Insertion methods and gap/void formation in atraumatic restorative technique: A micro-CT analysis

Abstract Wetting the dentin is critical to atraumatic restorative treatment. The conventional insertion can be challenging when using high-viscosity glass-ionomer cement. This study evaluated the formation of gaps and voids after three insertion methods using micro-CT. Teeth underwent removal of occlusal and proximal caries through the atraumatic restorative treatment technique. Then, they were fixed in an artificial dental arch to simulate the clinical condition and were restored using three insertion methods: conventional, Centrix injection, and double-filling. Previous dentin conditioning procedures, steel matrix and wooden wedge application, and post-insertion procedures (digital compression and surface protection) were the same. The material was inserted using a manual instrument in the conventional technique and was inserted with a syringe in the Centrix injection group. In the double-filling technique, the tooth received a first layer of a flowable ionomer (through modifying the powder/liquid ratio), and a second layer (with standard ratio) was applied before the final set of the first one. A micro-CT unit scanned each tooth before and after restoration. Each cavity was defined as the volume of interest, and the volumes of gaps and voids were calculated. Data were analyzed using one-way ANOVA and Tukey posthoc test (p < .05). Double-filling had improved filling volume with lower values for gap volume, followed by Centrix injection. The conventional technique had the highest gap volume. No statistically significant difference was observed for void volume. Double-filling demonstrated fewer gaps, followed by Centrix injection, which is critical to obtain better adhesive, remineralizing, and antibacterial activities.

Resumo O molhamento da dentina parcialmente desmineralizada no fundo da cavidade dentária é fundamental para o sucesso do tratamento restaurador atraumático. No entanto, o método de inserção convencional pode ser desafiador ao usar cimento de ionômero de vidro de alta viscosidade. Este estudo avaliou a formação de gaps e vazios internos após três métodos de inserção de cimento de ionômero de vidro de alta viscosidade usando micro-CT. Dez terceiros molares foram submetidos à remoção de cárie oclusal através da técnica de tratamento restaurador atraumático e complementação proximal (com ou sem lesão pré-existente). Em seguida, foram fixados em uma arcada dentária artificial para simular a condição clínica. Os dentes foram restaurados usando a técnica de tratamento restaurador atraumático com três métodos de inserção: convencional, injeção Centrix e dupla inserção. Os procedimentos anteriores de condicionamento dentinário, inserção de matriz de aço, aplicação de cunha de madeira e procedimentos pós-inserção do material (como compressão digital e proteção de superfície) foram os mesmos para os três grupos testados. O material foi inserido com instrumento manual na técnica convencional, seguindo a metodologia clássica do tratamento restaurador atraumático. O material foi inserido com um dispositivo desenvolvido especificamente para esse fim na técnica de inserção com seringa tipo Centrix. Na técnica de dupla obturação, o dente recebeu uma primeira camada do cimento de ionômero de vidro mais fluido (obtido através da modificação da relação pó/líquido), e uma segunda camada (com relação pó/líquido padrão) foi aplicada antes da presa final da primeira. Um micro-CT escaneou cada dente antes e depois da restauração. Cada cavidade foi definida como o volume de interesse, e os volumes de gaps e vazios foram calculados. Os dados foram analisados por ANOVA one-way e teste post-hoc de Tukey com nível de significância de 5%. A dupla inserção melhorou significativamente o volume de preenchimento com valores percentuais mais baixos para o volume do gap, seguido pela injeção com seringa tipo Centrix. A técnica convencional apresentou o maior percentual de volume de gap. Nenhuma diferença estatisticamente significativa foi observada para o volume de vazios internos. O grupo de dupla inserção demonstrou menor formação de gaps, seguido pelo grupo de injeção com seringa tipo Centrix, que é fundamental para obter melhores atividades adesivas, remineralizantes e antibacterianas.

Efectividad de las Técnicas de Retratamiento Endodóntico en la Remoción de ementos Biocerámicos como Material de Obturación Radicular: Revisión Sistemática

El retratamiento no quirúrgico es la primera opción ante el fracaso del tratamiento endodóntico, por lo que se vuelve importante asegurar el completo retiro del material de relleno del conducto radicular, para mejorar el pronóstico del procedimiento. Los cementos biocerámicos en base a silicatos cálcicos han aparecido en los últimos años, caracterizados principalmente por su bioactividad, lo que adicionalmente se puede traducir en una mayor dificultad para su retiro del conducto radicular. El objetivo de esta revisión es determinar qué técnica de retratamiento es más efectiva en la eliminación de cementos selladores biocerámicos, en base al volumen de material remanente en el conducto radicular, evaluado a través del análisis de imágenes con micro-CT. Se realizó una revisión sistemática mediante la búsqueda de publicaciones en las bases de datos Pubmed, ScienceDirect y SciELO, de los últimos 10 años, en idioma español e inglés. Se incluyeron sólo estudios in vitro de dientes obturados con cemento biocerámico y diferentes técnicas de retratamiento endodóntico, en los que se evalúe la limpieza del conducto post eliminación del relleno mediante micro-CT. De un total de 174 artículos encontrados, 7 fueron seleccionados, analizados y se incluyeron en esta revisión sistemática. Los resultados de los estudios seleccionados no encuentran diferencias significativas en la eliminación de material entre las diferentes técnicas de retratamiento evaluadas. A pesar de la heterogeneidad presente en las metodologías de los artículos analizados, ninguna técnica de retratamiento ni técnicas complementarias lograron dejar completamente limpios los conductos radiculares, por lo que se sugiere realizar nuevos estudios en el futuro que evalúen nuevas técnicas de desobturación radicular.

