Fracture Resistance of Endodontically Restored Teeth with Two System Root Post

ABSTRACT: The objective of this study was to determinate the fracture resistance of endodontically treated teeth and restored with two root post systems: i) resin post, ii) fiber post. A total of 60 teeth were freshly extracted, endodontic ally treated and randomly divided in two groups (n= 30/each group) for standardized restoration; Group 1 (Group R): Resin post and resin restoration, Group 2 (Group FP): Fiberglass post and resin restoration. Both groups' samples were mounted in a metallic base at 135º to allow them to be stabilized and held in the universal testing machine by applying a vertical force at cross speed of 1mm/min. Data were recorded in Newtons (N) Previous to test the fracture resistance; all samples were stored in distilled water at 37 ºC for 24 hours. Data were subject to the Saphiro-Wilk test for normality distribution and Student's t test. Significance was considered at 0.05 values. The values of fiber post group showed normal distribution compared to the resin group, demonstrating less variability among the values. The group FP displayed higher fracture resistance (299.77±100 N) than group R (205.57±86.40 N), with significant differences (p= 0.00002). The greatest fracture resistance was recorded for the group having fiber post reinforced and composite cores. It is suggested that fiberglass post restoration is the first option when endodontic treatment requires core restoration.

RESUMEN: El objetivo del estudio fue determinar la resistencia a la fractura de dientes tratados endodónticamente y restaurados con dos sistemas de endopostes radiculares: I) poste de resina, II) poste de fibra. Un total de 60 dientes recién extraídos fueron tratados endodónticamente y divididos al azar en dos grupos (n= 30/ cada grupo) para la restauración estandarizada; Grupo 1 (Grupo R): Pilares de resina y restauración, Grupo 2 (Grupo FP): Pilares de fibra de vidrio y restauración de resina. Las muestras de ambos grupos se montaron en una base metálica a 135º para permitir su estabilización y sujeción en la máquina universal de ensayos aplicando una fuerza vertical a velocidad transversal de 1 mm/min. Los datos se registraron en Newtons (N), para probar la resistencia a la fractura; todas las muestras se almacenaron en agua destilada a 37 ºC durante 24 horas. Los datos se sometieron a la prueba de normalidad de Saphiro-Wilk y la pruebas t de Student. La significancia se consideró con un valor de 0,05. Los valores del grupo de postes de fibra mostraron una distribución normal en comparación con el grupo de resinas, demostrando menor variabilidad entre los valores. El grupo FP mostró mayor resistencia a la fractura (299,77±100 N) que el grupo R (205,57±86,40 N) que el grupo con diferencias significativas (p= 0,00002). La mayor resistencia a la fractura se registró para el grupo que tenía núcleos compuestos y reforzados con postes de fibra. Se sugiere que la restauración posterior de fibra de vidrio es la primera opción cuando el tratamiento de endodoncia requiere una restauración del núcleo.

Traumatic dental injuries in 6 to 12 years old schoolchildren: a multicenter cross-sectional study in Mexico

Abstract The aim of this study was to determine the prevalence of dental trauma in schoolchildren 6 to 12 years of age and associated clinical, sociodemographic, and socioeconomic variables. A cross-sectional study was conducted in 477 children from public elementary schools in four locations in Mexico. The dependent variable was dental trauma, which was dichotomized in 0 = without dental trauma and 1 = with dental trauma. For the statistical analysis, a multivariate binary logistic regression model was generated in Stata. Average age was 9.06±1.94 years and 51.1% were girls. The prevalence of dental trauma was 18.2%. Falls, automobile accidents and sports had the highest number of instances (p < 0.01). In the multivariate model, it was observed that the risk of dental trauma increased with age (OR = 1.28) and among boys (OR = 1.45). Schoolchildren with decreased overjet (OR = 0.38) had lower dental trauma. Father's age (OR = 1.03) and educational level (OR = 1.78) were associated with dental trauma. Schoolchildren without health insurance (OR = 0.62) presented dental trauma less often. This study provided important information regarding the association of different sociodemographic, socioeconomic and clinical variables with dental trauma in Mexican schoolchildren. Identifying factors associated with dental trauma may support health promotion opportunities to ameliorate the prevalence of dental trauma.

Remineralizing Effect of Xilitol, Juniperus Communis and Camellia Sinensis Added to a Toothpaste: An In Vitro Study / Efecto remineralizante del Xilitol, Juniperus Communis y Camellia Sinensis adicionados en pastas dentales: Estudio in vitro

ABSTRACT The aim of this study was to explore the remineralizing effect of toothpastes based on Xilitol, Camellia Sinensis and Juniperus Communis. An in vitro experimental study was carried out in an 18 human premolars sample, which were treated with one of the 3 evaluated toothpastes and a control fluoride one. The atomic percentages of Ca and P were evaluated by Energy Dispersive X-ray Spectroscopy (EDS). In addition, the enamel surface of treated teeth was visualized by Scanning Electron Microscopy (SEM). The evaluations were carried out in three stages: pre-treatment, after an artificial demineralization process and after the treatment with the toothpastes. In the statistical analysis, the one-way ANOVA and Pearson correlation tests were used. Xilitol and Juniperus Communis showed the greatest gain of P ions compared to the control group (p<0.01). As for Ca, the group treated with xylitol-based toothpaste showed more ion gain compared with the control group (p<0.01). In the Pearson correlation test between Ca and P, statistically significant correlations were observed in all groups (p<0.01), ranging between r=0.7413 (Xylitol Group) and r=0.9510 (Control Group). We concluded that Xylitol paste showed the highest remineralizing property, both in the EDS analysis and in the SEM images.

