Ultrastructural Alterations and Physical Changes on Bovine Dentin After Internal Bleaching with 35 % Hydrogen Peroxide / Alteraciones Ultraestructurales y Cambios Físicos en la Dentina Bovina Después del Blanqueamiento Interior con un 35 % de Peróxido de Hidrógeno

ABSTRACT: The aim of the study was to investigate the effect of internal bleaching on physical proprieties and ultrastructure of the bovine dentin.40 bovine incisors were used, divided in four experimental groups: control group, composed by teeth that did not receive the bleaching agent (G1); teeth submitted to a single internal bleaching session (G2); teeth submitted to two internal bleaching sessions (G3); teeth submitted to three internal bleaching sessions (G4). In each of the sessions, 35 % hydrogen peroxide was applied for 45 minutes on the dentin surface. Tests were performed (microhardness and roughness) and were analyzed using one-way analysis of variance (ANOVA) and Tukey's post-hoc test (p≤0.05). Electromicrographs were captured for quality analysis. In the analysis of the superficial microhardness of the dentin, the internal bleaching reduced the Knoop microhardness since the first session, being observed statistically significant differences between the experimental groups and the control. The surface roughness gradually increased in the G2, G3 and G4 groups, but only G4 presented a statistically significant difference from the others. The qualitatively evaluated electromicrographs showed damage to the dentin ultrastructure, with areas of erosion and greater involvement of the intertubular when compared to peritubular dentin. Internal bleaching with 35 % hydrogen peroxide caused injuries in bovine dentin from the first treatment session. Both modifications in physical properties and dentin ultrastructure have been identified. These changes were intensified the higher the number of dentin internal bleaching sessions was exposed.

RESUMEN: El objetivo de este estudio fue investigar el efecto del blanqueamiento interno sobre las propiedades físicas y la ultraestructura de la dentina bovina. Se utilizaron 40 incisivos bovinos, divididos en cuatro grupos experimentales: grupo de control, compuesto por dientes que no recibieron el agente blanqueador (G1); dientes sometidos a una única sesión interna de blanqueamiento (G2); dientes sometidos a dos sesiones internas de blanqueamiento (G3); dientes sometidos a tres sesiones internas de blanqueamiento (G4). En cada una de las sesiones, se aplicó peróxido de hidrógeno al 35 % durante 45 minutos en la superficie de la dentina. Se realizaron pruebas (microdureza y rugosidad). Los datos se analizaron mediante análisis de varianza de una vía (ANOVA) y prueba post-hoc de Tukey (p≤0,05). Las electromicrografías fueron capturadas para el análisis cualitativo. En el análisis de la microdureza superficial de la dentina, el blanqueamiento interno redujo la microdureza de Knoop desde la primera sesión, observándose diferencias estadísticamente significativas entre los grupos experimentales y el control [NF2]. La rugosidad superficial aumentó gradualmente en los grupos G2, G3 y G4, pero solo G4 presentó una diferencia estadísticamente significativa con respecto a los otros [NF3]. Las electromicrografías evaluadas cualitativamente mostraron daño a la ultraestructura de la dentina, con áreas de erosión y una mayor participación de la dentina intertubular en comparación con la dentina peritubular. El blanqueamiento interno con peróxido de hidrógeno al 35 % causó lesiones en la dentina bovina en la primera sesión del tratamiento. Ambas modificaciones, en propiedades físicas y en la ultraestructura dentinaria, han sido identificadas. Estos cambios se intensificaron a medida que se expuso a mayor número de sesiones de blanqueamiento interno en la dentina.

Dental enamel bleached for a prolonged and excessive time: Morphological changes.

