“Valores DIAGNOdent en Esmalte Temporal Acondicionado con Láser Er: YAG VS. Autograbado Después de la Disolución Ácida

Se determinaron los valores DIAGNOdent del esmalte de dientes temporales acondicionados con láser Er: YAG vs. autograbado después de la disolución ácidaLas resinas para restauración dental requieren de un acondicionamiento previo del esmalte para una adhesión adecuada, ya sea con ácido, autograbado, y más recientemente con láser. Dentro de las ventajas de la aplicación del láser esta, por una parte la simplificación del procedimiento y por otra la posibilidad de incrementar la resistencia a la disolución ácida. O: Determinar los valores DIAGNOdent del esmalte de dientes temporales acondicionados con láser Er: YAG vs. autograbado después de la disolución ácida. M: Estudio experimental, cuya muestra incluyó 30 piezas dentarias temporales extraídas por razones terapéuticas, divididas aleatoriamente en 3 grupos (n=10); Grupo I Control (sin acondicionamiento), Grupo II Irradiado con láser Er: YAG, Grupo III Autograbado. Después del acondicionamiento, las muestras fueron colocadas en una solución ácida e incubadas, posteriormente se retiraron de la solución, se lavaron, secaron y se procedió al análisis con DIAGNOdent. Para determinar las diferencias entre los grupos se aplicó la prueba de Kruskal-Wallis (p ≤ 0.05). R: El 100% de las muestras del grupo I, III y el 80% del II mostraron valores DIAGNOdent de 0-13, sin diferencias estadísticamente significativas. D: Los reportes en la literatura indican que a pesar de que el acondicionamiento con láser Er: YAG proporciona alta resistencia, provoca un daño considerable a la superficie de los órganos dentales y se considera que la técnica de autograbado es más segura. Sin embargo en el presente estudio aun cuando los datos muestran mayor desmineralización esto únicamente se presenta en un bajo porcentaje de muestras lo cual se puede deber a otros factores. C: Los valores DIAGNOdent del grupo II mostraron en mayor cantidad una ligera desmineralización del esmalte temporal a la disolución ácida, pero no es estadísticamente significativo.Universidad Autónoma del Estado de Méxic

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 (

Evaluation of Self-Etching Adhesive and Er:YAG Laser Conditioning on the Shear Bond Strength of Orthodontic Brackets

The purpose of this study was to evaluate the shear bond strength, the adhesive remnant index scores, and etch surface of teeth prepared for orthodontic bracket bonding with self-etching primer and Er:YAG laser conditioning. One hundred and twenty bovine incisors were randomly divided into four groups. In Group I (Control), the teeth were conditioned with 35% phosphoric acid for 15 seconds. In Group II the teeth were conditioned with Transbond Plus SEP (5 sec); III and IV were irradiated with the Er:YAG 150 mJ (11.0 J/cm2), 150 mJ (19.1 J/cm2), respectively, at 7–12 Hz with water spray. After surface preparation, upper central incisor stainless steel brackets were bonded with Transbond Plus Color Change Adhesive. The teeth were stored in water at 37°C for 24 hours and shear bond strengths were measured, and adhesive remnant index (ARI) was determined. The conditioned surface was observed under a scanning electron microscope. One-way ANOVA and chi-square test were used. Group I showed the significantly highest values of bond strength with a mean value of 8.2 megapascals (MPa). The lesser amount of adhesive remnant was found in Group III. The results of this study suggest that Er:YAG laser irradiation could not be an option for enamel conditioning

Chemical Changes Associated with Increased Acid Resistance of Er:YAG Laser Irradiated Enamel

Background. An increase in the acid resistance of dental enamel, as well as morphological and structural changes produced by Er:YAG laser irradiation, has been reported. Purpose. To evaluate the chemical changes associated with acid resistance of enamel treated with Er:YAG laser. Methods. Forty-eight enamel samples were divided into 4 groups (n=12). Group I (control); Groups II, III, and IV were irradiated with Er:YAG at 100 mJ (12.7 J/cm2), 200 mJ (25.5 J/cm2), and 300 mJ (38.2 J/cm2), respectively. Results. There were significant differences in composition of irradiated groups (with the exception of chlorine) and in the amount of calcium released. Conclusions. Chemical changes associated with an increase in acid resistance of enamel treated with Er:YAG laser showed a clear postirradiation pattern characterized by a decrease in C at.% and an increase in O, P, and Ca at.% and no changes in Cl at.%. An increased Ca/P ratio after Er:YAG laser irradiation was associated with the use of higher laser energy densities. Chemical changes produced by acid dissolution showed a similar trend among experimental groups. Stable or increased Ca/P ratio after acid dissolution was observed in the irradiated groups, with reduction of Ca released into the acid solution

Microhardness, Structure, and Morphology of Primary Enamel after Phosphoric Acid, Self-Etching Adhesive, and Er:YAG Laser Etching

Background. Phosphoric acid is the traditional etching agent; self-etching adhesives and Er:YAG laser are alternative methods. Knowledge of deciduous enamel etching is required. Aim. To evaluate primary enamel microhardness, structure, and morphology after phosphoric acid, self-etching, and Er:YAG laser etching. Design. Seventy primary incisors were assigned to five groups (n=14): I (control), II (35% phosphoric acid), III (self-etching adhesive), IV (Er:YAG laser at 15 J/cm2), and V (Er:YAG laser at 19.1 J/cm2). Microhardness was evaluated by Vickers indentation. Chemical composition was analyzed by energy dispersive X-ray spectroscopy and morphological changes by scanning electron microscopy. One-way ANOVA, Kruskal–Wallis, Mann–Whitney U, and Pearson bivariate correlation were employed (α=0.05). Results. Vickers microhardness showed differences and no correlation with Ca/P ratio. Group II showed differences in carbon, oxygen, and phosphorus atomic percent and group V in Ca/P ratio. Morphological changes included exposed prisms, fractures, craters, and fusion. Conclusions. Enamel treated with phosphoric acid showed different chemical characterization among groups. Self-etching and Er:YAG laser irradiation at 19.1 J/cm2 showed similar microhardness and chemical characterization. Er:YAG laser irradiation at 15 J/cm2 maintained microhardness as untreated enamel. Er:YAG laser irradiation at 19.1 J/cm2 enhanced mineral content. Morphological retentive changes were specific to each type of etching protocol