Microtensile bond strength of resin cements to 3-D printed and milled temporary restorative resins / Resistencia de unión en microtracción de cementos resinosos a resinas para provisionales impresas y fresadas

Abstract To evaluate the microtensile bond strength (µTBS) of two resin cements to 3D printed and milled CAD/CAM resins used for provisional fixed partial dentures. Blocks (5 x 5 x 5 mm) of three 3D-printed resins (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) were printed (Photon, Anycubic Technology Co.). A milled material (VitaCAD-Temp, VITA) was used as control. Half the specimens were sandblasted and the rest were untreated. Two blocks were bonded with the corresponding resin cement: PanaviaV5 (Kuraray Noritake) and RelyX Ultimate (3M Oral Care). After 24 hours, the bonded blocks were sectioned into 1 x 1 mm side sticks. Half the beams were tested for µTBS and the other half was thermocycled (5000 cycles, 30s dwell-time, 5s transfer time) before µTBS testing. A four way Generalized Linear Model (material*sandblasting*cement*aging) analysis was applied. VITA exhibited the lowest µTBS, regardless of the cement, sandblasting and thermocycling. Sandblasting significantly improved the µTBS of VIT, especially after aging, but did not improve the µTBS of 3D printed resins. Sandblasting was not beneficial for 3D printed resins, although is crucial for adhesive cementation of milled temporary resins. Airborne particle abrasion affects the integrity of 3D-printed resins, without producing a benefit on the microtensile bond strength of these materials. However, sandblasting is crucial to achieve a high bond strength on milled temporary resins.

Resumen Evaluar la resistencia adhesiva en microtracción (µTBS) de dos cementos resinosos a resinas CAD/CAM impresas y fresadas indicadas para restauraciones provisionales. Bloques (5 x 5 x 5mm) de tres resinas impresas (Cosmos3DTemp / Yller; Resilab3D Temp / Wilcos and SmartPrint BioTemp, / MMTech) y una resina fresada (VitaCAD-Temp, VITA) fueron fabricados. La mitad de los especímenes fueron arenados y el resto no recibió tratamiento mecánico. Dos bloques con condiciones de tratamiento iguales fueron cementados con cemento resinoso (PanaviaV5 / Kuraray Noritake y RelyX Ultimate / 3M Oral Care). Después de 24 horas los bloques fueron seccionados en palitos de 1 mm² de área. En la mitad de los especímenes se midió la TBS inmediatamente y el resto fue termociclado (5000 ciclos, 30s remojo, 5s transferencia) antes de la prueba de TBS. Se aplica un análisis estadístico por Modelo Linear General con 4 factores (material*arenado*cemento*termociclado). La resina VITA presentó la menor µTBS, independientemente del cemento usado, el arenado y el termociclado. Sin embargo, el arenado aumentó la µTBS de VIT, especialmente después del termociclado. Por otro lado, el arenado no resultó en un aumento significativo de la µTBS de las resinas impresas. El arenado no fue beneficiosos para las resinas impresas, aunque es un paso crucial para la cementación adhesive de las resinas fresadas. El arenado afecta la integridad de las capas de las resinas impresas, sin generar un beneficio en la TBS.

Limitaciones Técnicas del Método de Conteo de Anulaciones del Cemento para Estimación de Edad. Hallazgos a Partir de Una Revisión con Búsqueda Sistemática / Technical Limitations of Cementum Annulation Count Method for age Estimation. Findings From A Scoping Review

En la última década, la odontología forense se ha enfocado en el desarrollo de metodologías para la estimación de edad (EE) debido a la gran demanda en procesos identificatorios. Entre esas técnicas, el conteo de anulaciones del cemento dental (TCA) ha ofrecido resultados promisorios, pero también contradictorios que han generado dudas sobre su precisión y confiabilidad. El objetivo de este trabajo fue caracterizar, establecer alcances, e identificar las limitaciones del conteo de TCA según los actuales estándares normativos y metodológicos. Se realizó una revisión con búsqueda sistemática del método de conteo de TCA para EE incluyendo estudios experimentales y notas técnicas en las bases PubMed/Medline, Scopus, Web of Science (WoS) y Embase. Se emplearon los términos "estimation", "age" y "cementum", con búsqueda manual complementaria en Google Scholar. Se excluyeron revisiones, estudios en colecciones arqueológicas, estudios radiológicos y cartas al editor. La búsqueda arrojó un total de 273 artículos, seleccionándose 27 que cumplieron con los criterios de inclusión. La mayoría de los estudios fueron publicados en Asia, particularmente en India (n=21). Sólo 6 artículos declararon el número total de individuos, tipos de diente y de cortes histológicos, siendo el premolar el más estudiado. Apenas dos artículos evaluaron la calidad de la muestra a analizar mediante legibilidad de los cortes obtenidos. El test más empleado para evaluar la precisión del método fue el coeficiente de correlación de Pearson (n=21). Estos hallazgos exponen la alta heterogeneidad reportada en las metodologías de EE mediante conteo por TCA, por lo que aún no existe un proceso estandarizado que abarque todas sus etapas y entregue resultados confiables siguiendo los estándares jurídicos actuales para la evidencia científica. Un mayor control de las limitaciones técnicas detectadas aumentará el valor como prueba en un contexto identificatorio legal o forense.

SUMMARY: In the last decade, forensic odontology has focused on the development of age estimation (AE) methodologies due to the great request in identification processes. Among these techniques, the tooth cementum annulation (TCA) count method has offered promising but also contradictory results, raising questions about its accuracy and reliability. The aim of this work was to characterize, establish the scope, and identify the limitations of the TCA count method according to the current normative and methodological standards. A scoping review was carried out for TCA count methods for AE, including experimental studies and technical notes in the PubMed/Medline, Scopus, Web of Science (WoS) and Embase databases. The terms "estimation", "age" and "cementum" were used, with a complementary manual search in Google Scholar. Reviews, studies in archaeological collections, radiological studies and letters to the editor were excluded. The search yielded a total of 273 articles, selecting 27 of them that met the inclusion criteria. Most of the studies were published in Asia, particularly India (n=21). Only 6 articles declared the total number of individuals, types of teeth, and histological sections, with the premolar being the most studied. Only two articles evaluated the quality of the sample to be analyzed through the legibility of the cuts obtained. The most widely used test to assess the precision of the method was the Pearson correlation coefficient (n=21). These findings expose the high heterogeneity reported in EE methodologies by counting TCA, so there is still no standardized process that covers in all its stages and delivers reliable results following current legal standards for scientific evidence. More control of the detected technical limitations will increase the value as evidence in a legal or forensic identification context.