Non-surgical retreatment is the first option in the case of endodontic treatment failure, so it becomes important to ensure complete removal of the root canal filling material, to improve the prognosis of the procedure. Bioceramic cements based on calcium silicate have appeared in recent years, characterized mainly for their bioactivity, which can additionally translate into greater difficulty in their removal from the root canal. The aim of this review is to determine which retreatment technique is most effective in the removal of bioceramic sealer cements, evaluated through micro-CT image analysis. A systematic review was performed by searching for publications in Pubmed, ScienceDirect and SciELO databases, of the last 10 years in Spanish and English. Only in vitro studies of teeth filled with bioceramic cement and different endodontic retreatment techniques were included, in which the cleaning of the canal after removal of the filling was evaluated by micro- CT. From a total of 174 articles found, 7 were selected, analyzed and included in this systemic review. The results of the included studies did not find significant differences in the removal of material between the different retreatment techniques evaluated. Despite the heterogeneity in the methodologies of the studies, no retreatment technique or complementary techniques were able to completely clean the root canals, it is therefore suggested that new studies be carried out in the future to evaluate new techniques.

Observation of the growth and development of subchondral bone in rat condyles exposed to fluoride at the level of bone microarchitecture / 中华地方病学杂志

Objective:To observe the effect of fluoride on growth and development of bone microstructure of rats condyle subchondral bone (RCSB).Methods:Forty two 3-week-old SD rats (half male and half female) were fed adaptively for 1 week, and 3 females and 3 males were sacrificed and recorded as 0 month. The remaining rats were randomly divided into control group ( n = 18) and fluoride exposed group ( n = 18) according to their body weight (55 - 70 g), half male and half female. The fluoride exposed group was fed with 150 mg/L sodium fluoride (NaF) aqueous solution, and the control group was fed with tap water. The two groups of experimental animals were sacrificed at 3, 5 and 7 month, respectively, 6 rats in each group, half male and half female. The right mandibular condyle was separated, and Micro CT scanning was performed to detect the microstructure parameters of RCSB. Results:In fluoride exposed group (3 month), bone surface/tissue volume (BS/TV), bone surface/bone volume (BS/BV), trabecular thickness (Tb.Th), trabecular number (Tb.N), structure model index (SMI), connectivity, connectivity density (Conn.D) and total porosity of female rats were significantly different from those of male rats ( t = - 5.10, - 5.58, 4.52, - 4.32, - 4.03, - 2.81, - 6.71, - 3.32, P < 0.05). There was no significant difference in each index between female and male rats in fluoride exposed group (5, 7 month, P > 0.05). Conclusion:In chronic fluorine exposure bone environment, the RCSB bone microarchitecture of male and female rats is different with time, showing the tendency of fluoride injury that the bone changes of female rats are slowed and the bone changes of male rats are active.

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.

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.

Investigating the effect of the Toll-like receptor-4 inhibitor TAK-242 on alveolar bone resorption in severe periodontitis in rats / 口腔疾病防治

Objective@# The goal of this study was to investigate the effect of the Toll-like receptor-4 (TLR-4) inhibitor TAK-242 on bone resorption in severe periodontitis in rats in order to provide an experimental basis for finding new adjuvant treatments for severe periodontitis.@*Methods @# Eighteen three-week-old male Wistar rats were randomly divided into three groups (n=6). One group was the control group, and the other two groups were modelled with severe periodontitis in bilateral maxillary molars ligated with 5-0 silk thread containing P. gingivalis ATCC33277 (periodontitis and TAK-242 groups, respectively). The TAK-242 group was injected with TAK-242 (2 mg/kg) in DMSO every other day through the tail vein from the first day of silk ligation, and the other two groups were injected with DMSO solvent at the same proportion of body weight for 8 consecutive weeks. At the end of the 8th week, rats in the 3 groups were sacrificed, and maxillary specimens were taken. Three-dimensional reconstruction was achieved after micro-CT scanning to measure the distance between the enamel cementum boundary and alveolar crest at specific sites to assess the amount of bone loss. The parameters related to alveolar bone and bone microstructure were analyzed, and the pathological changes of periodontal tissue were observed by hematoxylin-eosin (HE) staining. Alveolar bone resorption was observed by Methyl Green staining, and the distribution of osteoclasts was observed by anti-tartrate acid phosphatase double staining (TRAP).@*Results@#Micro-CT quantitative analysis showed that alveolar bone resorption in the periodontitis group and TAK-242 group was significantly higher than that in the control group. Compared with the periodontitis group, bone loss of the mesial and distal root resorption sites of maxillary first molars was significantly reduced in the TAK-242 group (P < 0.001), the bone mineral density (P < 0.05) and bone volume/total volume fraction (P < 0.01) were significantly increased, and the number of trabeculae and the trabeculae thickness (P < 0.01) were relatively increased. The trabecular separation (P < 0.01) and trabecular structure model index were significantly decreased. In the periodontitis group, the bone exhibited a sparse and porous honeycomb structure, with deterioration of the trabecular structure and a shift towards a rod-strength structure. In the TAK-242 group, the bone microstructure was improved, the bone volume was enriched, the distribution of trabeculae was relatively denser and the trabecular structure shared more similarities with the control group. HE staining displayed that the attachment loss and bone absorption were significantly higher in the periodontitis group and TAK-242 group than in the control group. Compared with the periodontitis group, MG staining displayed significantly alleviated bone absorption in the TAK-242 group. TRAP staining showed that osteoclast infiltration decreased in the TAK-242 group compared with the periodontitis group (P < 0.001)@*Conclusions @#The TLR-4 inhibitor TAK-242 can alleviate bone resorption in severe periodontitis and improve the porous, sparse and disorganized inflammatory bone trabecular structure in rats.

