Microcomputed-Tomographic Analysis of the Root Canal Morphology of the Mandibular First Molars in a Malaysian Subpopulation Using Two Classification Systems / Análisis por Tomografía Microcomputada de la Morfología del Conducto Radicular de los Primeros Molares Mandibulares en una Subpoblación de Malasia Utilizando dos Sistemas de Clasificación

SUMMARY: This work investigated the morphology of the root canal system of the mandibular first molar in a Malaysian subpopulation. Using micro-computed tomography with an isotropic resolution of 22 µm, 140 mandibular first molars were scanned. MIMICS software was used for segmentation, 3-D reconstruction and analysis of the acquired images. The canal configuration was described using Vertucci [supported by the supplementary configurations proposed by Sert & Bayirli (2004)] and Ahmed et al. (2027), coding systems. The chi-square test was used to assess the association between qualitative variables. By non-considering intercanal communications, Vertucci types IV (17.1%) and I (76.4%) were the most frequently reported configurations in the mesial and distal roots, respectively. Of the reported configurations, 24.3% and 4.3% were non-classifiable by Vertucci system in the mesial and distal roots, respectively. Up to 63.6% and 9.3% of the reported configurations were non- classifiable, and type I was the most frequent when considering intercanal communications (7.1% and 76.4% in the mesial and distal roots, respectively). According to Ahmed et al., system, almost half of the sample had more than four digits (47.9%), followed by the 3-digits category (20.71%). In both systems, a significant association was found between the canal configuration and the root type (p<0.001). The mandibular first molar of this Malaysian subpopulation demonstrated a wide range of root canal morphology. When compared to the Vertucci system, the system developed by Ahmed et al., successfully classified all molars configurations despite their level of complexity. The complex canal anatomy of mandibular first molars in this subpopulation warrants special attention during root canal treatment procedures.

En este trabajo se investigó la morfología del sistema de conductos radiculares del primer molar mandibular en una subpoblación de Malasia. Utilizando tomografía microcomputada con una resolución isotrópica de 22 µm, se escanearon 140 primeros molares mandibulares. Se utilizó el software MIMICS para segmentar (enmascarar), reconstruir en 3D, visualizar y analizar las imágenes adquiridas. La configuración del canal se describió utilizando Vertucci respaldado por las configuraciones complementarias propuestas por Sert & Bayirli (2004)] y Ahmed et al. (2017, 2020), sistemas de codificación. Se utilizó la prueba de chi-cuadrado para evaluar la asociación entre variables cualitativas. Sin considerar las comunicaciones intercanales, los tipos Vertucci IV (17,1%) y I (76,4%) fueron las configuraciones reportadas con mayor frecuencia en las raíces mesiales y distales, respectivamente. De las configuraciones reportadas, el 24,3 % y el 4,3 % fueron no clasificables por el sistema de Vertucci en las raíces mesial y distal, respectivamente. Hasta el 63,6 % y el 9,3 % de las configuraciones reportadas fueron no clasificables, siendo la tipo I la más frecuente al considerar las comunicaciones intercanales (7,1 % y 76,4 % en las raíces mesiales y distales, respectivamente). Según Ahmed et al. (2017, 2020) en el sistema, casi la mitad de la muestra tenía más de cuatro dígitos (47,9 %), seguido por la categoría de 3 dígitos (20,71 %). En ambos sistemas se encontró una asociación significativa entre la configuración del canal y el tipo de raíz (p<0,001). El primer molar mandibular de esta subpoblación de Malasia demostró una amplia gama morfológica del conducto radicular. En comparación con el sistema Vertucci, el sistema desarrollado por Ahmed et al. (2017, 2020) clasificaron con éxito todas las configuraciones de los molares a pesar de su nivel de complejidad. La compleja anatomía del canal de los primeros molares mandibulares en esta subpoblación merece una atención especial durante los procedimientos de tratamiento de conducto.

Continuous Wave of Condensation Improves the Filling of Curved Canals: a Micro-CT Study / La condensación de onda contínua mejora el selle de canales curvos: un estudio de micro-CT

Abstract The aim of this study was to compare the filling capacity in curved root canal using a new continuous wave of condensation technique (Termo Pack II, Easy Dental Equipments, Brazil) or lateral compaction. The percentage of voids in the filling of mesial root canals of mandibular molars was assessed by micro-computed tomography (micro-CT). Mesial root canals (n=24) of mandibular molars with a degree of curvature between 20° and 40° were prepared using rotary system (ProDesign Logic, Easy, Brazil) up to #35, .05 taper. The root canals were filled by using the continuous wave of condensation system or lateral compaction and AH Plus sealer (n=12). Scanning at 9 µm was performed after preparation and after filling by using micro-CT SkyScan 1176. The volumetric percentage of filling material and voids (total length and in each root canal third) were calculated. Data were analyzed using ANOVA/ Tukey and Student's t tests (α=0.05). Before the filling techniques, the root canals volume after preparation was similar (p>0.05). The root canals filled by the continuous wave of condensation technique presented the lowest percentage of voids, and the greatest percentage of filling material in total length and thirds (cervical, middle and apical) (p<0.05). Both techniques were not able of completely filling the root canals. The continuous wave of condensation technique Termo Pack II promoted better root canal filling in curved root canals, when compared with lateral compaction.

Resumen El objetivo de este estudio fue comparar la capacidad de obturación en conductos radiculares curvos utilizando una nueva técnica de condensación de onda continua (Termo Pack II, Easy Dental Equipments, Brasil) vs compactación lateral. El porcentaje de brechas en la obturación de los conductos radiculares mesiales de los molares mandibulares se evaluó mediante microtomografía computarizada (micro-CT). Se prepararon conductos radiculares mesiales (n=24) de molares mandibulares con un grado de curvatura entre 20° y 40° utilizando un sistema rotatorio (ProDesign Logic, Easy, Brasil) al #35, conicidad 0,05. Los conductos radiculares se obturaron utilizando un sistema de condensación de onda contínua o compactación lateral y cemento AH Plus (n=12). Se realizó un escaneo de 9 µm después de la preparación y después de la obturación usando el micro-CT SkyScan 1176. Se calculó el porcentaje volumétrico de material de obturación y vacíos (longitud total y en cada tercio del conducto radicular). Los datos se analizaron utilizando las pruebas ANOVA/Tukey y t de Student (α=0,05). Antes de las técnicas de obturación, el volumen de los conductos radiculares después de la preparación fue similar (p>0,05). Los conductos radiculares obturados con la técnica de condensación por onda contínua presentaron el menor porcentaje de vacíos y el mayor porcentaje de material de obturación en longitud total y en tercios (cervical, medio y apical) (p<0,05). Ambas técnicas no fueron capaces de llenar completamente los conductos radiculares. La técnica de condensación de onda contínua Termo Pack II promovió un mejor relleno del conducto radicular en conductos radiculares curvos en comparación con la compactación lateral.

