Physico-Chemical comparison of four commercially available mineral trioxide aggregates / Comparación fisicoquímica de cuatro mineral trióxido agregados disponibles comercialmente

Abstract To compare the physicochemical composition of 4 MTAs commercially available in Latin America. ProRoot MTA (Dentsply, USA), MTA Angelus (Angelus, Brazil), MTA Flow (Ultradent, USA), and MTA Viarden (Viarden, Mexico) were physically and chemically compared. Scanning electron microscopy (SEM) images were obtained from the MTA powder and the prepared presentations. Energy Dispersive X-Ray Spectroscopy (EDS) analyses were performed by triplicate, to calculate the mass proportion of calcium (Ca), silicon (Si), the Ca/Si proportion among the 4 brands. Thermogravimetric analyses (TGA) were conducted (50ºC-1000ºC), and mass loss and inflection points were calculated for each material. Statistical differences for Ca and Si content were determined by ANOVA (p<0.05). SEM images showed evident differences in the appearance of both the powder and the prepared MTAs among brands. Angelus MTA showed cubic prisms not observed in the other 3 brands. ProRoot MTA and MTA Flow showed similar homogeneous structures. MTA Viarden was the less homogeneous, with random structures (>15um). When comparing the mass proportions of Ca and Si between the 4 powder samples, MTA Viarden showed a significantly lower proportions of both elements when compared with the other brands (p<0.005). TGA análisis showed a similar behavior for ProRoot MTA, MTA Angelus and MTA Flow, with less than 2% mass loss when the 1000C temperature was reached. MTA Viarden showed a mass loss of 9,94% before the 700C, indicating the presence of different content sensible to temperature degradation. The analyzed MTAs demonstrated to vary significantly in their chemical composition and physical characteristics. Clinicians must be aware of the differences between different brands of a same material, and future research should focus on the clinical implications of these differences.

Resumen Comparar la composición fisicoquímica de 4 MTA disponibles comercialmente en América Latina. Se compararon física y químicamente ProRoot MTA (Dentsply, EE. UU.), MTA Angelus (Angelus, Brasil), MTA Flow (Ultradent, EE. UU.) y MTA Viarden (Viarden, México). Se obtuvieron imágenes de microscopía electrónica de barrido (SEM) del polvo de MTA y de las presentaciones preparadas. Los análisis de espectroscopía de dispersión de energía de rayos X (EDS) se realizaron por triplicado para calcular la proporción de masa de calcio (Ca), silicio (Si), la proporción Ca/Si entre las 4 marcas. Se realizaron análisis termogravimétricos (TGA) (50ºC-1000ºC), y se calcularon las pérdidas de masa y los puntos de inflexión para cada material. Las diferencias estadísticas para el contenido de Ca y Si se determinaron mediante ANOVA (p<0,05). Los análisis SEM mostraron diferencias evidentes en la apariencia tanto del polvo como las preparaciones de los MTA, entre las diferentes marcas. MTA Angelus mostró prismas cúbicos no observados en las otras 3 marcas. ProRoot MTA y MTA Flow mostraron estructuras homogéneas similares. MTA Viarden fue el menos homogéneo, con estructuras aleatorias (>15um). Al comparar las proporciones de masa de Ca y Si entre las 4 muestras de polvo, MTA Viarden mostró proporciones significativamente más bajas de ambos elementos en comparación con las otras marcas (p<0,005). El análisis TGA mostró un comportamiento similar para ProRoot MTA, MTA Angelus y MTA Flow, con menos del 2 % de pérdida de masa al alcanzar los 1000 °C de temperatura. El MTA Viarden mostró una pérdida de masa de 9,94% antes de los 700 °C, indicando la presencia de diferentes contenidos sensibles a la degradación por temperatura. Los MTA analizados demostraron diferencias significativas en su composición química y características físicas. Los clínicos deben ser conscientes de las diferencias entre las diferentes marcas de un mismo material, y futuras investigaciones deben enfocarse en las implicaciones clínicas de estas diferencias.