Effect of Jinlida Granules on Visceral Fat Accumulation in Prediabetic Rats / 中国实验方剂学杂志

ObjectiveTo study the effect of Jinlida granules on visceral fat accumulation and its induced inflammatory response in prediabetic rats. MethodMale SD rats were randomly divided into normal group， model group， Jinlida low-dose group （1.5 g·kg-1）， Jinlida high-dose group （3.0 g·kg-1） and atorvastatin group （10 mg·kg-1）. Prediabetic rat model was established using high-carbohydrate， high-fat diet combined with low-dose streptozotocin （STZ） by multiple small-dose intraperitoneal injections. After 8 weeks of modeling and drug intervention for 13 consecutive weeks， body weight， oral glucose tolerance test（OGTT）， fasting blood glucose （FBG）， fasting insulin （FINS）， insulin resistance index （HOMA-IR）， total cholesterol （TC）， low-density lipoprotein cholesterol （LDL-C） and high-density lipoprotein cholesterol （HDL-C） were measured in each group of rats. The content of visceral fat was quantified by micro-computed tomography （Micro-CT）. Hematoxylin-eosin staining （HE） was used to observe the pathological changes of fat cells. The levels of tumor necrosis factor-α （TNF-α） and interleukin- 6 （IL-6） in rat visceral fat and serum were determined by enzyme linked immunosorbent assay （ELISA）. The expression of macrophage marker CD68 in visceral fat was detected by immunofluorescence and Western blot. ResultCompared with normal group， model group had increased oral glucose tolerance， FBG， FINS， HOMA-IR， TC， LDL-C （P<0.01）， elevated body weight and visceral fat accumulation （P<0.05， P<0.01）， enhanced CD68 protein expression and TNF-α and IL-6 levels （P<0.01）， decreased HDL-C （P<0.01）， and abnormal hypertrophy of adipocytes. Compared with model group， Jinlida high- and low-dose groups lowered oral glucose tolerance， HOMA-IR， TC and LDL-C （P<0.05， P<0.01）， body weight and visceral fat accumulation （P<0.05）， and CD68 protein expression and TNF-α and IL-6 levels （P<0.05， P<0.01） and lessened hypertrophy of fat cells. ConclusionJinlida can improve the insulin resistance in prediabetic rats by reducing visceral fat accumulation and its induced inflammatory response， which provides a new pharmacological basis for clinical treatment of prediabetes by Jinlida granules.

Effects of long-term high-fat diet on bone mineral density and intestinal flora / 中华内分泌代谢杂志

Objective:To investigate the effects of long-term high-fat diet on bone mineral density and intestinal flora in mice.Methods:Sixteen male C57BL/6 mice were randomly divided into control group (NC group) and high-fat group (HF group). After 24 weeks of high-fat feeding, biochemical indicators such as blood glucose and blood lipids were detected, bilateral femurs were taken and bone microstructure was analyzed with micro-computered tomography (micro-CT), and changes of intestinal microbial composition and proportion were revealed using 16S rDNA sequencing technology.Results:Compared with the control group, the serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) in HF group were significantly increased. Micro-CT uncovered that the bone mineral density (Tb.BMD), bone volume fraction (BV/TV) and the number of trabecular bone (Tb.N) decreased, yet structural model index (SMI) and the trabecular fraction (Tb.Sp) increased in the HF group mice. The gut microbiota 16S rDNA sequence analysis showed that the proportion of Proteobacter was significantly increased and the proportions of pachycete, warty microbacterius, and actinomycete were reduced in HF group at the phyla level. The proportion of Bacteroidetes S24-7_norank in the NC group was significantly higher than that in the HF group, and the multilevel discriminant analysis of species differences (LEfSe) identified that the difference was significant, yet the proportion of Bacteroides, Pseudo-Prevotella, Desulfovibrio, Altobacter, and Helicobacter in the HF group were higher than those in the NC group, which were significant differences in Altobacter and Helicobacter at genus level.Conclusion:Long-term high-fat feeding can cause the destruction of femoral trabecular structure, decrease in the number of trabeculus bones, and bone mineral density in C57BL/6 mice. It also leads to significant changes in the composition and proportion of the intestinal flora.

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.

Effect of handpiece light and material used in pulp chamber on dentin removal during root canal retreatment

Abstract This study evaluated the effect of the use of glass ionomer cement (GIC) and flowable bulk-fill resin composite (BFRC) for filling pulp chambers and the type of high-speed handpiece light used on dentin removal during access preparation for endodontic retreatment in molar teeth. Twenty maxillary molars were treated endodontically. BFRC (Opus Bulk Fill Flow APS, FGM) was used to fill the pulp chamber and replace coronal dentin (n = 10). In the remaining teeth, the pulp chamber was filled with GIC (Maxion R, FGM). Conventional resin composite (Opallis, FGM) was used to restore the enamel layer in all teeth. The samples in each group were divided into two subgroups, and the root canals were reaccessed using a handpiece with white or ultraviolet light. The teeth were scanned using micro-CT before and after root canal reaccess. The dentin volume removed was calculated and analyzed using 2-way analysis of variance and Tukey's test (α = 0.05). The crown and pulp chamber locations with dentin removal are described using frequency distribution. During the access, fewer pulp chamber walls were affected and a lower volume of dentin was removed from the pulpal floor in the group restored with GIC than in the group restored with BFRC. No effect was observed on the coronal dentin walls with respect to the filling protocols and type of light used. For dentin removal from the pulp chamber, handpieces with white light performed better than those with ultraviolet light, irrespective of the filling protocol used. The use of GIC to fill the pulp chamber and use of white handpiece light reduced dentin removal from the pulpal floor and resulted in fewer affected dentin walls.

