Assessment of enamel surface roughness and hardness with metal and ceramic orthodontic brackets using different etching and adhesive systems: An in vitro study.

Background: This study aimed to evaluate enamel surface roughness and microhardness following the use of different bracket materials (metal or ceramic), etchants (total- and self-etchants), and adhesive systems (precoated or flash-free). Method: A total of 99 extracted human premolars were selected for the analysis. The surface roughness was first assessed (roughness control). One specimen from each subgroup was examined using a scanning electron microscope to illustrate the surface topography. Eighty-eight teeth were prepared using total- or self-etchants and bonded to precoated or flash-free adhesive metal or ceramic brackets. The remaining 11 specimens were not bonded to brackets (microhardness controls). The brackets were debonded after immersion in distilled water for 24 h. The specimens were again scanned for surface roughness and topography imaging. Finally, the microhardness was assessed using a micro-Vickers hardness test at a force of 200 g for 10 s. Result: An overall statistically significant increase in surface roughness and reduced surface microhardness were observed in all experimental groups when compared with those in the control groups. The etchant type was the only variable found to contribute to the measured surface properties, with increased roughness and reduced microhardness introduced by total-etching compared to those by self-etching. Conclusion: Orthodontic brackets introduced a significant increase in enamel surface roughness and reduce microhardness compared with untreated enamel, regardless of the bracket material, etchant type, and adhesive system. The etchant type was the only variable contributing to these changes, with total etching having a more pronounced effect.

Uso de adhesivo universal con pregrabado y autograbado en tejidos duros del diente / Use of universal adhesive with pre-etch and self etch strategies on hard tooth tissues

RESUMEN Introducción: Buscando satisfacer la demanda con procedimientos adhesivos más rápidos, menos sensibles a la técnica y facilidad de uso, se han desarrollado los adhesivos universales, que brindan al profesional la opción de seleccionar la estrategia de adhesión con diferentes modos de grabado, ya sea con grabado y enjuague, autograbado o grabado selectivo. Debido a la poca información existente, se han generado dudas sobre el rendimiento, propiedades y la aplicación de una técnica adhesiva adecuada sobre los tejidos dentales. Objetivo: Determinar el nivel de adhesión con el uso de adhesivos universales en modo de grabado y enjuague y autograbado. Métodos: Se realizó una revisión de la literatura, a través de la búsqueda electrónica en las bases de datos: SciELO, Scopus, PubMed, Springer y EBSCO. Inicialmente se seleccionaron por título y resumen, artículos duplicados se consideraron solo una vez, se incluyeron artículos de acceso libre y pagos, escritos en idioma español e inglés, publicados desde el año 2015, de los cuales 39 artículos fueron seleccionados para el estudio. Conclusiones: El uso de adhesivos universales sobre dentina presenta un nivel de adhesión mayor cuando se aplica en modo de autograbado. La aplicación activa del adhesivo universal en esmalte mejora la fuerza y resistencia de unión. El nivel de adhesión en el esmalte es mayor cuando se aplica en modo de grabado y enjuague. La resistencia inicial y por fatiga del adhesivo, no mejora con los tiempos prolongados del grabado ácido.

ABSTRACT Introduction: universal adhesives have been developed to satisfy the demand with faster adhesive procedures, less sensitive to the technique and ease of use, which offer the professional the option of selecting the adhesion strategy with different etching modes, either with etch-and-rinse, self-etch or selective etching ones. Doubts have been generated about the performance, properties and application of an adequate adhesive technique on dental tissues due to the little existing information. Objective: to determine the level of adhesion with the use of universal adhesives in etch-and-rinse and self-etch modes Methods: an electronic search of the literature was carried out in SciELO, Scopus, PubMed, Springer and EBSCO databases. Initially, articles were selected by title and abstract, duplicate ones were considered only once, free and paid access articles, written in Spanish and English and published since 2015 were included; 39 of them were selected for the study. Conclusions: the use of universal adhesives on dentin presents a higher level of adhesion when applied in self-etch mode. The active application of the universal adhesive improves the enamel bond strength. The level of adhesion on the enamel is higher when applied in etch-and-rinse. The initial fatigue resistance of the adhesive does not improve with prolonged acid etching times.