Comparison Between Radiographs, White and Fluorescent Images in the Diagnosis and Treatment Decisions for Occlusal Caries: An Ex Vivo Study

ABSTRACT Objective: To compare the agreement of images in white light (WL), fluorescence (FL), and digital radiographs (DR), on the diagnosis and treatment decisions for occlusal caries lesions against a micro-CT gold standard. Material and Methods: Ten extracted third molars, with enamel and/or dentin caries (ICDAS 2-4), were included. Occlusal surface images were acquired with an intraoral camera (SoproLife®) in WL and FL modes. DR was obtained using an intraoral X-ray and a semi-direct digital system. A total of 780 images were needed, organized in a template, to be later examined by twenty-six dentists invited to compose the study. The Generalized Estimation Equations model was used to compare the proportions of the correct answers between the three methods and the gold standard. When significant, Bonferroni post-hoc test was used to identify differences (α=5%). Results: Most of the examiners were specialists (76.9%) with 14.5 years of experience. All diagnostic methods were similar and showed low agreement (DR 12.7%, WL 16.5%, and FL 16.5%) compared with gold standard caries diagnostic scores. Regarding treatment decisions, mean agreement for all diagnostic methods was higher (43.2%; p<0.001), and among all methods, WL (48.1%) and FL (51.2%) modes performed better than DR (30.4%, p<0.001). Conclusion: SoproLife® images could help clinicians to propose rational, minimally invasive treatments for occlusal caries lesions.

Investigation of the effect of indirect pulp capping materials on dentin mineral density

Aim: To evaluate the potential of inducing mineral density changes of indirect pulp capping materials applied to demineralized dentin. Methods: A total of 50 cavities were prepared, 5 in each tooth, in extracted ten molars without caries, impacted or semi-embedded. The cavities were scanned by microcomputed tomography (µ-CT) after creating artificial caries by microcosm method (pre-treatment). Each cavity was subjected to one of 5 different experimental conditions: control (dental wax), conventional glass ionomer cement (Fuji IX GP Extra), resin-modified calcium silicate (TheraCal LC), resin-modified calcium hydroxide (Ultra-Blend Plus), MTA (MM-MTA) and the samples were kept under intrapulpal pressure using simulated body fluid for 45 days. Then, the second µ-CT scan was performed (post-treatment), and the change in dentin mineral density was calculated. Afterward, elemental mapping was performed on the dentinal surfaces adjacent to the pulp capping agents of 5 randomly selected samples using energy dispersive X-ray spectroscopy (EDS) apparatus attached to a scanning electron microscope (SEM). The Ca/P ratio by weight was calculated. Friedman test and Wilcoxon Signed Ranks test were used to analyze the data. Results: There was a significant increase in mineral density values of demineralized dentin after treatment for all material groups (p<0.05). Resin-modified calcium silicate had similar efficacy to MTA and conventional glass ionomer cement, but was superior to resin-modified calcium hydroxide in increasing the mineral density values of demineralized dentin. Conclusions: Demineralized dentin tissue that is still repairable can be effectively preserved using materials with remineralization capability

Influence of different working lengths on the shaping ability of Reciproc Blue in the apical third and apical foramen: a micro-computed tomographic study

Aim: This study aimed to assess the shaping ability of Reciproc Blue in the apical third and apical foramen of moderately curved canals at different working lengths (WLs), by micro-computed tomography. Methods: Thirty-six mesial roots (mesiobuccal and mesiolingual canals) were included, each with 2 separate root canals and independent apical foramina, according to type IV of Vertucci's classification of first and second mandibular molars. The canals were instrumented at three different WLs: G-1, 1mm short of the major apical foramen; G0, at the major apical foramen; G+1, 1mm beyond the major apical foramen. The groups were assessed for changes in root canal volume and untouched wall area in the apical third. Groups G0 and G+1 were also compared for percentage of untouched walls at the apical foramen. One-way ANOVA (post hoc Tukey test) and Student's t-test adopted a 5% level of significance. Results: Root canal volumes (mm3) in the apical third were 22.86±10.46, 44.48±24.91, and 55.71±21.32 in G-1, G0 and G+1, respectively. G-1 volume following instrumentation increased significantly less than that of G0 or G+1 (P>.05); G0 did not differ from G+1. The percentage of untouched wall area in the apical third did not differ among the three groups (P>.05). G0 and G+1 did not differ regarding untouched walls in the major apical foramem walls. Conclusion: Extending the WL from 1mm short of the apical foramen to a point at and beyond the WL increases the apical third volume without increasing the prepared area. Untouched surface areas of the apical foramen were not modified by instrumentation at or beyond the foramen

Relevant anatomical details in rats regarding otologic research / Detalles anatómicos relevantes en ratas para la investigación otológica

SUMMARY: The objective of the study was to provide a detailed anatomical description of the rat's ear anatomy that will prove insightful to different experimental otologic surgical procedures regardless of scope. Three male Wistar rats were enrolled in the study. Candidates were screened for systemic and otologic pathology. External ear canal endoscopy was carried out with a 30˚ rigid endoscope through an image capture system. Middle ear anatomical elements were analyzed under stereomicroscopy. 3D computer tomography image reconstruction was realized with a micro-CT to describe the anatomy. Image data from all three rats were analyzed. Anatomical annotations and surgical exposure recommendations were added for key elements. The most relevant images from all three rats were selected for representation. Detailed visualization of the structural elements of the tympanic cavity were clearly visible: promontory, round window, stapedial artery, stapes, incus, and tympanic membrane were all constant findings. We describe a step wise ventral surgical approach of the middle and inner ear for which we found that the clavotrapezius muscle was a reliable landmark. For the transtympanic approach the endoscopic transcanal access was an easy and reliable method for which a detailed anatomical representation was depicted. Further, anatomical similarities to humans were observed by stereomicroscopy and Micro-CT imaging reiterating that the rat model is suitable for otologic research. The endoscopic approach to the tympanic membrane is comfortable and less expensive than a microscope. The tendon of the clavotrapezius muscle can be a reliable landmark for discovering the tympanic bulla when considering a ventral approach. 3D Micro-CT reconstruction allows intact evaluation of the samples, simultaneously being a diagnostic and also a learning tool.