Resumo Este estudo avaliou os efeitos do cimento de ionômero de vidro (GIC) e da resina composta fluida bulk fill (BFRC) usados como preenchimento da câmara pulpar; e o tipo de iluminação das turbinas de alta rotação na remoção dentinária após cavidades de acesso para retratamento endodôntico em dentes molares. Vinte molares superiores foram tratados endodonticamente. Dez dentes foram restaurados usando BFRC (Opus Bulk Fill Flow APS, FGM) para preencher a câmara pulpar e dentina coronária; e resina composta convencional (Opallis, FGM) para restaurar a camada de esmalte. Os outros dentes foram restaurados usando GIC (Maxion R, FGM) para preencher a câmara pulpar e resina composta (Opallis, FGM). As amostras foram divididas em dois grupos e os canais radiculares foram novamente acessados com turbina de alta-rotação com iluminação branca ou ultravioleta. Os dentes foram escaneados usando micro-CT antes e após o novo acesso ao canal radicular. O volume de dentina removida foi calculado e os dados foram analisados por ANOVA bidirecional e teste de Tukey (α=0,05). As regiões na coroa e na câmara pulpar que apresentaram dentina removida no acesso dos canais foram descritas por meio de distribuição por frequência. A reabertura do canal radicular com GIC resultou em menos paredes afetadas da câmara pulpar e menor volume de dentina removida no assoalho. Nenhum efeito foi observado nas paredes de dentina coronária considerando aos protocolos de preenchimento. A turbina de alta rotação com iluminação branca reduziu a remoção de dentina da câmara pulpar, independentemente do protocolo de restauração utilizado. O uso de turbina de alta rotação com iluminação branca e GIC para preencher a câmara pulpar reduziram a remoção de dentina do assoalho e afetaram menos paredes dentinárias.

Micro-CT analysis of hyperuricemia on alveolar bone destruction caused by short-term periodontal infection in mice / 口腔疾病防治

Objective@# Establish a murine model for hyperuricemia (HU) and periodontitis to explore whether there is correlation between them and provide a basis for periodontal treatment.@*Methods@#Fourteen male KM mice were divided into 2 groups; the HU group (n=7) was fed food supplemented with potassium oxonate and uric acid, the NC group (n=7) was fed standard food, and the induction period was 35 days. On the 25th day, the molars on one side were ligated to induce periodontitis (P side), while the opposite was true for the control (C side). Baseline and terminal serum uric acid (UA) levels were detected, and alveolar bone resorption was analyzed by micro-CT.@*Results@#The serum UA level of HU mice was (112.94 ± 26.82 )mol/L, that of the NC group was (72.21 ± 19.95) μmol/L, and the difference in UA level was statistically significant (P < 0.05). The P side bone volume fractions of the HU and NC groups were( 29.01 ± 11.09)% and (29.56 ± 15.27)%, respectively, which were not significantly different (t=-0.072, P=0.944). The P side bone mineral densities of the HU and NC groups were(0.53 ± 0.16) g/cm3 and (0.52 ± 0.14) g/cm3, respectively, which were not significantly different (t=0.038, P=0.970). Additionally, there was no correlation between HU or serum UA and alveolar bone resorption (P > 0.05). @* Conclusion @#This research established a murine model for HU and periodontitis, but based on micro-CT analysis of alveolar bone, no relationship between HU or UA levels and periodontitis was found.

Mechanism of Bushen Huatan Prescription in Regulating Th17/Treg Balance in Ovariectomized Osteoporosis Rats / 中国实验方剂学杂志

Objective:To study the effect of Bushen Huatan prescription on helper T cell 17 （Th17）/T regulatory cells （Treg） balance of immune T cell subsets in the prevention and treatment of postmenopausal osteoporosis. Method:Sixty 6-month-old female SD rats were randomly divided into sham operation group， model group， estradiol valerate group （0.184 mg·kg^-1） and Bushen Huatan prescription low， medium and high groups （4.7， 9.4， 18.8 g·kg^-1） according to the random number table. All the groups except the sham operation group received ovariectomy to make postmenopausal osteoporosis model. Intragastric administration was started 1 week after operation， and the rats in model group and sham operation group received equal volume of normal saline， once a day for 12 weeks. Microcomputed tomography （Micro CT） was then used to detect bone mass and microstructure of rats， the contents of Forkhead box protein （Foxp3） and retinoic acid related nuclear orphan receptor （ROR<italic>γ</italic>t） in serum were detected by enzyme-linked immunosorbent assay （ELISA）， the mRNA expression levels of Foxp3 and ROR<italic>γ</italic>t in bone tissues were detected by Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） and Western blot was used to detect the protein expression of Foxp3 and ROR<italic>γ</italic>t in bone tissues， the number of Th17 and Treg cells in each group was analyzed and compared by flow cytometry. Result:Compared with the sham operation group， the bone mass and trabeculae of the model group decreased （<italic>P</italic><0.01）， the bone microstructure was destroyed， the concentration of Foxp3 in serum decreased， the concentration of ROR<italic>γ</italic>t increased （<italic>P</italic><0.01）， the mRNA and protein expression levels of Foxp3 in bone tissues decreased， ROR<italic>γ</italic>t increased， the number of Treg cells in bone tissues decreased， number of Th17 cells increased （<italic>P</italic><0.01）， and Th17/Treg ratio increased （<italic>P</italic><0.01） in model group. Compared with the model group， the bone mass in each treatment group increased （<italic>P</italic><0.05， <italic>P</italic><0.01）， Foxp3 concentration in serum increased， ROR<italic>γ</italic>t concentration decreased （<italic>P</italic><0.01）， the mRNA and protein expression levels of Foxp3 in bone tissues increased significantly （<italic>P</italic><0.05， <italic>P</italic><0.01）， but no statistical difference was shown in mRNA expression between low dose group and the model group. In addition， the mRNA and protein expression of ROR<italic>γ</italic>t decreased （<italic>P</italic><0.05， <italic>P</italic><0.01）， number of Treg cells increased， number of Th17 cells decreased （<italic>P</italic><0.05， <italic>P</italic><0.01）， and Th17/Treg ratio decreased in treatment groups （<italic>P</italic><0.01）. Conclusion:Bushen Huatan prescription can increase bone mass， improve bone microstructure， increase the number of Treg cells and decrease the number of Th17 cells in ovariectomized rats. It is concluded that Bushen Huatan prescription may play a role in preventing and treating postmenopausal osteoporosis by regulating Th17/Treg balance.