Influence of different surface treatments on bond strength of a Self-Adhesive resin cement to CAD-CAM materials / Influencia de los diferentes tratamientos superficiales en la unión del cemento resinoso autoadhesivo a los materiales CAD-CAM

To evaluate the shear bond strength (SBS) of self-adhesive resin cement when used with two different computer-aided design (CAD)-computer-aided manufacturing (CAM) materials after various surface treatments. Nanoceramic resin Lava Ultimate (LU) and feldspathic ceramic Vita Mark II (VM) CAD-CAM block samples were prepared with 1.5-mm thickness, and a total of 90 samples were obtained (N=90), with five samples of each block. The samples were divided into the following five groups according to the surface treatments (n=9): group 1, untreated (control); group 2,5% hydrofluoric acid etching; group 3, Er: YAG laser irradiation; group 4, tribochemical silica coating (Cojet); and group 5, air-abrasion with Al2O3. After silane application, resin cement was applied on a transparent matrix (diameter, 3mm; height, 2mm) on the blocks. SBS was determined using a universal testing device at a crosshead speed of 1mm/min. Two-way analysis of variance (ANOVA) and Tukey's post hoc tests were used to analyze the SBS values. LU showed the highest SBS value in group 4. The average SBS values in groups 3 and were found to be lower than that in the control group (p<0.05). When VM was examined, while all surface treatments increased the SBS values significantly, the highest SBS value was observed in group 4 (p<0.05). This study revealed that all surface treatments used negatively affected the bond strength values of self-adhesive resin cement to LU, except for Cojet application. The SBS values of resin cement with VM increased in all surface treatment application groups.

Evaluar la resistencia de unión al corte (SBS) del cemento de resina autoadhesivo cuando se utiliza con dos materiales diferentes de diseño asistido por computadora (CAD) y fabricación asistida por computadora (CAM) después de varios tratamientos superficiales. Se prepararon muestras de bloques CAD-CAM de resina Lava Ultimate (LU) y cerámica feldespática Vita Mark II (VM) con un espesor de 1,5mm, y se obtuvieron un total de 90 muestras (N=90), con cinco muestras de cada bloque. Las muestras se dividieron en los siguientes cinco grupos según los tratamientos superficiales (n=9): grupo 1, sin tratar (control); grupo 2, grabado con ácido fluorhídrico al 5%; grupo 3, irradiación con láser Er: YAG; grupo 4, recubrimiento triboquímico de sílice (Cojet); y grupo 5, aire-abrasión con Al2O3. Después de la aplicación de silano, se aplicó cemento de resina sobre una matriz transparente (diámetro, 3mm; altura, 2mm) sobre los bloques. La SBS se determinó usando un dispositivo de prueba universal a una velocidad de cruceta de 1mm/min. Se utilizaron análisis de varianza bidireccional (ANOVA) y pruebas post hoc de Tukey para analizar los valores de SBS. LU mostró el valor más alto de SBS en el grupo 4. Los valores promedio de SBS en los grupos 3 y fueron más bajos que en el grupo de control (p<0,05). Cuando se examinó VM, mientras que todos los tratamientos superficiales aumentaron significativamente los valores de SBS, el valor más alto de SBS se observó en el grupo 4 (p<0,05). Este estudio reveló que todos los tratamientos de superficie utilizados afectaron negativamente los valores de resistencia de la unión del cemento de resina autoadhesivo a LU, a excepción de la aplicación Cojet. Los valores de SBS del cemento de resina con VM aumentaron en todos los grupos de aplicación de tratamiento de superficie.

Resistencia de unión al cizallamiento de diferentes agentes de fijación a aleaciones metálicas odontológicas / Shear bond strength of different bonding agents to dental metal alloys

Introducción: La fijación de las restauraciones indirectas es uno de los pasos más importantes, para conseguir una adecuada retención y sellado de la interfase entre el material restaurador y el diente. Objetivo: Evaluar la resistencia de unión al cizallamiento de diferentes agentes de fijación a dos aleaciones metálicas utilizadas en odontología. Métodos: Estudio experimental in vitro. Cien especímenes de aleaciones de metales base, 50 de níquel-cromo y 50 de níquel-cromo-titanio fueron preparados y divididos de manera aleatoria en 5 grupos. Esta división se realizó acorde con el agente de fijación utilizado: sistema autograbante de dos pasos (Clearfil SE Bond; CSB), sistema adhesivo universal (Single Bond Universal; SBU), cemento resinoso autoadhesivo (Maxcem Elite; ME), ionómero de vidrio (IV) y fosfato de zinc (ZnPO). Posteriormente a la aplicación de cada agente de fijación, los especímenes tratados fueron almacenados en agua destilada por 24 h a 37 ºC y sometidos a un ensayo de resistencia de unión al cizallamiento. Resultados: La resistencia de unión al cizallamiento fue influenciada significativamente por el tipo de agente de fijación (p = 0,002) y el tipo de aleación utilizada (p < 0,001). La resistencia de unión al cizallamiento fue mayor, al utilizar el sistema Clearfil SE Bond, seguida de Single Bond Universal; las diferencias entre Maxcem Elite y el Fosfato de zinc no fueron significativas. Finalmente, el IV no mostró adhesión a ninguna de las aleaciones metálicas utilizadas. Conclusiones: El uso de Clearfil SE Bond aumentó la resistencia de unión de los cementos resinosos a las aleaciones metálicas(AU)

Introduction: The bonding of indirect restorations is one of the most important steps, in order to achieve adequate retention and sealing of the interface between the restorative material and the tooth. Objective: To evaluate the shear bond strength of different bonding agents to two metal alloys used in dentistry. Methods: In vitro experimental study. One hundred specimens of base metal alloys, 50 nickel-chromium and 50 nickel-chromium-titanium were prepared and randomly divided into 5 groups. This division was made according to the bonding agent used: two-step self-etching system (Clearfil SE Bond; CSB), universal adhesive system (Single Bond Universal; SBU), self-adhesive resin cement (Maxcem Elite; ME), glass ionomer (IV) and zinc phosphate (ZnPO). After the application of each bonding agent, the treated specimens were stored in distilled water for 24 hr at 37 ºC and subjected to a shear bond strength test. Results: Shear bond strength was significantly influenced by the type of bonding agent (p = 0.002) and the type of alloy used (p < 0.001). Shear bond strength was highest when using the Clearfil SE Bond system, followed by Single Bond Universal; the differences between Maxcem Elite and Zinc Phosphate were not significant. Finally, IV did not show adhesion to any of the metal alloys used. Conclusions: The use of Clearfil SE Bond increased the bond strength of resinous cements to metallic alloys(AU)

Effect of recombinant human fibroblast growth factor 21 on the mineralization of cementoblasts and its related mechanism / 华西口腔医学杂志

