Effect of phytic acid on bond strength and interfacial integrity of universal adhesive to deep dentin

Abstract This study investigated the effect of phytic acid (IP6) in different concentrations and application times on microtensile bond strength (µTBS) and interfacial integrity of universal adhesive to deep dentin. Flat deep dentin surfaces of 48 human molars were either etched with 37% phosphoric acid (PA) for 15 sec (control); or received no acid treatment and universal adhesive was applied directly in a self-etch mode (SE); or divided according to IP6 concentration (C) into two main groups: C1, 0.5%, and C2, 1%. Specimens of IP6 groups were further subdivided into three subgroups according to application time of IP6 (T) where; T1, 15 sec; T2, 30 sec and T3, 60 sec. Single Bond Universal Adhesive was then applied and resin composite blocks were built-up. Forty Specimens were then sectioned to produce resin/dentin beams that were used for µTBS testing using a universal testing machine. The remaining eight specimens were sectioned into slabs that were immersed into ammonical silver nitrate solution and nanoleakage was observed using a field emission scanning electron microscope (FE-SEM). The results showed that the application of IP6 in 0.5% and 1% produced significantly higher µTBS and less nanoleakage compared to PA and SE groups. Also, the application of IP6 for 60 sec recorded the highest µTBS and the lowest nanoleakage followed by 30 sec, and 15 sec respectively. Therefore, conditioning of deep dentin with IP6 enhances µTBS and interfacial integrity of universal adhesive to deep dentin in comparison to PA etching or using the universal adhesive in SE mode.

Resumo Este estudo investigou o efeito do ácido fítico (IP6) em diferentes concentrações e tempos de aplicação na resistência da ligação microtensiva (µTBS) e na integridade interfacial do adesivo universal à dentina profunda. As superfícies planas de dentina profunda de 48 molares humanos foram preparadas com ácido fosfórico (PA) a 37% durante 15 seg. (controlo); ou não receberam tratamento ácido e o adesivo universal foi aplicado diretamente em modo de auto-adesivo (SE); ou dividido de acordo com a concentração de IP6 (C) em dois grupos principais: C1, 0,5%, e C2, 1%. Os espécimes dos grupos IP6 foram ainda subdivididos em três subgrupos de acordo com o tempo de aplicação do IP6 (T) em que; T1, 15 seg; T2, 30 seg e T3, 60 seg. Aplicou-se então Single Bond Universal Adhesive e construíram-se blocos compostos de resina. Quarenta espécimes foram então seccionados para produzir feixes de resina/dentina que foram usados para testes µTBS usando uma máquina de testes universal. Os restantes oito espécimes foram seccionados em placas que foram imersas em solução amoniacal de nitrato de prata e observou-se uma nano-infiltração utilizando um microscópio eletrônico de varrimento de emissões de campo (FE-SEM). Os resultados mostraram que a aplicação de IP6 em 0,5% e 1% produziu µTBS significativamente mais elevado e menos nano-infiltração em comparação com os grupos PA e SE. Além disso, a aplicação de IP6 durante 60 seg registou o µTBS mais alto e o mais baixo de nano-infiltração seguido de 30 seg, e 15 seg respectivamente. Portanto, o condicionamento da dentina profunda com IP6 melhora o µTBS e a integridade interfacial do adesivo universal à dentina profunda em comparação com a gravação de PA ou utilizando o adesivo universal no modo SE.

Sellado marginal aplicando hipoclorito de sodio versus ácido fosfórico como acondicionador dental / Marginal sealing applying sodium hypochlorite versus phosphoric acid as dental conditioner

RESUMEN Introducción: La microfiltración es uno de los problemas principales de todas las obturaciones a base de resina. Muchos estudios buscan optimizar un buen sellado marginal utilizando diversos acondicionadores, como el hipoclorito de sodio, que permite que el adhesivo penetre bien, al generar desproteinización, y el ácido fosfórico que permite remover el barro dentinario, y así de esta manera formar una capa híbrida al colocar el adhesivo. Objetivo: Evaluar el grado de sellado marginal de la resina Bulk Fill aplicando gel de hipoclorito de sodio 10 por ciento comparado con el gel de ácido fosfórico al 37 por ciento en el acondicionamiento dental in vitro. Métodos: El universo fue de 72 dientes con cavidades clase I; se separaron en 4 grupos por muestra de 18 dientes cada uno; después de obturar se realizó el termociclaje a 500 ciclos entre 5 °C a 55 °C; luego se sumergieron en azul de metileno 2 por ciento, durante 12 h y 24 h a temperatura de 37 °C. Finalmente se evaluó el sellado marginal en el estereomicroscopio, según el ISO / TS 11405: 2015, con los criterios siguientes: grado 0 (sin microfiltración), grado 1 (microfiltración hasta esmalte), grado 2 (microfiltración hasta dentina) y grado 3 (microfiltración hasta piso pulpar). Resultados: El acondicionamiento con ácido fosfórico 37 por ciento a las 12 h presentó grado 0 (55,6 por ciento) y grado 1 (33,3 por ciento), y a las 24 h, grado 1 (55,6 por ciento). Con respecto al hipoclorito de sodio 10 por ciento a las 12 h, grado 0 (44.4 por ciento) y a las 24 h predominó grado 1 (55,6 por ciento). Para la contrastación de hipótesis en muestras relacionadas se obtuvo en ácido fosfórico 37 por ciento e hipoclorito de sodio al 10 por ciento a las 12 h y 24 h un p= 0,052 y p= 0,584, respectivamente. Para comparaciones entre muestras independientes a las 12 h y 24 h se obtuvo p= 0,462 y p= 0,406, respectivamente. Conclusiones: El gel de hipoclorito de sodio al 10 por ciento presenta similar eficacia en el sellado marginal respecto al gel de ácido fosfórico al 37 por ciento, al utilizarlo como acondicionador dental(AU)