Therapeutic Effect of Guizhi Shaoyao Zhimutang on Osteoporosis in Rats Based on RANKL/OPG / 中国实验方剂学杂志

Objective:To investigate the therapeutic effect of Guizhi Shaoyao Zhimutang （GSZT） on the osteoporosis （OP） in SD female rats induced by ovariectomy （OVX） combined with glucocorticoid injection and its related mechanisms. Method:The rats were divided into a sham operation group and an experimental group for OVX. One week later， the experimental rats were divided into an OP model group， a calciferol （positive control， 0.1 mg·kg^-1） group， and low（0.8 g·kg^-1）， medium（1.6 g·kg^-1）， and high-dose （3.2 g·kg^-1） GSZT groups. Except for those in the sham operation group， the rats received an intramuscular injection of dexamethasone （1 mg·kg^-1） twice per week for six weeks. After the rats were treated correspondingly for eight weeks， the rats were sacrificed for thighbone sample collection. The computer microtomography （Micro CT） was used to analyze the parameters of bone mineral density （BMD）， bone volume （BV）， tissue volume （TV）， structure model index （SMI）， connectivity density （Conn.D）， trabecular number （Tb.N）， trabecular thickness （Tb.Th）， trabecular pattern factor （Tb.Pf）， and trabecular separation （Tb.Sp）. In addition， hematoxylin-eosin （HE） and Masson staining was used for the histopathological examination of the thighbone. Tartrate-resistant acid phosphatase （TRAP） staining was used to analyze osteoclasts in bone tissues. The enzyme-linked immunosorbent assay （ELISA） was used to determine matrix metalloproteinase-9 （MMP-9）， cathepsin K （CTSK）， and TRAP5b in bone tissues， and Western blot was carried out to determine receptor activator of NF-kappaB ligand （RANKL）， osteoprotegerin （OPG）， alkaline phosphatase （ALP） in bone tissues. Result:Compared with normal group， the number of bone trabeculae in cancellous part of OP model rats decreased significantly， the spacing widened， the thickness became thinner， and the continuity was poor. Compared with model group， GZST medium and high-dose groups could improve the changes of femoral bone trabecular cancellous bone. Masson staining showed that compared with the normal group， the growth plate thickness of the distal femur epiphysis was thinner and the area of new bone was smaller in the OP model group， while the reduction of new bone was inhibited in the high dose group of calcitol and GZST. TRAP staining results showed that the number of osteoclasts in OP group was significantly increased compared with the normal group， and the number of osteoclasts in medium-high dose GZST group was reduced. Micro CT results showed that compared with normal group， BMD， BV， Tb.N， Tb.Th and Conn.D of OP rats were decreased， SMI and Tb.Sp were significantly increased（<italic>P</italic><0.01）. Compared with model group， medium and high dose of GZST could improve the degree of osteoporosis in OP rats， BV， Tb.N were significantly increased， SMI， Tb.Sp were significantly decreased （<italic>P</italic><0.01）. ELISA results revealed that compared with the sham operation group， the OP model group showed decreased ALP content （<italic>P</italic><0.01） and increased MMP-9， TRAP5b， and CTSK （<italic>P</italic><0.01）. Compared with the OP model group， the high-dose GSZT group showed increased ALP content （<italic>P</italic><0.01） and decreased MMP-9， TRAP5b， and CTSK （<italic>P</italic><0.01）. Western blot results demonstrated that compared with the OP model group， the calciferol group and the high-dose GSZT group showed inhibited expression of the RANKL protein （<italic>P</italic><0.05）， and increased OPG expression （<italic>P</italic><0.05）. Conclusion:The findings suggest that GZST has a potential therapeutic effect on OP caused by OVX combined with glucocorticoids in rats， and the underlying mechanism is associated with the regulation of RANKL/OPG in bone tissues. This study is expected to lay a preliminary foundation for its clinical application and modern preparation development.

Enhanced osseointegration of porous titanium scaffold implanted with preload: an experiment study in rabbits / Osteointegración mejorada de malla de titanio poroso implantada con precarga: un estudio experimental en conejos

Porous titanium alloy scaffold was widely used in treating bone defect caused by traumatic injury and osteomyelitis, which was incapable of self-healing. The implantation of scaffold produced stress shielding thereby forming osteolysis. The objective of this study was to analysis trabecular morphological features of osseointegrated bone. 14 New Zealand rabbits were divided into two groups, surgery group and healthy control group. 7 rabbits in surgery group were selected to perform 3D printed porous titanium alloy scaffold implantation surgery with preload at the defect of femoral condyle for osseointegration. The other 7 rabbits in control group were feed free. After 90 days healing, femoral condyles were extracted to perform micro-CT scanning with hydroxyapatite calibration phantom. Mean bone mineral density (BMD), bone volume fraction (BV/TV), BS/TV (bone surface area ratio), Tb.Th (thickness of trabeculae), Tb.N (number of trabeculae), Tb.Sp (trabecular separation) and DA (degree of anisotropy) were calculated from micro-CT images. The results revealed that osseointegration inside and at the surface of scaffolds worked well from grey values of micro-CT images. After 12 weeks healing, mean bone mineral densities (BMD) in surgery group and healthy control group were calculated as 800±20mg/cm3 and 980±90mg/cm3, respectively. This revealed that the strength of trabeculae in surgery group might lower than that in the healthy group. Trabecular morphological parameters test showed that trabecular morphological parameters at the surface of scaffolds in the surgery group deteriorated significantly. It was found from micro-CT images that ingrowth bone was filled with pores of scaffold. Overall, the effect of osseointegration was promoted through the change of mechanical micro-environment in the scaffold region. Overall, preload could improve osseointegration effect in the long-term after surgery. However, the trabecular morphology in the surgery group was deteriorated, which might bring secondary fracture risk again.