RESUMEN El objetivo de este studio fue explorer el efecto remineralizante de las cremas dentales compuestas de Xilitol, Camelia Sinensis y Juniperus Communis. Se llevó a cabo un estudio experimental in vitro en una muestra de 18 premolares humanos, los cuales fueron tratados con una de las tres pastas dentales evaluadas y una fluorada. Los porcentajes atomicos de Ca y P fueron evaluados por Espectroscopia de rayos X de energía dispersive (EDS). Además, la superficie del esmalte de los dientes tratados fue examinada por Microscopia Electronica de Barrido (SEM). Las evaluaciones fueron llevadas a cabo en tres etapas: pre-tratamiento, despues de un proceso artificial de desmineralizacion y después del tratamiento con las pastas dentales. Se usaron ANOVA de una via y correlacion de Pearson para el analisis estadistico. Xilitol y Juniperus Communis mostraron la mayor ganancia de iones P comparados con el grupo control (p<0.01), con rangos entre r=0.7413 (Grupo con Xylitol) and r=0.9510 (Group Control). Se concluyó que la pasta con Xilitol mostró las mayores propiedades remineralizantes, tanto en el analisis EDS y las imágenes SEM.

Vickers microhardness comparison of 4 composite resins with different types of filler / Comparación de la Microdureza Vickers de 4 resinas compuestas con diferente tipo de relleno

Composite resins are the material of choice to restore minimal invasive cavities; conversely, it is important to explore the mechanical properties of commercially available dental materials. Objective: To compare the Vickers microhardness (VHN) of four available commercial composite resins using standardized samples and methods. Methodology: Composite cylinders were manufactured in a Teflon mould. We used the follow composite resins (n=4/gp): Microhybrid resins [Feeling Lux (Viarden) and AmelogenPlus (Ultradent)], Hybrid resin [Te-Econom Plus (Ivoclar)] and Nanohybridresin [Filtek Z350 (3M ESPE)]. All samples were incubated in distilled water at 37ºC for five days. The test was carried out with microhardness indenter at 10 N, and a dwelling time of 10 s for 9 indentations across the specimens resulting in a total of 36 indentations for each group. Data were subjected to Kolmogorov-Smirnov normality test and ANOVA (post-hoc) Tukey test. Results: The VHN mean values ranged from harder to softer as follows: Filtek Z350 (71.96+/-6.44) (p<0.01)> Amelogen Plus (59.90+/-4.40) (p<0.05)> Feelinglux (53.52+/-5.72)> Te-Econom Plus (53.26+/-5.19). Conclusion: According to our results, the microhardness of the evaluated conventional composite resins can withstand the masticatory forces; however nanohybrid composite resins showed better Vickers microhardness and therefore are a more clinically suitable option for minimal invasion treatments...

Las resinas son los materiales de elección para restaurar cavidades mínimamente invasivas, sin embargo, es importante conocer sus propiedades mecánicas de los materiales dentales disponibles comerciales. Objetivo: Comparar la microdureza Vickers (VHN) de cuatro resinas compuestas comerciales disponibles con muestras y métodos estandarizados. Metodología: Cilindros de resina compuesta fueron conformados en un molde de Teflón. Se utilizaron las siguientes resinas compuestas (n=4/gp): resina microhíbrida [Feeling Lux (Viarden) y Amelogen Plus (Ultradent)], resina híbrida [Te-Econom Plus (Ivoclar)] y resina nanohíbrida [Filtek Z350 (3M ESPE)]. Todas las muestras fueron incubadas en agua destilada a 37°C durante cinco días. El análisis fue realizado con un indentador de microdureza a 10 N y 10s de presión sobre la muestra, nueve indentaciones fueron realizadas a lo largo de la muestra resultando un total de 36 indentaciones por cada grupo. Los datos fueron sometidos a prueba de normalidad de Kolmogorov-Smirnov y un análisis de ANOVA (post-hoc) de Tukey. Resultados: Los valores de VHN correspondieron de la resina más dura a la más suave como se muestra a continuación: Filtek Z350 (71.96+/-6.44) (p<0.01)> Amelogen Plus (59.90+/-4.40) (p<0.05)> Feeling lux (53.52+/-5.72)> Te-Econom Plus (53.26+/-5.19). Conclusiones: De acuerdo con nuestros resultados, la dureza de las resinas compuestas convencionales evaluadas puede soportar las fuerzas masticatorias pero las resinas compuestas nanohíbridas mostraron una mejor microdureza Vickers que clínicamente puede resultar como una adecuada opción para restaurar tratamientos mínimamente invasivos...