OBJECTIVES@#To investigate the effect of recombinant human fibroblast growth factor 21 (rhFGF21) on the proliferation and mineralization of cementoblasts and its mechanism.@*METHODS@#Hematoxylin eosin, immunohistochemical staining, and immunofluorescence were used to detect the expression and distribution of fibroblast growth factor 21 (FGF21) in rat periodontal tissues and cementoblasts (OCCM-30), separately. Cell Counting Kit-8 was used to detect the proliferation of OCCM-30 under treatment with rhFGF21. Alkaline phosphatase staining and Alizarin Red staining were used to detect the mineralization state of OCCM-30 after 3 and 7 days of mineralization induction. The transcription and protein expression of the osteogenic-related genes Runx2 and Osterix were detected by real-time quantitative polymerase chain reaction (PCR) and Western blot analysis. The expression levels of genes of transforming growth factor β (TGFβ)/bone morphogenetic protein (BMP) signaling pathway in OCCM-30 were detected through PCR array analysis.@*RESULTS@#FGF21 was expressed in rat periodontal tissues and OCCM-30. Although rhFGF21 had no significant effect on the proliferation of OCCM-30, treatment with 50 ng/mL rhFGF21 could promote the mineralization of OCCM-30 cells after 7 days of mineralization induction. The transcriptional levels of Runx2 and Osterix increased significantly at 3 days of mineralization induction and decreased at 5 days of mineralization induction. Western blot analysis showed that the protein expression levels of Runx2 and Osterix increased during mineralization induction. rhFGF21 up-regulated Bmpr1b protein expression in cells.@*CONCLUSIONS@#rhFGF21 can promote the mineralization ability of OCCM-30. This effect is related to the activation of the TGFβ/BMP signaling pathway.

How does radiotherapy affect the adhesion of universal adhesive to enamel and dentin? A qualitative and quantitative analysis? / Efecto de la radioterapia a la adhesión del adhesivo universal al esmalte y dentina? Un análisis cualitativo y cuantitativo?

Abstract This study investigated the shear bond strength (SBS) of a universal adhesive to enamel/dentin; 1) that had undergone radiotherapy (RT) and 2) that were readily restored and had undergone RT. Enamel and dentin surfaces were obtained from 90 intact human molars. They were randomly divided into six groups according to the presence and timing of irradiation (RT0:no radiotherapy/control, RT1:RT before restoration, RT2:RT after restoration groups) and adhesive application modes (etch&rinse/ER, self-etch/SE)(n=15). A universal adhesive and resin composites were applied. The radiotherapy protocol was conducted with 60 Gy. The SBS test was subjected (1mm/min) and failure type analysis was performed. The resin-enamel/dentin interfaces were examined. Data were statistically analyzed. For enamel and dentin, the presence and timing of irradiation did not significantly influence the SBS values (p>0.05). For enamel, significantly higher SBS values were obtained using etch&rinse mode than self-etch mode (p<0.05). The predominant failure was mixed type. Loss of enamel prisms and obliterated irregular dentinal tubules were found for the radiotherapy-treated specimens. Resin tags were clearer in the irradiated enamel treated with ER than SE. Irradiation with different timings did not influence the bond strength to enamel and dentin, negatively. Irrespective of radiotherapy, the etch&rinse mode caused higher bond strength to enamel than self-etch mode.

Resumen Este estudio investigó la fuerza de unión al cizallamiento (SBS) de un adhesivo universal al esmalte/dentina en piezas que se habían sometido a radioterapia (RT). Se obtuvieron superficies de esmalte y dentina de 90 molares humanos intactos. Se dividieron aleatoriamente en seis grupos según la presencia y el momento de la irradiación (RT0: sin radioterapia/control, RT1: RT antes de la restauración, RT2: RT después de la restauración considerando los modos de aplicación del adhesivo (n=15). Se aplicó un adhesivo universal y resinas compuestas. El protocolo de radioterapia se realizó con 60 Gy. Se sometió a la prueba adhesiva (1mm/min) y se realizó análisis del tipo de falla. Se examinaron las interfases resina-esmalte/dentina. Los datos fueron analizados estadísticamente. Para el esmalte y la dentina, la presencia y el momento de la irradiación no influyeron significativamente en los valores adhesivos (p>0,05). Para el esmalte, se obtuvieron valores adhesivos significativamente más altos utilizando el modo de grabado y enjuague que el modo de autograbado (p<0,05). La falla predominante fue de tipo mixto. Se encontró pérdida de prismas de esmalte y túbulos dentinarios irregulares obliterados en las muestras tratadas con radioterapia. La irradiación con diferentes tiempos no influyó negativamente en la fuerza de unión al esmalte ni a la dentina. Independientemente de la radioterapia, el modo de grabado ácido y enjuague provocó una mayor fuerza de adhesión al esmalte que el modo de autograbado.

Reparación de fractura aislada del mango del martillo con cemento ionomérico vidrioso autocurado / Repair of a malleus handle fracture using glass ionomer luting cement

Resumen La fractura aislada del mango del martillo es una entidad clínica poco habitual, pero frecuentemente subdiagnosticada. Lo fundamental es la sospecha clínica. El diagnóstico se confirma con la otoscopia neumática o la otomicroscopia con maniobra de Valsalva, en la cual se observa una movilidad anormal del mango del martillo. El rasgo de fractura se puede demostrar con tomografía computada de alta resolución o cone beam. Existen diferentes opciones de tratamiento como interposición de cartílago o uso de prótesis de reemplazo osicular así como cemento óseo. El cemento ionomérico vidrioso autocurado, muy utilizado en odontología, se ha usado en distintas cirugías otológicas con buenos resultados y biocompatibilidad. A nuestro saber no se ha usado en esta patología por lo que presentamos esta serie de tres casos en los cuales se ha usado esta novedosa técnica con buenos resultados clínicos.

Abstract Isolated fracture of the manubrium of the malleus is a rare clinical entity. Clinical suspicion is paramount. The usual clinical presentation is acute otalgia followed by tinnitus and fluctuating hearing loss after a brisk introduction and withdrawal of a finger into the external auditory canal. On physical examination, the eardrum looks normal on otoscopy. Only in pneumatic otoscopy or otomicroscopy with Valsalva an abnormal motility of the manubrium could bee seen. High-resolution computed tomography (CT) or cone beam CT is able to show the fracture line. Several treatment options have been proposed, such as interposition of bone or cartilage between the manubrium and the incus, total or partial ossicular replacement prosthesis; and the use of bone cement. Glass ionomer luting cement, with wide use in dentistry, has been used in several otological procedures with good biocompatibility and results, however, to our best knowledge, it has not been used to repair this type of fractures, so we present this novel material in three cases.