Comparison of two obturation techniques on adhesion and proliferation of human periodontal ligament fibroblasts / Comparación de la adhesión y proliferación de fibroblastos periodontales humanos en dos técnicas de obturación endodóntica

The present study aimed to compare the adhesion and proliferation of human periodontal ligament fibroblasts (hPDL) in transverse sections of the teeth sealed with two different obturation techniques, BioRoot RCS/hydraulic obturation (HO) and AH-Plus/continuous-wave condensation (CWC). The techniques were tested using an in vitro model to simulate the interaction between periodontal tissues and the materials. The root canals were instrumented and sterilized. A total of 15 samples were obturated with BioRoot RCS/HO and 15 samples with AH-Plus/CWC. Then, roots were sectioned to obtain obturated teeth slices, and hPDL cells were seeded onto the root slices. The results were obtained at intervals of 4 and 24h for cell adhesion; and at 3,7,14, and 21 days for cell proliferation. Empty cell culture plates were use as controls. The cell adhesion was increased at 4 and 24h for both groups, with an increased response observed in the BioRoot RCS/HO group (p<0.05). The difference in cell proliferation was also found between experimental groups. After 14 days of culture, BioRoot RCS/HO group showed an increase response than control and AH-Plus/CWC groups (p<0.05), and after 21 days both groups behaved better than control group, with an increased response observed in the BioRoot RCS/HO group. This study demonstrated that both root canal sealers allow the attach and growth of periodontal ligament fibroblasts, with an increased biological response in the BioRoot RCS/HO group.

El presente estudio se enfocó en comparar la adhesión y proliferación de fibroblastos de ligamento periodontal humano (hPDL) en secciones transversales de raíces previamente obturadas con dos técnicas de obturación diferentes: obturación hidráulica empleando cono único de gutapercha y BioRoot RCS como sellador (HO), y obturación de condensación de onda continua y AH-Plus como sellador (CWC). Los selladores se usaron en un modelo in vitro que simula la interacción entre los tejidos periodontales y los materiales de obturación. Los conductos radiculares fueron instrumentados, esterilizados y obturados. La muestra se compuso de un total de 15 raíces con la técnica BioRoot RCS/HO y 15 raíces con la técnica AH-Plus/CWC. Las células de hPDL fueron sembradas en condiciones estándar de cultivo sobre las raíces seccionadas. Los resultados fueron obtenidos a intervalos de 4 y 24h para adhesión celular, y a los 3,5,7,14 y 21 días de cultivo para proliferación celular. La adhesión celular a las 4 y 24 horas mostró ser diferente para ambas técnicas en comparación con el grupo control, siendo más importante en el grupo BioRoot RCS/HO. La diferencia en la proliferación entre grupos se observó a los 14 días de cultivo, únicamente para el grupo BioRoot RCS/HO; Sin embargo para el día 21 ambas técnicas mostraron mayor proliferación celular que el grupo control, con mejor respuesta para el grupo BioRoot RCS/HO. Este estudio ha demostrado que ambos selladores de conductos permiten la adhesión y crecimiento de fibroblastos de ligamento periodontal, siendo el grupo BioRoot RCS/HO el que mostró mayor biocompatibilidad.

Evaluation of dentin microroughness and composite bond strength after multiple uses of diamond burs / Evaluación de la micro rugosidad dentinaria y la resistencia adhesiva de composites tras múltiples usos de fresas de diamante

Abstract Using a bur multiple times to prepare dental structure may produce a smoother final surface on dentin than a new one. This superficial roughness may affect adhesion with resin-based materials by modifying the substrates' characteristics. The aim of this study was to evaluate the effect of multiple uses of diamond burs on dentin's superficial microroughness and bond strength with resin composite when using a self-etch adhesive. Diamond dental burs were used to simulate a preparation (dentin flat surface) on extracted third molars. Samples were distributed into groups according to burs' number of previous uses as follows: 0, 1, 5 and 10. Scanning electron microscopy images at 70x, 350x, and 1000x were used to illustrate burs' deformation. Each specimen's dentin microroughness was measured three times to compare between experimental groups and the micro-shear bond strength test (n=15) was performed for the 0 and 10 uses groups using a universal adhesive in a self- etching mode. Diamond crystals wear and dislodgements were evident among groups where the burs were used more times. As the number of uses increased the mean microroughness of the dentin surface decreased with significant differences between the 0 and 10 uses groups. No statistical differences between experimental groups resulted from bond strength tests. When using a universal adhesive in a self-etching mode, the number of previous uses of a diamond bur seems to have no significant effect on dentin/resin composite bond strength.