This work aimed to evaluate the roughness, microhardness, ultrastructure, chemical composition and crystalline structure in submitted teeth to a prolonged home bleaching regimen with 10% carbamide peroxide (10% PC) for different periods. The specimens were divided into the following groups: G1: negative control (application of water-soluble gel); G2: tooth whitening group (positive control), under application time recommended by the manufacturer (4h/14 days); G3: prolonged whitening 50%, under prolonged time recommended by the manufacturer in 50% (4h/21 days); G4: excessive whitening 100%, under exceeded manufacturer recommended time by 100% (4h/ 28 days). The results were evaluated descriptively and analytically. There were no changes in the roughness in any of the evaluated groups. However, the microhardness decreased in the G4 group. Scanning electron microscopy showed changes in the enamel surface of groups G2, G3 and G4. Dispersive X-ray spectroscopy identified changes in the concentration of chemical elements O, Mg, P, K in all groups. Thus, this study showed that prolonged home bleaching could cause changes in the ultrastructure, chemical composition and microhardness of the enamel.

Epithelial rests of Malassez: from latent cells to active participation in orthodontic movement.

INTRODUCTION:: The epithelial rests of Malassez (ERM) represent a group of cells in the periodontal ligament classically consisting of latent or quiescent structures associated with pathological processes. However, recent evidence shows that these structures cannot be considered only as cellular debris. The ERM is a major tissue structure, with functions in maintaining the homeostasis of periodontal tissue, including the maintenance of orthodontic movement. OBJECTIVE:: The present literature review aims at presenting the potential functions of ERM, with emphasis on orthodontic movement and the functional structure of the periodontium. CONCLUSION:: ERM cells have a functional activity in modulation of orthodontic movement, trough their potential for differentiation, maintenance functions and the capacity of repairing periodontium.

Epithelial rests of Malassez: from latent cells to active participation in orthodontic movement

ABSTRACT Introduction: The epithelial rests of Malassez (ERM) represent a group of cells in the periodontal ligament classically consisting of latent or quiescent structures associated with pathological processes. However, recent evidence shows that these structures cannot be considered only as cellular debris. The ERM is a major tissue structure, with functions in maintaining the homeostasis of periodontal tissue, including the maintenance of orthodontic movement. Objective: The present literature review aims at presenting the potential functions of ERM, with emphasis on orthodontic movement and the functional structure of the periodontium. Conclusion: ERM cells have a functional activity in modulation of orthodontic movement, trough their potential for differentiation, maintenance functions and the capacity of repairing periodontium.

RESUMO Introdução: os remanescentes epiteliais de Malassez (REM) se configuram como um grupo de células epiteliais presentes no ligamento periodontal, classicamente consideradas estruturas latentes ou quiescentes, associadas a processos patológicos. Entretanto, ao longo dos anos, esse paradigma vem sendo rompido e hoje não mais são consideradas apenas como restos celulares, mas sim uma importante estrutura tecidual, com funções na manutenção da homeostase do periodonto, inclusive durante a movimentação ortodôntica. Objetivo: na presente revisão da literatura, buscou-se apresentar as funções dessas estruturas, com ênfase nelas durante a movimentação ortodôntica, rompendo o conceito errôneo de que são meros restos celulares, e defendendo sua compreensão como uma estrutura funcional do periodonto. Conclusão: os REM possuem uma atividade funcional na modulação da movimentação ortodôntica, por meio de seu potencial para diferenciação, de suas funções de manutenção e de sua capacidade de reparação periodontal.

Root and canal morphology of permanent mandibular incisors / Morfología de raíz y ranal de incisivos molares permanentes

There are no studies in the literature reporting the prevalence of root canal ramifications in samples of lower incisors in the population of northern Brazil. The knowledge of the usual endodontic morphology and its possible anatomical variations is important. The aim of this study was to evaluate the prevalence of canals in the lower incisors in the population of northern Brazil using the descaling and diaphanization method. In addition, external measurements were performed and the direction of the apical foramen was observed. One hundred teeth were used for this study, and 18 % of them had two canals, with type 3 being the most prevalent, and the lowest incidence was type 5. The average length of the teeth was 18.5 mm, with 76.31 % of the teeth having a foramen that coincided with the long axis of the tooth. Prior knowledge of such changes should be considered before endodontic therapy.