RESUMEN: El objetivo de este trabajo fue proporcionar una descripción anatómica detallada de la anatomía del órgano vestíbulococlear de la rata que resultará útil para diferentes procedimientos quirúrgicos otológicos experimentales, independientemente del alcance. En el estudio se usaron tres ratas Wistar macho. Los ejemplares fueron evaluados por patología sistémica y otológica. La endoscopía del meato acústico externo se realizó con un endoscopio rígido de 30˚ a través de un sistema de captura de imágenes. Los elementos anatómicos del oído medio se analizaron bajo estereomicroscopía. La reconstrucción de la imagen de tomografía computarizada en 3D se realizó con un micro-CT para describir la anatomía. Se analizaron los datos de imagen de las tres ratas. Se agregaron anotaciones anatómicas y recomendaciones de exposición quirúrgica para elementos clave. Las imágenes más relevantes de las tres ratas fueron seleccionadas para su representación. La visualización detallada de los elementos estructurales de la cavidad timpánica era claramente visible: promontorio timpánico, ventana coclear, arteria estapedial, estapedio, yunque y membrana timpánica eran hallazgos constantes. Describimos un abordaje quirúrgico ventral escalonado del oído medio e interno para el cual encontramos que el músculo clavotrapecio era un punto de referencia confiable. Para el abordaje transtimpánico, el acceso transcanal endoscópico fue un método fácil y confiable para el cual se describió una representación anatómica detallada. Además, se observaron similitudes anatómicas con los humanos mediante estereomicroscopía e imágenes Micro-CT, lo que reitera que el modelo de rata es adecuado para la investigación otológica. El abordaje endoscópico de la membrana timpánica es cómodo y menos costoso que un microscopio. El tendón del músculo clavotrapecio puede ser un punto de referencia fiable para descubrir la bulla timpánica cuando se considera un abordaje ventral. La reconstrucción 3D Micro- CT permite la evaluación intacta de las muestras, siendo simultáneamente una herramienta de diagnóstico y también de aprendizaje.

Efficacy of 30% and 38% Silver Diamine Fluoride in Arresting Caries Lesions After Different Application Times: An in Vitro Study

Abstract Objective: To evaluate the efficacy of silver diamine fluoride (SDF) in arresting dentin caries lesions when applied under different concentrations and times. Material and Methods: Forty-two bovine blocks were selected and fixed in 24-well plates. Each well received a mixed bacterial inoculum added to the culture medium with 5% sucrose. The plates were incubated in microaerophilia (7 days) for caries formation, confirmed by micro-CT (M1). SDF was applied over the carious lesions for different times and concentrations (n=6): SDF 30% - immediate removal, 1 minute and 3 minutes; SDF 38%, - immediate removal, 1 minute and 3 minutes. The group without treatment was the control. Then, the samples were again scanned by micro-CT (M2) and submitted to a second cariogenic challenge for 21 days. Then, a final scan was performed (M3). Results: Mean pH at the culture medium and lesion depth were compared using Kruskal-Wallis and Wilcoxon tests. 38% SDF showed the lowest metabolic activity of the biofilm. All 38% groups and 30% 1 and 3 minutes did not show an increase in mean lesion depth comparing M3 with M1. However, only 30% 3 minutes and 38% 1 and 3 minutes showed a significant reduction of lesion depth. Conclusion: The minimum application time of 30% SDF to arrest dentin caries lesion was 1 minute, while 38% SDF arrested with application and immediate removal.

Estudio microtomográfico de la porosidad en la cementación de postes de fibra / Microtomographic study of the porosity in the cementation of fiber posts

El objetivo de este estudio fue evaluar con microto-mografía los poros existentes entre el cemento de resina, poste de fibra y paredes del conducto en los distintos tercios radiculares en premolares inferio-res. Se utilizaron 15 premolares inferiores unirra-diculares humanos recientemente extraídos. Se les realizó el tratamiento endodóntico, y se obturó con conos de gutapercha y cemento endodóntico a base de resina. Una vez desobturados se procedió a la ce-mentación de los postes. Cada muestra se posicionó en un accesorio personalizado y se escaneó utilizan-do un Microtomógrafo. Con el software CTAn v.1.12 (Bruker-microCT) se analizaron las microtomografías para obtener el volumen de interés (VOI) que permi-tió calcular el área de superficie (mm2) y volumen de cada poro (mm3) entre la dentina y el poste a nivel co-ronal, medio y apical. Los datos fueron analizados me-diante las pruebas estadísticas de Friedman o ANOVA de medidas repetidas. El volumen de los poros entre los tres tercios radiculares mediante la prueba de Friedman, encontró una diferencia global significativa (F = 30,00; p < 0,05). El tercio en donde los poros presentaron un mayor volumen (mm3) fue el tercio coronal (mediana: 0,29250), seguido por los tercios medio (mediana: 0,03200), y apical (mediana: 0,00140). La comparación de la superficie de los poros entre los 3 tercios brindó un resultado análogo al de la comparación del volumen. La mayor superficie (mm2) correspondió al tercio coronal (media ± DE = 1,66377 ± 0,27175), seguido por los tercios medio (media ± DE = 1,16210 ± 0,20343) y apical (media ± DE = 0,41074 ± 0,12641). La microtomografía permitió realizar un análisis cuantitativo y cualitativo de los poros en toda la muestra, sin deterioro de la misma. Se puede concluir que el tercio coronal presenta más poros que el tercio apical con la técnica de cementación utilizada. En cuanto a la superficie y volumen de los poros, los resultados encontrados son similares a los reporta-dos por diversos autores (AU)

