A novel bioactive glass-ceramic for treating dentin hypersensitivity

Dentin hypersensitivity (DH) is a painful response to stimulus applied to the open dentinal tubules of a vital tooth. It's a common oral condition, however, without an ideal treatment available yet. This work evaluated in vitro the effect of micron-sized particles from a novel bioactive glass-ceramic (Biosilicate) in occluding open dentinal tubules. A dentin disc model was employed to observe comparatively, using scanning electron microscopy (SEM), dentinal tubule occlusion by different products and deposition of hydroxyl carbonate apatite (HCA) on dentin surface by Biosilicate, after a single application: G1 - Dentifrice with potassium nitrate and fluoride; G2 - Two-step calcium phosphate precipitation treatment; G3 - Water-free gel containing Biosilicate particles (1%); G4 - Biosilicate particles mixed with distilled water in a 1:10 ratio; all of them after 1, 12 and 24 hours of immersion in artificial saliva. Fourier transform infrared spectroscopy (FTIR) was performed to detect HCA formation on dentin discs filled with Biosilicate after 2 minutes, 30 minutes and 12 hours of immersion in artificial saliva. SEM showed a layer of HCA formed on dentin surface after 24 hours by G4. G1, G2 and G3 promoted not total occlusion of open dentinal tubules after 24 hours. FTIR showed HCA precipitation on the dentin surface induced by Biosilicate after 30 minutes. The micron-sized particles from the bioactive glass-ceramic thus were able to induce HCA deposition in open dentinal tubules in vitro. This finding suggests that Biosilicate may provide a new option for treating DH.FAPESPCNP

Marginal adaptation of lithium disilicate crowns obtained by scanning techniques (CAD/CAM): in vitro confocal microscopy analysis

Objetivo. El objetivo de este estudio fue evaluar la adaptación marginal de coronas de disilicato de litio obtenidas mediante técnicas de escaneo (CAD/CAM), antes y después de la cristalización, a través de análisis in vitro con microscopía confocal (MC). Métodos. Fueron confeccionadas 16 réplicas en poliuretano a partir de la pieza 1.4, de modelo typodont, tallada para corona total. Las réplicas fueron divididas en dos grupos, de acuerdo a la técnica de escaneo: Técnica Indirecta (Grupo IND, n=08), donde modelos de yeso fueron escaneados con escáner de laboratorio (inEos X5, Sirona Dental Systems) y Técnica Directa (Grupo DIR, n=08), donde modelos typodont fueron escaneados con escáner intraoral (CEREC BlueCam, Sirona Dental Systems). A seguir, se fresaron (inLab MC XL, Sirona Dental Systems) coronas en disilicato de litio (IPS e.max CAD, Ivoclar Vivadent) y se adaptaron a las réplicas. Se evaluó la adaptación marginal con análisis de MC en dos momentos, antes y después de la cristalización del disilicato de litio. Los datos fueron analizados con la prueba de Mann-Whitney, t de Student y Wilcoxon (α= 0,05). Resultados. Hubo una diferencia estadísticamente significativa en la adaptación marginal horizontal entre los grupos IND y DIR después de la cristalización (p=0,05). En el grupo IND, la comparación de la adaptación marginal vertical antes y después de la cristalización mostró una diferencia estadísticamente significativa (p=0,038). Conclusiones. Las coronas de disilicato de litio obtenidas mediante escaneo directo (CAD/CAM) presentaron menor desajuste marginal vertical. La etapa de cristalización afectó la adaptación marginal de las coronas.Objective. This study aimed to evaluate lithium disilicate marginal adaption on crowns by scanning techniques (CAD/CAM), before and after crystallization, through confocal microscopy (CM) in vitro analysis. Methods. Sixteen polyurethane replicas were performed from tooth 1.4, of a typodont model, prepared for a full crown. The replicas were divided into two groups, according to the scanning technique: Indirect Technique (Group IND, n=08), where dental stone models were scanned with a laboratory scanner (inEos X5, Sirona Dental Systems) and Direct Technique (Group DIR, n=08), where typodont models were scanned with an intraoral scanner (CEREC BlueCam, Sirona Dental Systems). Then, the lithium disilicate crowns (IPS e.max CAD, Ivoclar Vivadent) were milled (inLab MC XL, Sirona Dental Systems) and adapted to the replicas. Marginal adaptation was evaluated with CM analysis before and after lithium disilicate crystallization. Data were analyzed with the Mann-Whitney, t test, and Wilconxon test (α=0.05). Results. There was a statistically significant difference in horizontal marginal adaptation between IND and DIR groups after crystallization (p=0.05). In IND group, the comparison of vertical marginal adaptation before and after crystallization showed a statistically significant difference (p=0.038). Conclusions. Lithium disilicate crowns obtained by direct scanning technique (CAD/CAD) showed less vertical marginal maladjustment. The crystallization stage affected the crown’s marginal adaptation