Influence of laser deproteinization of acid-etched dentin on marginal microleakage of class V composite restoration

Aim: Recent reports indicate that deproteinization of acid-etched dentin surface can extend penetration depth of adhesive agents. The main goal of the present research was to investigate the deproteinization effect of Nd:YAG and diode 940 lasers on acid-etched dentin and microleakage grade in class V composite restorations. Methods: 36 extracted human premolar teeth were selected to make standard buccal and lingual class V cavities. These samples were randomly split into three sub-groups: 1.Control group, in which composite was applied for restoration after etch and bonding process without deproteinization; 2.Nd:YAG laser group, in which the teeth were deproteinized with Nd:YAG laser after etching and painting internal surfaces of cavities with Van Geison stain and then composite restorations applied just as control group; 3.Diode laser group, in which the process was similar to Nd:YAG laser group, but instead, diode 940 laser was irradiated. The teeth were bisected into two equal longitudinal buccal and lingual halves. Marginal microleakage of samples was scored by using a stereomicroscope. Kruskal- Wallis, Mann-Whitney U and Fisher's statistical tests were employed for analysis of the obtained data. Results: A significant reduction in marginal microleakage was observed for both groups treated with laser (Nd:YAG and diode 940)compared to control (p=0.001 & p=0.047). There was no significant difference in marginal microleakage between Nd:YAG laser and diode 940groups (P = 0.333). Conclusion: Nd:YAG and diode 940 laser deproteinization of acid-etched dentin decreased the marginal microleakage of in-vitro class V resin composite restorations

Shortening of etching time of the dentin in primary teeth restorations: a randomized clinical trial

Abstract The aim of this study was to investigate the influence of shortening of etching time for dentin on the restoration survival after selective carious tissue removal in primary molars. This two-arm randomized clinical trial included sixty-two subjects (5-8 year-old) and 100 primary molars presenting moderate dentin carious lesions on occlusal surface. The sample was randomly assigned into groups previously to adhesive application (Adper Single Bond 2; 3M ESPE): etching time recommended by manufacturer (15 s) or reduced (7 s). Resin composite (Filtek Bulk Fill Posterior Restorative; 3M ESPE) was inserted in a single increment for all restorations. Restorations were evaluated at 1, 6, 12, and 18 months using FDI criteria. Survival estimates for restorations' longevity were evaluated with Kaplan-Meier method. Multivariate Cox regression analysis with shared frailty was used to assess the factors associated with failures (p < 0.05). The etching time did not influence the restorations' survival (HR 0.35 95%CI 0.11-1.12; p = 0.06). Mean estimated time of survival was 17.6 months (95%CI, 17.2-17.9). The survival rates at the 18-month follow-up were 75.7% and 91.4% (AFR: 16.9% and 5.7%) when primary dentin was acid etched for 15 and 7 s, respectively (log-rank p = 0.06). In conclusion, the etching time for dentin did not influence the clinical behavior of adhesives restorations. However, there was a tendency for better clinical outcome when using etching time of 7 s.

Effects of quercetin on the dentin resistance to erosion / 中华口腔医学杂志

Objective@#To evaluate the effects of quercetin on dentin resistance to erosion and provide evidence-based recommendations for the prevention and therapy of dental erosion.@*Methods@#One hundred and twenty-eight dentin samples were prepared from 50 extracted human wisdom teeth (collected from Department of Oral Surgery, School and Hospital of Stomatology). Ninety-six samples were randomly divided into 8 groups using the following different soaking solutions: deionized water, ethanol (control groups), 12.300 mg/L sodium fluoride, 0.120 mg/L chlorhexidine, 0.183 mg/L epigallocatechin gallate (EGCG), and 0.075, 0.150 and 0.300 mg/L quercetin. In each group, twelve specimen was prepared. Before daily acid challenge, the samples were immersed in the respective solutions for 2 min, rinsed with deionized water, and immersed in artificial saliva for 2 h. The samples were then subjected to 4 cycles of in vitro acid challenges. This protocol was applied for 7 d. The surface microhardness (SMH) and surface profiles were measured before and after erosion using the surface microhardness tester and contact profilometry, respectively. The change in surface profiles and reduction in SMH were used to calculate the substance loss and reduction percentage of SMH (SMH%) respectively. Scanning electron microscope (SEM) images were taken to observe the surface morphology of the samples. Additionally, another thirty two samples were divided into 8 groups (n=4) as mentioned above. The specimens were treated with 10% phosphoric acid and desiccated, immersed in the respective solutions for 2 min, rinsed, and immersed in the artificial saliva at 37 ℃ for 7 d. The content of cross-linked carboxyterminal telopeptide of type Ⅰ collagen (ICTP) in the soaking solutions were measure quantitatively.@*Results@#Compared with the control groups, the application of chlorhexidine, quercetin, and EGCG were effective in preventing the surface softening and substance loss of human dentin after erosion. More specifically, the specimens treated with 0.300 mg/L quercetin exhibited the lowest SMH% [(8.75±4.95)%], the lowest surface substance loss [(2.26±1.16) μm], and the lowest contents of ICTP in the soaking solution [(5.72±0.88) ng], showing significant differences to the chlorhexidine and EGCG treated samples (P<0.05). No significant differences were found in the substance loss and ICTP contents in the three soaking solutions with different concentrations of quercetin(P>0.05). However, the specimens treated with 0.300 mg/L quercetin exhibited significantly lower SMH% than those treated with the other two concentrations of quercetin (P<0.05).@*Conclusions@#Within the limitations of the current study, immersion in the quercetin solution is effective in improving the dentin resistance to erosion by inhibiting the dentinal MMP. Among all the concentrations tested, 0.300 mg/L quercetin showed the best performance.

