Expiration Date Effect on Mechanical and Chemical Properties of Glass Ionomer Cements / Efecto de La Fecha de Vencimiento sobre las Propiedades Mecánicas y Químicas de los Cementos de Ionómero de Vidrio

The glass ionomer cements (GICs) is a generic name given to a group of materials widely used in clinical dentistry which if used after the specified expiration date, material properties may be affected. to evaluate the Vick ers microhardness, surface morphology and the energy dispersive X-ray microanalysis (EDX), of GICs with different expiration dates that were stored at room temperature. specimens of highly viscous glass ionomer cement (HVGIC) (Ketac Cem and Ketac Molar) and resin-modified glass ionomer cement (RMGIC) (Vitrebond) with different expiration dates (current, close to their expiration and expired) were prepared for Vickers microhardness test and scanning electronic microscopy (SEM) with EDX, measuring 5 mm in diameter and 2 mm length, per the manufacturer's instructions, in standard cylindrical teflon molds. For the comparison of obtained values, the ANOVA test was used, while Tukey test was used for the multiple comparisons. In all the GICs used, the microhardness decreased as the expiration date approached, finding a significant statistical differen ce (P<0.05) in Ketac Molar and Vitrebond. SEM sample analysis revealed similar cohesive cracks in all tested materials. The EDX analysis revealed the presence of the elements F, Al and Si in all GICs and Ca only in Ketac Molar and Ketac Cem. The elements were found in a higher atomic percentage in the GICs with an current date and in a lower percentage in those with an expired date. HVGIC and RMGIC with an expiration date finish and that were stored at room temperature, suffer significant physical and chemical changes, which could put doubts its clinical effectiveness.

El cemento de ionómero de vidrio (CIV) es un nombre genérico que se le da a un grupo de materiales ampliamente utilizados en odontología clínica que si se usan después de la fecha de vencimiento especificada, las propiedades del material pueden verse afectadas. evaluar la microdureza Vickers, la morfología superficial y el microanálisis de energía dispersa de rayos X (EDX), de CIV con diferentes fechas de caducidad almacenados a temperatura ambiente. Muestras de cemento de ionómero de vidrio de alta viscosidad (CIVAV) (Ketac Cem y Ketac Molar) y cemento de ionómero de vidrio modificado con resina (CIVMR) (Vitrebond) con diferentes fechas de vencimiento (vigente, próximo a su vencimiento y vencido) de 5 x 2 mm, fueron preparadas para microscopía electrónica de barrido (MEB) con EDX y microdureza Vickers, según las instrucciones del fabricante, en moldes de teflón cilíndricos estándar. Para la comparación de los valores obtenidos se utilizó la prueba ANOVA, mientras que para las comparaciones múltiples se utilizó la prueba de Tukey. En todos los CIV utilizados, la microdureza disminuyó a medida que se acercaba la fecha de vencimiento, encontrándose una diferencia estadística significativa (P <0.05) en Ketac Molar y Vitrebond. El análisis de la muestra en MEB reveló grietas cohesivas similares en todos los materiales probados. El análisis EDX reveló la presencia de los elementos F, Al y Si en todos los GIC y Ca solo en Ketac Molar y Ketac Cem. Los elementos se encontraron en mayor porcentaje atómico en los GIC con fecha vigente y en menor porcentaje en aquellos con una fecha vencida. Los CIVAV y CIVMR con fecha de caducidad vencida y que fueron alma- cenados a temperatura ambiente, sufrieron cambios físicos y químicos importantes, lo que podría poner en duda su efectividad clínica.

Characterization of Enamel After the Use of Oral Hygiene Auxiliaries with Whiteners / Caracterización del esmalte después del uso de auxiliares de higiene bucal con blanqueadores

ABSTRACT The purpose of this study was to evaluate the effect of the use of the combined auxiliaries of oral hygiene with whitening agents on the micro-hardness and micro-morphology of dental enamel. Materials and Methods. 40 human incisors were used and sectioned to obtain 4x4mm samples and divided into four study groups. Group 1: Electric brushing with Toothpaste (BTP); Group 2: Electric brushing with Toothpaste+mouthwash (BTP+MW); Group 3: Electric brushing with Toothpaste+whitening pen (BTP+WP); Group 4: Electric brushing with Toothpaste+mouth wash+whitening pen (BTP+MW+WP). Samples were submitted toVickers micro-hardness test and visualized using scanning electron microscopy (SEM). Results. All groups, with the exception of group 1, showed a decrease in micro- hardness values after applying the treatments (p<0.05). Likewise, when comparing the values after the treatments between the groups, significant statistical differences were found in all of comparisons except for those of groups 2 and 4. SEM images showed changes in the morphology in all the study groups with the exception of group 1. Conclusion. Significant changes such as decrease in micro-hardness as well as in the topography of the enamel surface such as elevations, craters, porosities and etching patterns were founded after the use of the combination of auxiliaries of oral hygiene with whitening agents.