La malla de aleación de titanio poroso se usó ampliamente en el tratamiento de defectos óseos causados por lesiones traumáticas y osteomielitis. El implante de la malla generó una protección contra el estrés, formando así osteolisis. El objetivo de este estudio fue analizar las características morfológicas trabeculares del hueso osteointegrado. Se dividieron 14 conejos (Neozelandeses) en dos grupos, grupo cirugía y grupo control saludable. Se seleccionaron 7 conejos en el grupo de cirugía para realizar una implantación de mallas de aleación de titanio poroso, impresas en 3D con precarga en el defecto del cóndilo femoral para la osteointegración. Los 7 conejos restantes del grupo control se mantuvieron sin alimentación. Después de 90 días de curación, se extrajeron los cóndilos femorales para realizar una exploración por micro-CT con un espectro de calibración de hidroxiapatita. Se calcularon a partir de imágenes de micro-CTDensidad mineral ósea media (DMO), fracción de volumen óseo (BV / TV), BS / TV (relación de área de superficie ósea), Tb.Th (espesor de trabéculas), Tb.N (número de trabéculas), Tb.Sp (trabecular separación) y DA (grado de anisotropía). Los resultados revelaron que la osteointegración dentro y en la superficie de los andamios funcionó bien a partir de los valores grises de las imágenes de micro-CT. Después de 12 semanas de curación, las densidades medias de minerales óseos (DMO) en el grupo cirugía y en el grupo control sano se calcularon como 800 ± 20 mg/cm3 y 980 ± 90 mg/cm3, respectivamente. Esto reveló que la fuerza de las trabéculas en el grupo de cirugía podría ser menor que la del grupo sano. La prueba de parámetros morfológicos trabeculares mostró que en el grupo de cirugía, la superficie de las mallas, se deterioraron significativamente. Se descubrió a partir de imágenes de microCT que el hueso en crecimiento estaba lleno de poros de andamio. En general, el efecto de la osteointegración se promovió mediante el cambio del microambiente mecánico en la región de la malla. En general, la precarga podría mejorar el efecto de osteointegración a largo plazo después de la cirugía. Sin embargo, la morfología trabecular en el grupo de cirugía se deterioró, lo que podría traer un nuevo riesgo de fractura secundaria.

A micro-CT study of different regions of the atlas / Un estudio de micro-CT de diferentes regiones del atlas

This study aimed to examine the differences in bone microarchitecture between different regions of the atlas in 28 dry atlas specimens using micro-CT, in order to explain the mechanism of the predilection sites of atlas fractures from the morphological point of view. A total of 28 dry specimens of intact adult atlas were randomly selected, scanned by micro-CT, and divided into a region from the anterior arch midpoint (AAM) to the lateral masses (LM), a LM region, and a region from the LM to the posterior arch midpoint (PAM). Trabecular thickness, separation, number, connectivity, and structure model index were measured for each of the three regions using the built-in software of the CT scanner. Trabecular thickness was all measured to be 0.11 ± 0.00 mm for AAM to LM, LM, and LM to PAM. Trabecular separation: AAM to LM > LM to PAM > LM. Trabecular number: LM > LM to PAM > AAM to LM. Connectivity: LM > LM to PAM > AAM to LM. Structure model index: LM > LM to PAM > AAM to LM. A lower trabecular number and connectivity and higher trabecular separation were seen in the anterior and posterior arches of the atlas, in which higher fracture rates were reported. By contrast, a higher trabecular number and connectivity and lower trabecular separation were seen in the lateral masses, in which lower fracture rates were reported.

Este estudio tuvo como objetivo examinar las diferencias en la microarquitectura ósea entre diferentes regiones del atlas en 28 muestras de atlas secas utilizando micro-CT, con el fin de informar el área de mayor frecuencia en las fracturas de atlas, desde el punto de vista morfológico. Se seleccionaron al azar un total de 28 muestras secas de atlas adultos intactas las que se escanearon por micro-CT y se dividieron en una región desde el punto medio del arco anterior (MAA) hasta las masas laterales (ML), una región ML y una región desde el ML hasta el punto medio del arco posterior (MAP). Se midió el grosor trabecular, la separación, el número, la conectividad y el índice del modelo de estructura para cada una de las tres regiones utilizando el software incorporado del escáner CT. El grosor trabecular se midió en 0,11 ± 0,00 mm para MAA a ML, ML y ML a MAP. Separación trabecular: MAA a ML> ML a MAP> ML. Número trabecular: ML> ML a MAP> MAA a ML. Conectividad: ML> ML a MAP> MAA a ML. Índice del modelo de estructura: ML> ML a MAP> MAA a ML. Se observó un menor número de estructuras trabeculares y conectividad y una mayor separación trabecular en los arcos anterior y posterior del atlas, en los que se informaron tasas de fracturas más altas. Por el contrario, se observó un mayor número de estructuras trabeculares y conectividad, y una menor separación trabecular en las masas laterales, en las que se observó un número menor de fracturas.