[Effect of two kinds of materials on the prevention of early erosive enamel wear].

Objective: To investigate the preventive effect of resin infiltration and adhesive on early erosive enamel wear. Methods: Orthodontic reduction premolars collected from Central Laboratory of Nanjing Stomatological Hospital, Medical School of Nanjing University were used to prepare 70 specimens. Forty samples were divided into eight groups (n=5) and treated with different conditions (pH=1.6, 2.4, 3.2 or 4.0 hydrochloric acid solution, etching time was 30 or 60 s), and the conditions for obtaining early erosive enamel samples were selected. Based on this procedure, thirty early erosive enamel samples were made and divided into three groups: control group, resin infiltration group, and adhesive group. And the treatment of 30 days acid abrasion cycle was carried out. Confocal microscopy was used to measure the thickness changes of enamel or material before and after cycle. Results: Early erosive enamel samples was obtained when pH was 4.0 and etching time was 60 s. After 30 days cycle, the wear of enamel was (29.71±6.72) µm in control group, (5.60±2.24) µm in resin infiltration group and (2.89±1.03) µm in adhesive group. In infiltration group and adhesive group, lower enamel was not affected by the cycle, and the material loss ratios of the infiltration resin group and adhesive group were 0.41±0.14 and 0.29±0.13, respectively. The ratio of material loss was not significantly different (P>0.05). But infiltration group lost (12.95±2.22) µm of enamel during the application of the material. Conclusions: Resin infiltration and adhesive have the same short-term protective effect against early erosive enamel wear. Adhesive has less damage to enamel and better effect.

Marginal filling and adhesive resistance of bulk fill resin applying 18% edta gel compared with 37% phosphoric acid gel in vitro dental conditioning / Sellado marginal y resistencia adhesiva de resina bulk fill aplicando gel de edta al 18% comparado con el gel de ácido fosfórico al 37% en el acondicionamiento dental in vitro

Objective. To evaluate the degree of marginal sealing and adhesive strength in Bulk-Fill resin by applying 18% EDTA gel compared to 37% phosphoric acid gel in dental conditioning. Materials and methods. The study was transversal, experimental comparative, and applied. The sample group consisted of 60 teeth with Class I cavities, which were later subjected to conditioning. This was carried out separately with phosphoric acid gel for 15 seconds, and 18% EDTA gel within two different time frames: 60 and 90 seconds. All samples were incubated at 37ºC for a period of 24 hours and thermocycled between 5 to 55ºC for 500 cycles. To assess microfiltration, they were immersed in methylene blue at 37ºC for 4 hours, and were later sectioned and observed through a stereomicroscope. In order to perform the traction, the conventional testing machine was used at a speed of 0.75mm/min until the screw with the resin detached. Results: Samples conditioned with 37% phosphoric acid showed a greater degree 1 microfiltration and a mean adhesive resistance of 7.97 MPa. The same number of microfiltration grades 1 and 2 was found when using EDTA gel for 60 seconds, with a mean tensile strength of 8.8 MPa. On the other hand, applying EDTA gel for 90 seconds showed mostly grade 1 microfiltrations, and to a lesser extent, grade 0 and 2, with a mean resistance of 9.2 MPa. Conclusion: There are no statistically significant differences regarding adhesive strength between the two gels; however, better marginal filling was observed when samples were conditioned with 18% EDTA gel for 90 seconds.

Objetivo. Evaluar el grado de sellado marginal y resistencia adhesiva en resina Bulk ­ Fill aplicando gel de EDTA al 18% en comparación al gel de ácido fosfórico al 37% en el acondicionamiento dental. Materiales y métodos. El tipo de estudio fue transversal, comparativo, de nivel aplicativo y diseño experimental. La muestra estuvo conformada por 60 dientes con cavidades clase I; se realizó el acondicionamiento con gel de ácido fosfórico, gel del EDTA al 18% en 60 segundos y 90 segundos. El total de las muestras fueron incubados a 37°C por 24 horas, se termocicló con 500 ciclos entre 5 a 55ºC. Para evaluar microfiltración, fueron sumergidos en azul de metileno a 37ºC por 4 horas, fueron seccionadas y observados al estereomicroscopio, para realizar la tracción se empleó la máquina de ensayos universales a una velocidad de 0.75mm/min hasta que se desprendiera el tornillo con la resina. Resultados. Las muestras acondicionadas con ácido fosfórico al 37% presenta mayor microfiltración grado 1 y el promedio de su resistencia adhesiva es de 7.97Mpa, la microfiltración obtenida con EDTA en 60 segundos presenta equidad entre grado 1 y 2; promedio de resistencia a la tracción de 8.8 Mpa y el EDTA 90 segundos presentó mayor microfiltración grado 1 y el resto 0 y 2; el promedio de resistencia fue 9.2 Mpa. Conclusión. No existen diferencias estadísticamente significativas al comparar los acondicionantes para la prueba de resistencia adhesiva, sin embargo se observó mejor sellado marginal cuando se acondicionó con gel de EDTA al 18 % por 90 segundos.