Synthesis, characterization, and evaluation of nano-hydroxyapatite based experimental calcium silicate cement as a root repair material / Síntesis, caracterización y evaluación de cemento experimental de silicato de calcio a base de nanohidroxiapatita como material de reparación radicular

Introduction: This study aimed to prepare a new root repair material including Portland cement, bismuth oxide, and nano-hydroxyapatite and analyze its physicochemical properties and its effects on the proliferation and differentiation of human dental pulp stem cells (hDPSCs). Material and Methods: Bismuth oxide as a radiopaque component and nano-hydroxyapatite particles were added to white Portland cement at 20% and 5% weight ratio, respectively. Characterization of the prepared cement was done using conventional methods. To examine the bioactivity of this new material, atomic absorption spectroscopy (AAS) was used for the investigation of the rate of calcium ions dissolution in simulated body fluid media. The viability of hDPSCs was assessed by an MTT assay after 1, 3 and 7 days. The odontogenic potential of this substance was evaluated by measuring alkaline phosphatase activity and alizarin red S staining. Results: Based on the bioactivity results, the cement presented high bio-activity, corroborating sufficiently with the calcium release patterns. The cell viability was significantly increased in new root repair material containing hydroxyapatite nanoparticles after 3 and 7 days (p<0.05). Conclusion: Moreover, alkaline phosphatase activity increased over 7 days in all experimental groups. The new cement containing nano-hydroxyapatite particles could be a good root repair material.

Objetivo: Este estudio tuvo como objetivo preparar un nuevo material de reparación de raíces que incluye cemento Portland, óxido de bismuto y nano-hidroxiapatita y analizar sus propiedades fisicoquímicas y sus efectos sobre la proliferación y diferenciación de células madre de pulpa dental humana. Material y Métodos: El óxido de bismuto como compo-nente radiopaco y las partículas de nano-hidroxiapatita se agregaron al cemento Portland blanco en una proporción en peso del 20 % y el 5 %, respectivamente. La caracterización del cemento preparado se realizó utilizando métodos con-vencionales. Para examinar la bioactividad de este nuevo material, se utilizó la espectroscopia de absorción atómica para investigar la velocidad de disolución de los iones de calcio en medio fluido corporal simulado. La viabilidad de las células madre de pulpa dental humana se evaluó mediante un ensayo MTT después de 1, 3 y 7 días. El potencial odontogénico de esta sustancia se evaluó midiendo la actividad de la fosfatasa alcalina y la tinción con rojo de alizarina S.Resultados: Con base en los resultados de bioactividad, el cemento presentó alta bioactividad, corroborando suficientemente con los patrones de liberación de calcio. La viabilidad celular aumentó significativamente en el nuevo material de reparación de raíces que contenía nanopartículas de hidroxiapatita después de 3 y 7 días (p<0,05). Conclusión: Además, la actividad de la fosfatasa alcalina aumentó durante 7 días en todos los grupos experimentales. El nuevo cemento que contiene partículas de nanohidroxiapatita podría ser un buen material de reparación radicular.

Cisto ósseo simples: relato de 7 casos / Simple bone cyst: report of 7 cases / Quiste óseo simple: reporte de 7 casos

Introdução: O cisto ósseo simples (COS) é definido como uma cavidade intraóssea de etiologia desconhecida, desprovida de revestimento epitelial e vazia ou preenchida com líquido. Na região facial, o COS é mais comumente observado no corpo da mandíbula. Objetivo: O objetivo deste artigo é relatar uma série de casos de COS, discutindo aspectos relevantes das características clínicas e terapêutica adequada. Relato de caso: A série de casos demonstrou que a presença de lesões radiolúcidas assintomáticas nos maxilares, nos quais os diagnósticos clínico, laboratorial e imaginológico não foram conclusivos, a realização de uma biópsia é sempre indicada. Considerações finais: Os casos de múltiplas lesões de COS, ou quando estão associadas a displasias cemento-ósseas, uma abordagem cirúrgica torna-se imperiosa... (AU)

Introduction: Simple bone cyst (COS) is defined as an intraosseous cavity of unknown etiology, devoid of epithelial lining and empty or filled with fluid. In the facial region, COS is most commonly seen in the body of the mandible. Objective: The aim of this article is to re port a series of COS cases, discussing relevant aspects of the clinical characteristics and adequate treatment. Case report: The case series demonstrated that the presence of asymptomatic radiolucent lesions in the jaws, in which clinical, laboratory and imaging diagnoses were not conclusive, a biopsy is always indicated. Final considerations: In cases of multiple COS lesions, or when they are associated with cemento-osseous dysplasias, a surgical approach is imperative... (AU)

Introducción: El quiste óseo simple (COS) se define como una cavidad intraósea de etiología desconocida, desprovista de revestimiento epitelial y vacía o llena de líquido. En la región facial, la COS se observa con mayor frecuencia en el cuerpo de la mandíbula. Objetivo: El objetivo de este artículo es reportar una serie de casos de COS, discutiendo aspectos relevantes de las características clínicas y el tratamiento adecuado. Caso clínico: La serie de casos demostró que ante la presencia de lesiones radiotransparentes asintomáticas en los maxilares, en las que los diagnósticos clínicos, de laboratorio y de imagen no fueron concluyentes, siempre está indicada una biopsia. Consideraciones finales: En casos de múltiples lesiones de COS, o cuando se asocian a displasias cemento-óseas, es imprescindible un abordaje quirúrgico... (AU)

Uso de dientes bovinos como elección para trabajos de investigación en odontología / The use of bovine teeth as a choice for dental investigation papers

Los dientes animales de las diferentes especies (hu- mano, equino, cerdo, etc.) están constituidos histológi- camente por cuatro tejidos fundamentales. Ellos son: esmalte, dentina, cemento y pulpa dental. Su compo- sición, estructura, morfología y tamaño son disímiles para cada género. Según numerosas investigaciones, los dientes de bovino serían los de elección por ser de fácil obtención y por tener muy pocas, o ninguna, diferencias tanto a nivel macro como microscópico con respecto a los dientes humanos. El objetivo de la presente revisión es aportar información actualizada acerca de las características histológicas de los tejidos dentarios bovinos y profundizar el conocimiento de las similitudes y diferencias de los dientes bovinos y humanos dando soporte a otros estudios compa- rativos y promoviendo la utilización de las piezas dentarias bovinas en trabajos de investigación en odontología (AU)

The animal teeth of the different species (human, equine, pig, etc.) are histologically constituted by four fundamental tissues: enamel, dentin, cement and dental pulp. Their composition, structure, morphology and size are dissimilar for each gender. According to numerous investigations, bovine teeth would be the ones of choice because they are easy to obtain and have very few or no differences, both at the macro and microscopic levels, with respect to human teeth. The objective of this review is to provide updated information about the histological characteristics of bovine dental tissues and deepen the knowledge of the similarities and differences between bovine and human teeth, supporting other comparative studies and promoting the use of bovine dental pieces in research work in dentistry (AU)