ABSTRACT Introduction: Microfiltration is one of the main problems of all resin sealings. Many studies aim to optimize marginal sealing using a variety of conditioners, such as sodium hypochlorite, which allows good penetration of the adhesive by generating deproteinization, and phosphoric acid, which allows removal of the dental smear layer, thus creating a hybrid layer when the adhesive is placed. Objective: Evaluate the marginal sealing degree of Bulk Fill resin applying 10 percent sodium hypochlorite gel versus 37 percent phosphoric acid gel in in vitro dental conditioning. Methods: The study universe was 72 teeth with class I cavities, divided into four groups of 18 teeth. Upon sealing, thermal cycling was performed at 500 cycles from 5 ºC to 55 ºC. Next the teeth were submerged in 2 percent methylene blue for 12 h and 24 h at a temperature of 37 ºC. Finally marginal sealing was evaluated in the stereo microscope according to ISO / TS 11405: 2015, using the following scale: grade 0 (no microfiltration), grade 1 (microfiltration as far as the enamel), grade 2 (microfiltration as far as the dentin), and grade 3 (microfiltration as far as the pulp floor). Results: Conditioning with 37 percent phosphoric acid was grade 0 (55.6 percent) and grade 1 (33.3 percent) at 12 h, and grade 1 (55.6 percent) at 24 h, whereas conditioning with 10 percent sodium hypochlorite was grade 0 (44.4%) at 12 h, and predominantly grade 1 (55.6 percent) at 24 h. Hypothesis contrast in related samples yielded 37 percent phosphoric acid and 10 percent sodium hypochlorite at 12 h and 24 h, p= 0.052 and p= 0.584, respectively. Comparison between independent samples at 12 h and 24 h yielded p= 0.462 and p= 0.406, respectively. Conclusions: The 10 percent sodium hypochlorite gel has similar marginal sealing effectiveness as the 37 percent phosphoric acid gel when used as dental conditioners(AU)

Effects of methacryloyloxydecyl dihydrogen phosphate on bond durability of zirconia / 中华口腔医学杂志

Objective@#To evaluate the bond performance of primers, universal adhesives and self-adhesive resin cements containing methacryloyloxydecyl dihydrogen phosphate (MDP) to zirconia.@*Methods@#Two hundred and ten yttria-stabilized tetragonal zirconia polycrystal (Y-TZP) plates were prepared and divided into seven groups according to each of six MDP-containing products and one MDP-free resin cement. Two primers, two universal adhesives and two self-adhesive resin cements were applied on the specimens after these specimens recived alumina air abrasion. The group of MDP-free resin cement was set as control. Each group contained 30 specimens. Y-TZP plates were bonded to resin composite to build resin bonding specimens, and half of these plates were stored in distilled water at 37 ℃ for 24 hours, the other half were stored for 12 months. Shear bond strength (SBS) test and fracture modes analysis were performed.@*Results@#The SBS values of all the experimental groups were above 9.51 MPa, which increased 24-hour values compared to the (5.04±0.50) MPa of the control group. Group using one of the self-adhesive resin cement yielded the highest SBS, (11.06±0.84) MPa. SBS of all groups decreased significantly compared to 24-hour SBS after aging (P<0.05), however, the SBS values of MDP-containing products groups can still be maintained above 7.44 MPa. Two self-adhesive cement groups and one of the universal adhesive group maintained higher SBS values, and the values were statistical different from those from the two primer groups (P<0.05) .@*Conclusions@#Different MDP-containing products have different effects on the bond durability of zirconia.

Effect of conditioning protocols and ultrasonic application of an infiltrant resin in white spot lesions

Abstract The aim of this study was to evaluate different conditioning protocols and sonic/ultrasonic application of an infiltrant resin (IR) in artificial white spot lesions (AWSL). the V/L surfaces of 48 molars were induced to an AWSL and divided in 6 groups, according to the conditioning protocols and application technique: 15% hydrochloric acid (HA) + manual application of the IR; HA + 37% phosphoric acid (PA) + manual application of the IR; HA + ultrasonic application (U) of the IR; HA + sonic application (S) of the IR; PA+HA+S; and PA+HA+U. For the Penetration Depth (PD), the crowns were etched with HA for 120s. The IR Icon® (DMG) was applied according to the manufacturer`s instructions. The crowns were dye penetrated (0.1% red fluorophore rhodamine B isothiocyanate for 12h) and bleached with 30% hydrogen peroxide for 12 h. The discs were immersed in a 50% ethanol solution, containing 100 µM of sodium fluorescein. The PD (in µm) was measured using confocal laser scanning microscopy (20x). The bond strength (BS) was performed by michoshear test (0.5 mm/min). Data were submitted to 2-way ANOVA and Tukey (α=0.05). For BS, the interaction was not significant (p>0.05). For PD, the main factors were significant (application - p<0.001; conditioning technique - p=0.003). The ultrasonic application showed the highest PD values. PA+HA presented higher results than HA. The sonic/ultrasonic applications and the use of phosphoric acid prior to hydrochloric acid improved PD of the infiltrant resin. Conditioning protocols or application techniques did not influence BS values.