No hay estudios en la literatura que reporten la prevalencia de las ramificaciones del canal radicular en muestras de incisivos inferiores en la población del Norte de Brasil. El conocimiento de la morfología dentaria en endodoncia y sus posibles variaciones anatómicas es importante. El objetivo del estudio fue evaluar la prevalencia de canales en los incisivos inferiores en la población del Norte de Brasil utilizando el método de descalcificación y diafanización. Además, se realizaron mediciones externas y se observó la dirección del foramen apical. Cien dientes fueron utilizados en este estudio, 18 % tenían dos canales, siendo el tipo 3 el más prevalente, y solo un diente presentó el tipo 5. La longitud promedio de los dientes fue de 18,5 mm, de los cuales en el 76,31 % de éstos se observó un foramen que coincidió con el eje longitudinal del diente. El conocimiento previo de éstas variaciones debe ser considerado antes de la terapia endodóntica.

Knowledge and attitudes of pregnant women about oral health / Conocimientos y actitudes de las mujeres embarazadas sobre la salud oral

There are evidences that maternal profile, habits and health knowledge, influence in the oral health of children. The aim of this study was to assess pregnant women knowledge on oral hygiene practices and maintenance of Baby´s oral cavity. A descriptive epidemiological survey was conducted with 147 pregnant women. Sample was predominantly formed by young women and 33.33 % had incomplete primary education and most were housewives with family income between 1-2 minimum wages. Family was considered the primary means in the transfer of information about oral hygiene.

Hay evidencia de que los perfiles, hábitos y conocimientos de la salud influyen en la salud oral de los niños. El objetivo de este estudio fue evaluar el conocimiento de las mujeres embarazadas en las prácticas de higiene oral y el cuidado de la cavidad oral del bebé. Una encuesta epidemiológica se llevó a cabo en 147 mujeres embarazadas. La muestra estuvo compuesta predominantemente por mujeres jóvenes, de las cuales el 33,33 % no había completado la escuela primaria y la mayoría eran amas de casa con ingresos familiares entre 1-2 salarios mínimos. La familia fue considerado el principal medio de transmisión de información sobre la higiene oral.

Effectiveness of NaviTip FX on intracanal calcium hydroxide removal / Efectividad de NaviTip FX para la remoción intracanal de hidróxido de cálcio

Remnants of calcium hydroxide (Ca(OH)2) post-irrigation can compromise cleansing and permeability of dentinal walls in endodontic therapy. The aim of this study was to evaluate effectiveness of irrigation needle NaviTip FX on intracanal Calcium Hydroxide removal. Twenty-two single-rooted human teeth were randomly assigned according to irrigation needle used after calcium hydroxide removal: G1- NaviTip; G2- NaviTip FX, both with n= 9; as well as negative and positive control groups, with n= 2. The samples were analyzed in scanning electron microscopy, with 500x magnification. The difference between groups were analysed by Student t test, for p 0.01. In apical third, G2 group presents better cleaning in comparison with G1 (p= 0.0007). In middle third, no differences between groups were observed. NaviTip FX irrigation needle shows greater effectiveness in removing calcium hydroxide medication than NaviTip needle in the apical third of the canal.

La presencia de hidróxido de calcio post-irrigación compromete la limpieza y la permeabilidad de la pared de la dentina durante el tratamiento endodóntico. El objetivo deste estudio fue evaluar la eficacia de la cánula de irrigación Navitip Fx en la eliminación de hidróxido de cálcio intracanalicular. Veintidós dientes unirradiculares humanos fueron divididos aleatoriamente de acuerdo con la cánula de irrigación, después de la eliminación del hidróxido de calcio, en grupos: G1- Navitip; G2- Navitip FX, ambos con n= 9; así como los grupos de control positivos y negativos, con n= 2. Las muestras fueron analizadas bajo microscopía electrónica de barrido, con magnificación de 500x. La diferencia entre los grupos fue analizada con la prueba t de Student (p 0,01). En el tercio apical, el grupo G2 presentó mejor limpieza en comparación con el grupo G1 (p= 0,0007). En el tercio medio, no se observaron diferencias entre los grupos. La cánula de irrigación Navitip FX muestra una mayor eficiencia en la eliminación de la medicación hidróxido de calcio en comparación con Navitip cánula en el tercio apical del canal.