Using histological staining techniques to improve visualization and interpretability of tooth cementum annulation analysis / Uso de técnicas de tinción histológica para mejorar la visualización y la interpretación del análisis de la anulación del cemento dental

SUMMARY: The aim of the present study was to evaluate the effect of different staining techniques on applicability and accuracy of tooth cementum annulation (TCA) method. Nine decalcination techniques, 8 dehydration protocols and 8 different techniques were applied in 3 teeth from the persons of a known age. Black and white, and color images of histological sections were captured. An x- ray was taken of each tooth and they were photographed. Researchers were asked to observe both black/white and color images of histological sections. Researchers were divided into two groups. The first group analyzed histological images only, and the second group had photos of teeth and X-rays. In the first group of observers (without X ray) the differences in age estimation between real and observed age were significant for 2 younger patients, but not for the oldest patient, where the observed and real values matched. Of the 6 raters, the assesments of the last 3 (that used x-ray images together with histological sections) did not differ significantly from the real values. Extensive analysis and multiple repetitions performed in the present investigation revealed that the most optimal method of decalcification for TCA method was EDTA II for a period longer than 14 days at a section thickness of 2-3mm, while the most optimal protocol for dehydration was number IV. When it comes to staining, the most optimal staining protocol used for the cemental lines visualization and counting was Crocein Scarlet/Acid Fuchsin staining and Toluidine blue staining used at semithin section. Additional use of preexperimental evaluation employing x-ray of analyzed teeth decreased the errors of age estimation.

RESUMEN: El objetivo del presente estudio fue evaluar el efecto de diferentes técnicas de tinción sobre la aplicación y precisión del método de anulación de cemento dental (TCA). Se usaron nueve técnicas de descalcinación, 8 protocolos de deshidratación y 8 técnicas diferentes en 3 dientes de personas de edad conocida. Se capturaron imágenes en blanco y negro y en color de cortes histológicos. Se tomó una radiografía de cada diente y se fotografiaron. Los investigadores observaron las imágenes en blanco y negro y en color de las secciones histológicas. Los investigadores se dividieron en dos grupos; el primer grupo analizó solo imágenes histológicas y el segundo grupo tenía fotografías de los dientes y las radiografías. En el primer grupo de observadores (sin rayos X) las diferencias en la estimación de la edad entre la edad real y la edad observada fueron significativas para 2 pacientes más jóvenes, pero no para el paciente de mayor edad, donde los valores observados y reales coincidieron. De los 6 evaluadores, las valoraciones de los 3 últimos (que utilizaron imágenes de rayos X junto con cortes histológicos) no difirieron significativamente de los valores reales. El análisis exhaustivo y las múltiples repeticiones realizadas en la presente investigación revelaron que el método de descalcificación más óptimo para el método TCA fue EDTA II durante un período superior a 14 días con un grosor de sección de 2-3 mm, mientras que el protocolo óptimo para la deshidratación fue el número IV. En lo que respecta a la tinción, el protocolo de tinción más óptimo utilizado para la visualización y el recuento de las líneas de cemento fue la tinción con croceína escarlata / fucsina ácida y la tinción con azul de toluidina utilizada en la sección semifina. El uso adicional de la evaluación pre-experimental que emplea los rayos X de los dientes analizados disminuyó los errores de estimación de la edad.

Mechanical and thermal stress analysis of hybrid ceramic and lithium disilicate based ceramic CAD-CAM inlays using 3-D finite element analysis / Análise do estresse mecânico e térmico de inlays de cerâmica hibrida e de cerâmica a base de dissilicato de lítio através da análise em 3D de elementos finitos

Objective: The aim of this study was to analyze mechanical and thermal stresses of hybrid ceramic and lithium disilicate based ceramic of CAD/CAM inlays using 3D Finite element analysis. Material and Methods:A three dimensions finite element model of permanent maxillary premolar designed according to standard anatomy with class II cavity preparation for inlay restored with two different ceramic materials: 1- Hybrid ceramic (Vita Enamic), 2- Lithium disilicate based ceramic (IPS e.max CAD). Totally six runs were performed on the model as: One loading case for each restorative material was tested in stress analysis; seven points of loading with 140N vertically applied at palatal cusp tip and cusp slop, marginal ridges and central fossa while the models base was fixed as a boundary condition in the two cases. Two thermal analysis cases were performed for each restoration material by applying 5ºC and 55ºC on the crown surface including the restoration surface. Results:The results of all structures were separated from the rest of the model to analyze the magnitude of stress in each component. For each group, maximum stresses on restorative materials, cement, enamel, and dentin were evaluated separately. Both ceramic materials generated similar stress distribution patterns for all groups when a total occlusal load of 140 N was applied. Conclusion: Thermal fluctuations of temperature have a great influence on the stresses induced on both restoration and tooth structure. IPS e.max CAD produced more favorable stresses on the tooth structure than Vita Enamic. (AU)

Objetivo: O objetivo deste estudo foi analisar o estresse mecânico e térmico de inlays de cerâmica hibrida e a base de dissilicato de lítio através da análise em 3D de elementos finitos. Material e Métodos: Foi realizado o design de um modelo de três dimensões em elementos finitos de um pré-molar superior de acordo com os padrões anatômicos de um preparo de cavidade classe II para restauração de inlay em dois tipos de cerâmicas diferentes: 1 Cerâmica hibrida (Vita Enamic), 2 ­ Cerâmica a base de dissilicato de lítio (IPS e.max CAD). No total, seis execuções foram realizadas no modelo como: Uma carga para cada material restaurador foi testado para análise de tensão; sete pontos de carga com 140N foi aplicado verticalmente na ponta da cúspide palatina, saliência da cúspide, cristas marginais e fossa central enquanto a base do modelo foi fixada como uma condição de limite nos dois casos. Duas análises térmicas foram realizadas para cada material de restauração, aplicando 5ºC e 55ºC na superfície da coroa, incluindo a superfície da restauração. Resultados: Os resultados de todas as estruturas foram separados do resto do modelo para analisar a magnitude do estresse de cada componente. Para cada grupo, o máximo de estresse nos materiais restauradores, cemento, esmalte e dentina foram avaliados separadamente. Padrões similares de distribuição de estresse foram gerados em todos os grupos para ambos os materiais cerâmicos, quando a carga oclusal de 140 N foi aplicada. Conclusão: As variações térmicas de temperatura têm uma grande influência nas tensões induzidas na restauração e na estrutura dentária. IPS e.max CAD produziu tensões mais favoráveis na estrutura dentária do que o Vita Enamic (AU)

Influence of Powder-to-Gel Ratio on Physicochemical Properties of a Calcium Silicate Sealer / Influencia de la relación polvo-gel sobre las propiedades fisicoquímicas de un sellador de silicato de calcio