The aim of this study was to evaluate with microtomography the existing pores between the resin cement, fiber post and canal walls in the different in thirds of the canal, in single-root lower premolars. Fifteen recently extracted human single root lower premolars were used, endodontically treated, and filled with gutta-percha cones and resin-based endodontic cement. Once unfilled, the posts were cemented. Each sample was positioned on a custom fixture and scanned using a Microtomograph. Each sample was evaluated using CTAn v.1.12 software (Bruker-microCT) to obtain the surface area (mm2), volume of interest (mm3) of each pore between dentin and post at the coronal, middle and apical levels. Data were analyzed using Friedman's tests or repeated measures ANOVA. The volume of the pores between the three root thirds using the Friedman test, a significant global difference was found (F = 30.00; p < 0.05). The third in which the pores presented a greater volume (mm3) was the coronal third (means: 0.29250), followed by the middle (means: 0.03200) and apical (means: 0.00140) thirds. The comparison of the pore surface between the 3 thirds gave an analogous result to that of the volume comparison. The largest surface area (mm2) corresponded to the coronal third (mean ± SD 1.66377 ± 0.27175), followed by the middle (mean ± 1.16210 ± 0.20343) and apical (mean ± 0.41074 ± 0.12641) thirds.Microtomography allowed a quantitative and qualitative analysis of the pores in the entire sample without deterioration. It can be concluded that the coronal third has more pores than the apical third with the cementation technique used. Regarding the surface and volume of the pores, the results found are similar to those reported by various authors (AU)

Avaliação da perda óssea utilizando diferentes parâmetros na análise microtomográfica: estudo em ratos / Bone loss assessment using different parameters in the microtomographic analysis: study in rats

Introdução: o desafio no uso do Micro-Ct tem sido estabelecer e padronizar padrões adequados para escaneamento e tratamento das imagens, para que se obtenha o máximo desempenho do equipamento, e permitir a comparação dos achados entre diferentes estudos. Objetivo: o presente estudo tem como objetivo comparar a porcentagem de volume ósseo em regiões com perda óssea periodontal utilizando diferentes metodologias para definição da área a ser analisada (ROI). Material e método: dez ratos foram submetidos à indução de doença periodontal, e, após a eutanásia, as mandíbulas foram escaneadas com cortes de 9 µ e 18 µm de espessura, com passo de rotação de 0.3mm. As imagens foram reconstituídas utilizando o software NRecon, e em seguida, utilizando o software CTAnalyser - CTAn, foram definidas as áreas de interesse (ROI) ao redor dos segundos molares. A primeira área de interesse (ROI1) foi definida em um padrão retangular que se restringiu às regiões interproximais e furca, onde a área total de tecido ósseo foi obtida somando os resultados dos 3 ROIs. A segunda área (ROI2) foi definida no sentido corono/apical ao redor do segundo molar até suas limitações proximais com os dentes vizinhos, onde a porcentagem de tecido ósseo pertencente às raízes foram excluídas das avaliações. As análises foram realizadas com cinco diferentes valores de thresholds (130-50, 130-60, 130-70, 130-80, 130-90 e 130-100). Resultado: a análise entre os diferentes ROIs demonstrou que em ambas as análises foi observada a tendência a menor porcentagem de tecido ósseo quanto maior o contraste de tons de cinza utilizado, no entanto, nos resultados obtidos no ROI2 essa diferença não foi estatisticamente significante. Conclusão: com os resultados obtidos pode se concluir que a utilização de diferentes thresholds para quantificação óssea, em áreas onde houve doença periodontal, pode trazer resultados divergentes; a definição da área de interesse interfere com os resultados obtidos e que a obtenção de uma área de interesse com a remoção das raízes mostrou-se menos susceptível à variação dos parâmetros de escaneamento.

Introduction: the challenge in the use of Micro-Ct has been to establish and standardize adequate standards for scanning and image processing to obtain the maximum performance of the equipment and to allow the comparison of findings between different studies. Objective: this study aims to compare the percentage of bone volume in regions with periodontal bone loss using different methodologies to define the area to be analysed (ROI). Material and method: ten rats were submitted to periodontal disease induction, and, after euthanasia, the mandibles were scanned with slices of 9µ and 18 µm thickness, with a rotation step of 0.3mm. The images were reconstructed using the NRecon software, and then, using the CTAnalyser - CTAn software, the areas of interest (ROI) around the second molars were defined. The first area of interest (ROI1) was defined in a rectangular pattern that was restricted to the interproximal and furcation regions, where the total area of bone tissue was obtained by adding the results of the 3 ROIs. The second area (ROI2) was defined in the coronal/apical direction around the second molar to its proximal limitations with the neighboring teeth, in which the percentage of bone tissue belonging to the roots was excluded from the evaluations. Analyses were performed with five different threshold values (130-50, 130-60, 130-70, 130-80, 130-90, and 130-100). Result: the analysis between the different ROIs showed that, in both analyses, there was a tendency towards a lower percentage of bone tissue the greater the grayscale contrast used. However, in the results obtained in ROI2, this difference was not statistically significant. Conclusion: with the results obtained, it can be concluded that the use of different thresholds for bone quantification, in areas where there was a periodontal disease, can bring divergent results; the definition of the area of ​​interest interferes with the results obtained; and that obtaining an area of interest with the removal of the roots, proved to be less susceptible to the variation of the scanning parameters.

Effect of implant crestal position on primary stability before and after loading: an in vitro study / Efeito do posicionamento crestal do implante na estabilidade primária antes e após carga: um estudo in vitro

Introduction: Primary stability is one of the goals of modern implant dentistry and if achieved, reduces treatment time for prosthetic rehabilitation and the number of interventions made in patients mouth. Several companies state as protocol for connical conection implants, a subcrestally positioning. Objective: This in vitro study aimed to evaluate the effect of placing a conical connection implant equicrestally and subcrestally on static and loading condition in two types of bone density. Material and method: A total of 200 bone cylinders were extracted from femur of pigs, standardized by means of x-rays and computerized microtomography scan (microCT) and separated in low and high density specimens. The implants were placed on the center of the bone cylinders and were evaluated before and after loading by means of microCT and histomorphometry. Result: The results showed that placing the evaluated implant subcrestally provided better primary stability and performance on static and loading situations on low and high density bone. Conclusion: Placing implant subcrestally improve primary stability outcomes under loading and static situations.

