To identify the diametral tensile strength of Brazilian brands of conventional glass ionomer cements (GIC) when modified powder ratio in their composition compared to each other, and with high viscosity glass ionomer cement for Atraumatic Restorative Treatment (ART). Methods: Experimental study with five groups (n=10 each) and specimens (2.5 mm in height and 5.0 mm in diameter), considering G1 (Maxxion R-MR), G2 (Vidrion R-VR) and G3 Vitro molar (VM-control) according to manufacturer recommending powder/liquid (1:1), G4 (MR) and G5 (VR) plus powder (2:1). The specimens were stored in an oven at 37 ± 1 ° C for 1 day. Diametral Tensile Test was performed by the Instron model 4444. Means differences were tested by Student´s T-Test (α = 5%). Results: There significant differences were in the means (standard deviation) of diametral tensile strength of MR (1:1) 4.24 (±1.47) and MR (2:1), 5.74 (±1.51) (p=0.039) and VR (1:1) 4.50 (±1.27) and VR (2:1) 6.20 (±1.89) (p=0.029). When comparing MR and VR (2:1) with MV (1:1) 4.82 (±1.17), VR 2: 1, 6.20 (±1.89) showed significant differences (p=0.0336). Conclusion: There was a significant increase in the means of diametral tensile strength of Brazilian brands conventional GICs when powder increment, approaching the performance observed by the high viscosity GIC.

RESUMO Objetivo: Identificar a resistência à tração diametral de marcas nacionais de cimentos de ionômero de vidro (CIV) convencionais quando acrescidos de pó em sua composição comparados entre si e com cimento de ionômero de vidro de alta viscosidade para Tratamento Restaurador Atraumático (TRA). Métodos: Pesquisa experimental com cinco grupos (n=10 cada) e confeccionados corpos de prova (2,5 mm de altura e 5,0 mm de diâmetro), considerando G1 (Maxxion R/FGM-MR), G2 (Vidrion R/SS White-VR) e G3 Vitro molar (DFL-VM-controle) manipulados segundo fabricante pó/líquido (1:1), G4 (MR) e G5 (VR) acrescidos de pó (2:1). Os espécimes foram armazenados em estufa a 37 ± 1° C por 1 dia. Teste de Tração Diametral foi realizado pelo equipamento Instron modelo 4444. As diferenças das médias foram testadas pelo Test T de Student (α=5%). Resultados: Foram encontradas diferenças significativas das médias (desvio-padrão) de resistência à tração diametral de MR (1:1) 4,24 (±1,47) e MR (2:1), 5,74(±1,51) (p=0,039) e VR (1:1) 4,50 (±1,27) e VR (2:1) 6,20(± 1,89) (p=0,029). Quando da comparação entre MR e VR (2:1) com VM (1:1) 4,82(±1,17), VR 2:1, 6,20 (±1,89) apresentou média superior e significante (p=0,0336). Conclusão: Observou-se aumento significativo nas médias de resistência mecânica à tração diametral dos CIVs convencionais nacionais a partir do incremento de pó, aproximando-se do desempenho observado pelo CIV de alta viscosidade.

Cytotoxicity of Reparative Endodontic Cements on Human Periodontal Ligament Stem Cells

ABSTRACT Objective To compare the cytotoxicity of commercial reparative endodontic cements on human periodontal ligament stem cells (hPDLSCs). Material and Methods The culture of hPDLSCs was established. Cell density was set at 2 × 104 cells/well in 96-well plates. Extracts of Biodentine, Bio-C Repair, Cimmo HD, MTA Repair HP and White MTA were prepared. Then, the extracts were diluted (pure, 1:4 and 1:16) and inserted into cell-seeded wells for 24, 48, and 72 h to assess cell viability through MTT assay. hPDLSCs incubated with culture medium alone served as a negative control group. Data were analyzed by Two-Way ANOVA and Tukey's test (α=0.05). Results At 24 h, pure extract of MTA Repair HP and Biodentine 1:16 presented higher cell viability compared to control. Lower cell viability was found for pure extract of Cimmo HD, MTA Repair HP 1:4 and 1:16, and White MTA 1:16. At 48 h, pure extract of Bio-C Repair and MTA Repair HP presented higher cell viability compared to control. At 72 h, only the pure extract of MTA Repair HP led to higher cell proliferation compared to control. Conclusion Biodentine, Bio-C Repair and MTA Repair HP were able to induce hPDLSCs proliferation. Cimmo HD and White MTA were found to be mostly cytotoxic in hPDLSCs.

