Grafting biomaterials associated to topical glucocorticoid: effects on pre-osteoblastic cells (MC3T3-E1)

Abstract The topical glucocorticoid budesonide has been prescribed before and after sinus lift surgery as adjuvant drug treatment for maxillary sinus membrane inflammation. However, there is no study on the effects of budesonide on the regenerative process of bone grafting biomaterials. We investigated the effect of the association of budesonide with some biomaterials on the growth and differentiation capacity of pre-osteoblastic cells (MC3T3-E1 subclone 4). Xenogeneic (Bio-Oss and Bio-Gen) and synthetic hydroxyapatites (Osteogen, Bonesynth, and HAP-91) were tested in conditioned medium (1% w/v). The conditioned medium was then supplemented with budesonide (0.5% v/v). Cell viability was assessed using the MTT assay (48, 96, and 144 h), and mineralized nodules were quantified after 14 days of culture using the Alizarin Red Staining. Alkaline phosphatase activity was assessed through the release of thymolphthalein at day seven. All biomaterials showed little or no cytotoxicity. The Bio-Gen allowed significantly less growth than the control group regardless of the experimental time. Regarding differentiation potential of MC3T3-E1, the HAP-91-conditioned medium showed remarkable osteoinductive properties. In osteodifferentiation, the addition of budesonide favored the formation of mineral nodules when cells were cultured in medium conditioned with synthetic materials, whereas it weakened the mineralization potential of cells cultured in xenogeneic medium. Regardless of whether budesonide was added or not, Osteogen and Bio-Oss showed higher alkaline phosphatase activity than the other groups. Budesonide may improve bone formation when associated with synthetic biomaterials. Conversely, the presence of this glucocorticoid weakens the mineralization potential of pre-osteoblastic cells cultured with xenogeneic hydroxyapatites.

Ultramorphology of pre-treated adhesive interfaces between self-adhesive resin cement and tooth structures / Ultramorfologia de interfaces adesivas entre cimento resinoso auto-adesivo e estruturas dentárias pré-tratadas

Introduction: Convencional resin cements can be used in combination with a total-etch system in a conventional mode or as self-adhesive resin cements. The latter are less technique sensitive and able to bond to dental tissues without previous treatment or adhesive layer and requires only a single step to be applied to dental structures. Objective: To compare qualitatively the adhesive interfaces of two self-adhesive resin cements and one conventional resin cement after different tooth surface treatments under scanning electron microscopy. Material and method: 42 crowns of bovine incisors were sectioned and flattened exposing enamel (E) or dentine (D) substrate. Subgroups were defined according to conditioning type and time: E1—no treatment, E2—37% phosphoric acid for 15 seconds, E3—37% phosphoric acid for 30 seconds; D1—no treatment, D2—37% phosphoric acid for 5 seconds; D3—11.5% polyacrylic acid for 15 seconds. A resin block was bonded to each substrate using the self-adhesive resin cements RelyX U100 (3M ESPE) and RelyX U200 (3M ESPE). As a reference hybrid layer, six resin blocks were luted with RelyX ARC and Scotchbond Multi-Purpose adhesive system (3M ESPE) (enamel—EA; dentine—DA). After aging for 7 days in a moist environment at 37±1°C, samples were prepared for microscopy analysis. Result and Discussion: In the ARC specimens, there was hybrid layer formation in both EA and DA. U100 E1 showed gaps at the adhesive interface, while E2 and E3 showed interaction for both self-adhesive cements. There was superficial interaction with bothU100 and U200 in D1, while in D2 and D3, resin tags were only observed in the case of U100. Conclusion: It was concluded that substrate conditioning may enhance the interaction between self-adhesive resin cements and dental tissues, although this is not the case for RelyX U200 and dentine.