Introdução: A estabilidade primária é um dos objetivos da implantodontia moderna e, caso atingida, reduz o tempo de tratamento para a reabilitação protéticas e o número de intervenções realizadas. Diversas empresas preconizam a posição subcrestal no uso de implantes com conexão cônica interna. Objetivo: Este estudo in vitro avaliou o efeito do posicionamento de implantes de conexão conica interna sub e equicrestal sob condições estáticas e em função, considerando dois tipos de densidades ósseas. Material e método: um total de 200 espécimes de osso extraído do femur de suínos e padronizados por meio de radiografias e microtomografias computadorizadas foram separados em densidade alta e baixa. Implantes foram instalados no centro dos especimes e for a avaliados por meio de microCT e histomorfometria. Resultado: Os resultados demonstraram que a colocação de implante subcrestalmente promoveu melhor estabilidade primária e performance em todas as situações, irrespectivamente à densidade óssea. Conclusão: A colocação de implantes subcrestalmente melhora a estabilidade primária em todas as situações, sendo indicada quando da utilização de conexões cônicas internas.

Effect of straight-line minimally invasive access cavity on the mechanical properties of maxillary first premolars: a finite element analysis / 中华口腔医学杂志

Objective: To investigate the effects of straight-line minimally invasive access cavity on the mechanical properties of endodontically treated maxillary first premolars using finite element analysis. Methods: Micro-CT data of twenty maxillary first premolars were collected for three-dimensional reconstruction. Three access cavities, including the conventional access cavity (ConvAC), the truss access cavity (TrussAC) and the straight-line minimally invasive access cavity (SMIAC), as well as the root canal treatment procedure, were simulated in all the 20 reconstruction samples of three-dimensional models, respectively. The peak von Mises stress on the cervical area of each model, as well as the stress distribution under vertical and oblique loading circumstances, were subsequently determined by using finite element analysis. Results: In comparison to the stresses of ConvAC [buccal cervical (BC): (188.7±13.4) MPa, palatal cervical (PC): (200.9±25.7) MPa], the stresses of TrussAC [BC: (146.0±12.9) MPa, PC: (167.6±15.9) MPa] (t=9.01, P<0.001; t=4.59, P<0.001) and SMIAC [BC: (142.6±13.7) MPa, PC: (168.1±17.4) MPa] (t=9.64, P<0.001; t=3.76, P=0.004) significantly reduced the peak von Mises stress on the cervical area of the maxillary first premolars after root canal treatment. Under vertical loading conditions, SMIAC also reduced the central tendency of stresses on the occlusal surface, cervical area and root. In the case of oblique loading conditions, similar results were observed. Under both loading conditions, there was no significant difference in the peak von Mises stress on the cervical area of the maxillary first premolar between TrussAC and SMIAC groups. Conclusions: The design of SMIAC could preserve the mechanical properties of the maxillary first premolar following root canal treatment, which might have certain clinical feasibility.

Anti-inflammatory effects of aucubin in cellular and animal models of rheumatoid arthritis / 中国天然药物

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease. It is known that aucubin (AU) exerts anti-inflammatory activity, but its effects and mechanisms in RA are unclear. This study investigated the anti-inflammatory effects and mechanisms of AU in vivo and in vitro. Human fibroblast-like synoviocyte cells from patients with RA (HFLS-RA), RAW264.7 cells, and MC3T3-E1 cells were used to evaluate the effects of AU on migration, invasion, apoptosis, osteoclast differentiation and production. Immunofluorescence was used to observe nuclear translocation of nuclear factor (NF)-κB, the double luciferase reporter gene method was used to observe NF-κB-p65 activity in AU-treated MC3T3-E1 cells. RT-qPCR was used to measure expression of bone metabolism and inflammation-related genes, and western blot was used to measure bone metabolism and NF-κB protein expression levels. Collagen-induced arthritis (CIA) rat model was used for pharmacodynamics study. Arthritis indexes were measured in the ankle and knee, histological staining and Micro-computed tomography were performed on the ankle joints. Also, inflammatory factor gene expression and the levels of NF-κB-related proteins were detected as in vitro. AU effectively inhibited HFLS-RA cell migration and invasion, promoted apoptosis, and inhibited RAW264.7 cell differentiation into osteoclasts, as well as inhibited NF-κB-p65 activity in MC3T3-E1 cells. Notably, AU significantly reduced the gene expression levels of three cell-related inflammatory factors and bone metabolism factors, effectively inhibited the expression of p-Iκκα β, p-IκBα, and p-p65 proteins. In vivo, AU relieved joint inflammation, reduced related inflammatory factors, and inhibited NF-κB signaling. It could be used to treat RA-related synovial inflammation and bone destruction through the NF-κB pathway.

Effect of Taohong Siwu Decoction() early intervention on mesenchymal stem cells homing in fracture healing in rats / 中国骨伤

OBJECTIVE@#To observe the effects of Taohong Siwu Decoction(, THSWD) on the mesenchymal stem cells(MSCs) migration, homing number and cytokine expression in callus during the early process of fracture healing, and to explore the mechanism of THSWD on accelerationg fracture healing by regulating the homing of MSCs in rats.@*METHODS@#A rat model of right femoral shaft open fracture was established. Thirty-two 5-week-old male Sprague-Dawley rats, weighting 110 to 130 g, were divided into control group, low-dose group, medium-dose group and high-dose group by using random number table. Distilled water was given to the control group, and the other groups were given Taohong Siwu Decoction. The rats were gavaged twice a day for 5 consecutive days after surgery. Bone volume/tissue volume(BV/TV) and bone mineral density(BMD) were observed using micro-computed tomography (micro-CT) at 21 days after surgery. At 5 days post-fracture, peripheral blood MSCs from THSWD treated and untreated rats were cultured in vitro. Subsequently, the migration ability of MSCs was observed by cell migration assay. The number of MSCs homing to the callus at the early stage of fracture (5 d) was detected by Immunohistochemistry (IHC). Protein chip was used to detect the expression of cytokines in callus.@*RESULTS@#Micro-CT results showed that BV/TV was higher in the high-dose group than in the medium-dose group (P=0.032), and higher in the medium-dose group than in the low-dose group(P=0.041), with no difference between the control and low-dose group (P=0.651). In addition, there was no difference in BMD between low-dose group and the model group (P=0.671), and lower in the low-dose group than in the medium-dose group(P=0.018), and the medium-dose group was lower than the high-dose group(P=0.008). Cell migration assay showed that THSWD promotes enhanced the migration ability of peripheral blood MSCs. IHC assay revealed that CD45-, CD90+, CD29+ MSCs significantly increased in bone callus after THSWD intervention compared with the control group. Protein chip showed that THSWD promoted the upregulation of CINC-1(×2.91), CINC-3(×1.59), LIX(×1.5), Thymus Chemokine (×2.55), VEGF (×1.22) and the down-regulation of TIMP-1 (×2.98).@*CONCLUSION@#THSWD, a representative formula of "promoting blood circulation and removing blood stasis", can significantly accelerate fracture healing, and its mechanism may be related to enhancing the migration ability of peripheral blood MSCs and up-regulating CINC-1, CINC-3, LIX, Thymus Chemokine, VEGF and down-regulating TIMP-1 in bone callus, which promotes the peripheral blood MSCs homing in the early stage of fracture.