Effect of grape seed extract-containing phosphoric acid formulations on bonding to enamel and dentin

Abstract The aim was to evaluate the effect of 2% grape seed extract (GSE) containing phosphoric acid (PhA) on the bond strength to enamel and dentin. The control group was 37% PhA. The following three PhA formulations with 2% GSE and 20% ethanol were obtained: GSE5 = 5% PhA; GSE10 = 10% PhA; and GSE20 = 20% PhA. The enamel and dentin surfaces of molars were etched with the acid solutions, followed by Scotchbond Multi-Purpose adhesive and composite resin application. The tensile bond strength (TBS) test evaluated the bond to enamel after 24 h, and the microtensile bond strength (μTBS) test evaluated the bond to dentin after 24 h and 12-month water storage. Etched enamel and dentin were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM), respectively. The TBS data were submitted to one-way ANOVA, while µTBS data were submitted to two-way ANOVA and Tukey's test (α = 0.05). The TBS (MPa) to enamel did not significantly differ among the control (48.1 ± 15.7), GSE5 (46.1 ± 9.6), GSE10 (49.8 ± 13.6) and GSE20 (44.1 ± 11.9) groups (p = 0.537). The µTBS (MPa) to dentin of the control (28.4 ± 14.4) and GSE20 (24.1 ± 8.1) groups were significantly higher than those of the GSE5 (16.8 ± 7.4) and GSE10 (17.5 ± 6.6) groups at 24 h (p < 0.006). After 12-month storage, only GSE5 (21.0 ± 7.8) and GSE10 (17.6 ± 8.0) did not show significantly decreased μTBS (p > 0.145). SEM micrographs showed a shallower enamel etching pattern for GSE5. AFM images showed the formation of collagenous globular structures for GSE5 and GSE10. The different acid solutions did not influence the TBS to enamel, and the µTBS to dentin was stable over time when dentin was etched with GSE5 and GSE10.

Effect of hydrofluoric acid concentration and etching time on resin-bond strength to different glass ceramics

Abstract: The objective of this study was to evaluate the effect of the hydrofluoridric acid (HF) concentration and time of acid conditioning on bond strength of three glass ceramics to a resin cement. Thus, fifty blocks (10 mm x 5 mm x 2 mm) of each ceramic (LDCAD: IPS e.max CAD; LCAD: IPS Empress CAD and LDHP: IPS e.max Press) were made and embedded in acrylic resin. The surfaces were polished with sandpaper (#600, 800, 1000, and 1200 grits) and blocks were randomly divided into 15 groups (n = 10) according to the following factors: Concentration of HF (10% and 5%), conditioning time (20 s and 60 s) and ceramic (LDCAD, LDHP, and L). After conditioning, silane (Prosil / FGM) was applied and after 2 min, cylinders (Ø = 2 mm; h = 2 mm) of dual resin cement (AllCem / FGM) were made in the center of each block using a Teflon strip as matrix and light cured for 40 s (1,200 mW/cm2). Then, the samples were thermocycled (10,000 cycles, 5/55°C, 30s) and submitted to the shear bond test (50 KgF, 0.5 mm/min). The data (MPa) were analyzed with 3-way ANOVA and Tukey's test (5%). Failure analysis was performed using a stereomicroscope (20x) and a scanning electron microscope (SEM). ANOVA revealed that the "concentration" factor (p = 0.01) and the interaction "acid concentration X ceramic" (p = 0.009) had a significant effect, however, the "ceramic" (p = 0.897) and "conditioning time" (p = 0.260) factors did not influence the results. The LDHP10%60s (10.98 MPa)aA* group presented significantly higher bond strength than LDHP10%20s (6.57 MPa)bA, LCAD5%20s (6,90 ±3,5)aB and LDHP5%60s (5.66 ± 2,9MPa)aA* groups (Tukey). Failure analysis revealed that 100% of specimens had mixed failure. In conclusion, etching with 5% HF for 20 seconds is recommended for lithium disilicate and leucite-reinforced CAD/CAM ceramics. However, for pressed lithium disilicate ceramic, 10% HF for 60 s showed significantly higher bond strength to resin cement.