Abstract Differences in liquid-to-powder ratio can affect the properties of calcium silicate-based materials. This study assessed the influence of powder-to-gel ratio on physicochemical properties of NeoMTA Plus. Setting time (minutes), flow (mm and mm²), pH (at different periods), radiopacity (mm Al) and solubility (% mass loss) were evaluated using the consistencies for root repair material (NMTAP-RP; 3 scoops of powder to 2 drops of gel) and root canal sealer (NMTAP-SE; 3 scoops of powder to 3 drops of gel), in comparison to Biodentine cement (BIO) and TotalFill BC sealer (TFBC). Statistical analysis was performed using one-way ANOVA and Tukey tests (α=0.05). BIO had the shortest setting time, followed by NMTAP-RP and NMTAP-SE. TFBC showed the highest setting time and radiopacity. BIO, NMTAP-RP, and NMTAP-SE had similar radiopacity. All materials promoted an alkaline pH. NMTAP-RP/SE presented lower solubility than BIO and TFBC. Regarding the flow, TFBC had the highest values, followed by NMTAP-SE, and NMTAP-RP. BIO had the lowest flow. In conclusion, NMTAP in both powder-to-gel ratios showed high pH and low solubility. The increase in the powder ratio decreased the setting time and flow. These findings are important regarding the proper consistency and work time to clinical application.

Resumen Las diferencias en la proporción líquido/polvo pueden afectar las propiedades de los materiales a base de silicato de calcio. Este estudio evaluó la influencia de la proporción polvo/gel en las propiedades fisicoquímicas del cemento NeoMTA Plus. El tiempo de fraguado (minutos), la fluidez (mm y mm²), el pH (en diferentes períodos), la radiopacidad (mmAl) y la solubilidad (% de pérdida de masa) fueron evaluados utilizando las consistencias para el material de reparación radicular (NMTAP-RP; 3 cucharadas de polvo/2 gotas de gel) y para cemento sellador del conducto radicular (NMTAP-SE; 3 cucharadas de polvo/3 gotas de gel), en comparación con el cemento Biodentine (BIO) y el cemento TotalFill BC (TFBC). El análisis estadístico se realizó utilizando las pruebas ANOVA y Tukey unidireccionales (α=0.05). BIO tuvo el tiempo de fraguado más corto, seguido de NMTAP-RP y NMTAP-SE. TFBC mostró el mayor tiempo de fraguado y radiopacidad. BIO, NMTAP-RP y NMTAP-SE tuvieron una radiopacidad similar. Todos los materiales promovieron un pH alcalino. NMTAP-RP/ SE tuvieron una solubilidad menor que BIO y TFBC. Con respecto a la fluidez, TFBC tuvo los valores más altos, seguido de NMTAP-SE y NMTAP-RP. BIO tuvo la fluidez más baja. En conclusión, NMTAP en la relación polvo/gel mostró un pH alto y una baja solubilidad. El aumento en la proporción de polvo disminuyó el tiempo de fraguado y la fluidez. Estos hallazgos son importantes con respecto a su consistencia y tiempo de trabajo durante la aplicación clínica.

Microfiltración coronal según materiales de restauración temporal empleados en endodoncia / Coronal microleakage according to the temporary restorative materials used in endodontic treatment

RESUMEN Introducción: La microfiltración coronal causada por los materiales de restauración temporal es considerada una de las causas del fracaso de los tratamientos endodónticos. A raíz de ello, en los últimos años se ha buscado crear un material de restauración temporal que sea capaz de evitar este problema. Objetivo: Comparar in vitro la microfiltración coronal de un cemento experimental y cuatro materiales de restauración temporal usados en endodoncia. Métodos: Se realizaron cavidades clase I en 90 premolares, divididos en 10 grupos (n= 9) y evaluados en dos periodos de tiempo (1 y 2 semanas). Se realizó la elaboración del cemento experimental, posteriormente se llevó a cabo el sellado coronal de las piezas dentales con el cemento experimental, Clip F (VOCO), Eugenato (MOYCO), Ketac™ Molar Easymix 3M (ESPE) y Coltosol® F. Los especímenes fueron sumergidos en tinta china (Pelikan) durante 1 y 2 semanas. Se evaluó la microfiltración en la interfase pared dentinaria-restauración temporal utilizando un esteromicroscopio (Leica Microsystems LAS EZ versión 2.0.0). La medición se realizó en milímetros en el programa LAS EZ versión 2.0.0. Resultados: Se encontró diferencias estadísticamente significativas (p < 0,05) al comparar la microfiltración coronal de los cinco materiales de restauración temporal, según el tiempo de exposición en tinta (1 y 2 semanas). Conclusiones: El cemento experimental presentó menor microfiltración que el Coltosol® F y Ketac™ Molar EasyMix 3M (ESPE); sin embargo, ninguno de los cuatro materiales fue capaz de prevenir la microfiltración en su totalidad(AU)

ABSTRACT Introduction: Coronal microleakage caused by temporary restorative materials is viewed as one of the reasons for endodontic failure. Efforts have been made in recent years to create a temporary restorative material capable of preventing that problem. Objective: Compare in vitro coronal microleakage of an "experimental cement" and four temporary restorative materials used in endodontics. Methods: Class I cavities were made in 90 premolar teeth divided into 10 groups (n= 9) and evaluated at two time periods (1 and 2 weeks). The "experimental cement" was prepared and then coronal sealing of the teeth was performed with the experimental Cement, F (VOCO), Eugenato (MOYCO), Ketac™ Molar Easymix 3M (ESPE) and Coltosol® F. The pieces were submerged in India ink (Pelikan)for 1 and 2 weeks. Microleakage was evaluated on the interface dentin wall / temporary restoration using a stereo microscope (Leica Microsystems LAS EZ version 2.0.0). Measurement was made in millimeters using the software LAS EZ version 2.0.0. Results: Statistically significant differences were found (p < 0.05) when comparing coronal microleakage in the five temporary restorative materials according to exposure time in ink (1 and 2 weeks). Conclusions: The experimental cement had less microleakage than Coltosol® F and Ketac™ Molar EasyMix 3M (ESPE). However, none of the four materials was capable of completely preventing microleakage(AU)

Concrescence: can the teeth involved be moved or separated?