A Distinct DNA Methylation Shift in a Subset of Glioma CpG Island Methylator Phenotypes during Tumor Recurrence

Glioma diagnosis is based on histomorphology and grading; however, such classification does not have predictive clinical outcome after glioblastomas have developed. To date, no bona fide biomarkers that significantly translate into a survival benefit to glioblastoma patients have been identified. We previously reported that the IDH mutant G-CIMP-high subtype would be a predecessor to the G-CIMP-low subtype. Here, we performed a comprehensive DNA methylation longitudinal analysis of diffuse gliomas from 77 patients (200 tumors) to enlighten the epigenome-based malignant transformation of initially lower-grade gliomas. Intra-subtype heterogeneity among G-CIMP-high primary tumors allowed us to identify predictive biomarkers for assessing the risk of malignant recurrence at early stages of disease. G-CIMP-low recurrence appeared in 9.5% of all gliomas, and these resembled IDH-wild-type primary glioblastoma. G-CIMP-low recurrence can be characterized by distinct epigenetic changes at candidate functional tissue enhancers with AP-1/SOX binding elements, mesenchymal stem cell-like epigenomic phenotype, and genomic instability. Molecular abnormalities of longitudinal G-CIMP offer possibilities to defy glioblastoma progression

Comparative evaluation of a new biomterial and dessensitizing agents on detin hypersensitivity: in vitro and in vivo study

A hipersensibilidade dentinária é um problema que atinge de 8% a 35% da população. Os tratamentos para a hipersensibilidade dentinária no âmbito doméstico e clínico são diversos, entretanto a eficácia e duração dos mesmos não são absolutas. O objetivo deste estudo foi avaliar comparativamente, in vitro e in vivo, a eficácia do Biosilicato®, uma vitrocerâmica bioativa frente a agentes dessensibilizantes disponívies no mercado, no tratamento da hipersensibilidade dentinária. Os pacientes voluntários fizeram uso de: dentifrício dessensibilizante Sensodyne®; gel com Biosilicato® a 1%; Biosilicato® misturado à água destilada 10% e do produto Sensi Kill®. Por meio do modelo do disco de dentina (estudo in vitro) as mesmas substâncias testadas clinicamente foram avaliadas quanto ao seu potencial de oclusão dos túbulos dentinários. Foram observados clinicamente o tempo de ação de cada produto (em semanas) e posteriormente a duração do efeito do tratamento (mensalmente - por 06 meses). Os dados colhidos foram submetidos ao Teste estatístico de Kruskall Wallis e posterior Teste de Dunn (p<0.05). A avaliação qualitativa, por meio de MEV, mostrou diferentes padrões de capacidade de obliteração dos túbulos dentinários pelos agentes dessensibilizantes testados sendo que o Biosilicato® misturado à água destilada formou uma camada uniforme sobre a estrutura dentinária. Em relação ao tempo de ação dos diferentes produtos, no estudo in vivo, todos os produtos foram capazes de reduzir significantemente a dor proveniente da exposição dos túbulos em pelo menos 15 dias. Clinicamente, o Biosilicato® misturado à água destilada foi o produto que apresentou maior redução da dor no menor tempo, ou seja, apresentou a ação mais rápida. A duração dos tratamentos foi satisfatória para todos os produtos avaliados no prazo de 06 meses. No sexto mês os valores de dor observados foram significantemente menores que os valores iniciais para todos os agentes dessensibilizantes testados. A avaliação comparativa mostrou que o Biosilicato®, na apresentação em gel ou misturado à água destilada é eficiente no tratamento da hipersensibilidade dentinária.Dentin hypersensitivity (DH) is a problem with prevalence between 8% to 35%. There are various in office and over-the- counter products to treat DH, however the efficacy and duration of the effect are not ideal. The aim of this investigation was to analyze comparatively, in vitro and in vivo, the efficacy of one experimental crystalline bioactive material, named Biosilicate® on dentin hypersensitivity. Sensodyne® dentifrice, Biosilicate® in gel 1% or Biosilicate® mixed with distilled water (10%) and Sensi Kill® were employed on voluntaries with DH. The dentine disc model with a strict control procedure was also used to evaluate the performance of the substances in tubule occlusion. Clinically was observed the time of action and duration of the effect of the treatment. Data was analyzed with Kruskall Wallis and Dunn Test (p<0.05). Qualitative analysis obtained by scanning electron microscopy (SEM) showed different patterns of tubule occlusion. Biosilicate® mixed with distilled water demonstrated a homogeneous layer on dentin surface. Clinically, the time of action of the products showed that all desensitizing agents were able to reduce DH significantly. Biosilicate® mixed with distilled water was faster in reducing DH pain compared with the others. The duration of the effect of these treatments was satisfactory for all products tested in six months of evaluation. At the end of the study (on the sixty month) the pain values were significantly lower than the pain values observed at the beginning of the study for all the products tested. The comparative evaluation showed that Biosilicate® in gel or mixed with distilled water can be effective on dentin hypersensitivity