Effect of two kinds of materials on the prevention of early erosive enamel wear / 中华口腔医学杂志

Objective@#To investigate the preventive effect of resin infiltration and adhesive on early erosive enamel wear.@*Methods@#Orthodontic reduction premolars collected from Central Laboratory of Nanjing Stomatological Hospital, Medical School of Nanjing University were used to prepare 70 specimens. Forty samples were divided into eight groups (n=5) and treated with different conditions (pH=1.6, 2.4, 3.2 or 4.0 hydrochloric acid solution, etching time was 30 or 60 s), and the conditions for obtaining early erosive enamel samples were selected. Based on this procedure, thirty early erosive enamel samples were made and divided into three groups: control group, resin infiltration group, and adhesive group. And the treatment of 30 days acid abrasion cycle was carried out. Confocal microscopy was used to measure the thickness changes of enamel or material before and after cycle.@*Results@#Early erosive enamel samples was obtained when pH was 4.0 and etching time was 60 s. After 30 days cycle, the wear of enamel was (29.71±6.72) μm in control group, (5.60±2.24) μm in resin infiltration group and (2.89±1.03) μm in adhesive group. In infiltration group and adhesive group, lower enamel was not affected by the cycle, and the material loss ratios of the infiltration resin group and adhesive group were 0.41±0.14 and 0.29±0.13, respectively. The ratio of material loss was not significantly different (P>0.05). But infiltration group lost (12.95±2.22) μm of enamel during the application of the material.@*Conclusions@#Resin infiltration and adhesive have the same short-term protective effect against early erosive enamel wear. Adhesive has less damage to enamel and better effect.

[Effects of casein phosphopeptide-amorphic calcium phosphate on enamel erosion: an in situ study].

Objective: To evaluate the effects of casein phosphopeptide-amorphic calcium phosphate (CPP-ACP) on enamel erosion using an improved in situ experimental protocol. Methods: Forty-eight enamel blocks were prepared from fresh-extracted human premolars and further embedded in the acrylic resins. The present study was divided into 2 parts. In part 1 of the study, two volunteers were recruited to test the availability and safety of the in situ erosion protocol. Customized intraoral appliance was made with 4 reservoirs containing the specimens for each volunteer. For each intraoral applicance, 2 reservoirs were made with the openings and the other 2 remained intact. All volunteers were instructed to drink 150 ml cola within 5 min using the gargling method after placing appliances intraorally for 2 h. After erosion, the appliances were remained undisturbed intraorally for 1 h until the next erosive attack. The in situ erosion cycles were performed 4 times daily over 7 d. In part 2 of the study, forty specimens were randomly divided into 2 groups (n=20): CPP-ACP group and control group. The surfaces of specimens in CPP-ACP group were pretreated with CPP-ACP for 3 min before in situ erosion, whereas the specimens in control group were pretreated with deionized water for 3 min. For each intraoral applicance, 4 reservoirs were made with openings. Ten healthy volunteers were recruited and the above-mentioned in situ erosion protocol was applied to test the effects of CPP-ACP on enamel erosion. The surface microhardness and surface microstructure of the samples were examined before and after erosion in both parts of the study. The data were statistically analyzed using ANOVA and LSD tests. Data were considered statistically significant at a level of P<0.05. Results: Significant surface softening was observed in all specimens after erosion (P<0.001). The surface microhardness in the CPP-ACP group and control group were (198.8±23.2) and (152.4±42.1) HV, respectively (P=0.040). The specimens in the CPP-ACP group showed significantly fewer changes in surface microstructure compared with those in the control group. Conclusions: Based on this in situ experimental protocol, short-time consuming of acid beverages would produce significant effects on the surface microhardness of the human enamel, whereas the application of CPP-ACP can increase the erosion resistance of the enamel.

Effects of casein phosphopeptide-amorphic calcium phosphate on enamel erosion: an in situ study / 中华口腔医学杂志

Objective@#To evaluate the effects of casein phosphopeptide-amorphic calcium phosphate (CPP-ACP) on enamel erosion using an improved in situ experimental protocol.@*Methods@#Forty-eight enamel blocks were prepared from fresh-extracted human premolars and further embedded in the acrylic resins. The present study was divided into 2 parts. In part 1 of the study, two volunteers were recruited to test the availability and safety of the in situ erosion protocol. Customized intraoral appliance was made with 4 reservoirs containing the specimens for each volunteer. For each intraoral applicance, 2 reservoirs were made with the openings and the other 2 remained intact. All volunteers were instructed to drink 150 ml cola within 5 min using the gargling method after placing appliances intraorally for 2 h. After erosion, the appliances were remained undisturbed intraorally for 1 h until the next erosive attack. The in situ erosion cycles were performed 4 times daily over 7 d. In part 2 of the study, forty specimens were randomly divided into 2 groups (n=20): CPP-ACP group and control group. The surfaces of specimens in CPP-ACP group were pretreated with CPP-ACP for 3 min before in situ erosion, whereas the specimens in control group were pretreated with deionized water for 3 min. For each intraoral applicance, 4 reservoirs were made with openings. Ten healthy volunteers were recruited and the above-mentioned in situ erosion protocol was applied to test the effects of CPP-ACP on enamel erosion. The surface microhardness and surface microstructure of the samples were examined before and after erosion in both parts of the study. The data were statistically analyzed using ANOVA and LSD tests. Data were considered statistically significant at a level of P<0.05.@*Results@#Significant surface softening was observed in all specimens after erosion (P<0.001). The surface microhardness in the CPP-ACP group and control group were (198.8±23.2) and (152.4±42.1) HV, respectively (P=0.040). The specimens in the CPP-ACP group showed significantly fewer changes in surface microstructure compared with those in the control group.@*Conclusions@#Based on this in situ experimental protocol, short-time consuming of acid beverages would produce significant effects on the surface microhardness of the human enamel, whereas the application of CPP-ACP can increase the erosion resistance of the enamel.