Impact of economic factors and knowledge translation on public procurement for dental adhesive systems

Abstract: This study aimed to screen the public procurement for dental adhesives in a public health system and evaluate the variables associated with the type and cost of purchased materials. A time series was conducted with secondary data collated from the Brazilian Databank of Healthcare Prices (BDHP). All public procurements for adhesive systems registered from 2010 to 2019 were collated. The frequency of purchase was described, and a multiple linear regression model was used to assess the influence of unit price on predictor variables. Multinomial logistic regression was conducted to describe the influence of selected variables on the probability of purchase for different classes of adhesive systems. A total of 2,752 purchases were analyzed, and the total cost of these materials reached US$ 7,022,659.00 in the 10 analyzed years. The 3-step Etch & Rinse adhesives corresponded to 45.63% of the processes, with increased probability of being purchased over time. The process conducted by public universities in recent years, using the auction modality, presented lower unit prices. The year of purchase, the type of institutions, the institution's location, and the procurement modality influenced the procurement process. The performed analyses contribute to the understanding of the variables associated with the procurements for adhesive systems, providing valuable information for rationalizing public expenditure and for implementing evidence-based practices to guarantee cost-effective and clinically effective procedures for users of the Brazilian public healthcare system.

Durability of bond strength to dentin using two universal adhesives in different etching modes

Aim. To evaluate the bond durability of two universal adhesives; mild and ultra-mild in both etch-and-rinse and self-etch modes after simulated in-vitro degradation by long-term water storage or thermocycling. Methods. A total of 144 specimens were used in this study; 120 specimens (prepared from 30 teeth) for microshear bond strength testing and fracture mode assessment, and 24 specimens for scanning electron microscopic evaluation (prepared from 24 teeth). Specimens were prepared from 54 recently extracted caries free third molars and randomly divided into 12 groups, according to the adhesive treatment (All Bond or Scotchbond Universal), etching mode (etch-andrinse or self-etch) and aging method (thermocycling or water storage). Each tooth was sectioned mesio-distally into two halves exposing free dentin surface for bonding where dentin substrate 1 mm below the dentino-enamel junction was used. After adhesive application and composite build up, specimens were tested in shear mode after storing in distilled water at 37˚C for 24 hours or 1 year, or after being thermocycled between 5 and 55 °C for 10,000 cycles (n=10). Microshear bond strength (µSBS) was tested using a universal testing machine. Adhesive-dentin interface was examined using scanning electron microscope (SEM) (n=2). Data were analyzed using 3 way AN0VA and pairwise comparisons was performed using Bonferroni correction at significance level of α ≤0.05. Results. Statistical analysis revealed non-significant difference for etching mode in both adhesives (p=0.596). After aging, the bond strength was only reduced in Scotchbond Universal after one year of water storage in both modes (p<0.001). SEM evaluation revealed intact hybrid layer and longer resin tags for etch-and-rinse mode than selfetch mode of both adhesives. Conclusion. The bond strength of universal adhesives is not affected by the etching mode, however its durability was shown to be material dependent

Calcium silicate-based cements affect the cell viability and the release of TGF-β1 from apical papilla cells

Abstract This study investigated the cytotoxicity and release of Transforming Growth Factor Beta 1 (TGF-β1) from cultured human apical papilla cells (APCs) after application of four bioactive materials. Culture of APCs was established and used for cytotoxic and quantitative assays. Extracts of Biodentine, Bio-C Repair, MTA Repair and White MTA were prepared and diluted (1, 1:4 and 1:16) and used for MTT assays up to 72 h. Total TGF-β1 was quantified by ELISA. Data were analyzed by ANOVA and Tukey's test (α = 0.05). For Biodentine, at 24 h and 48 h, cell viability was lower than control (p < 0.05). At 72 h, only undiluted extract of Biodentine were cytotoxic (p < 0.05). At 24 h, a cytotoxic effect was found for undiluted and 1:4 dilution of Bio-C Repair (p < 0.05). At 48 h, however, Bio-C Repair at 1:4 and 1:8 dilution showed higher cell viability (p < 0.05). At 24 and 48 h, the cell viability for undiluted MTA Repair were higher than control (p < 0.05). For White MTA, at 24 and 48 h, all dilutions were cytotoxic (p < 0.05). All cements led to reduced release of total TGF-β1 from the APCs (p < 0.05). In conclusion, cell viability varied depending on the material and dilution. Only Bio-C repair and MTA repair led to higher cell viability of APCs. All materials induced a decrease in the release of total TGF-β1 from the APCs.

Resumo Este estudo investigou a citotoxicidade e liberação do Fator de Crescimento Transformador Beta 1 (TGF-β1) em células da papila apical humana (APCs) cultivadas após a aplicação de quatro materiais bioativos. A cultura de APCs foi estabelecida e usada para ensaios citotóxicos e quantitativos. Extratos de Biodentine, Bio-C Repair, MTA Repair e White MTA foram preparados e diluídos (1, 1: 4 e 1:16) e usados para ensaios de MTT por até 72 h. O TGF-β1 total foi quantificado por ELISA. Os dados foram analisados por ANOVA e teste de Tukey (α = 0,05). Para o Biodentine, em 24 h e 48 h, efeito citotóxico foi observado (p <0,05). Em 72 h, apenas o extrato não diluído de Biodentine teve efeito citotóxico (p <0,05). Em 24 h, valores mais baixos de viabilidade celular foram encontrados para o extrato não diluído e diluidi 1:4 de Bio-C Repair (p <0,05). Em 48 h, no entanto, Bio-C Repair na diluição 1:4 e 1:8 mostrou maior viabilidade celular (p <0,05). A viabilidade celular para MTA Repair não diluído em 24 e 48 h foi maior que o controle (p <0,05). Para White MTA, às 24 e 48 h, a viabilidade celular em todas as diluições foram citotóxicas (p <0,05). Todos os cimentos levaram à redução da liberação de TGF-β1 total das APCs (p <0,05). Em conclusão, a viabilidade celular variou dependendo do material e da diluição. Biodentine, Bio-C Repair e MTA Repair levaram a uma maior viabilidade celular de APCs. Todos os materiais induziram uma diminuição na liberação de TGF-β1 total das APCs.