Resumo: O objetivo deste estudo foi avaliar diferentes protocolos de condicionamento e a aplicação sônica/ultrassônica de uma resina infiltrante (RI) em lesões de mancha branca produzidas artificialmente (LMBA). As superfícies vestibulares/linguais de 48 molares foram induzidas à formação de LMBA e divididas em 6 grupos, de acordo com os protocolos de condicionamento e técnica de aplicação da resina infiltrante: ácido hidroclorídrico 15% (AH) + aplicação manual da RI; AH + ácido fosfórico 37% (AF) + aplicação manual da RI; AH + aplicação ultrassônica da RI (U); AH + aplicação sônica da RI (S); AF + AH + S; e AF + AH + U. para o grau de penetração (GP), condicionou-se as coroas com AH por 120 s. A RI Icon® (DMG) foi aplicada de acordo com as instruções do fabricante. As coroas foram coradas (rodamina B 0,1% por 12 h) e clareadas com peróxido de hidrogênio 30% por 12 h. os discos foram imersos em solução de etanol 50%, contendo 100 µM de fluoresceína sódica. O GP (em µm) foi mensurado por meio de microscopia confocal a laser (20´). A resistência de união (RU) foi calculada pelo teste de microcisalhamento (0,5 mm/min). Os dados foram submetidos ao teste ANOVA 2 fatores e Tukey (α=0,05). Para RU, a interação não foi significante (p>0,05). Para GP, os fatores principais foram significantes (técnica de aplicação - p<0,001; protocolos de condicionamento - p=0,003). A aplicação U mostrou os maiores valores de GP. AF+AH demonstrou resultados superiores ao grupo AH. As aplicações sônica/ultrassônica e o uso do ácido fosfórico antes do ácido hidroclorídrico aumentaram o GP da resina infiltrante. Os protocolos de condicionamento ou as técnicas de aplicação não influenciaram os valores de RU.

Effect of surface treatment reagents and treatment time on bond strength of glass fiber posts to resin cement / 中国组织工程研究

BACKGROUND: At present, there is no uniform standard for the treatment time of chemical reagents for surface treatment of glass fiber posts. Therefore, studying the effect of treatment time of glass fiber post surface treatment reagents on the bond strength between fiber posts and resin cements is of great significance. OBJECTIVE: To evaluate the effect of two chemical agents on the bonding strength of glass fiber post and resin cement after surface pretreatment of glass-fiber posts at different times. METHODS: Forty-eight glass fiber posts were randomly divided into eight groups according to different surface treatment methods, six in each group. Group A received no special treatment; group B was treated with silanization for 1 minute; group C1 underwent a 30% hydrogen peroxide surface treatment for 5 minutes prior to 1-minute silanization; group C2underwent a 30% hydrogen peroxide surface treatment for 10minutes prior to 1-minutesilanization; group C3 underwent a 30% hydrogen peroxide surface treatment for 15 minutes prior to 1-minute silanization; group D1 underwent a 35% phosphoric acid surface treatment for 30 seconds prior to 1-minute silanization; group D2 underwent a 35% phosphoric acid surface treatment for 60 seconds prior to 1-minute silanization; group D3 underwent a 35% phosphoric acid surface treatment for 90 seconds prior to 1-minute silanization. The surface morphology of the treated glass fiber posts was observed under scanning electron microscope. The glass fiber post was bonded to the resin cement to form a cylindrical resin block and cut into a thin sample. The sheet was placed on a universal testing machine for micro-extrusion experiments. The failure mode of the specimens was observed under a stereomicroscope. RESULTS AND CONCLUSION: (1) Scanning electron microscope: the surface of the fiber post had different degrees of matrix dissolution and fiber bundle exposure after hydrogen peroxide and phosphoric acid treatment, but did not destroy the integrity of the fiber bundle. (2) Micro-extrusion experiments: the order of the bonding strength was as follows: group C3 > group C2 > group C1 > group D2 > groupD3 > groupD1> group B > group A, and there was significant difference between groups (P< 0.05) except for groups A and B, groups C2 andC3, and groups D2and D3. (3) Stereo microscope: the failure mode in the groups A and B was almost destruction in adhesion. The other six groups showed destruction in adhesion, but the cohesive failure and mixed failure were increased, and the failure mode changed from destruction in adhesion into cohesive failure and mixed failure. (4) These results indicate that the optimal treatment time of 30% hydrogen peroxide is 10 minutes, and the optimal treatment time of 35% phosphoric acid is 60 seconds. 30% hydrogen peroxide solution treatment of fiber post surface for 10 minutes has great clinical application value.

Effect of beta-carotene on learning, memory and expression of caspase-3 and phosphorylated tau in hippocampus of rats with obstructive sleep apnea syndrome / 临床神经病学杂志

Objective To observe the effect of β-carotene ( β-C ) on the learning and memory and the expression of caspase-3 and p-tau expression in hippocampus of obstructive sleep apnea syndrome ( OSAS) rats. Methods Twenty-four adult SD rats were randomly divided into normal control group, OSAS model group ( model group) and β-C intervention group (intervention group), with 8 rats in each group. A hypoxic chamber was used to establish an OSAS rat animal model. The rats in model group and intervention group were given by gavage before intragastric administration, and no treatment was performed in the normal group. After completion of the modeling, the Morris water maze was used to test the learning and memory ability of the experimental rats. Observing the pathological changes of hippocampal tissue in rats by HE staining. The protein expression of caspase-3 and p-tau in hippocampus was detected by Western Blotting. Results Escape latency time of model group in each time point were significantly prolonged than those in normal control group ( all P<0. 05), and escape latency time of intervention group at 2-5 d were significantly shorter than those in model group (all P<0. 05). The number of times of crossing the platform in model group was significantly less than that in normal control group and intervention group ( all P<0. 05). Compared with those in model group, the expression of caspase-3 and p-tau in normal control group and intervention group were significantly lower (all P<0. 05). Conclusion β-C can reduce the impairment of learning and memory ability caused by OSAS, and the mechanism may be related to its inhibition of caspase-3 and p-tau protein expression.