Influence of EDC ethanol solution on dentin shear bond strength with a self-etch adhesive system / 北京大学学报(医学版)

Objective:To evaluate the bonding ability of one representative self-etch adhesive system by applying the micro-shear bond strength test method with different concentrations of carbodiimide [1-ethyl3-(3-dimethylaminopropyl) carbodiimide,EDC] ethanol solution pretreatment.Methods:Extracted sound human third molars were collected from patients ranging 18 to 40 years.In the study,80 molars were first sectioned to prepare a flat middle coronal dentin surface and then were randomly divided into 5 groups (n =16) according to without/with different surface treatments [blank control;80％ (volume fraction) ethanol control;EDC ethanol solution of three concentrations (0.01 mol/L,0.3 mol/L and 0.5 mol/L)].Each specimen underwent a micro-shear bond strength test and failure mode observation.The data collected were subjected to statistical analysis using one-way ANOVA and post hoc Tukey's test to analyze the difference of the micro-shear bond strength,and chi-square test/Fisher's exact test for the failure mode frequency of the micro-shear bond strength test specimens at a significance level of P =0.05.Results:The micro-shear bond strength of the three concentration EDC treatments were (35.29 ± 8.97) MPa (0.01 mol/L EDC treatment group),(40.24 ±9.68) MPa (0.3 mol/L EDC treatment group),(37.38 ±9.66) MPa (0.5 mol/L EDC treatment group) separately;and that of the 80％ ethanol group was (37.49 ± 7.76) MPa.All micro-shear bond strength value of the above four groups was statistically higher than that of the blank control group [(33.81 ± 7.98) MPa].The immediate microshear bond strength and failure mode was of no statistically significant difference among all the groups.It was noticed that the immediate micro-shear bond strength of 0.3 mol/L was higher than that of all the other groups,especially higher than that of the 80％ ethanol pretreatment group despite that there was no significant difference among all the groups.And the test of failure mode indicated that the cohesive failure was more common,while the frequency of adhesive failure was rare in each experimental group.Conclusion:EDC pretreatment had no adverse effect on the immediate micro-shear bond strengths of Clearfil SE Bond.Meanwhile,EDC treatment did not cause more adhesive failure in immediate micro-shear test,which had further denoted what was said above.However,it needs more research to illustrate the antienzymatic role of EDC in dentin bonding.

Protocolo das possibilidades técnicas de aplicação dos sistemas adesivos universais: revisão de literatura com relato de caso / Clinical strategies using universal adhesive systems: literature review with case report

Este relato de caso demonstra a utilização clínica de um novo sistema adesivo universal, Xeno Universal (Dentsply DeTrey, Alemanha) descrevendo quatro formas possíveis de aplicação: autocondicionante, com ou sem condicionamento seletivo do esmalte, ou com condicionamento ácido total, seguido da aplicação do adesivo sobre dentina seca ou úmida. Os adesivos universais de uma maneira geral são de fácil aplicação e versáteis, uma vez que o mesmo produto pode ter várias formas de aplicação, reduzindo o tempo clínico e em muitas situações a sensibilidade técnica. No entanto, mais estudos laboratoriais e clínicos que comprovem a eficácia deste novo adesivo universal em particular são necessários, antes que seu uso seja bem indicado aos cirurgiões-dentistas.

This case report describes the clinical application of a new universal adhesive system, Xeno Universal (Dentsply DeTrey, Germany) describing four application modes: self-etching, with or without selective enamel etching, or total etching followed by adhesive application on dry or moist dentin. Universal adhesive systems usually are versatile and easy to use, facilitating the operator, since the same product has several technical possibilities, thus reducing the operating time and the technique sensitivity. However, long-term laboratory studies and more clinical reports and/or clinical trials are needed to prove the quality of this new universal adhesive system, before dentists can start using them in their dental offices.

Effect of Re-Etching of Oxalate-Occluded Dentin on Microleakage of Composite Resin Restorations.