Introdução: Restaurações estéticas indiretas são preferencialmente cimentadas utilizando-se cimentos resinosos convencionais e sistema adesivo de condicionamento total ou cimentos resinosos autoadesivos. Estes últimos são tecnicamente menos sensíveis e aderem aos tecidos dentários sem tratamento prévio ou aplicação de adesivo, com um único passo para sua aplicação aos tecidos dentários. Objetivo: Comparar qualitativamente as interfaces adesivas de dois cimentos resinosos autoadesivos e um cimento resinoso convencional, sob microscopia eletrônica de varredura. Material e método: 42 coroas de incisivos bovinos foram seccionadas e as faces vestibulares planificadas expondo esmalte (E) ou dentina (D). Os subgrupos foram definidos de acordo com o tipo e tempo de condicionamento: E1-sem tratamento, E2-37% de ácido fosfórico por 15 segundos, E3-37% de ácido fosfórico por 30 segundos; D1-sem tratamento, D2-37% de ácido fosfórico durante 5 segundos; D3-11,5% de ácido poliacrílico durante 15 segundos. Um bloco de resina foi unido a cada substrato usando os cimentos resinosos autoadesivos RelyX U100 e RelyX U200 (3M ESPE) (n=3). Como referência de camada híbrida, foram cimentados seis blocos de resina com RelyX ARC e o sistema adesivo Scotchbond Multi-Purpose(esmalte-EA, dentina-DA). Após armazenamento (7 dias, umidade, 37±1°C), as amostras foram preparadas para análise microscópica. Resultado: Nos espécimes ARC, houve formação de camada híbrida em EA e DA. U100 E1 mostrou lacunas na interface adesiva, enquanto E2 e E3 apresentaram boa interação para ambos os cimentos autoadesivos. Houve interação superficial com U100 e U200 em D1, enquanto em D2 e ​​D3, foram observadas tags de resina apenas para U100. Conclusão: Concluiu-se que o condicionamento do substrato pode aumentar a interação entre cimentos resinosos autoadesivos e os tecidos dentários, embora este não seja o caso do RelyX U200 e da dentina.

Comparison of Resin Cement Insertion Techniques for Luting Fiberglass Posts

Objective: To evaluate the effect of two insertion techniques of self-adhesive dual resin cement on the bond strength of fiberglass posts in different portions of the root. The homogeneity of the cement layer along the root canal was also evaluated. Material and Methods: The root canals of 28 bovine teeth were instrumented, filled, and 14mm-space was prepared for luting fiberglass posts (Reforpost #3, Angelus), maintaining 4mm of apical sealing. The roots were randomly allocated into two groups according to the cement insertion technique (n=14): Lentulo Drill (Dentsply/Maillefer) or Centrix syringe (Dentsply). The posts were fixed with self-adhesive resin cement (RelyX U200, 3M ESPE). After 7 days, the roots were cross-sectioned to obtain three 1.0-mm-thick samples of each third of the space prepared for the post. Two samples of each third were subjected to push-out test (0.5 mm/min; 200N) and the third specimen was used for the analysis of cementation layer homogeneity. Images of specimens (40x magnification) were assessed and classified by two calibrated examiners (Kappa = 0.87) according to the presence or absence of voids and misfit. Data were analyzed by two-way ANOVA and Pearson Chi-Square test. Results: There was no statistically significant effect of insertion technique (p=0.278) or post-space thirds (p = 0.521) on bond strength of fiberglass posts. Chi-Square test showed that cement insertion with the Lentulo drill produced more cement voids than Centrix syringe (p = 0.023). Conclusion: The cement insertion technique did not influence bond strength of fiberglass posts in bovine root dentin. The use of Centrix syringe for cement insertion is preferred since it produced more homogenous cement layer.

LED and Halogen Light Transmission through a CAD/CAM Lithium Disilicate Glass-Ceramic

The effect of thickness, shade and translucency of CAD/CAM lithium disilicate glass-ceramic on light transmission of light-emitting diode (LED) and quartz-tungsten-halogen units (QTH) were evaluated. Ceramic IPS e.max CAD shades A1, A2, A3, A3.5, high (HT) and low (LT) translucency were cut (1, 2, 3, 4 and 5 mm). Light sources emission spectra were determined. Light intensity incident and transmitted through each ceramic sample was measured to determine light transmission percentage (TP). Statistical analysis used a linear regression model. There was significant interaction between light source and ceramic translucency (p=0.008) and strong negative correlation (R=-0.845, p<0.001) between ceramic thickness and TP. Increasing one unit in thickness led to 3.17 reduction in TP. There was no significant difference in TP (p=0.124) between shades A1 (ß1=0) and A2 (ß1=-0.45) but significant reduction occurred for A3 (ß1=-0.83) and A3.5 (ß1=-2.18). The interaction QTH/HT provided higher TP (ß1=0) than LED/HT (ß1=-2.92), QTH/LT (ß1=-3.75) and LED/LT (ß1=-5.58). Light transmission was more effective using halogen source and high-translucency ceramics, decreased as the ceramic thickness increased and was higher for the lighter shades, A1 and A2. From the regression model (R2=0.85), an equation was obtained to estimate TP value using each variable ß1 found. A maximum TP of 25% for QTH and 20% for LED was found, suggesting that ceramic light attenuation could compromise light cured and dual cure resin cements polymerization.