Resumen El uso de una fresa múltiples veces para preparar la estructura dental puede producir una superficie final más lisa en la dentina que una fresa nueva. Esta rugosidad superficial modifica las características del sustrato y puede afectar la adhesión con materiales resinosos. El objetivo de este estudio fue evaluar el efecto de los múltiples usos de las fresas de diamante sobre la micro rugosidad superficial de la dentina y la resistencia adhesiva con la resina compuesta cuando se utiliza un adhesivo de autograbado. Se utilizaron fresas dentales de diamante para simular una preparación (superficie plana de la dentina) en terceros molares extraídos. Las muestras se distribuyeron en grupos según el número de usos previos de las fresas de la siguiente manera: 0, 1, 5 y 10. Se utilizaron imágenes de microscopía electrónica de barrido a ×70, ×350 y ×1000 para ilustrar la deformación de las fresas. Se midió la micro rugosidad de la dentina de cada espécimen tres veces para comparar entre los grupos experimentales y se realizó la prueba de resistencia a la adhesión por micro cizallamiento (n=15) para los grupos de 0 y 10 usos utilizando un adhesivo universal en modo de autograbado. El desgaste de los cristales de diamante y los desprendimientos fueron evidentes entre los grupos en los que las fresas se utilizaron más veces. A medida que aumentaba el número de usos, la micro rugosidad media de la superficie de la dentina disminuyó, con diferencias significativas entre los grupos de 0 y 10 usos. En las pruebas de resistencia adhesiva no se observaron diferencias estadísticas entre los grupos experimentales. Cuando se utiliza un adhesivo universal en modo de autograbado, el número de usos previos de una fresa de diamante no parece tener un efecto significativo en la resistencia de la unión dentina/resina del composite.

2020: Renewing the paradigms for orofacial pain / 2020: renovando los paradigmas para el dolor orofacial

Abstract In 2020, two important changes were adapted by the international health community: a new definition of pain and a new classification for orofacial pain conditions. With these changes new tasks and challenges also emerged, and clinicians from several disciplines begun to adopt and reconsidered classic paradigms, and the policies derived from them. This new perspective article, examine the new definition of pain proposed by the International Association for the Study of Pain, and the new International Classification of Orofacial Pain; analyzing the positive impact and further perspectives of these.

Resumen En 2020, dos importantes cambios fueron adaptados por la comunidad internacional en salud: una nueva definición de dolor y una nueva clasificación para las condiciones de dolor orofacial. Con estos cambios, también emergieron nuevos retos y tareas, y los clínicos de diversas disciplinas empezaron adaptar y reconsiderar los paradigmas clásicos; y las políticas derivadas de estos. En este artículo de nueva perspectiva, examinaremos nueva definición de dolor propuesta por la Asociación Internacional para el Estudio del Dolor, y la nueva Clasificación Internacional de Dolor Orofacial; analizando el impacto positivo y las próximas perspectivas de estos cambios.

Effects of heat on seven endodontic sealers.