OBJECTIVES: This study aimed to assess the effect of re-etching of desensitized dentin for five and 10 seconds on marginal microleakage of composite restorations. MATERIALS AND METHODS: Class V cavities (4×2×2mm) were prepared on the buccal surfaces of 64 third molars and randomly divided into four groups of 16. In the control group, Single Bond (SB) adhesive was applied after etching. In BB+SB group, after application of BisBlock (BB) desensitizer agent (which needs etching), SB adhesive was used. In BB+5E+SB group, re-etching of dentin was done for five seconds after application of desensitizer, and then the adhesive was applied. The process in BB+10E+SB was the same as BB+5E+SB group except for re-etching time, which was 10 seconds. The cavities were restored with composite resin. After 24 hours of storage in distilled water and 10,000 thermal cycles, all samples were subjected to dye penetration test. The teeth were sectioned buccolingually in the middle of restorations. A blind examiner observed the sections under a stereomicroscope. RESULTS: At the occlusal margins, no significant difference in microleakage was observed among the groups (P>0.05). Application of BB in combination with SB had no effect in comparison to the control group (P>0.05); while there were significant differences in microleakage scores between BB+10E+SB and control (P=0.002), BB+10E+SB and BB+SB (P<0.001) and BB+5E+SB and BB+SB groups (P=0.009). CONCLUSIONS: Dentin re-etching after application of BB desensitizer increased the gingival microleakage of class V composite restorations. Application of BB desensitizer combined with SB adhesive enhanced marginal seal.

Antibacterial effect of self-etching adhesive systems on Streptococcus mutans / 北京大学学报(医学版)

Objective:To investigate the antibacterial effect of different self-etching adhesive systems against Streptococcus mutans (S.mutans).Methods:Six reagents ClearfilTM SE Bond primer (SP), ClearfilTM SE Bond adhesive (SA),ClearfilTM Protect Bond primer (PP),which contained antibacterial monomer methacryloyloxydodecylpyridinium bromide (MDPB),ClearfilTM Protect Bond adhesive (PA), positive control chlorhexidine acetate [CHX,1% (mass fraction )],and negative control phosphate buffer solution (PBS)were selected.They were mixed with S.mutans for 30 s respectively,then colony-forming units (CFU)were counted after incubated for 48 h on brain heart infusion (BHI)agar medium. The 6 reagents were applied to the sterile paper discs,and distributed onto the BHI agar medium with S. mutans and incubated for 24 h,then the inhibition zones were observed.CHX,PBS,PP,and SP were added on the dentin with artificial caries induced by S.mutans and kept for 30 s,then confocal laser scanning microscope (CLSM)was used to observe the live and dead bacteria after staining.The ratio of live to dead bacteria was calculated.PP+PA and SP+SA were applied on the dentin according to the manual and light cured.S.mutans were incubated on the samples for 2 h,ultrasonically treated and in-cubated on BHI agar medium for 48 h,then CFU was counted.The data were analyzed by non-parametric analysis and one-way ANOVA.Results:Compared with PBS,the PP,SP,PA,SA and CHX showed the antibacterial effect on free S.mutans (P<0.05 );SP and PP showed stronger antibacterial effect than PA,SA and CHX (P<0.05).CHX,SP and PP presented inhibition zones,while PBS,SA and PA did not.Compared with PBS,the CHX,SP and PP could lower the ratio of the live to dead bacteria significantly (P<0.05).Cured self-etching adhesive systems did not show any antibacterial effect on the free S.mutans.Conclusion:The primer of self-etching adhesives ClearfilTM SE Bond and ClearfilTM Pro-tect Bond showed significant antibacterial effect on free and attached S.mutans.The adhesive only showed antibacterial effect on free S.mutans before light-cured polymerization.After being cured,the self-etching adhesive systems did not show antibacterial effect anymore.

Effect of Bonding Application Time on Bond Strength of Composite Resin to Glass Ionomer Cement.

OBJECTIVES: This experimental study evaluated the effect of bonding application time on the microshear bond strength of composite resin to different types of glass ionomer cements (GICs). MATERIALS AND METHODS: One-hundred and sixty specimens (two conventional and two resin-modified GICs) were prepared and divided into 16 groups. The surface of all specimens was prepared using two different bonding systems (Frog and Stea) at three different times. After setting, the composite resin (Z100) was placed over the GICs. The specimens were then stored in distilled water for 24 hours (37°C) and exposed to microshear stresses at a crosshead speed of 1 mm/min. The results were analyzed using three-way ANOVA and Tukey's test (P<0.05). RESULTS: In conventional GICs, bond strength was affected by the type of bonding system at different times, and bond strength was significantly higher in the Fuji II group compared to Riva Self Cure group. In the Riva Self Cure group, bond strength was significantly affected by time; whereas, the type of bonding system failed to exert a significant effect on bond strength. There was no significant correlation between the type of bonding system and the two brands of resin-modified GICs. Bond strength was not affected by the type of bonding agent; however, among the two brands of resin-modified GICs, Fuji II LC yielded a significantly stronger bond. CONCLUSION: It appears that the type of bonding agent does not affect the microshear bond strength, and the bonding application time affects the microshear bond strength in Riva Self Cure GICs.

Temperature Rise Induced by Light Curing Unit Can Shorten Enamel Acid-Etching Time.