Influence of Application Method on Shear Bond Strength and Microleakage of Newly Developed 8th Generation Adhesive in Primary Teeth / 대한소아치과학회지

The purpose of this study was to evaluate the effect of application time and phosphoric acid etching of 8th generation adhesives containing functional monomer on adhesive performance in primary teeth.80 extracted non-carious human primary teeth were selected and divided into 8 groups based on 3 factors: (1) adhesive: G-Premio bond and Single bond universal; (2) application time: shortened time and manufacture's instruction; (3) acid etching mode: self-etching and total-etching. Shear bond strength was measured using a universal testing machine, and fractured surface were observed under scanning electron microscope. Microleakage was evaluated by dye penetration depth.G-Premio bond were not significant different in shear bond strength and microleakage depending on application time of adhesive and acid etching mode. In Single bond universal, shear bond strength of short application time was significantly lower than that of long adhesive application time (p = 0.014). Clinically applicable shear bond strength values (> 17 MPa) were identified in all groups.These results suggested that G-Premio bond be used clinically for a short application time without phosphoric acid etching.

Alternative Pretreatment Methods for Resin Infiltration in Primary Anterior Teeth / 대한소아치과학회지

Resin infiltration has been used as a treatment option for the management of early caries lesions recently. However, the etching procedure with hydrochloric acid might be somewhat stressful for the clinicians due to safety problem especially for young children, leading to less utility.This study aims at searching for some alternative surface pretreatment methods of resin infiltration for the early caries lesions in primary anterior teeth by comparing penetration depth of various methods.No significant difference was found in penetration ratio between etched surface with 15% hydrochloric acid and 35% phosphoric acid. However, the penetration ratio was significantly higher in groups pretreated either with dental pumice or abrasive metal strip (p < .05).By the result of this study, etching with phosphoric acid as an alternative of hydrochloric acid was thought clinically acceptable as a pretreatment method for resin infiltration in early caries lesions for primary anterior teeth.It was notable that surface conditioning with dental pumice or metal strip before etching was effective in increasing the penetration. This procedural modification might be much more correspondent with minimally invasive concept and hopefully contribute to increased safety and utility in pediatric dentistry.

Efficacy and safety of phosphoric acid phosphate combined metformin in the treatment of diagnosis of type 2 diabetes mellitus / 中国生化药物杂志

Objective To evaluate the efficacy and safety of phosphoric acid phosphate combined metformin in the treatment of diagnosis of type 2 diabetes mellitus.Methods A total of 86 cases with diagnosis of type 2 diabetes mellitus included in this study were dividing into control group and experiment group with each 43 cases.The patients in the both groups were give regular treatment.Patients in the control group were given metformin hydrochloride sustained release tablets 500mg by oral administration with 3 times a day and patients in the experiment group revieved phosphoric acid phosphate by oral administration with once a day.A cycle of 2 groups of patients were 28d,a total of 3 cycles of treatment.The ADP,APAF1,D25-(OH)D3),CysC and adverse drug reactions were compared between the two groups.Results The clinical efficacy in experiment group was 93.02％,which significant higher than that in control group 76.74％(P<0.05).The serum level of ADP,APAF1 and CysC decreased after treatment with experiment group much lower than the control group(P<0.05).The serum D25-(OH)D3l elevated in the two groups with experiment group much higher than the control group(P<0.05).The adverse drug reactions was not statistically different between the two groups.Conclusion Phosphoric acid phosphate combined metformin in the treatment of diagnosis of type 2 diabetes mellitus was effective with high safety.

Micromorfología superficial de 2 cerámicas grabables tratadas con diferentes ácidos / Superficial micromorphology of 2 etchable ceramics treated with different acids

Para lograr una unión fuerte entre las restauraciones de cerámica sin metal y las resinas de cementación se indican acondicionamientos de superficie previos a la cementación. Nuestro objetivo es describir y comparar al MEB las superficies de cerámicas feldespáticas y reforzadas con disilicato de litio antes y después de ser tratadas con 2 procedimientos ácidos. Se utilizaron 8 bloques de cerámica feldespática (A) y 8 de cerámica reforzada con disilicato de litio (B). Se subdividieron en 2 grupos de 4 bloques (A1 y A2) y (B1 y B2). Los grupos A1 y B1 fueron tratados con ácido fluorhídrico 9% (HF) y los grupos A2 y B2 con ácido fluorhídrico, seguido de ácido fosfórico al 35%. Posteriormente, se observaron al MEB (1.000 ×) y se procesaron las imágenes con el programa Matlab R2012a, que mide el contraste. Los estadísticos utilizados fueron el test ANOVA y el test «t¼ no pareado Resultados El ácido fluorhídrico 9% crea irregularidades en ambos tipos de cerámicas. Al aplicar HF, seguido de ácido fosfórico sobre la cerámica feldespática no se aprecian diferencias en el contraste, con respecto a utilizar solo HF. Al usar ambos ácidos, en la cerámica reforzada con disilicato de litio se aprecian menos irregularidades respecto a las tratadas con un solo ácido. Conclusiones El ácido fluorhídrico 9% crea microrretenciones en ambas cerámicas. El HF al 9%, seguido del ácido fosfórico 35% parece modificar los valores de contraste de la cerámica colada, en cambio en las feldespáticas no hay diferencias significativas con ambos tratamientos.

Surface conditioning prior to cementing is indicated to achieve a strong bond between metal-free ceramic restorations and resin cements. The aim of this study is to describe and compare the scanning electron microscopy (SEM) images of the surfaces of Feldspathic ceramic and Lithium disilicate glass ceramic before and after being treated with two acid procedures. For this, 8 blocks of Feldspathic ceramic (A) and 8 of Ceramic lithium disilicate (B) were used. They were subdivided into two groups of 4 blocks (A1 and A2) and (B1 and B2). Groups A1 and B1 were treated with 9% Hydrofluoric Acid (HF) and the A2 and B2 groups, with 9% Hydrofluoric Acid followed by 35% Phosphoric Acid. Subsequently, they were observed using SEM (1,000 ×) and the images processed with the program Matlab R2012a, which measures the contrast. The statistics used were ANOVA test and the unpaired t test. Results 9% Hydrofluoric Acid creates irregularities in both types of ceramics. When applying HF followed by Phosphoric Acid on Feldspathic ceramics, no differences in contrast were found, compared to using only HF. With ceramic lithium disilicate using both acids, there are fewer irregularities with respect to those treated with a single acid. Conclusion 9% Hydrofluoric Acid creates micro-retentions in both ceramics. 9% HF followed by 35% Phosphoric Acid appears to significantly modify the Lithium disilicate glass ceramic contrast values. On the other hand, the Feldspathic ceramic showed no significant differences with both treatments.