PURPOSE: To examine the microscopic surface features, chemical composition, and thermodynamic profile of seven endodontic sealers (AH Plus, Adseal, MTA-Fillapex, RoekoSeal, GuttaFlow 2, GuttaFlow BioSeal, and EndoRez) exposed to high-temperature changes using an endodontic obturation device. METHODS: The thermal properties were examined using scanning calorimetry (DSC) and thermogravimetric analysis (TGA). Then, six disc-shaped specimens of each sealer were prepared and divided into two groups - a room temperature group and a heat exposure group - for analysis of surface and chemical changes using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). RESULTS: DSC analysis showed that AH Plus had the highest exothermal signal (122.9°C), while TGA analysis showed that MTA-Fillapex was most affected by increased temperature (32.4% mass loss at 230ºC). SEM analysis showed that while AH Plus and GuttaFlow BioSeal maintained their surface integrity after heat exposure, the EDS profiles demonstrated changes in the chemical composition of the sealers after heat exposure for 5 s. High-temperature exposure had a negative impact on the properties of five of the sealers (Adseal, MTA-Fillapex, RoekoSeal, GuttaFlow 2, and EndoRez). CONCLUSION: AH Plus and GuttaFlow BioSeal showed minimal changes upon high-temperature exposure, suggesting their suitability for thermal endodontic obturation techniques.

E-Learning in Dental Schools in the Times of COVID-19: A Review and Analysis of an Educational Resource in Times of the COVID-19 Pandemic / E-learning en las escuelas de odontología en los tiempos de COVID-19: Una revisión y análisis de un recurso educativo en tiempos de la pandemia de COVID-19

Abstract While countries are facing different stages in their COVID-19 infection rates, worldwide there are millions of students affected by universities' facilities closures due to the pandemic. Some institutions have enforced strategies to transfer some courses to a virtual modality, but many Dental Schools have been challenged to deal with a situation which requires emergency measures to continue the academic course in the middle of lock-downs and social distancing measures. Despite the fact that the number of online academic programs available, especially graduate programs, has increased in diverse modalities, this pandemic forced e-learning processes to develop abruptly. The likelihood of using e-learning strategies in dentistry was substantiated in the scientific literature and an overview of these opportunities is presented. Additionally, the experience of the University of Costa Rica Faculty of Dentistry is presented, as it was evident that some of the key elements in a e-learning environment needed a quick enhancement and initiation of some processes was required. First, it was necessary to categorize the academic courses depending on their virtualization's possibility (curricula analysis and classification), to better understand the extent of the impact and the work needed to contain, as far as the possibilities allowed, negative consequences on students learning process. Second, teachers needed further training in the application of virtual strategies which they hadn't used before. do Third, an evaluation of the students' conditions and needs was conducted in a form of a survey. Finally, teachers and students activated the available virtual platforms. For many Dental Schools, this virtualization process is an ongoing progress although it was abruptly imposed, but this moment indeed represents an enormous opportunity to move forward and get immerse in the virtualization environment as a teaching/learning experience.

Resumen Mientras muchos países están enfrentando distintas etapas en sus tasas de contagio de COVID-19, millones de estudiantes alrededor del mundo han sido afectados por el cierre de instalaciones universitarias debido a la pandemia. Algunas instituciones han aplicado estrategias para transferir algunos cursos a una modalidad virtual, pero muchas facultades de odontología se han visto enfrentadas a una situación que requiere medidas de emergencia para continuar el curso académico en medio de bloqueos y medidas de distanciamiento social. A pesar de que el número de programas académicos en línea disponibles, especialmente los programas de postgrado, ha aumentado en diversas modalidades, esta pandemia obligó a desarrollar abruptamente los procesos de aprendizaje electrónico. La probabilidad de utilizar estrategias de aprendizaje electrónico en odontología se vió corroborada en la literatura científica y se presenta una visión general de estas oportunidades. Además, se presenta la experiencia de la Facultad de Odontología de la Universidad de Costa Rica, ya que fue evidente que algunos de los elementos clave en un entorno de aprendizaje electrónico necesitaban una rápida mejora y se requería la iniciación de algunos procesos. En primer lugar, era necesario clasificar los cursos académicos en función de las posibilidades de su virtualización (análisis y clasificación de los planes de estudio), para comprender mejor el alcance de las repercusiones y la labor necesaria para contener, en la medida de las posibilidades, las consecuencias negativas en el proceso de aprendizaje de los estudiantes. En segundo lugar, los profesores necesitaban más capacitación en la aplicación de estrategias virtuales que no habían utilizado antes. En tercer lugar, se realizó una evaluación de las condiciones y necesidades de los estudiantes en forma de encuesta. Finalmente, los profesores y estudiantes activaron las plataformas virtuales disponibles. Para muchas escuelas de odontología, este proceso de virtualización es un continuo progreso y a pesar de haber tenido un inicio abrupto, pero este momento representa, de hecho, una enorme oportunidad para avanzar y sumergirse en el entorno de la virtualización como una experiencia de enseñanza/aprendizaje.