Retreatment of mesial roots of mandibular molars filled with resin-based and bioceramic sealers

Aim: The aim of this study was to evaluate, by micro-computed tomography (micro-CT) analysis, the remaining filling material during endodontic retreatment performed with Protaper retreatment without solvent. Methods: Forty mandibular molars were divided into two groups (n = 20) according to the sealer used in the obturation: the bioceramic TotalFill BC (TF) or the resin-based AH Plus (AHP). The specimens were scanned before instrumentation, after obturation and after filling removal. Only the mesial roots were analysed. The filling volumes and the remaining filling material were calculated in the entire root canal and in the cervical, middle and apical thirds. Results: The volume of obturation and the volume of remaining filling material in the entire root canal and in the cervical, middle and apical thirds of the canal between the groups were not statistically different (independent t-test, p > 0.05). In the AHP group, there was a higher percentage of remaining filling material in the middle third than in the cervical third (p < 0.05). Conclusion: The filling material could not be entirely removed from any specimen

Alveolar bone loss with microarchitecture changes in aged rat / Pérdida ósea alveolar con alteraciones en la microarquitectura en ratas envejecidas

SUMMARY: The aim of the present study was to evaluate the changes of alveolar bone in aged rats. The mandibles of the 4- month and 22-month aged rats were scanned by micro-CT. After the reconstruction of the alveolar bone,the distance between the cemento enamel junction (CEJ) and the alveolar bone crest (ABC) was measured. The micro architectures of the inter-radicular alveolar bone were analyzed. The 22-month rats experienced the reduction in alveolar crest height in the buccal side and the lingual side, and significant increase in alveolar bone loss compared with the 4-month rats. The 22-month rats had a porous microarchitecture, the trabecular arrangement was obviously dissociated with the expanded inter-bone spaces of marrow, and the bone histomorphometry analysis showed the decreased bone volume/tissue volume and trabecular thickness in the 22-month rats. These results suggest that alveolar bone loss and alveolar trabecular bone deterioration might contribute to the weakening of molar support in the elderly.

RESUMEN: El objetivo del presente estudio fue evaluar los cambios del hueso alveolar en ratas envejecidas. Las mandíbulas de las ratas de 4 y 22 meses se escanearon mediante micro-TC. Después de la reconstrucción del hueso alveolar, se midió la distancia entre la unión cementoesmalte (CEJ) y la cresta ósea alveolar (ABC). Se analizaron las microarquitecturas del hueso alveolar interradicular. Las ratas de 22 meses experimentaron la reducción de la altura de la cresta alveolar. en el lado bucal y lingual, y un aumento significativo en la pérdida de hueso alveolar en comparación con las ratas de 4 meses. Las ratas de 22 meses tenían una microarquitectura porosa, la disposición trabecular estaba obviamente disociada con los espacios interóseos expandidos de la médula y el análisis de histomorfometría ósea mostró una disminución del volumen óseo / volumen tisular y del grosor trabecular en las ratas de 22 meses. Estos resultados sugieren que la pérdida ósea alveolar y el deterioro del hueso trabecular alveolar podrían contribuir al debilitamiento del soporte molar en los ancianos.

Marginal gaps and internal voids after root-end filling using three calcium silicate-based materials: A Micro-CT analysis

Abstract This study evaluated the 3D quality of root-end filling, assessing the presence (volume and percentage) of marginal gaps and internal voids formed after retro-filling with three calcium silicate-based materials: MTA Angelus (Angelus Soluçoes Odontologicas, Londrina, PR, Brazil), Biodentine (Septodont Ltd., Saint Maur-des-Faussés, France) and Neo MTA Plus (Avalon Biomed Inc., Bradenton, Florida, US). Thirty human, extracted, single rooted teeth were used. Orthograde root canal treatment, root resection (3mm shorter than the apex) and retrograde cavity preparation with ultrasonic tips were performed. Teeth were divided into 3 groups (n =10 each) following a stratified randomization according to the initial volume of the root-end cavity. After retrofilling, samples were stored for 7 days. Then, two rounds of micro-CT scans were performed: soon after root-end preparation (with the cavity still empty) and 7 days after root-end filling. Marginal gaps, internal voids volume (mm3 and %), as well as, the overall defects (sum of gaps and voids) were evaluated. Statistics compared the three groups in relation to those defects. There was not statistical difference between groups regarding the marginal gaps (P≥ 0.05), the internal voids (P≥ 0.05), and the overall defects (P≥ 0.05). Median (mm3) and % of overall air-entrapment defects (gaps and/or voids) was: 0.004mm3 and 1.749% for MTA Angelus, 0.018mm3 and 6.660% for Biodentine, and 0.012mm3 and 4.079% for Neo MTA Plus. All materials had gaps and/or voids. No differences were found between MTA Angelus, Biodentine and Neo MTA Plus.