Active and Passive Application of the Phosphoric Acid on the Bond Strength of Lithium Disilicate

Abstract The objective of this study was to evaluate the effect of passive or active phosphoric acid (PA) application after hydrofluoric acid (HA) treatment on the microshear bond strength of lithium disilicate. Thirty ceramic discs were made with IPS Emax 2 (10 mm thick and 10 mm diameter). The specimens were divided into 3 groups, A: 9.6% HA application; AF: 9.6% HA application + cleaning with 37% PA in passive mode and AFF: 9.6% HA application + cleaning with 37% PA in active mode. For the microshear test, four tygons (0.9 mm diameter and 0.2 mm high) were filled with resin cement (RelyX Ultimate) and placed on the ceramic disks. After testing, the fracture modes were examined under scanning electron microscopy. Data were analyzed by one-way ANOVA and Tukey's post test (α=0.05). The bond strength values were significantly higher in Group AFF (11.0±2.5 MPa) compared with group A (8.1±2.6 MPa) (p<0.002). AF group was not statistically different (9.4±2.5 MPa) from Group A. It was concluded that the active application of 37% PA after 9.6% HA increases the microshear bond strength values between the resin cement and lithium disilicate ceramic.

Resumo O objetivo desse estudo foi avaliar o efeito da aplicação passiva ou ativa do ácido fosfórico após o tratamento com ácido hidrofluorídrico na resistência de união ao microcisalhamento entre cimento resinoso e dissilicato de lítio. Trinta discos foram confeccionados com IPS Emax 2 (10 mm de espessura e 10 mm de diâmetro). Os espécimes foram divididos em três grupos (A: aplicação do ácido hidrofluorídrico 9,6%; AF: aplicação do ácido hidrofluorídrico 9,6% + limpeza com ácido fosfórico 37% em modo passivo; AFF: aplicação do ácido hidrofluorídrico 9,6% + limpeza com ácido fosfórico 37% no modo ativo). Para o teste de microcisalhamento, quatro tygons (0,9 de diâmetro e 0,2 mm de altura) foram preenchidos com cimento resinoso (RelyX Ultimate) e dispostos sobre os discos de cerâmica. Após o teste, os modos de fratura foram examinados por microscopia eletrônica de varredura. Os dados foram analisados estatisticamente por ANOVA e pós-teste de Tukey (α=0,05). Os valores de resistência de união foram significativamente superiores para o grupo AFF (11,0±2,5 MPa), comparado ao grupo A (8,1±2,6 MPa) (p<0,002), mas este não estatisticamente diferente do grupo AF (9,4±2,5 MPa). Concluiu-se que a aplicação ativa do ácido fosfórico 37% após o uso do ácido hidrofluorídrico 9,6% aumenta a resistência de união entre o cimento resinoso e a cerâmica de dissilicato de lítio.

A selectivity study of the examination of radionuclides Cesium-1 37 for foods based on different detection conditions / 预防医学

Objective Aselectivitystudywasconductedthroughtheexaminationofradionuclides137Cs(Cesium-137)for foodbasedondifferentdetectionconditions.Methods Atotalof48foodsampleswereselectedfromthreeareasincluding Qinshan nuclear power plant,Sanmen nuclear power plant and Hangzhou and Zhoushan respectively.1 37 Cs of these samples were determined by γspectrometry and Phosphoric acid ammonium molybdate method.The level of 48 foods were statistically analyzed,and then the time consuming,sample size requirements,influence factors were comprehensively discussed,thustheselectionreferenceproposaloftheexaminationmethodcouldbeprovided.Results Therewereno significant difference for the data of two examination method (P>0.05 ).The limit of detection of the γspectrometry was lower (P <0.05 ).Compared with Phosphoric acid ammonium molybdate method,γspectrometry had lower limit of detection,and could detect a variety of radionuclides at a time,but need more sample and time-consuming when multi-sample were detected.The limit of detection of the Phosphoric acid ammonium molybdate method was high,and the chemicalprocessingstepswerecumbersomeandwaseasytobeinterferedby134Cs.Conclusion Thelimitofdetectionof the γspectrometry is low,and the sensitivity of the Phosphoric acid ammonium molybdate method is high.Most food are recommended to be detected by γspectrometry in the practical work,and the food which were difficult collected,less ash or low content,are recommended to be detected by Phosphoric acid ammonium molybdate method.

Research advances in poly (ADP-ribose) polymerase inhibitors in combination with radiotherapy / 中华放射肿瘤学杂志

As a DNA damage sensor,poly (ADP-ribose) polymerase (PARP) is involved in a wide variety of cellular activities,such as DNA damage repair.PARP inhibitors regulate a series of cellular activities by inhibiting PARP function,which have become a focus of current research.Recently,several in vivo and in vitro studies showed that PARP inhibitors combined with radiotherapy effectively enhanced the efficacy of radiotherapy.This paper reviews the research advances in the mechanisms of action of PARP inhibitors and their combination with radiotherapy.