Nocebo/Placebo Effects in Dental Practice: Two Key Protagonists / Efectos Nocebo/Placebo en la práctica dental: Dos protagonistas clave

ABSTRACT Understanding the possible effects that a patient's psycho-neurobiological processes (such as the nocebo effect) may have on the every-day dental treatments, could assist the clinicians in preventing the onset of adverse events not related directly with the clinical procedure. At the same time, employing pathways to trigger plausible placebo effects could aid the clinician to enhance the outcome of ordinary clinical procedures and the patient's perspective. Identified factors, which could lead both to positive or negative effects, may be present in different ways. Prior personal experiences, second-hand information, alternative medicine, catastrophizing or patient motivation; all could have an indirect effect in the treatment outcome. A well-informed clinician should use such factors to individualize each patient treatment.

RESUMEN Comprender los posibles efectos que los procesos psico-neurobiológicos de un paciente (como el efecto nocebo) pueden tener en los tratamientos dentales diarios, podría ayudar a los clínicos a prevenir la aparición de eventos adversos que no estén relacionados directamente con el procedimiento clínico. Al mismo tiempo, el uso de vías para favorecer posibles efectos placebo podría ayudar al clínico a mejorar el resultado de sus procedimientos rutinarios y la perspectiva del paciente. Los factores identificados, ya sean positivos o negativos, pueden estar presentes de diferentes maneras. Experiencias personales anteriores, información de segunda mano, medicina alternativa, actitud catastrófica o motivación del paciente; todos podrían tener un efecto indirecto en el resultado del tratamiento. Un médico bien informado debe usar dichos factores para individualizar el tratamiento de cada paciente.

Evaluation of Surgical Bur Deformation and Bone Surface Roughness After Multiple Uses.

PURPOSE: The aim of the present in vitro study was to microscopically evaluate and describe the deformation of Lindeman surgical burs and the bone surface roughness after repeated osteotomies and sterilization cycles. MATERIALS AND METHODS: Twenty-one Lindeman surgical burs were analyzed under scanning electron microscopy (SEM) to evaluate the damage of the bur's integrity after 0, 1, 3, 5, 7, or 9 osteotomies on bovine ribs. Eighteen bone specimens were obtained after osteotomy for roughness analysis using profilometry. One-way analysis of variance was used to compare the mean roughness values across the experimental groups, and P ≤ .05 was considered to indicate statistical significance. RESULTS: Representative SEM images illustrated that all analyzed burs presented with some type of deformation at both the tip and the body, even after their first use. The mean roughness values were independent of the number of uses (P > .05); however, the standard deviation increased with the number of uses of the burs. CONCLUSIONS: These results suggest that even after their first use, rotatory surgical burs will have some type of deformation and that their cutting efficiency on the bone will vary and will be difficult to predict.

Evaluation of Microleakage by Gas Permeability and Marginal Adaptation of MTA and BiodentineTM Apical Plugs: In Vitro Study / Evaluación de la microfiltración por permeabilidad de gas y adaptación marginal de tapones apicales de MTA y BiodentineTM: Estudio in vitro