OBJECTIVES: The aim of this in-vitro study was to assess the thermal effect of light emitting diode (LED) light curing unit on the enamel etching time. MATERIALS AND METHODS: Three treatment groups with 15 enamel specimens each were used in this study: G1: Fifteen seconds of etching, G2: Five seconds of etching, G3: Five seconds of etching plus LED light irradiation (simultaneously). The micro shear bond strength (µSBS) of composite resin to enamel was measured. RESULTS: The mean µSBS values ± standard deviation were 51.28±2.35, 40.47±2.75 and 50.00±2.59 MPa in groups 1, 2 and 3, respectively. There was a significant difference between groups 1 and 2 (P=0.013) and between groups 2 and 3 (P=0.032) in this respect, while there was no difference between groups 1 and 3 (P=0.932). CONCLUSION: Simultaneous application of phosphoric acid gel over enamel surface and light irradiation using a LED light curing unit decreased enamel etching time to five seconds without compromising the µSBS.

Replacement of fractured amalgam restoration in shallow cavities using a new category of adhesive system: case report / Substituição de restaurações de amálgama rasas e fraturadas utilizando uma nova categoria de sistema adesivo: relato de casos clínicos

Diversas são as falhas relacionadas às restaurações de amálgama, sendo necessário o reparo ou a substituição. Objetivo: O objetivo deste relato de casos clínicos foi apresentar uma condição comumente encontrada no consultório odontológico: restaurações de amálgama rasas fraturadas aliadas ao desejo do paciente de restaurações estéticas. Caso clínico: Foram realizadas em duas pacientes sete trocas de restaurações de amálgama fraturadas, provavelmente devido à profundidade inadequada dos preparos cavitários. As substituições foram executadas por 3 operadores diferentes, utilizando-se um sistema autocondicionante “multi-mode” com a técnica de condicionamento seletivo do esmalte e uma resina composta nanoparticulada com boas propriedades mecânicas e polimento. Ao final, pode-se verificar resultados estéticos satisfatórios para todas as restaurações, porém com variação entre os operadores, salientando a importância do treinamento do profissional, assim como atender o desejo estético do paciente. Conclusão: Dessa forma, pode-se concluir que a forma de resistência e retenção dos preparos para amálgama foi a principal causa das falhas das restaurações neste estudo. Além do mais, na presença de restaurações de amálgama com falhas, estas devem ser reparadas ou substituídas criteriosamente para evitar prejuízo ao remanescente dental; sendo a resina composta o material de eleição para substituição, por ser mais conservador e estético.

Several failures have been related in amalgam restorations that require repair or replacement. Objective: The aim of this case report was to demonstrate a usual clinical condition found in the dental office: fractured in amalgam restorations associated with the esthetic patient desire. Case report: Seven fractured amalgam restoration replacements, probably due to improper cavity design, were performed in two patients. Three different operators accomplished the replacements. It was applied a “multi-mode” adhesive system using the selective enamel etching technique and a nanofilled resin composite with good mechanical proprieties and polishing. At the end, satisfactory esthetic results were achieved for all restorations. However, differences among operators were detected, stressing the importance of professional training and esthetic desire. Conclusion: Thus, it was concluded that the resistance and retention form of amalgam design was the major concern on the failed amalgam restorations in this study. In addition, amalgam restorations must be replaced carefully to prevent damage the dental remaining, and the resin composite has been selected as a preferred option for amalgam replacement, since it is more conservative and esthetic.

Brushing abrasion of eroded enamel using bioactive glass toothpaste in different time after acid etching / 中国组织工程研究

BACKGROUND:Bioactive glass has good biocompatibility, which can promote the remineralization effects of demineralized enamel and enhance the resistance of enamel to erosion. OBJECTIVE:To evaluate the effect of bioactive glass toothpaste versus fluoride toothpaste on brushing abrasion of enamel after acid etching. METHODS:Fifty-six enamel specimens were prepared from bovine incisors, and were embedded in acrylic resin with exposed buccal surface. The exposed area was 6 mm×6 mm and two amalgam fil ings were placed into the enamel and polished. Al specimens were divided into seven groups with eight specimens each. In six groups, specimens were brushed with ordinary toothpaste, fluoride toothpaste, bioactive glass toothpaste immediately and 30 minutes after being eroded by the Sprite. The last one group was brushed with ordinary toothpaste without acid etching as control. The treatment course was cycled 60 times. The surface abrasion loss of the specimens between two amalgam fil ings compared with respective amalgam reference surfaces was final y observed and calculated under laser scanning confocal microscope. RESULTS AND CONCLUSION:The abrasion loss amount of teeth with no acid etching was significantly lower than that with acid etching (P<0.05). The abrasion loss amount of teeth brushed with bioactive glass toothpaste was less than that with fluoride toothpaste at the same brushing time (P<0.05). For the same toothpaste, the abrasion loss amount of teeth brushed 30 minutes after eroded was less than that bushed instantly after eroded (P<0.05). Use of bioactive glass toothpaste can effectively reduce enamel loss caused by acid etching and brushing. The loss amount can also be reduced by brushing teeth 30 minutes after acid etching.