Resumo Este estudo avaliou a qualidade 3D de retro-obturações, avaliando a presença (volume e percentagem) de "gaps" marginais e "voids" internos formados a partir da retro-obturação com três materiais à base de silicato de cálcio: MTA Angelus (Angelus Soluções Odontológicas, Londrina, PR, Brasil), Biodentine (Septodont Ltd., Saint Maur-des-Faussés, França) and Neo MTA Plus (Avalon Biomed Inc., Bradenton, Flórida, US). Trinta dentes humanos unirradiculares extraídos foram usados. Após tratamento de canal ortrógrado, resecção radicular (3 mm apicais), o prepare da cavidade retrógrada com pontas ultrassônicas foi realizado. Os dentes foram divididos em três grupos (n= 10 cada) seguindo uma randomização estratificada, de acordo com o volume inicial da cavidade retrógrada. Depois da retro-obturação as amostras foram armazenadas por 7 dias. Duas rodadas de escaneamento de micro-CT foram realizadas: logo após o preparo retrógrado (com a cavidade ainda vazia) e 7 dias após a retro-obturação. O volume de "gaps" marginais e de "voids" internos (mm3 e %), bem como, os defeitos totais (soma de "gaps" e "voids") foram avaliados. Não houve diferença estatística entre os grupos em relação aos "gaps" marginais (P≥ 0,05), "voids" internos (P≥ 0,05), e aos defeitos totais (P≥ 0,05). A mediana (mm3) e porcentagem dos defeitos totais de aprisionamento de ar foi 0,004mm3 e 1,749% para o MTA Angelus, 0,018mm3 e 6,660% para o Biodentine, e 0,012mm3 e 4,079% para o Neo MTA Plus. Todos os materiais tiveram defeitos ("gaps"e/ou "voids"). Não houve diferença entre MTA Angelus, Biodentine e Neo MTA Plus.

Influência da agulha e fluxo de irrigação na limpeza do canal radicular e extrusão apical de irrigante: análise em micro-CT / Influence of needle and irrigation flow rate on root canal cleaning and apical extrusion of irrigant: Micro-CT analysis

Introdução: O tipo de agulha e fluxo de irrigação é importante para a limpeza adequada no terço apical do canal radicular. Objetivo: Avaliar a influência do tipo de agulha e fluxo de irrigação na limpeza do canal radicular e canais laterais simulados e na extrusão apical do irrigante. Métodos: Trinta e dois dentes de resina foram utiliza- dos. Após a instrumentação do canal radicular, foram feitos quatro canais laterais a 2 e 7 mm do ápice. Os canais radiculares foram preenchidos com solução de contraste. Os canais foram irrigados com dois tipos de agulha, 29G e 31G, com diferentes designs (abertura lateral e apical) e dois fluxos (2 ou 5 mL/min), a 1 mm aquém do comprimento de trabalho. O volume da solução de contraste nos canais principal e laterais após irrigação e a extrusão apical do irrigante (mm3 ) foi avaliado por micro-CT, em comparação com a análise inicial. Os dados em porcentagem foram analisados pelos testes ANOVA e Tukey (α=0,05). Resultados: não houve diferença entre os protocolos de irrigação para limpeza da solução de contraste. Maior volume de extrusão apical com agulha 29G com abertura apical e 5 mL/min foi observado, em comparação ao mesmo tipo de agulha e 2 mL/min (p<0,05). Conclusão: Todos os protocolos de irrigação foram associados à limpeza dos canais radiculares. Maior extrusão apical foi observada com agulha 29G ­ abertura apical com maior fluxo de irrigação (5 mL/min). Implicações clínicas: Irrigação endodôntica com agulha com abertura apical e maior fluxo da solução pode favorecer a extrusão dos irrigantes para os tecidos periapicais (AU).

Introduction: needle and irrigation flow rate are important for proper cleaning of the root canal. Aim: to evaluate the influence of type of needle and irrigation flow rate on cleaning of root canal and simulated lateral canals and the apical extrusion of irrigant. Methods: Thirty-two resin teeth were used. After root canal instrumentation, four lateral canals were made at 2 and 7 mm from the apex. Root canals were filled with contrast solution. The root canals were irrigated with two types of needle, 29G and 31G, with different designs (side and apical opening) and two flow rates (2 or 5 mL/min), at 1 mm short of the working length. The volume of the contrast solution in the main and lateral canals after irrigation and apical extrusion of the irrigant (mm3) were evaluated by Micro-CT, in comparison with the initial analysis. Data in percentage were analyzed by ANOVA and Tukeys tests (α = 0.05). Results: no difference among the irrigation protocols for contrast solution cleaning was observed. Higher volume of apical extrusion using needle 29G-apical opening and 5 mL/min in comparison with the same type of needle and 2 mL/min was observed (p < 0.05). Conclusion: all irrigation protocols were associated with root canals cleaning. Greater apical extrusion was observed for needle 29G-apical opening with higher irrigation flow rate (5 mL/min). Clinical implications: endodontic irrigation using a needle with apical opening and higher flow rate of solution may favor extrusion of irrigant to the periapical tissues (AU).

Effect of different dimensions of test samples on the volumetric change assessment of endodontic materials

Abstract New methodologies using micro-CT to evaluate solubility besides dimensional and morphological changes of endodontic materials are proposed. However, there is no standardization in the methods. The aim of this study was to assess the effect of different dimensions of test samples on volumetric change evaluation of different endodontic materials. AH Plus, FillCanal and Sealapex root canal sealers, Biodentine, IRM and MTA root-end filling cements were used in the tests. Samples of each material with a thickness of 1.5 mm and different diameters were manufactured: 6.3, 7.75, and 9.0 mm. The samples were scanned in micro-computed tomography (micro-CT) after setting and after 7 days of immersion in distilled water. The volumetric change was evaluated by means of the difference in the total volume of the specimens before and after immersion. Data were submitted to ANOVA and Tukey tests (p<0.05). The size of the samples did not affect the percentage of volumetric change of the materials (p>0.05). All sample sizes had greater volume loss for Sealapex among the sealers and Biodentine for the cements (p<0.05). In conclusion, Biodentine and Sealapex had the highest volume loss after immersion. Samples with 1.5 mm thickness, and diameters ranging between 6.3 and 9.0 mm can be used to assess the stability of endodontic materials using micro-CT without affecting the percentage of volumetric change.