Radiopacity and microhardness changes and effect of X-ray operating voltage in resin-based materials before and after the expiration date

This study observed alteration in the radiopacity and microhardness of expired resin-based materials compared to non-expired materials and the operating characteristics of the X-ray source used. Five 2 mm-thick cured specimens were prepared for each material: composite resins (P60®, Z100®), and a compomer (Dyract AP®). Radiopacity of the specimens was evaluated comparing the density of the resin-based material to an equivalent (mm) density of a 99.5% pure aluminum step wedge using a transmission densitometer. Surface microhardness measurements were carried out using a calibrated Vickers indenter on three different points of the same surface. ANOVA and Tukey tests (pre-set alpha = 0.05) revealed that expired materials showed no significant change in radiopacity. One material (Filtek P60) demonstrated lower radiopacity with lower KVp. Change in microhardness wa s statistically significant for Z100: for this material, the microhardness after expiration was significantly lower than before the expiration date

Effect of Methods of Biosilicate Microparticle Application on Dentin Adhesion

Restorative procedures associated with bioglasses have shown to be a strategy to satisfy the contemporary concept of minimally invasive dentistry. Thus, the aim of this study was to evaluate bond strength to dentin treated by two different methods of biosilicate microparticle application. Dentin surfaces from 30 sound human molars were exposed and randomly assigned into three groups (n = 10) according to the surface treatment: (1) blasting with biosilicate microparticles (distance = 1 cm/pressure = 5 bar/time = 1 min); (2) 10% biosilicate microparticles paste; and (3) control (no treatment). After, dentin surfaces were restored with self-etch adhesive (Adper Easy Bond) and nanofilled composite (Filtek Z350). Specimens were sectioned perpendicularly to the adhesive interface to obtain sticks (cross-section area = 1 mm2), which were submitted to microtensile test (0.5 mm/min; 50 kgf). Data were analyzed by ANOVA and Tukey&#8217;s test (&#945; = 5%). Dentin/adhesive interfaces were morphologically analyzed by scanning electron microscopy (SEM). Data analysis showed that biosilicate-treated groups reached similar results (p &gt; 0.05) and both of them demonstrated higher values (p &lt; 0.05) than control group. SEM micrographs revealed hybridization with clear resin tags and no separation between resin-dentin adhesive interfaces. Within the limitations of this study, surface treatment with biosilicate positively influenced the adhesion to dentin and does not alter the morphology of the adhesive interface

Expression of NMDA receptor and microRNA-219 in rats submitted to cerebral ischemia associated with alcoholism

ABSTRACT Alcohol consumption aggravates injuries caused by ischemia. Many molecular mechanisms are involved in the pathophysiology of cerebral ischemia, including neurotransmitter expression, which is regulated by microRNAs. Objective: To evaluate the microRNA-219 and NMDA expression in brain tissue and blood of animals subjected to cerebral ischemia associated with alcoholism. Methods: Fifty Wistar rats were divided into groups: control, sham, ischemic, alcoholic, and ischemic plus alcoholic. The expression of microRNA-219 and NMDA were analyzed by real-time PCR. Results: When compared to the control group, the microRNA-219 in brain tissue was less expressed in the ischemic, alcoholic, and ischemic plus alcoholic groups. In the blood, this microRNA had lower expression in alcoholic and ischemic plus alcoholic groups. In the brain tissue the NMDA gene expression was greater in the ischemic, alcoholic, and ischemic plus alcoholic groups. Conclusion: A possible modulation of NMDA by microRNA-219 was observed with an inverse correlation between them