The use of a liner under different bulk-fill resin composites: 3D GAP formation analysis by x-ray microcomputed tomography

Abstract Gap formation of composite resin restorations is a serious shortcoming in clinical practice. Polymerization shrinkage stress exceeds the tooth-restoration bond strength, and it causes bacterial infiltration within gaps between cavity walls and the restorative material. Thus, an intermediate liner application with a low elastic modulus has been advised to minimize polymerization shrinkage as well as gap formation. Objective: The purpose of this in vitro study was to assess gap formation volume in premolars restored with different bulk-fill composites, with and without a resin-modified glass-ionomer cement (RMGIC) liner, using x-ray micro-computed tomography (micro-CT). Methodology: Sixty extracted human maxillary premolars were divided into six groups according to bucco-palatal dimensions (n=10). Standardized Class II mesio-occluso-distal cavities were prepared. G-Premio Bond (GC Corp., Japan) was applied in the selective-etch mode. Teeth were restored with high-viscosity (Filtek Bulk Fill, 3M ESPE, USA)-FB, sonic-activated (SonicFill 2, Kerr, USA)-SF and low viscosity (Estelite Bulk Fill Flow, Tokuyama, Japan)-EB bulk-fill composites, with and without a liner (Ionoseal, Voco GmbH, Germany)-L. The specimens were subjected to 10,000 thermocycles (5-55°C) and 50,000 simulated chewing cycles (100 N). Gap formation based on the volume of black spaces at the tooth-restoration interface was quantified in mm3 using micro-computed tomography (SkyScan, Belgium), and analyses were performed. Data were analyzed using repeated-measures ANOVA and the Bonferroni correction test (p < 0.05). Results: The gap volume of all tested bulk-fill composites demonstrated that Group SF (1.581±0.773) had significantly higher values than Group EB (0.717±0.679). Regarding the use of a liner, a significant reduction in gap formation volume was observed only in Group SFL (0.927±0.630) compared with Group SF (1.581±0.773). Conclusion: It can be concluded that different types of bulk-fill composite resins affected gap formation volume. Low-viscosity bulk-fill composites exhibited better adaptation to cavity walls and less gap formation than did sonic-activated bulk-fill composites. The use of an RMGIC liner produced a significant reduction in gap formation volume for sonic-activated bulk-fill composites.

Comparative study on icariin and Bu-Shen-Gu-Chi-Wan for alveolar reconstruction in chronic periodontitis in rats / 口腔疾病防治

Objective@#To observe the effects of icariin (ICA) and Bu-Shen-Gu-Chi-Wan on the alveolar bone absorption of chronic periodontitis in rats, and to explore the effect and possible mechanism of ICA in the treatment of chronic periodontitis. @*Methods@#After the establishment of the periodontitis model, the rats were divided into the periodontitis group (group P), ICA high dose group (group H), ICA low dose group (group L) and Bu-Shen-Gu-Chi-Wan treatment group (group B). Each group received treatment for one month and two months, separately, and the serum osteocalcin (OCN) level was measured. Three-dimensional reconstruction was performed after micro computed tomography (micro CT) scanning to measure the bone parameters of specific points, and the distance between the enamel cementum boundary and alveolar crest (CEJ-ABC) was recorded as alveolar bone resorption value. Tissue sections were generated to evaluate the effect of ICA on alveolar bone repair and reconstruction in rats with experimental periodontitis. @*Results@# Compared with the periodontitis group (group P), OCN levels in the serum in treatment groups (groups H, L and B) were decreased significantly (P < 0.05); the values of bone volume/tissue volume (BV/TV) and trabecular number (Tb.N) in treatment groups (groups H, L and B) were significantly higher than that in group P (P < 0.05). Compared with group P, trabecular thickness (Tb.Th) values of groups H and B significantly increased, and trabecular separation (Tb.Sp) of groups H and B significantly decreased (P < 0.05). The changing trend of parameters in group L was the same as that in group H but only after two months of administration. The difference between Tb.Sp values in groups L and P was statistically significant (P < 0.05). Compared with group P, the CEJ-ABC distance significantly reduced in group L (1 month and 2 months after administration), group H (1 month and 2 months after administration), and group B (only 2 months after administration) (P < 0.05).@*Conclusion@#ICA and Bu-Shen-Gu-Chi-Wan improve the alveolar bone resorption in an experimental model of chronic periodontitis in rats, and the mechanism may be related to the regulation of osteocalcin serum levels.

Changes of bone mineral density and related factors during maxillary teeth occlusion after tooth extraction in diabetic mice / 中国组织工程研究

BACKGROUND: Defective dentition is a common oral disease, if it is not treated in time, there will be adverse effects such as tilting of the adjacent teeth and elongation of the jaws, causing occlusal disorder and interference, which will seriously affect the later repair. Especially in the diabetic patients with dentition loss, the impacts of diabetes on the occlusal elongation of the jaw teeth, and how osteonectin changes in this process, are still unclear. OBJECTIVE: To investigate the effect of diabetes on tooth occlusion and elongation in mice by establishing a model of the occlusion of the jaws in diabetic mice. METHODS: A diabetic model was established by intraperitoneal injection of streptozotocin in C57 BL/6J mice (purchased from the Animal Experimental Center of Shanxi Medical University). The mice were intraperitoneally injected with sodium citrate buffer. Thirty mice with successful modeling and control mice were removed, and the three right maxillary molars were removed to establish an experimental model of the extensional movement of the maxillary teeth. After 0, 3, 6, 9 and 12 days, the right jaw was taken. The bone mineral density was measured by micro-CT. The number of osteoclasts was counted by tartrate resistant acid phosphatase staining. The expression level of osteonectin was detected by RT-qPCR. The study was approved by the Ethical Committee of Shanxi Medical University. RESULTS AND CONCLUSION: (1) With the time increasing, the bone mineral density of the right mandible in the two groups was gradually increased. The bone mineral density in the diabetic group was significantly lower than that in the control group at 3, 6, 9 and 12 days after surgery (P < 0.05). (2) With the time increasing, the number of osteoclasts in the right mandible of both groups was gradually increased. The number of osteoclasts in the diabetic group was significantly lower than that in the control group at 3, 6, 9 and 12 days after surgery (P < 0.05). (3) The expression level of osteonectin mRNA in the right mandible of both groups was gradually increased. The expression level of osteonectin mRNA in the diabetic group was significantly higher than that in the control group at 0, 3,6, 9 and 12 days after surgery (P< 0.05). (4) These results indicate that diabetes can reduce the bone construction ability during the extensional movement and promote osteonectin mRNA expression.