Resumo Avaliou-se o efeito da espessura, cor e translucidez de uma cerâmica vítrea a base de dissilicato de lítio para CAD / CAM sobre a transmissão da luz de unidades de diodos emissores de luz (LED) e de quartzo-tungstênio-halogênio (QTH). Cerâmica IPS e.max CAD nas cores A1, A2, A3, A3.5 de translucidez alta (HT) e baixa (LT) foram cortadas (1, 2, 3, 4, 5 mm). Os espectros de emissão das fontes de luz foram determinados. A intensidade da luz incidente e transmitida através de cada espécime de cerâmica foi medida para determinar a percentagem de transmissão de luz (TP). Um modelo de regressão linear foi utilizado para a análise estatística. Houve interação significativa entre a fonte de luz e translucidez cerâmica (p = 0.008) e forte correlação negativa (r = -0.845, p <0.001) entre a espessura da cerâmica e TP. O aumento da espessura em uma unidade levou a uma redução média de 3.17 em TP. Não houve diferença significativa em TP (p = 0.124) entre as cores A1 (ß1 = 0) e A2 (ß1 = -0.45), mas ocorreu redução significativa para as cores A3 (ß1 = -0.83) e A3.5 (ß1 = -2.18). A interação QTH/HT proporcionou maior TP (ß1 = 0) do que LED/HT (ß1 = -2.92), QTH/LT (ß1 = -3.75) e LED/LT (ß1 = -5.58). A transmissão de luz foi mais eficaz utilizando QTH e cerâmica de alta translucidez, diminuiu à medida que a espessura de cerâmica aumentou, e foi maior para as cores A1 e A2. A partir do modelo de regressão (R2 = 0.85), obteve-se uma equação para estimar o valor de TP utilizando os valores de ß1 encontrado. Foi observada TP máxima de 25% para QTH e 20% para LED, sugerindo que a atenuação promovida pela cerâmica pode comprometer a ativação de um cimento resinoso fotoativado e de ativação dupla.

Efeito da espessura, cor e translucidez de uma cerâmica de dissilicato de lítio sobre a transmissão da luz halógena e de diodo emissor de luz, o grau de conversão e a microdureza de diferentes cimentos resinosos / Effect of thickness, shade and translucency of a lithium disilicate glass-ceramic on the light transmission of halogen or light emitting diode, degree of conversion and microhardness of different resin cements

Avaliou-se o efeito da espessura, cor e translucidez de uma cerâmica vítrea sobre a transmissão da luz halógena (HAL) e diodo emissor de luz (LED) e sobre o grau de conversão e microdureza de diferentes cimentos resinosos. Quarenta bloco da cerâmica IPS e.max CAD (Ivoclar Vivadent) de translucidez (alta-HT e baixa-LT) cores A1, A2, A3.5, foram cortados (1, 2, 3, 4 e 5mm) e cristalizados (200 corpos de prova). Os espectros de emissão de HAL (Demetron LC) e LED (Bluephase, Ivoclar Vivadent) foram determinados. A intensidade da luz (mW/cm2) incidente sobre o detector e da luz transmitida através da cerâmica foram medidas em triplicata para cada fonte de luz. Os coeficientes de absorção de luz...

The influence of silane evaporation procedures on microtensile bond strength between a dental ceramic and a resin cement.

Aim: To assess the influence of silane evaporation procedures on bond strength between a dental ceramic and a chemically activated resin cement. Materials and Methods: Eighteen blocks (6 mm Χ 14 mm Χ 14 mm) of ceramic IPS Empress 2 were cemented (C and B) to composite resin (InTen-S) blocks using a chemical adhesive system (Lok). Six groups were analyzed, each with three blocks divided according to ceramic surface treatment: two control groups (no treatment, NT; 10% hydrofluoric acid plus silane Monobond-S dried at room temperature, HFS); the other four groups comprised different evaporation patterns (silane rinsed and dried at room temperature, SRT; silane rinsed in boiling water and dried as before, SBRT; silane rinsed with boiling water and heat dried at 50°C, SBH; silane dried at 50 ± 5°C, rinsed in boiling water and dried at room temperature, SHBRT). The cemented blocks were sectioned to obtain specimens for microtensile test 7 days after cementation and were stored in water for 30 days prior to testing. Fracture patterns were analyzed by optical and scanning electron microscopy. Statistics and Results: All blocks of NT debonded during sectioning. One way ANOVA tests showed higher bond strengths for HFS than for the other groups. SBRT and SBH were statistically similar, with higher bond strengths than SRT and SHBRT. Failures were 100% adhesive in SRT and SHBRT. Cohesive failures within the "adhesive zone" were detected in HFS (30%), SBRT (24%) and SBH (40%). Conclusion: Silane treatment enhanced bond strength in all conditions evaluated, showing best results with HF etching.