Use of acids as additives in sugarcane silage / Uso de ácidos como aditivos en el ensilaje de caña de azúcar / Uso de ácidos como aditivos na silagem de cana de açúcar

Background: sugarcane silage often becomes a problem for the producers due to its high population of yeast and its high content of soluble carbohydrates. Objective: to evaluate the effect of formic and phosphoric acid on the chemical composition, fermentation characteristics, and digestibility of sugarcane silages. Methods: sugarcane was ensiled in experimental mini-silos. Five treatments were evaluated in the ensilage process (sugarcane added with 0.5 or 1% formic acid and 0.5 or 1% phosphoric acid, and a control treatment without additives). A completely randomized design was used. Results: the dry matter content of silages containing phosphoric acid was lower. Lower values of NDF, ADF, and hemicellulose were observed in the control and formic acid treatments. Conclusions: formic and phosphoric acids promote beneficial changes in the chemical composition of sugar cane silage.

Antecedentes: debido a la elevada presencia de levaduras y a la alta proporción de carbohidratos, el ensilaje de caña de azúcar presenta problemas de manejo para los productores. Objetivo: evaluar el efecto de la adición de ácidos fórmico y fosfórico sobre la composición química, características fermentativas y digestibilidad del ensilaje de caña de azúcar. Métodos: la caña de azúcar se ensiló en mini silos. Fueron evaluados cinco tratamientos en el proceso de ensilaje de caña de azúcar (caña de azúcar adicionada con 0,5 o 1% de ácido fórmico, o con 0,5 o 1% de ácido fosfórico, y un tratamiento control sin aditivos). Se utilizó un diseño completamente aleatorizado. Resultados: la proporción de materia seca de los ensilajes con ácido fosfórico fue menor. Se observaron menores proporciones de NDF, ADF y hemicelulosa en los ensilajes sin adición de ácido y en los adicionados con ácido fórmico. Conclusiones: el uso de ácidos fórmico y fosfórico en el ensilaje de caña de azúcar promueve modificaciones benéficas en su composición química.

Antecedentes: devido à elevada presença de leveduras como também excessiva proporção de carboidratos, a silagem de cana apresenta problemas de manejo para os produtores. Objetivo: avaliar o efeito da adição do ácido fórmico e ácido fosfórico sobre composição química, características fermentativas e digestibilidade de silagens de cana-de-açúcar. Métodos: a cana-de-açúcar foi ensilada em mini silos. Foram avaliados cinco tratamentos no processo de ensilagem de cana de açúcar (cana-de-açúcar adicionada com 0,5 ou 1% de ácido fórmico ou com 0,5 ou 1% de ácido fosfórico, e um tratamento controle sem aditivos), utilizando um delineamento inteiramente casualizado. Resultados: os teores de matéria seca das silagens contendo ácido fosfórico foram menores. Menores valores de NDF, ADF e hemicelulose foram observados para as silagens de cana-de-açúcar in natura e adicionadas de ácido fórmico. Conclusões: o uso de ácido fórmico e fosfórico promove mudanças benéficas na composição química da silagem de cana de açúcar.

Adhesión convencional en dentina, dificultades y avances en la técnica / Conventional dentin bonding. Difficulties and progress in the technique

INTRODUCCIÓN: estudios respecto a la adhesión en dentina han reportado que, contrario a la estabilidad lograda sobre esmalte dental, en dentina los mecanismos adhesivos todavía son sensibles, impredecibles e inestables. El objetivo de este trabajo es revisar la literatura actual sobre la adhesión en dentina, con el fin de caracterizar la adhesión convencional describiendo las modificaciones actuales del protocolo convencional, encaminadas a mejorar el desempeño adhesivo de los materiales dentales. Métodos: se hizo una revisión de la literatura evaluando 3 bases de datos: ScienceDirect, Springer y Medline, de las cuales se escogieron los 52 artículos más relevantes, publicados entre los años 2004 y 2013. Se usaron, como criterios de búsqueda, las palabras clave: dentin, dentin bonding, bond strength y acid etching. Resultados: al revisar los artículos seleccionados, se logró una descripción del protocolo de adhesión convencional que muestra la formación del barrillo dentinario (smear layer), la acción del ácido fosfórico y la formación de la interfase adhesiva propiamente dicha, junto con las dificultades propias de la técnica y las posibles soluciones planteadas hasta la fecha. Conclusión: la adhesión convencional sobre dentina es un procedimiento estricto y delicado, que evidencia inconvenientes como la degradación hidrolítica y proteolítica de la matriz de colágeno por parte de enzimas liberadas en el momento de la desmineralización, lo que deteriora la interfase adhesiva. Por tanto, se han sugerido sustancias que pueden ser utilizadas como agentes de protección del colágeno, sin alterar e incluso mejorando la resistencia adhesiva.

INTRODUCTION: studies on dentin bonding have reported that, contrary to the achieved stability on dental enamel, adhesive mechanisms on dentine are still sensitive, unpredictable, and unstable. The objective of this study is to review the current literature on dentin bonding in order to characterize conventional bonding, describing current modifications of the conventional protocol aimed at improving the adhesive performance of dental materials. METHODS: a literature review was conducted within 3 databases: ScienceDirect, Springer, and Medline, choosing the 52 most relevant articles published between 2004 and 2013. The following key words were used as search criteria: dentin, dentin bonding, bond strength, and acid etching. RESULTS: the review of the selected articles provided a description of the conventional adhesion protocol showing the formation of smear layer, the action of phosphoric acid, and the actual formation of adhesive interface, as well as the difficulties of the technique and possible solutions suggested to date. CONCLUSIONS: conventional dentin bonding is a precise and delicate procedure that shows disadvantages such as the hydrolytic and proteolytic degradation of collagen matrix by enzymes released at the time of demineralization, which damages the adhesive interface. Therefore, several substances have been suggested to be used as agents of collagen protection without altering adhesive strength, and even improving it.studies on dentin bonding have reported that, contrary to the achieved stability on dental enamel, adhesive mechanisms on dentine are still sensitive, unpredictable, and unstable. The objective of this study is to review the current literature on dentin bonding in order to characterize conventional bonding, describing current modifications of the conventional protocol aimed at improving the adhesive performance of dental materials. Methods: a literature review was conducted within 3 databases: ScienceDirect, Springer, and Medline, choosing the 52 most relevant articles published between 2004 and 2013. The following key words were used as search criteria: dentin, dentin bonding, bond strength, and acid etching. Results: the review of the selected articles provided a description of the conventional adhesion protocol showing the formation of smear layer, the action of phosphoric acid, and the actual formation of adhesive interface, as well as the difficulties of the technique and possible solutions suggested to date. Conclusion: conventional dentin bonding is a precise and delicate procedure that shows disadvantages such as the hydrolytic and proteolytic degradation of collagen matrix by enzymes released at the time of demineralization, which damages the adhesive interface. Therefore, several substances have been suggested to be used as agents of collagen protection without altering adhesive strength, and even improving it.