Influence of tooth bleaching on the bonding strength of silorane-based restorative system / Influencia del aclaramiento dental en la fuerza de adhesion del sistema restaurativo a base de silorano

Bleaching procedures can interfere on adhesive bonding of methacrylate-based restorative materials. After introduction of silorane-based composites, little information is available about this interaction. The objective is evaluate the influence of bleaching on enamel shear bond strength of silorane-based restorative system. Forty sound incisive bovine teeth were randomly divided into 04 groups (n= 10), being: G1 (control) ­ not bleached + Clearfil SE Bond (CSEB)/Filtek Z250 (Z250), G2 (control) not bleached + Silorane Adhesive (SA)/Filtek P90 (P90), G3 ­ bleached + CSEB/Z250; G4 ­ bleached + SA/P90. The teeth were sectioned, had crowns included in a PVC rings, and the enamel surfaces gridded and polished with silicon carbide abrasive papers. G1 and G2 were stored in artificial saliva (37 C), daily renewed, for a period of 04 days. G3 and G4 were exposed to 02 sessions of 38% hydrogen peroxide (38HP), with 03 applications of 15 min in each session. Composite resin cylinders were built up on the enamel surfaces. Bonding procedures were performed according the manufacturer's instructions. After storage in distilled water for 24 h (37 C), the samples were submitted to shear bond test. Data were analyzed by two-way ANOVA and t (LSD) tests (5%). Intra group comparison showed significant difference for Z250 after bleaching, but not for P90. Shear strength was significant lower for P90, despite bleaching procedures. In conclusion, 38HP bleaching had no influence on the enamel bond strength of P90, even though presenting lower bond strength than Z250.

Los procedimientos de blanqueamiento dental pueden interferir en la unión adhesiva de los materiales de restauración a base de metacrilato. Después de la introducción de materiales compuestos a base de silorano, hay poca información disponible acerca de esta interacción. El objetivo fue evaluar la influencia del blanqueamiento en la cizalladura de la fuerza de adhesion sobre esmalte del sistema restaurativo a base de silorano. Cuarenta dientes incisivos bovinos fueron divididos aleatoriamente en 4 grupos (n= 10), siendo: G1 (control) - no aclarado + Clearfil SE Bond (CSEB)/Filtek Z250 (z250), G2 (control) - no aclarado + adhesivo de silorane (AS)/Filtek P90 (P90), G3 - aclarado + CSEB / Z250; g4 - aclarado + AS/P90. Los dientes fueron seccionados, tenían coronas incluidas en anillos de pvc, y las superficies de esmalte fueron molidas y pulidas con papeles abrasivos de silicona de silicio. G1 y G2 fueron almacenados en saliva artificial (37 °C), renovada diariamente, durante un período de 04 días. G3 y G4 se expusieron a 2 sesiones de peróxido de hidrógeno al 38% (38 HP) con 03 aplicaciones de 15 min en cada sesión. Los cilindros de resina compuesta fueron construidos en las superficies de esmalte. Los procedimientos de unión se realizaron según las instrucciones del fabricante. Después del almacenamiento en agua destilada durante 24 h (37 °C), las muestras fueron sometidas al ensayo de resistencia de adhesión al cizallamiento. Los datos fueron analizados por ANOVA de dos vías y prueba t (5%). La comparación intragrupo mostró diferencias significativas para Z250 después del aclaramiento, pero no para P90. La resistencia al corte fue significativamente menor para P90, a pesar de los procedimientos de blanqueamiento. En conclusión, el blanqueamiento con 38HP no tuvo influencia en la resistencia de la unión esmalte de P90, a pesar de presentar una fuerza de unión más baja que Z250.