Resumo Novas metodologias utilizando micro-CT são propostas para avaliar a solubilidade além de alterações dimensionais e morfológicas em materiais endodônticos. No entanto, não há padronização nos métodos. O objetivo deste estudo foi avaliar o efeito de diferentes dimensões de corpos de prova na avaliação da alteração volumétrica de diferentes materiais endodônticos. Os cimentos obturadores AH Plus, FillCanal e Sealapex e os cimentos retrobturadores Biodentine, IRM e MTA foram utilizados nos testes. Foram confeccionadas amostras de cada material com espessura de 1.5 mm e diâmetros diferentes: 6.3, 7.75 e 9.0 mm. As amostras foram escaneadas em microtomografia computadorizada (micro-CT) após a presa e após 7 dias de imersão em água destilada. A alteração volumétrica foi avaliada por meio da diferença no volume total dos corpos de prova antes e após a imersão. Os dados foram submetidos aos testes ANOVA e Tukey (p<0,05). A dimensão das amostras não afetou o percentual de alteração volumétrica dos materiais (p>0,05). Todos os diâmetros de amostra mostraram maior perda de volume para Sealapex entre os cimentos obturadores e Biodentine entre os cimentos retrobturadores (p<0,05). Como conclusão, Biodentine e Sealapex mostraram a maior perda volumétrica após a imersão. Amostras com 1.5 mm de espessura e diâmetros variando entre 6.3 e 9.0 mm podem ser usadas para avaliação da estabilidade de materiais endodônticos utilizando micro-CT, sem influenciar no percentual de alteração volumétrica.

Influence of base materials on stress distribution in endodontically treated maxillary premolars restored with endocrowns / 北京大学学报(医学版)

OBJECTIVE@#To evaluate the influence of base materials on stress distribution in endodontically treated maxillary premolars restored with endocrowns using three-dimensional finite element analysis.@*METHODS@#A maxillary second premolar was scanned by Micro-CT and a three-dimensional finite element model of ceramic endocrown with 1 mm thickness of base was established. A model without base was also established as a negative control. Four kinds of conventional base materials with different elastic modulus were adopted: light cure glass ionomer(3M Vitrebond, 3 657 MPa), flowable composite resin(3M Filtek Z350XT Flowable Restorative, 7 300 MPa), high strength glass ionomer(GC Fuji Ⅸ, 13 130 MPa), and posterior composite resin(3M Filtek P60, 19 700 MPa). With a 200 N force loaded vertically and obliquely, the distribution and magnitude of stress in the tooth tissue and adhesive layer were investigated by three-dimensional finite element analysis.@*RESULTS@#The maximum von Mises stress values(vertical/oblique) in dentin and adhesive layer were measured as follows: (1) no base material: 19.39/70.49 MPa in dentin and 6.97/17.97 MPa in adhesive layer; (2) light cure glass ionomer: 19.00/69.75 MPa in dentin and 6.87/16.30 MPa in adhesive layer; (3) flowable composite resin: 18.78/69.33 MPa in dentin and 6.79/16.17 MPa in adhesive layer; (4) high strength glass ionomer: 18.71/69.20 MPa in dentin and 6.74/16.07 MPa in adhesive layer; (5) posterior composite resin: 18.61/69.03 MPa in dentin and 6.70/16.01 MPa in adhesive layer. Under the same loading condition, models with different elastic moduli of base materials had similar stress distribution patterns. The von Mises stress of tooth tissue was mainly concentrated in the tooth cervix. Under oblique load, the regions where von Mises stress concentrated in were similar to those under a vertical load, but the values increased. The stress concentration in the tooth cervix was alleviated in models with base materials compared with the model without base material. The maximum von Mises stress in the tooth tissue and adhesive layer decreased when the elastic modulus of base materials increased and got close to that of dentin.@*CONCLUSION@#The posterior composite resin of which the elastic moduli is high and close to that of dentin is recommended as base material for premolar endocrowns to alleviate the concentration of stress in tooth cervix and adhesive layer.

In vivo study of liposome-modified polyetheretherketone implant on bacteriostasis and osseointegration / 北京大学学报(医学版)

OBJECTIVE@#To develop dexamethasone plus minocycline-loaded liposomes (Dex/Mino liposomes) and apply them to improve bioinert polyetheretherketone (PEEK) surface, which could prevent post-operative bacterial contamination, enhance ossification for physiologic osseointegration, and finally reduce implant failure rates.@*METHODS@#Dex/Mino liposomes were covalently grafted onto the PEEK surface using polydopamine (pDA) coating as a medium. Confocal laser scanning microscopy was used to confirm the binding of fluorescently labeled liposomes onto the PEEK substrate, and a microplate reader was used to semiquantitatively measure the average fluorescence intensity of fluorescently labeled liposome-decorated PEEK surfaces. Moreover, the mouse subcutaneous infection model and the beagle femur implantation model were respectively conducted to verify the bioactivity of Dex/Mino liposome-modified PEEK in vivo, by means of micro computed tomography (micro-CT) and hematoxylin and eosin (HE) staining analysis.@*RESULTS@#The qualitative and quantitative results of fluorescently labeled liposomes showed that, the red fluorescence intensity of the PEEK-pDA-lipo group was stronger than that of the PEEK-NF-lipo group (P < 0.05); the liposomes were successfully and uniformly decorated on the PEEK surfaces due to the pDA coating. After mouse subcutaneous implantation of PEEKs for 24 hours, HE staining results showed that the number of inflammatory cells in the PEEK-Dex/Mino lipo group were lower than that in the inert PEEK group (P < 0.05), indicating a lower degree of infection in the test group. These results suggested that the Mino released from the liposome-functionalized surface provided an effective bacteriostasis in vivo. After beagle femoral implantation of PEEK for 8 weeks, micro-CT results showed that the PEEK-Dex/Mino lipo group newly formed more continuous bone when compared with the inert PEEK group; HE staining results showed that more new bones were formed in the PEEK-Dex/Mino lipo group than in the inert PEEK group, which were firmly bonded to the functionalized PEEK surface and extended along the PEEK interface. These results suggested that the Dex released from the liposome-functionalized surface induced effective bone regeneration in vivo.@*CONCLUSION@#Dex/Mino liposome modification enhanced the bioactivity of inert PEEK, the functionalized PEEK with enhanced antibacterial and osseointegrative capacity has great potential as an orthopedic/dental implant material for clinical application.