RESUMEN El propósito de este estudio fue evaluar el efecto del uso de los auxiliares de higiene oral combinados con agentes blanqueadores sobre la microdureza y la micro-morfología del esmalte dental. Materiales y métodos. Se utilizaron 40 incisivos humanos y se seccionaron para obtener muestras de 4x4 mm los cuales se dividieron en cuatro grupos de estudio. Grupo 1: cepillado eléctrico con pasta de dientes (BTP); Grupo 2: cepillado eléctrico con pasta dental+enjuague bucal (BTP+MW); Grupo 3: cepillado eléctrico con pasta dental+pluma blanqueadora (BTP+WP); Grupo 4: cepillado eléctrico con pasta dental+enjuague bucal+pluma blanqueadora (BTP+MW+WP). Las muestras fueron analizadas por medio de microdurezaVickers y microscopía electronica de barrido (SEM). Resultados. Todos los grupos, con la excepción del grupo 1, mostraron una disminución en los valores de microdureza después de aplicar los tratamientos (p<0.05). Del mismo modo, al comparar los valores después de los tratamientos entre los grupos, se encontraron diferencias estadísticamente significativas en todas las comparaciones, excepto en las de los grupos 2 y 4. Las imágenes de SEM nos muestran cambios en la morfología en todos los grupos de estudio con la excepción del grupo 1 Conclusión. Cambios significativos como la disminución de la microdureza y los cambios en la topografía de la superficie del esmalte, como elevaciones, cráteres, porosidades y patrones de grabado, se encontraron después del uso de la combinación de auxiliares de la higiene oral con agentes blanqueadores.

Evaluation of laser fluorescence in monitoring non-cavitated caries lesion progression on smooth surfaces in vitro.

The aim of this study was to evaluate the performance of a pen-type laser fluorescence (LF) device (LFpen: DIAGNOdent pen) to detect and monitor the progression of caries-like lesions on smooth surfaces. Fifty-two bovine enamel blocks were submitted to three different demineralisation cycles for caries-like lesion induction using Streptococcus mutans, Lactobacillus casei and Actinomyces naeslundii. At baseline and after each cycle, the enamel blocks were analysed under Knoop surface micro-hardness (SMH) and an LFpen. One enamel block after each cycle was randomly chosen for Raman spectroscopy analysis. Cross-sectional micro-hardness (CSMH) was performed at different depths (20, 40, 60, 80 and 100 µm) in 26 enamel blocks after the second cycle and 26 enamel blocks after the third cycle. Average values of SMH (± standard deviation (SD)) were 319.3 (± 21.5), 80.5 (± 31.9), 39.8 (± 12.7), and 29.77 (± 10.34) at baseline and after the first, second and third cycles, respectively. Statistical significant difference was found among all periods (p < 0.01). The LFpen values were 4.3 (± 1.5), 7.5 (± 9.4), 7.1 (± 7.1) and 5.10 (± 3.58) at baseline and after the first, second, and third cycles, respectively, among all periods (p < 0.05). The CSMH values after the second and third cycles at 20, 40, 60, 80 and 100 µm were 182.8 (± 69.8), 226.1 (± 79.6), 247.20 (± 69.36), 262.35 (± 66.36) and 268.45 (± 65.49), and for the third cycle were 193.7 (± 73.4), 239.5 (± 81.5), 262.64 (± 82.46), 287.10 (± 78.44) and 284.79 (± 72.63) (n = 24 and 23), respectively. No correlation was observed between the LFpen and SMH values (p > 0.05). One sample of each cycle was characterised through Raman spectroscopy analysis. It can be concluded that LF was effective in detecting the first demineralisation on enamel; however, the method did not show any effect in monitoring lesion progression after three cycles of in vitro demineralisation.

Effect of two different commonly available energy drinks on surface micro hardness of tooth color restorative materials

AIM: The objective of present study was to assess the effect of commonly used energy drinks on surface micro hardness of tooth color restorative materials. MATERIAL AND METHODS: Sixty discs of all material were prepared in polytetrafluoroethylene mold which was 10 mm in diameter and 2 mm in thickness. Two groups were made for each material containing 10 discs; G1/G2 (vitofil), G3/G4 (vitremere), G5/G6 (Filtek Z350). After 24 hours, the discs were polished. Group 1, group 3 and group 5 were immersed in red bull for 2 minutes during whole expereiment. Group 2, group 4 and group 6 were immersed in jolt cola for 2 minutes during whole expereiment. Microhardness test were performed in digital micro hardness tester before and after immersion at different time interval. The results were statistically analyzed with the help of two-way ANOVA with repeated measurement and Tukey's test. RESULTS: According to time interval for vitofil and vitremere there is insignificant difference between baseline and day 1 surface micro hardness values (p>0.001). Significant difference is seen between baseline micro hardness and day 7 day 14,day 30 (p<0.001). Inverse is true for Filtek Z350 there is significant difference between base line and day 1 micro hardness values(p<0.001). The difference between base line, day 7, day 14 and day 30 is insignificant (p>0.001). According to immersion media there is insignificant difference between both of them (p>0.001). CONCLUSION: The effect of energy drinks on the surface micro hardness of a restorative material depends on the duration of contact time and the material composition not on the type of drink.

Microdureza profunda en una resina compuesta fotopolimerizada por diferentes fuentes de luz / Microhardness at depth of a dental composite resin fotocured troughthdiferents light sources

Introducción y Objetivo: Las lámparas fotopolimerizadoras son utilizadas actualmente en la práctica odontológica para estimular el endurecimiento de diferentes materiales de reconstruccióndental a base de resina compuesta, también llamada composite dental. El objetivo fue comparar la profundidad de polimerización provocada en una resina compuesta de uso dental, por dos sistemas convencionales de fotocurado y un láser Innova 300 adaptado experimentalmente a una longitud deonda de 488nm.

Introduction and Objective: The depth of polymerization caused in a dental composite resin through the fotoactivation with two conventional light sources and Innova 300 laser light adapted experimentally to 488nm length of wave were compared. Materials and Methods: 12 compositesamples were fotocured using 3 different sources of light in 2 different thickness dimensions,according to ISO 4049:2000 regulations. After 60 days of polymerization, micro hardness analyseswere carried out.