High fat and high sugar diet combined with streptozotocin to establish a rat model of type 2 diabetic osteoporosis / 中国组织工程研究

BACKGROUND: A high-fat and high-sugar diet to induce a diabetic osteoporosis model is time-consuming, with high cost and poor model stability. Induction by streptozotocin is one of the most common methods to establish an animal model of postmenopausal osteoporosis. At present, there are few reports on the identification of this disease model. OBJECTIVE: To establish a rat model of type 2 diabetic osteoporosis rat models, and to identify the animal model established. METHODS: Thirty-two male 7-week-old Sprague-Dawley rats were selected and randomly divided into a normal control group (n=16) and a model group (n=16) according to their body mass using a random number table method. The model group was fed with high-fat and high-sugar diet for 4 weeks, and a small dose of streptozotocin was intraperitoneally injected at 35 mg/kg to induce a type 2 diabetic osteoporosis model; the normal control group was fed with normal maintenance feed for 4 weeks, and an equal dose of 10 mL/kg citric acid-sodium citrate buffer was intraperitoneally injected. Two groups of rats were studied from the aspects of morphology, histology and imaging. An approval was obtained from the Animal Experimental Ethics Committee of Southwest Medical University. RESULTS AND CONCLUSION: There were 16 rats in the model group, 12 rats were modeled, and the modeling rate was 75%. Compared with the normal control group, in the model group, the body mass of rats showed a gradual downward trend and a slightly upward trend after the injection of streptozotocin. These rats presented symptoms of diabetes, such as polydipsia, polyuria and polyphagia. Fasting blood glucose level increased significantly (P < 0.05), and showed a continuous state. The histological section showed that the trabecular bone was sparsely distributed. Imaging results showed that the bone volume fraction and the number of trabeculae in rats were significantly reduced, and the separation of trabecular bone was significantly increased, indicating a significant osteoporosis. To conclude, the 7-week-old Sprague-Dawley rats which are fed with high-sugar and high-fat diet for 4 weeks can be given low-dose streptozotocin (35 mg/kg) to successfully establish the animal model of type 2 diabetic osteoporosis. From the aspects of morphology, histology, imaging, the successful establishment of diabetic osteoporosis model can be determined.

Effects of silymarin on liver injury and bone metabolism induced by carbon tetrachloride in mice / 中国组织工程研究

BACKGROUND: Studies have found that silymarin has a regulatory role in multiple genes, which contributes to bone remodeling and prevents bone loss. In a mouse model of fracture healing, silymarin supplementation can improve tibia healing by increasing bone mineral density and serum alkaline phosphatase and osteocalcin levels. OBJECTIVE: To study the effect of silymarin on liver injury and bone metabolism induced by carbon tetrachloride in mice. METHODS: Twenty-four common Kunming mice, 10 weeks old, half male and half female, were randomly divided into three groups according to body mass. In the control group, subcutaneous injection of peanut oil 10 μL/g (double first dose) was given once every 5 days, followed by intragastric administration of 10 mL/kg/d distilled water. In the model group, animal models were made by subcutaneous injection of 40% carbon tetrachloride, followed by the same treatments as described in the control group. In the silymarin group, intragastric administration of silymarin solution 50 mg/kg/d was given after modeling. Treatments in each group lasted for 4 weeks. Each mouse was weighed every other week and was fasted for 12 hours the night before the final treatment. Under anesthesia, the mouse eyeballs were taken and blood sample from each mouse was taken to determine the serum aspartate aminotransferase and alanine aminotransferase activity; the liver was taken to measure the levels of malondialdehyde, glutathione peroxidase and superoxide dismutase in the liver homogenate; the right femur was taken to measure the bone calcium content; and the right tibia was taken for Micro CT detection to detect the changes in bone structure parameters. An approval by the Animal Ethics Committee of Guangdong Medical University was obtained with an approval No. PJ2013011. RESULTS AND CONCLUSION: Compared with the control group, the activity of aspartate aminotransferase and alanine aminotransferase in the model group was significantly increased (P < 0.05), glutathione peroxidase activity was significantly reduced (P < 0.05), bone calcium and tibial bone volume fraction, bone mineral density, and connection density were significantly reduced (P < 0.05), structural model index and anisotropy degree were significantly increased (P < 0.05), and significant liver damage and decreased bone mass and bone microstructure damage were observed. Compared with the model group, silymarin significantly reduced the activity of alanine aminotransferase (P < 0.05), and also significantly reduced the structural model index and the degree of anisotropy (P < 0.05), making the trabecular bone structure and trend more consistent. There was a clear network structure, and the bone microstructure remained intact. After the administration of carbon tetrachloride, the mice suffered liver damage with decreased bone mass and damaged bone microstructure, and silymarin administration had a certain preventive effect on liver damage and bone loss caused by carbon tetrachloride in mice.