Abstract The endodontic treatment of teeth with incomplete development is always a complex task. Nowadays, biomaterials such as bioceramics offers promising clinical evidence that supports its use. However, the standardization of its use for apexification purpose still needs a deeper understanding of the materials' behavior. The aim of this investigation was to evaluate the marginal adaptability and microleakage by gas permeability of MTA and Biodentine™ apical plugs in an in vitro model. Materials and methods: Twenty- four single rooted human teeth were selected according to previously stablished inclusion criteria. All samples were prepared obtaining standard cylindrical internal canals with a diameter of 1.3 mm. Root canals were gently rinsed using 5.25% sodium hypochlorite and EDTA 17%. The apical 3mm and remaining coronal dental structure were sectioned to obtain 10mm roots. Roots were randomly assigned to 3 different groups as follows: GROUP A: MTA (n=10), GROUP B: Biodentine™ (n=10) and Group C: Control (positive n=1, negative n=3). MTA and Biodentine™ were prepared according to manufacturer's indications, and apical plugs of 4mm were passively placed in the correspondent teeth. All samples were stored in saline solution for 7 days at 37°C before evaluation. Samples were mounted in cylindrical sample-holders using epoxy resin. Microleakage was evaluated with an automatic permeability detector that calculates nitrogen diffusion between the material-root interphase. After microleakage evaluation, the samples were recovered and analyzed by scanning electron microscopy (SEM). Microleakage results were analyzed using Chi-square and adaptation was evaluated with a descriptive analysis. Results: None of the evaluated materials completely avoided the nitrogen microleakage (positive leakage of 10% and 20% of samples for MTA and Biodentine™ respectively); with no statistical significant difference between groups (p=0.527). All apical plugs showed good adaptation under SEM, at 30x, 200x, 1000x and 2500x; with microscopical structures similar to previous reports. Conclusions: Both bioceramics behave similar when used as apical barriers to avoid permeability, with acceptable marginal adaptation. Further in vivo studies are needed to validate these results.

Resumen El tratamiento endodóntico de dientes con desarrollo incompleto es siempre una tarea compleja. Hoy en día, biomateriales como las biocerámicas ofrecen una evidencia clínica prometedora que apoya su uso. Sin embargo, la estandarización de su uso para fines de apexificación todavía necesita una comprensión más profunda del comportamiento de los materiales. El objetivo de esta investigación fue evaluar la adaptabilidad marginal y microfiltración por permeabilidad de gas de los tapones apicales de MTA y Biodentine™ en un modelo in vitro. Materiales y métodos: Veiticuatro dientes humanos uniradiculares fueron seleccionados meticulosamente según criterios de inclusión previamente establecidos. Todas las muestras fueron preparadas con canales cilíndricos internos estandarizados de 1,3 mm de diámetro. Los conductos radiculares fueron gentilmente lavados con hipoclorito de sodio al 5,25% y EDTA al 17%. La estructura dental apical de 3 mm y la coronal restante se seccionó para obtener raíces de 10 mm de longitud. Las raíces se asignaron aleatoriamente a 3 grupos diferentes de la siguiente manera: GRUPO A: MTA (n = 10), GRUPO B: Biodentine™ (n = 10) y Grupo C: Control (n = 1 positivo, n = 3 negativos). El MTA y Biodentine™ se prepararon de acuerdo con las indicaciones de los fabricantes, y se colocaron pasivamente los tapones apicales de 4 mm en los dientes correspondientes. Todas las muestras se almacenaron en solución salina durante 7 días a 37ºC antes de la evaluación. Las muestras se montaron en porta-muestras cilíndricos utilizando resina epóxica. La microfiltración se evaluó con un detector de permeabilidad automática que calcula la difusión de nitrógeno entre la interfase material-raíz. Después de la evaluación de microfiltración, las muestras fueron recuperadas y analizadas por microscopía electrónica de barrido (SEM). Los resultados de microfiltración se analizaron utilizando una prueba estadística de Chi-cuadrado y la adaptación se evaluó con un análisis descriptivo. Resultados: Ninguno de los materiales evaluados evitó completamente la microfiltración de nitrógeno (fuga positiva de 10% y 20% de muestras para MTA y Biodentine™, respectivamente); sin diferencias estadísticamente significativas entre los grupos (p = 0,527). Todos los tapones apicales mostraron una buena adaptación bajo SEM, a 30x, 200x, 1000x y 2500x; con morfologías similares a las previamente reportadas. Conclusiones: ambas biocerámicas se comportan de forma similar cuando se usan como barreras apicales para evitar la permeabilidad de gas, con adaptación marginal aceptable. Se necesitan más estudios in vivo para validar estos resultados.