Propiedades y aplicación clínica de los ionómeros de vidrio de alta densidad disponibles en Lima-Perú / Properties and clinical application of high density glass ionomers available in Lima-Peru

El objetivo de la revisión fue conocer las propiedades y la aplicación clínica de los diferentes ionómeros de vidrio de alta densidad disponibles en Lima-Perú. Se realizó una revisión de la literatura científica desde enero 2010 hasta diciembre 2019 acerca de los ionómeros de vidrio de alta densidad. Esta revisión se realizó en las bases de datos SciELO, Pubmed y Google Scholar. Los descriptores para realizar la búsqueda fueron: cementos de ionómero de vidrio, ionómeros de vidrio de alta densidad y propiedades físicas, las combinaciones entre ellos y su equivalente en inglés. Se seleccionaron finalmente 40 artículos que cumplieron con los criterios de inclusión. Dentro de las marcas de ionómeros de alta densidad disponibles en Lima-Perú se encuentran: Ionofil® Plus (VOCO), KetacTM Molar Easymix (3M ESPE), Fuji IX GP (GC corporation) y EQUIA Forte™®GC (Europe GC). Se presentan las propiedades y aplicación clínica de todos estos ionómeros. De acuerdo a la revisión de la literatura, de los cinco grupos estudiados: EQUIA Forte presentó una excelente adhesión al esmalte y la dentina. Fuji IX GP puede ser usado en restauraciones de Clase I y II, sin contactos oclusales y; EQUIA Forte puede utilizarse en pequeñas Clase II con /sin contactos oclusales, y con cuidado en grandes cavidades MOD siguiendo las recomendaciones del fabricante.

The objective of the review was to understand the properties and clinical application of the different high-density glass ionomers available in Lima, Perú. A review of the scientific literature about high-density glass ionomers, was conducted from January 2010 to December 2019. This review was performed in SciELO, Pubmed and Google Scholar databases. The descriptors used in the search were: glass ionomer cements, high density glass ionomers and physical properties, the combinations between them and their equivalent in English. Ultimately forty articles that met the inclusion criteria, were selected. The high-density ionomers available in Lima-Peru are Ionofil® Plus (VOCO), KetacTM Molar Easymix (3M ESPE), Fuji IX GP (GC corporation) and EQUIA Forte™® GC (Europe GC). The properties and clinical application of all these ionomers are presented. According to the literature review, of the five groups studied; EQUIA Forte presented excellent adhesion to enamel and dentin. Fuji IX GP can be placed in Class II restorations without occlusal contacts and EQUIA Forte can be used in small Class II with / without occlusal contacts, and cautiously in large MOD cavities following the manufacturer's recommendations.

Evaluation of the Bond Strength of Densely Sintered Ceramics Subjected to Extended Firing.

INTRODUCTION: Critical failures in ceramic materials can be caused by the processing mode, which includes all steps taken in the manufacture of a ceramic part, from molding to firing. PURPOSE: To evaluate the effect of extended firing on bond strength in densely sintered ceramics of the zirconium reinforced lithium silicate, lithium disilicate, and feldspathic ceramic. MATERIALS AND METHODS: Three types of ceramics were evaluated: zirconium reinforced lithium silicate, lithium disilicate, feldspathic ceramic. A total of 6 ceramic blocks, two for each material were used in the study. Each block was cut into four square sections. A total of 24 ceramic surfaces were randomly distributed into 6 groups (n = 4 surfaces per group) divided according to the variables: heat treatment: conventional firing or extended firing; test time: immediate (24 hours after cementation) or longevity (after 1000 cycles of thermocycling). The bond strength tests were performed in a semi-universal test machine for microshear bond strength. For data analysis, the Shapiro-Wilk test was performed to evaluate the normality between the groups measured, and regarding homoscedasticity (homogeneity of variances) by the Bartlett test. The comparisons between the groups were made using the nonparametric Kruskal-Wallis test. RESULTS: There was no statistically significant difference of the resistance values in relation to the thermal treatment methods (conventional firing and extended firing) in any ceramic group (p <0.05). Among the times (immediate and long), there was a statistically significant difference (p <0.05), with higher resistance values for immediate time. CONCLUSION: Extended firing did not influence the micro-shear bond strength of zirconium reinforced lithium silicate, lithium disilicate, feldspathic ceramic.