ABSTRACT The atrophy of the periodontal ligament places the tooth very close to the bone or another tooth, as occurs in unerupted teeth. The absent interdental bone and the lack of functional periodontal stimulus may lead to the fusion of the appositional layers of cement between the roots of the teeth. Concrescence almost always occurs in the region of the maxillary molars. Asymptomatic, it should always be remembered when the proper response to orthodontic movement is not obtained, and there is no apparent explanation. When surgically extracting a tooth and there is resistance, insisting will not be the best strategy. Moving the teeth with concrescence is not convenient, as it requires very intense forces. Once separated, these teeth can be considered normal for movement. It is possible to separate two teeth presenting concrescence, but it depends on the extension of the area, the surgical access and, especially, the clinical convenience. The tooth to be extracted will be repaired with new cement deposited in the sectioned area. The simple separation with the maintenance of the proximity and the lack of function of one of the teeth will cause a new concrescence. After a period of 1 to 3 months, the separated teeth are biologically prepared to be moved. The most important detail in this separation of teeth presenting concrescence is that the diagnosis should be made in advance, and not at the time of the intervention.

RESUMO A atrofia do ligamento periodontal coloca o dente muito próximo do osso e/ou de outro dente, como ocorre em dentes não irrompidos. O osso interdentário ausente e a falta de estímulo funcional periodontal podem levar à fusão das camadas aposicionais de cemento entre as raízes dos dentes. A concrescência ocorre quase sempre na região dos molares superiores. Assintomática, ela deve sempre ser lembrada quando não se obtém a resposta adequada a uma movimentação ortodôntica, sem uma explicação aparente. Cirurgicamente, quando se está extraindo o dente e ele oferece resistência, insistir não será a melhor estratégia. Movimentar os dentes com concrescência não é conveniente, pois requer forças muito intensas. Depois de separados, esses dentes podem ser considerados normais para a movimentação. É possível separar dois dentes em concrescência, mas depende da extensão da área, do acesso cirúrgico e, em especial, da conveniência clínica. O dente a ser extraído vai reparar-se, com novo cemento depositado na região seccionada. A simples separação, com manutenção da proximidade e da falta de função de um dos dentes, fará com que uma nova concrescência se estabeleça. Transcorrido o período de 1 a 3 meses, os dentes separados poderão, biologicamente, ser movimentados. O detalhe mais importante nessa separação de dentes com concrescência é que o diagnóstico deve ser feito com antecedência, e não no momento da intervenção.

Microfiltraciones entre ionómero de vidrio y resina compuesta en lesiones clase-V no cariosas / Microfiltration between glass ionomer and composite resin in non-carious class-V injuries / Microfiltrações entre ionômeros de vidro e resina composta em lesões não cariosas de classe V

No se han establecido estándares para el tratamiento de cavidades cervicales no cariosas; un biomaterial adecuado permitirá buena adaptación y longevidad de la restauración. Objetivo: Determinar la microfiltración en cavidades clase V no cariosas restauradas con ionómero de vidrio y resina nanoparticulada. Materiales y métodos: Cavidades clase V realizadas en la superficie vestibular de 80 premolares sanos (1,5 mm de pro-fundidad x 3 mm de altura en sentido ocluso- gingival x 2 mm de ancho en sentido mesio-distal) se restauraron aleatoriamente con dos biomateriales (n = 40): 1) ionómero de vidrio y 2) resina de nano relleno. Después, los especímenes fueron aislados con barniz y sumergidos en azul de metileno por 24 horas. Posteriormente, las muestras se sometieron 500 ciclos de termociclado por 8 horas y 45 minutos con cambios térmicos de 37°, 72° y 75°C, cada ciclo con una duración de 17 segundos. Las muestras fueron lavadas con agua destilada y seccionadas longitudinalmente para determinar el grado de microfiltración utilizando un estereoscopio (Leica M60, Biosystems). Los datos categóricos se analizaron con el test Chi2 en SPSS 24®. Resultados: Se pudo apreciar que la filtración es significativamente menor en resina que con ionómeros de vidrio (p < 0,001). Sin embargo, ninguno de los materiales de restauración probados fue capaz de sellar los márgenes o las paredes de los dientes completamente. Conclusión: como resultado del presente experimento se determina que las restauraciones de clase V obturadas con resina de nano relleno presentan menor microfiltración marginal que las restauradas con ionómero de vidrio.

No standards have been established for the treatment of non-carious cervical cavities; a suitable biomaterial will allow good adaptation and longevity of the restoration. Objective: To determine microfiltration in non-car-ious class V cavities restored with glass ionomer and nanoparticulate resin. Materials and methods: Class V cavities made on the vestibular surface of 80 healthy premolars (1.5 mm deep x 3 mm high in the occlusion-gin-gival direction x 2 mm wide in the mesio-distal direction) were randomly restored with two biomaterials (n = 40): 1) glass ionomer and 2) nano-filled resin. Then, the specimens were isolated with varnish and immersed in methylene blue for 24 hours. Subsequently, the samples were subjected to 500 cycles of thermocycling for 8 hours and 45 minutes with thermal changes of 37°, 72° and 75° C, each cycle with a duration of 17 seconds. The samples were washed with distilled water and sectioned longitudinally to determine the degree of micro-filtration using a stereoscope (Leica M60 Biosystems). Categorical data were analyzed with the Chi2 test in SPSS 24®. Results: It was observed that filtration is significantly lower in resin than in those restored with glass ionomers (p < 0.001). However, none of the restoration materials tested were able to seal the margins or walls of the teeth completely. Conclusion: As a result of the present experiment, it is determined that class V resto-rations sealed with nano-filled resin have less marginal microfiltration than those restored with glass ionomer.

Ainda não foram estabelecidos padrões para o tratamento de cavidades cervicais não cariosas; um biomate-rial adequado permitirá boa adaptação e longevidade da restauração. Objetivo: Determinar a microfiltração em cavidades não cariosas da classe V restauradas com ionômero de vidro e resina nanoparticulada. Materi-ais e métodos: Cavidades de classe V feitas na superfície vestibular de 80 pré-molares saudáveis (1,5 mm de profundidade x 3 mm de altura na direção oclusão-gengival x 2 mm de largura na direção mesio-distal) foram restaurados aleatoriamente com dois biomateriais (n = 40): 1) ionômero de vidro e 2) resina nano-híbrida. Em seguida, as amostras foram isoladas com verniz e imersas em azul de metileno por 24 horas. Posteriormente, as amostras foram submetidas a 500 ciclos de termociclagem por 8 horas e 45 minutos com alterações tér-micas de 37°, 72° e 75° C, cada ciclo com duração de 17 segundos. As amostras foram lavadas com água destilada e seccionadas longitudinalmente para determinar o grau de microfiltração usando um estereoscópio (Leica M60, Biosystems). Os dados categóricos foram analisados com o teste Chi2 no SPSS 24®. Resul-tados: Observou-se que a filtração é significativamente menor na resina do que nos ionômeros de vidro (p <0,001). No entanto, nenhum dos materiais de restauração testados foram capazes de selar completamente as margens ou paredes dos dentes. Conclusão: como resultado do presente experimento, determina-se que restaurações de classe V seladas com resina nano-preenchida possuem menos microfiltração marginal do que aquelas restauradas com ionômero de vidro.