Impact of Intracoronal Dentin Treatment Prior to Bleaching on Bond Strength of Restorative Materials

Surface treatment of dentin before the bleaching procedure may affect its permeability and influence the bond strength of restorative materials. This study evaluated the influence of surface treatment before the bleaching on shear bond strength (SBT) of restorative materials to intracoronal dentin. Dentin slabs were subjected to surface treatment: no bleaching (control - CON), no surface treatment + bleaching (HP), 37% phosphoric acid + bleaching (PA) and Er:YAG laser + bleaching (L). After the bleaching procedure, specimens (n=10) were restored with: microhybrid composite resin (MH), flowable composite resin (F), and resin-modified glass-ionomer cement (RMGIC). The shear test was carried out. ANOVA and Tukey's test (α=0.05) showed significant difference for surface treatment and restorative materials (p<0.05). CON presented higher STB and was statistically different from HP (p<0.05). PA and L showed intermediate values and were statistically similar to CON and HP (p>0.05). STB for MH and F were higher than RMGIC (p<0.05), and did not differ from each other (p>0.05). The surface treatments with phosphoric acid and Er:YAG laser before the bleaching procedure provided shear bond strength at the same level of unbleached dentin and the composite resins presented superior bond strength to the intracoronal dentin.

O tratamento superficial da dentina previamente ao clareamento pode afetar a sua permeabilidade e influenciar a resistência de união de materiais restaurados. Este estudo avaliou a influência do tratamento superficial antes do clareamento na resistência ao cisalhamento (RC) de materiais restauradores à dentina intracoronária. Fragmentos de dentina foram submetidos ao tratamento de superfície: não clareadas (controle - CON), sem tratamento de superfície + clareamento (HP), ácido fosfórico 37% + clareamento (AF), e laser Er:YAG + clareamento (L). Após o procedimento clareador, os espécimes foram restaurados com (n=10): resina composta micro-híbrida (MH), resina composta fluida (F), e cimento de ionômero de vidro modificado por resina (CIVMR). O teste de cisalhamento foi realizado. ANOVA e teste de Tukey (α=0,05) mostraram diferença significante para tratamento superficial e material restaurador (p<0,05). O grupo controle apresentou maior resistência de união e foi estatisticamente diferente de HP (p<0,05). AF e L mostraram valores intermediários e foram similares ao CON e HP (p>0,05). A resistência de união para MH e F foi maior que CIVMR (p<0,05), e não diferiram entre si (p>0,05). O tratamento da superfície dentinária com ácido fosfórico e laser Er:YAG previamente ao clareamento promoveu resistência de união ao nível da dentina não clareada e a adesão à dentina intracoronária foi superior com as resinas compostas.

Effects of tri-ortho-cresyl phosphate on homeostasis of the glutamate-glutamine cycle and its key enzymes in the brains of hens / 中国组织工程研究

BACKGROUND:Although incidents of organophosphate-induced delayed neurotoxicity have been documented for over a century, the molecular mechanisms underlying the axonopathy remain poorly understood. OBJECTIVE:To discuss the effects of tri-ortho-cresyl phosphate (TOCP) on homeostasis of the glutamate-glutamine cycle and the expression of key enzymes in the brains of hens. METHODS:Twenty-four adult hens were randomly divided into three groups (n=8). TOCP group was treated with TOCP by gavage at a single dosage of 1 000 mg/kg, and control group was given an equivalent volume vehicle by gavage, while hens in the phenylmethylsulfonyl fluoride (PMSF)+TOCP group were subcutaneously injected with 40 mg/kg PMSF fol owed by 1 000 mg/kg TOCP 24 hours later. The hens were kil ed on days 5 and 21 post-dosing. The brains were taken out quickly and preserved in a-80℃deep freezer. ELISA was used to determination the content of glutamine synthetase and glutaminase and the activity of glutamine synthetase. Corresponding kits were used to measure the level of glutamate and glutamine. Fluo3-AM was used to measure cytosolic calcium concentration. RESULTS AND CONCLUSION:The activity and content of glutamine synthetase and the concentration of glutamine were down-regulated, while the concentrations of the intracellular Ca2+and glutamate were up-regulated in the early stage after TOCP administration. It is also suggested that the downregulated expression of glutamine synthetase may be associated with organophosphate-induced delayed neurotoxicity through the disruption of homeostasis of the glutamate-glutamine cycle and cytosolic calcium concentration.