Mechanical, antibacterial and bond strength properties of nano-titanium-enriched glass ionomer cement

The use of nanoparticles (NPs) has become a significant area of research in Dentistry. Objective The aim of this study was to investigate the physical, antibacterial activity and bond strength properties of conventional base, core build and restorative of glass ionomer cement (GIC) compared to GIC supplemented with titanium dioxide (TiO2) nanopowder at 3% and 5% (w/w). Material and Methods Vickers microhardness was estimated with diamond indenter. Compressive and flexural strengths were analyzed in a universal testing machine. Specimens were bonded to enamel and dentine, and tested for shear bond strength in a universal testing machine. Specimens were incubated with S. mutans suspension for evaluating antibacterial activity. Surface analysis of restorative conventional and modified GIC was performed with SEM and EDS. The analyses were carried out with Kolmogorov-Smirnov, ANOVA (post-hoc), Tukey test, Kruskal-Wallis, and Mann Whitney. Results Conventional GIC and GIC modified with TiO2 nanopowder for the base/liner cement and core build showed no differences for mechanical, antibacterial, and shear bond properties (p>0.05). In contrast, the supplementation of TiO2 NPs to restorative GIC significantly improved Vickers microhardness (p<0.05), flexural and compressive strength (p<0.05), and antibacterial activity (p<0.001), without interfering with adhesion to enamel and dentin. Conclusion GIC supplemented with TiO2 NPs (FX-II) is a promising material for restoration because of its potential antibacterial activity and durable restoration to withstand the mastication force. .

Quantitative analysis of S. mutans and S. sobrinus cultivated independently and adhered to polished orthodontic composite resins

In Orthodontics, fixed appliances placed in the oral cavity are colonized by microorganisms. OBJECTIVE: The purpose of this study was to quantitatively determine the independent bacterial colonization of S. mutans and S. sobrinus in orthodontic composite resins. MATERIAL AND METHODS: Seven orthodontic composite adhesives for bonding brackets were selected and classified into 14 groups; (GIm, GIs) Enlight, (GIIm, GIIs) Grengloo, (GIIIm, GIIIs) Kurasper F, (GIVm, GIVs) BeautyOrtho Bond, (GVm, GVs) Transbond CC, (GVIm, GVIs) Turbo Bond II, (GVIIm, GVIIs) Blugloo. 60 blocks of 4x4x1 mm of each orthodontic composite resin were made (total 420 blocks), and gently polished with sand-paper and ultrasonically cleaned. S. mutans and S. sobrinus were independently cultivated. For the quantitative analysis, a radioactive marker was used to codify the bacteria (³H) adhered to the surface of the materials. The blocks were submerged in a solution with microorganisms previously radiolabeled and separated (210 blocks for S. mutans and 210 blocks for S. sobrinus) for 2 hours at 37ºC. Next, the blocks were placed in a combustion system, to capture the residues and measure the radiation. The statistical analysis was calculated with the ANOVA test (Sheffè post-hoc). RESULTS: Significant differences of bacterial adhesion were found amongst the groups. In the GIm and GIs the significant lowest scores for both microorganisms were shown; in contrast, the values of GVII for both bacteria were significantly the highest. CONCLUSIONS: This study showed that the orthodontic composite resin evaluated in the GIm and GIs, obtained the lowest adherence of S. mutans and S. sobrinus, which may reduce the enamel demineralization and the risk of white spot lesion formation.

Efectos de la luz UV sobre placas de titanio para la adhesión osteoblástica / The effects of ultraviolet irradiation of titanium plates on osteoblastic adhesion

Objetivo: investigar los efectos de la irradiación ultravioleta (UV) sobre placas de titanio (Ti) para la adhesión osteoblástica por medio de un método colorimétrico simple y reproducile para determinar la densidad celular. Materiales y métodos: dos diferentes tamaños (10x10x0.5 mm y 20x20x0.5 mm) de placas (n=10 c/gp) fueron obtenidas de una hoja de Ti puro y divididas en dos grupos (n=5/gp) para cada tamaño de placa. La superficie de las placas de Ti fue pulida, observada con microscopía electrónica de barrido (MEB) y estimada la rugosidad de la superficie pulida. Para el grupo experimental, las placas de Ti fueron irradiadas a una longitud de onda de 253.7 nm con luz UV durante 5, 20, 40, 60 minutos ó 4 y 6 horas. Células odontoblásticas de ratón MC3T3-E1 fueron cultivadas en medio alfa mínimo esencial (-MEM) e inoculadas sobre cada placa de Ti. El número de células adheridas y proliferadas fue determinado por medio del método MTT y el consumo de animoácidos. Resultados: 20 minutos de irradiación UV de las placas de Ti fueron suficientes para incrementar significativamente (p<0.05) la adhesión y proliferación celular, acompañado de un mayor consumo de aminoácidos. Conclusiones: la irradiación UV sobre placas de Ti incrementó significatiamente la adhesión celular por medio del método MTT, confirmando la potencialidad de la luz UV.