Diente fusionado por concrescencia en un paciente pediátrico: reporte de caso / Dente fusionado por concrescência em paciente pediátrico: relato de caso / Tooth fused by concrescence in a pediatric patient: case report

Las anomalías dentales se definen como malformaciones congénitas por falta o aumento en el desarrollo de los tejidos dentarios, clasificadas según forma, número, tamaño y posición. La concrescencia es un término utilizado para referirse a un tipo de fusión que ocurre después de que la corona está completamente formada y los dientes se unen solo por el cemento. En el presente artículo se presenta el caso de un paciente masculino de 14 años que concurre al servicio de odontología del "Hospital Interzonal General de Agudos Presidente Perón de Avellaneda", con una fusión dentaria por concrescencia de los dientes 47 y 48. En este caso ante la inclusión del diente 47 y su fusión con el diente 48, se decidió la remoción quirúrgica teniendo en cuenta las patologías asociadas a un diente retenido y las molestias ocasionadas en el paciente

As anomalias dentárias são definidas como malformações congênitas devido à falta ou aumento do desenvolvimento de tecidos dentários, classificadas de acordo com a forma, número, tamanho e posição. A concrescência é um termo usado para se referir a um tipo de fusão que ocorre depois que a coroa é completamente formada e os dentes são unidos apenas pelo cimento. Neste artigo, apresentamos o caso de um paciente do sexo masculino de 14 anos de idade, que freqüenta o serviço odontológico do Hospital Interzonal Presidente Perón de Avellaneda, com fusão dentária para a união dos dentes 47 e 48, com a inclusão da peça de dente 4.7 e sua fusão com a peça de dente 4.8, a remoção cirúrgica foi decidida levando-se em consideração as patologias associadas a uma peça dentária retida e o desconforto causado no paciente.

Dental anomalies are defined as congenital malformations due to lack or increase in the development of dental tissues, classified according to shape, number, size and position. The concrescence is a term used to report a type of fusion that occurs after the crown is completely formed and adjacent teeth are joined only through cement. In this case report, we present the case of a 14-year-old male patient who attends the dentistry service of the "Interzonal Hospital of Agudos President Perón", with teeth fusion of 4.7 and 4.8. In this case, due to the fusion of 4.7 and 48 surgical removal was decided taking into account the associated pathologies of a retained tooth and the likely discomfort that may be caused for the patient

DNA Methylation patterns of immune response-related genes in inflammatory external root resorption

Abstract Inflammatory external root resorption (IERR) is a pathological process defined by the progressive loss of dental hard tissue, dentin, and cementum, resulting from the combination of the loss of external root protective apparatus and root canal infection. It has been suggested that healing patterns after tooth replantation may be influenced by the genetic and immunological profiles of the patients. The purpose of the present investigation was to evaluate the DNA methylation patterns of 22 immune response-related genes in extracted human teeth presenting with IERR. Methylation assays were performed on samples of root fragments showing IERR and compared with healthy bone tissue collected during the surgical extraction of impacted teeth. The methylation patterns were quantified using EpiTect Methyl II Signature Human Cytokine Production PCR Array. The results revealed significantly higher hypermethylation of the FOXP3 gene promoter in IERR (65.95%) than in the bone group (23.43%) (p < 0.001). The ELANE gene was also highly methylated in the pooled IERR sample, although the difference was not statistically significant (p= 0.054). Our study suggests that the differential methylation patterns of immune response-related genes, such as FOXP3 and ELANE, may be involved in IERR modulation, and this could be related to the presence of root canal infection. However, further studies are needed to corroborate these findings to determine the functional relevance of these alterations and their role in the pathogenesis of IERR.

Transcriptome profile of highly osteoblastic/cementoblastic periodontal ligament cell clones

Abstract Heterogeneous cell populations of osteo/cementoblastic (O/C) or fibroblastic phenotypes constitute the periodontal dental ligament (PDL). A better understanding of these PDL cell subpopulations is essential to propose regenerative approaches based on a sound biological rationale. Objective Our study aimed to clarify the differential transcriptome profile of PDL cells poised to differentiate into the O/C cell lineage. Methodology To characterize periodontal-derived cells with distinct differentiation capacities, single-cell-derived clones were isolated from adult human PDL progenitor cells and their potential to differentiate into osteo/cementoblastic (O/C) phenotype (C-O clones) or fibroblastic phenotype (C-F clones) was assessed in vitro. The transcriptome profile of the clonal cell lines in standard medium cultivation was evaluated using next-generation sequencing technology (RNA-seq). Over 230 differentially expressed genes (DEG) were identified, in which C-O clones showed a higher number of upregulated genes (193) and 42 downregulated genes. Results The upregulated genes were associated with the Cadherin and Wnt signaling pathways as well as annotated biological processes, including "anatomical structure development" and "cell adhesion." Both transcriptome and RT-qPCR showed up-regulation of WNT2, WNT16, and WIF1 in C-O clones. Conclusions This comprehensive transcriptomic assessment of human PDL progenitor cells revealed that expression of transcripts related to the biological process "anatomical structure development," Cadherin signaling, and Wnt signaling can identify PDL cells with a higher potential to commit to the O/C phenotype. A better understanding of these pathways and their function in O/C differentiation will help to improve protocols for periodontal regenerative therapies.

Accelerated tooth movement in Rsk2-deficient mice with impaired cementum formation / 国际口腔科学杂志·英文版

Coffin-Lowry-Syndrome (CLS) is a X-linked mental retardation characterized by skeletal dysplasia and premature tooth loss. We and others have previously demonstrated that the ribosomal S6 kinase RSK2, mutated in CLS, is essential for bone and cementum formation; however, it remains to be established whether RSK2 plays also a role in mechanically induced bone remodeling during orthodontic tooth movement (OTM). We, therefore, performed OTM in wild-type (WT) mice and Rsk2-deficient mice using Nitinol tension springs that were fixed between the upper left molars and the incisors. The untreated contralateral molars served as internal controls. After 12 days of OTM, the jaws were removed and examined by micro-computed tomography (µCT), decalcified histology, and immunohistochemistry. Our analysis of the untreated teeth confirmed that the periodontal phenotype of Rsk2-deficient mice is characterized by alveolar bone loss and hypoplasia of root cementum. Quantification of OTM using µCT revealed that OTM was more than two-fold faster in Rsk2-deficient mice as compared to WT. We also observed that OTM caused alveolar bone loss and root resorptions in WT and Rsk2-deficient mice. However, quantification of these orthodontic side effects revealed no differences between WT and Rsk2-deficient mice. Taken together, Rsk2 loss-of-function accelerates OTM in mice without causing more side effects.