Antibacterial effect, cytotoxicity, and bond strength of a modified dental adhesive containing silver nanoparticles.

This study aimed to evaluate the antibacterial effect, cytotoxicity, and microtensile bond strength of an adhesive system containing silver nanoparticles (NAg). NAg was synthesized and incorporated (500 and 1000 ppm) into Scotchbond Multi-Purpose (SBMP) primer and bond. A microtensile bond test (µTBS) was performed after 24 h and 1 year. The adhesive interface was characterized using a confocal Raman microscope. The antibacterial activity was assessed using agar diffusion and biofilm inhibition assays (S. mutans). MTT assay was used to assess the cytotoxicity of NAg-conditioned culture media on human dental pulp stem cells (hDPSCs). The results were statistically analyzed using analysis of variance and Tukey's tests (α = .01). Incorporating 500 and 1000 ppm of NAg in the SBMP did not affect the µTBS after 24 h (p > 0.05). However, in the 1 year evaluation, 500 ppm presented the highest µTBS values (p < 0.05). The addition of NAg at 500 and 1000 ppm in the primer and bond led to larger inhibition halos and colony-forming units than the control (p < 0.05). For the unpolymerized and polymerized groups, the combination of primer and bond presented the highest cytotoxic effects on hDPSCs (p < 0.05). In conclusion, incorporating 500 or 1000 ppm of NAg into an etch-and-rinse adhesive system led to an antibacterial effect without altering the cytotoxicity. SBMP at 500 ppm presented a higher µTBS at 1 year.

Influence of the Extended Use of Desensitizing Toothpastes on Dentin Bonding, Microhardness and Roughness

Abstract The aim of this study was to evaluate the influence of an extended use of desensitizing toothpastes (DTs) on dentin bonding, microhardness and roughness. One hundred and twenty bovine incisor teeth were randomly divided into four groups: G1, distilled water (WATER); G2, Colgate Total 12 (CT12); G3, Colgate Sensitive Pro-Relief (CSPR); and G4, Sensodyne Repair ?αμπ; Protect (SRP). Dentin surfaces were etched with 17% EDTA and 2 years of simulated tooth brushing (20,000 cycles) was performed on their surfaces. Knoop microhardness, surface roughness and scanning electron microscopy (SEM) were performed before and after the simulated tooth brushing. For microshear bonding test, a 2-step self-etching adhesive system (Clearfil SE Bond) was used and 0.8 mm diameter composite resin (Filtek Z350 XT) cylinders were built. Microshear test was performed with an orthodontic wire and with a crosshead speed of 0.5 mm/min. The data were analyzed for: 1) bond strength (one-way ANOVA), 2) microhardness intra-group (Student's test) and inter-group (one-way ANOVA/Tukey's test) comparisons, 3) roughness intra-group (Student's test/Wilcoxon's test) and inter-group (Kruskal-Wallis/Student-Newman-Keuls test) comparisons. The extended use of both dentifrices (conventional and for sensitive teeth) did not affect the bond strength and produced a significant increase in microhardness and roughness of the dentin, except for the microhardness of the SRP group. The simulated tooth brushing technique with water produced an increase in roughness, without reducing significantly the dentin microhardness.

Resumo O objetivo deste estudo foi avaliar a influência do uso prolongado de dentifrícios dessensibilizantes (DTs) na adesão, microdureza e rugosidade da dentina. Cento e vinte dentes incisivos bovinos foram divididos aleatoriamente em quatro grupos: G1, água destilada (WATER); G2, Colgate Total 12 (CT12); G3, Colgate Sensitive Pro-alívio (CSPR); e G4, Sensodyne Repair ?αμπ; Protect (SRP). As superfícies dentinárias foram condicionadas com EDTA a 17% e foram realizados 2 anos de escovação dental simulada (20.000 ciclos) em suas superfícies. A microdureza Knoop, rugosidade de superfície e microscopia eletrônica de varredura (MEV) foram realizadas antes e após escovação dental simulada. Para o teste de adesão por microcisalhamento, foi aplicado um sistema adesivo auto condicionante de 2 passos (Clearfil SE Bond) e foram construídos cilindros de resina composta (Filtek Z350 XT) de 0,8 mm de diâmetro. O teste de microcisalhamento foi realizado com um fio ortodôntico e com velocidade de 0,5mm/min. Os dados foram analisados para: 1) resistência de união (ANOVA 1 fator), 2) comparações de microdureza intra grupo (teste t de Student) e inter grupo (ANOVA 1 fator / teste de Tukey), 3) comparações de rugosidade intra grupo (teste t de Student / teste de Wilcoxon) e inter grupo (Kruskal Wallis / teste de Student-Newman-Keuls). O uso prolongado de ambos dentifrícios (convencional e para dentes sensíveis) não interferiu na resistência de união e produziu um aumento significativo na microdureza e rugosidade da dentina, exceto para a microdureza do grupo SRP. A técnica de escovação dental simulada com água promoveu aumento na rugosidade, sem reduzir significativamente a microdureza da dentina.

Influence of the Extended Use of Desensitizing Toothpastes on Dentin Bonding, Microhardness and Roughness.