A Clinical Investigation of a Dual Zinc plus Arginine Dentifrice in Reducing Established Dental Plaque and Gingivitis Over a Six-Month Period of Product Use.

OBJECTIVES: The objective of this single-center, double-blind, parallel-group, randomized six-month clinical study was to evaluate the clinical efficacy of a new Dual Zinc plus Arginine dentifrice (Colgate-Palmolive Co., New York, NY, USA) containing zinc (zinc oxide, zinc citrate) 0.96%, 1.5% Arginine, and 1450 ppm fluoride as sodium fluoride in a silica base in reducing established dental plaque and gingivitis over a six-month period, relative to that of a regular fluoride dentifrice containing 1450 ppm fluoride as sodium fluoride in a silica base (Colgate- Palmolive Co., New York, NY, USA). METHODS: A total of 100 adult male and female subjects from Santo Domingo, Dominican Republic were enrolled in this clinical study. During the baseline visit, the dental examiner clinically measured three gingival parameters (gingival index, gingival severity index, gingival interproximal index) and three plaque parameters (plaque index, plaque severity index, plaque interproximal index). The examining clinician also performed an assessment of the oral soft and hard tissues. All subjects were then assigned a subject identification number in chronological order from 001 to 100 and were randomly assigned to one of two treatment groups following a computer-generated randomization list. They were provided with their assigned dentifrice and an adult, soft-bristled toothbrush for home use, and were instructed to brush twice daily (morning and evening) for one minute with the assigned dentifrice for a period of six months. Subjects returned to the study facility site for their follow-up evaluation of plaque and gingivitis parameters after three and six months. RESULTS: Ninety-six (96) subjects completed the study. At the three-month evaluation, subjects in the Dual Zinc plus Arginine dentifrice group exhibited statistically significant (p < 0.001) reductions in all gingival and plaque parameters relative to subjects in the fluoride dentifrice group. For gingival parameters, reductions were 18.8% for gingival index, 33.3% for gingival severity index, and 19.1% for gingival interproximal index. For plaque parameters, reductions were 11.0% for plaque index, 22.4% for plaque severity index, and 9.8% for plaque interproximal index. At the six-month evaluation, subjects in the Dual Zinc plus Arginine dentifrice group presented continuous statistically significant (p < 0.001) reductions in all three gingival and plaque parameters when compared to the subjects in the fluoride dentifrice group. For gingival parameters, reductions were 26.3% for gingival index, 56.6% for gingival severity index, and 29.2% for gingival interproximal index. For plaque parameters, reductions were 30.1% for plaque index, 61.9% for plaque severity index, and 28.0% for plaque interproximal index after six months of product use. CONCLUSIONS: The overall results of this double-blind clinical study support the conclusion that a Dual Zinc plus Arginine dentifrice containing zinc (zinc oxide, zinc citrate) 0.96%, 1.5% Arginine, and 1450 ppm fluoride as sodium fluoride in a silica base provides significantly greater reduction in dental plaque and gingivitis parameters as compared to a regular fluoride dentifrice containing 1450 ppm fluoride as sodium fluoride in a silica base after three months and six months of product use.