A simplified etching technique to improve the adhesion of fiber post

PURPOSE: Numerous methods were used to etch the fiber posts to improve its bonding to root canal dentin. Our aim was to evaluate the efficacy of 37% phosphoric acid in etching fiber posts in comparison with 24% hydrogen peroxide. MATERIALS AND METHODS: Ninety human maxillary central incisors were taken and post space preparation was done. Ninety fiber posts were taken and divided into three groups (n=30) based on the surface treatment they received (H3PO4, H2O2, distilled water) and each group was further divided (n=10) based on the time period of application (15 seconds, 30 seconds, 60 seconds). All the posts were luted into canals using Rely X UniCem-2. Each tooth was then sectioned into six slices and subjected to push out test. Data obtained was subjected to statistical analysis at P<.05. The surface topography was evaluated using scanning electron microscopy. RESULTS: Highest bond strength values were noted in 15 seconds etched phosphoric acid group and 60 seconds etched hydrogen peroxide group with no significant difference between two groups. Surface topography revealed complete epoxy layer removal with no damage to its structural integrity in those groups. CONCLUSION: H3PO4 etching for a period of 15 seconds is an effective alternative in improving the adhesion of fiber post to root dentin.

Modification of surface pretreatment of white spot lesions to improve the safety and efficacy of resin infiltration / 대한치과교정학회지

OBJECTIVE: A low-viscosity resin (infiltrant) was used to inhibit the progression of white spot lesions (WSLs) and resolve associated esthetic issues. An alternative pretreatment was explored to increase the pore volume of the surface layer of the WSLs. Also, the penetration effects of the infiltrant were evaluated for various pretreatments. METHODS: Sixty two artificial lesions were fabricated on bovine teeth. As a positive control, 15% HCl gel was applied for 120 seconds. Further, 37% H3PO4 gel was applied for 30 seconds using three methods. The samples were divided as follows: H3PO4 only group, H3PO4 sponge group, and H3PO4 brush group. The acid was gently rubbed with the applicators (i.e., a sponge or brush) throughout the application time. To compare the effects of resin infiltration, twenty paired halves of specimens were treated with an infiltrant (ICON(R)). RESULTS: Thicknesses of the removed surface layers and infiltrated areas were evaluated by confocal laser scanning microscope. The positive control and the 37% H3PO4 brush group failed to show significant differences in the removed thickness (p > 0.05); however, the mean percentage of the infiltrated area was higher in the 37% H3PO4 brush group (84.13 +/- 7.58%) than the positive control (63.51 +/- 7.62%, p < 0.001). Scanning electron microscope observations indicate higher pore volumes for the 37% H3PO4 brush group than for the positive control. CONCLUSIONS: Application of 37% H3PO4 with a brush for 30 seconds increased the pore volume of WSL surface layers and the percentage of infiltrated areas in comparison to the use of 15% HCl for 120 seconds.

Microabrasion technique for enamel with fluorosis: a case report utilizing two distinct pastes / Técnicas de microabrasão no esmalte com fluorose: relato de caso clínico utilizando duas diferentes pastas

A técnica de microabrasão do esmalte é considerada uma alternativa conservadora e efetiva para remoção de manchas e irregularidades superficiais do esmalte e diferentes pastas podem ser usadas para essa finalidade. Objetivo: O objetivo desse estudo foi comparar a eficácia da técnica de microabrasão do esmalte com fluorose utilizando duas diferentes pastas. Material e Métodos: Paciente, gênero feminino, 18 anos de idade, foi submetida ao tratamento de microabrasão do esmalte, sendo que na arcada superior direita foi manipulada e aplicada a pasta à base de pedra-pomes (SSWhite) e ácido fosfórico a 37% (Alpha Etch, DFL) na proporção de 1:1 e na arcada superior esquerda uma pasta à base de ácido hidroclorídrico a 6,6% e óxido de silício (Micropol, DMC Equipamentos Ltda). Nas duas hemi-arcadas foi realizado o mesmo protocolo clínico por três vezes, sendo que a aplicação da pasta foi de 1 mm de espessura e a realização da microabrasão se deu por fricção mecânica com taça de borracha acoplada em baixa rotação por 10 s. Em seguida os dentes foram polidos com disco de feltro e pasta diamantada e aplicado flúor tópico APF 1,23% por 3 min. Resultados: Os resultados clínicos foram similares em ambas arcadas, independente da pasta utilizada. O sucesso na remoção de manchas no esmalte está dieretamente relacionada com o correto diagnóstico e a precisa indicação da técnica de microabrasão. Conclusões: Foi possível concluir que a as duas diferentes pastas utilizadas para a microabrasão do esmalte foram efetivas na remoção de machas intrínsecas por fluorose com resultados similares e com o restabelecimento estético dos dentes envolvidos.

The technique of enamel microabrasion is considered an aesthetic alternative conservative and effective for stain removal or surface irregularities of the enamel and different materials or pastes can be used for this purpose Objetives: The objective of this study was to compare the efficiency of the technique of enamel microabrasion using two different pastes at removing hypoplastic stains by fluorosis. Methods: The female patient, 18 years, was submitted to enamel microabrasion, and in the right half of the maxilla was manipulated in the proportion of 1:1 by volume a paste of pumice (SSWhite) and 37% phosphoric acid (Etch Alpha, DFL), and in the left half of the maxilla used paste based on hydrochloric acid and 6.6% silicon carbide (Micropol, DMC Equipment Ltd.). In both hemi-arches was performed the same clinical protocol and repeated three times, by the application of 1.0 mm thickness of paste and realized the enamel microabrasion through mechanical friction with rubber cup at low speed for 10 s. Then, the teeth were polished with felt disc and diamond paste, and topical fluoride APF 1.23% for 3 min was applied. Results: The clinical outcome was similar for both hemi-arches, regardless of the used technique. The success in removing stains on tooth enamel is directly related to a correct diagnosis and accurate indication of microabrasion technique. Conclusions: It can be concluded that the two pastes used in the enamel microabrasion were effective for removing intrinsic stains from fluorosis, with similar results and with the re-establishment of aesthetics of the teeth involved.