Morphological aspects and physical properties of enamel and dentine of Sus domesticus: A tooth model in laboratory research.

This study aims to describe and analyze morphological and physical properties of deciduous teeth of Sus domesticus. Ultrastructural analysis, mineral composition and microhardness of enamel and dentine tissues were performed on 10 skulls of S. domesticus. External anatomic characteristics and the internal anatomy of the teeth were also described. Data regarding microhardness and ultrastructural analysis were subjected to statistical tests. For ultrastructural analysis, we used the analysis of variance (ANOVA) with Tukey's post hoc (p≤0.05) test. In the analysis of microhardness, the difference between the enamel and dentine tissues was analyzed by a Student's t test. Values were expressed as mean with standard error. The results of ultrastructural analysis showed the presence of an enamel prism pattern. A dentinal tubule pattern was also observed, with a larger diameter in the pulp chamber and the cervical third, in comparison to middle and apical thirds. We observed an average microhardness of 259.2kgf/mm(2) for enamel and 55.17kgf/mm(2) for dentine. In porcine enamel and dentine, the chemical elements Ca and P showed the highest concentration. The analysis of internal anatomy revealed the presence of a simple root canal system and the occurrence of main canals in the roots. The observed features are compatible with the functional demand of these animals, following a pattern very similar to that seen in other groups of mammals, which can encourage the development of research using dental elements from the pig as a substitute for human teeth in laboratory research.

Genetic Autosomal Dominant Disorders: A Knowledge Review / Trastornos Autosómicos Dominantes: Una Revisión de los Conocimientos

Genetic disorders occur by excess or absence of chromosomal material, and the consequence of these changes is reflected in morphological and physiological changes. Autosomal disorders, which have dominant inheritance, as cleidocranial dysostosis, Craniofacial syndrome Apert, Treacher Collins and Achondroplasia have peculiar and similar characteristics. Because of their implications in the dental field, the aim of this review is to report on dysostoses, through exposure of general clinical factors and highlighting the signs in the oral cavity. Articles were selected from Lilacs, PubMed and Bireme databases, included in the year 2007­2014, and the keywords were: cleidocranial dysplasia, craniofacial dysostosis, mandibulofacial dysostosis, dysostosis and oral. Alterations of maxillofacial bones and craniofacial are well documented in the literature, but studies reporting an association between treatment odontologic and dysostoses are scarce. In conclusion, Oral pathological manifestations developed cause difficulty in speech, chewing, breathing, social involvement, and in a general perspective, psychological impairment and physical limitations.

Las enfermedades genéticas se producen debido a un exceso o ausencia de material cromosómico, y la consecuencia de estos cambios se refleja en los cambios morfológicos y fisiológicos. Trastornos autosómicos dominantes que tienen herencia dominante, como la disostosis cleidocraneal, el síndrome craneofacial de Apert, Treacher Collins y acondroplasia tiene características peculiares y similares. Debido a sus implicaciones en el campo de la odontología, el objetivo de esta revisión es hablar, a través de la exposición de los factores clínicos y generales, destacando los signos en la cavidad oral. Se seleccionaron los artículos de las bases de datos Lilacs, PubMed y BIREME, incluyendo los años 2007-2014, y las palabras clave fueron: displasia cleidocraneal, craneofacial mandibulofacial disostosis, disostosis y oral. Los cambios de huesos maxilofaciales y craneofaciales están bien documentados en la literatura, pero los estudios que informaron una asociación entre el tratamiento dental y disostosis son escasos. En conclusion, las manifestaciones orales son causas de dificultades del habla, masticación, respiración y la participación social.