The aim of this study was to evaluate the influence of an extended use of desensitizing toothpastes (DTs) on dentin bonding, microhardness and roughness. One hundred and twenty bovine incisor teeth were randomly divided into four groups: G1, distilled water (WATER); G2, Colgate Total 12 (CT12); G3, Colgate Sensitive Pro-Relief (CSPR); and G4, Sensodyne Repair ?αµπ; Protect (SRP). Dentin surfaces were etched with 17% EDTA and 2 years of simulated tooth brushing (20,000 cycles) was performed on their surfaces. Knoop microhardness, surface roughness and scanning electron microscopy (SEM) were performed before and after the simulated tooth brushing. For microshear bonding test, a 2-step self-etching adhesive system (Clearfil SE Bond) was used and 0.8 mm diameter composite resin (Filtek Z350 XT) cylinders were built. Microshear test was performed with an orthodontic wire and with a crosshead speed of 0.5 mm/min. The data were analyzed for: 1) bond strength (one-way ANOVA), 2) microhardness intra-group (Student's test) and inter-group (one-way ANOVA/Tukey's test) comparisons, 3) roughness intra-group (Student's test/Wilcoxon's test) and inter-group (Kruskal-Wallis/Student-Newman-Keuls test) comparisons. The extended use of both dentifrices (conventional and for sensitive teeth) did not affect the bond strength and produced a significant increase in microhardness and roughness of the dentin, except for the microhardness of the SRP group. The simulated tooth brushing technique with water produced an increase in roughness, without reducing significantly the dentin microhardness.

Influence of prolonged use of desensitizing dentifrices on dentin bond strength of self-etching adhesive system / Influencia del uso prolongado de pasta dentífrica desensibilizante en la fuerza de unión de la dentina de un sistema adhesivo autocondicionante

Dentin hypersensitivity is a relatively common clinical condition, which affects a large part of the world's population. The objective of this study was to evaluate the influence of previous and prolonged treatment with desensitizing dentifrices (DD) on bond strength to dentin, promoted by a self-etching adhesive system. Seventy non-carious bovine incisors were used, and divided into five groups (n= 14), according to the desensitizing toothpaste used, such as, G1: distilled water (WATER) (control); G2: Colgate Total 12 (CT12) (control); G3: Colgate Sensitive Pro-Relief (CSPR); G4: Sensodyne Rapid Relief (SRR); G5: Sensodyne Repair & Protect (SRP). Teeth had their buccal surfaces flattened until the exposure of dentin, and fragments of 4x4x2 mm were obtained. Fragments were included in polyvinyl chloride (PVC) cylinders and exposed to 17 % EDTA for 1 min. Subsequently, specimens were submitted to 20 000 cycles of simulated dental toothbrushing. After 24 h in artificial saliva, specimens were hybridized (Clearfil SE Bond ­ Kuraray), as well as resin composite cylinders built on dentin surfaces. Samples were stored in distilled water, at 37 C for 24 h, and the shear bond strength was determined. The highest bond strength (MPa) value was seen in CT12 group (4.39), and the lowest one in CSPR group (3.34). Data were statistically analyzed by 1-way ANOVA (ð= 0.05), and results showed that there were no significant differences (p= 0.5986) considering the DD factor. The predominant fracture pattern was cohesive on dentin. The previous and prolonged use of different DD did not affect dentin bond strength promoted by a self-etching adhesive system.

La hipersensibilidad dentinaria es una condición clínica relativamente común, que afecta a una gran parte de la población mundial. El objetivo fue evaluar la influencia del tratamiento previo y prolongado con dentífricos desensibilizantes (DD) en fuerza de adhesión a la dentina, que promueve un sistema adhesivo de autograbado. Se utilizaron 70 incisivos bovinos no cariados, y se dividieron en cinco grupos (n= 14), de acuerdo con la pasta de dientes desensibilizante utilizada: G1: agua destilada (agua) (control), G2: Colgate Total 12 (CT12) (control), G3: Colgate Sensitive Pro-Alivio (CSPR), G4: Sensodyne Rápido Alivio (SRR) y G5: Sensodyne Repair & Protect (SRP). Los dientes tenían sus superficies bucales aplanadas hasta la exposición de la dentina, y se obtuvieron fragmentos de 4x4x2 mm. Los fragmentos se incluyeron en cilindros de cloruro de polivinilo y se expusieron a 17 % de EDTA durante un 1 min. Después, las muestras se sometieron a 20 000 ciclos de cepillado dental simulado. Después de 24 h en saliva artificial, las muestras se hibridaron (Clearfil SE Bond - Kuraray), y cilindros de resina compuesta fueron construidos sobre superficies de dentina. Las muestras se almacenaron en agua destilada, a 37 °C durante 24 h y luego se determinó la resistencia al cizallamiento. El mayor valor de resistencia a la unión (MPa) se observó en el grupo CT12 (4,39), y el menor en el grupo CSPR (3,34). Los datos fueron analizados estadísticamente mediante ANOVA de un factor 1 (ð= 0,05), y los resultados no mostraron diferencias significativas (p= 0,5986) teniendo en cuenta el factor de los DD. El patrón de fractura predominante sobre la dentina fue el cohesivo. El uso previo y prolongado de diferente DD no afectó resistencia de unión a la dentina promovido por un sistema adhesivo de autograbado.