Efecto del tratamiento de superficie en la fuerza de adhesión de postes de resina reforzados con fibras de cuarzo a los cementos de resina: Estudio in vitro

14. El propósito de este estudio fue determinar el efecto que ejercen distintos tratmientos de superficie en la fuerza de adhesión entre el cemento de resina y los postes de resina reforzados con fibras de cuarzo. Materiales y métodos: Sesenta postes de fibra de cuarzo (DT Light-Post™, Bisco™) se asignaron aleatoriamente a 12 grupos experimentales (n=5), según el cemento de resina utilizado (Biscem™ o Duolink™) y el tipo de tratamiento de superficie: limpieza con alcohol (grupo control), silanizado, primer, arenado, arenado+silanizado o arenado+primer. Se obtuvieron especímenes cilíndricos de resina utilizando resina nanohíbrida. Los postes se cementaron a los discos de resina y se sometieron a pruebas de push-out. Los datos se analizaron con ANOVA y prueba T para comparación de promedios y la prueba Tukey HSD con un nivel de significancia del 95%. Resultados: El cemento Biscem™ presentó, en general, una mayor fuerza de adhesión a los postes al compararse con el Duolink™. Se encontró diferencia significativa entre en grupo control y los grupos de arenado+silano y arenado+primer al utilizar el cemento Duolink™. Con el cemento Biscem™ no hubo diferencias entre grupos o con el grupo control. Conclusión: Los tratamientos de superficie en los postes de resina reforzados con fibra de cuarzo parecen no tener un efecto significativo en la fuerza de adhesión a los cementos de resina evaluados en este estudio, excepto al utilizar el cemento Duolink™ realizando el arenado y además se utilizando el silano o el primer.

18. The purpose of this study was to determine the effect of different surface treatments on the bond strength between resin cements and quartz fiber-reinforced resin posts. Materials and methods: Sixty quartz fiber-reinforced resin posts (DT Light-Post™, Bisco™) were randomly divided into 12 experimental groups (n=5), according to the resin cement used (Biscem™ or Duolink™) and the surface treatment: Alcohol (control group), silanized, primer, sandblasted, sandblasted + silanized or sandblasted + primer. Cylindrical resin specimens were obtained using nanohybrid resin. The posts were cemented to the resin discs and push-out tests were conducted. Data were analyzed with ANOVA and T test for averages comparison and the Tukey HSD test with a 95% level of significance. Results: Biscem™ cement generally showed higher bond strength when compared to Duolink™ Significant differences were found between the control group and the sandblasted + silane and sandblasted + primer groups when using Duolink™cement. With Biscem™ cement, no differences between groups or with the control group were found.. Conclusion: Surface treatments on quartz fiber-reinforced resin poles seem to have no significant effect on the bond strength to resin cements, except when using Duolink™ cement with sandblasted posts and using silane or primer.

Sensitivity, Specificity, Predictive Values, and Accuracy of Three Diagnostic Tests to Predict Inferior Alveolar Nerve Blockade Failure in Symptomatic Irreversible Pulpitis.

INTRODUCTION: The inferior alveolar nerve block (IANB) is the most common anesthetic technique used on mandibular teeth during root canal treatment. Its success in the presence of preoperative inflammation is still controversial. The aim of this study was to evaluate the sensitivity, specificity, predictive values, and accuracy of three diagnostic tests used to predict IANB failure in symptomatic irreversible pulpitis (SIP). METHODOLOGY: A cross-sectional study was carried out on the mandibular molars of 53 patients with SIP. All patients received a single cartridge of mepivacaine 2% with 1 : 100000 epinephrine using the IANB technique. Three diagnostic clinical tests were performed to detect anesthetic failure. Anesthetic failure was defined as a positive painful response to any of the three tests. Sensitivity, specificity, predictive values, accuracy, and ROC curves were calculated and compared and significant differences were analyzed. RESULTS: IANB failure was determined in 71.7% of the patients. The sensitivity scores for the three tests (lip numbness, the cold stimuli test, and responsiveness during endodontic access) were 0.03, 0.35, and 0.55, respectively, and the specificity score was determined as 1 for all of the tests. Clinically, none of the evaluated tests demonstrated a high enough accuracy (0.30, 0.53, and 0.68 for lip numbness, the cold stimuli test, and responsiveness during endodontic access, resp.). A comparison of the areas under the curve in the ROC analyses showed statistically significant differences between the three tests (p < 0.05). CONCLUSION: None of the analyzed tests demonstrated a high enough accuracy to be considered a reliable diagnostic tool for the prediction of anesthetic failure.