Pre-Heating effect on the microhardness and depth of cure of Bulk-Fill composite resins / Efecto del precalentamiento de las resinas compuestas Bulk-Fill en la microdureza y la profundidad de curado

Abstract The aim of this study was to investigate the effect of preheating three bulk-fill and one conventional composite resin on the Vickers microhardness and depth of cure of these composites. In this study, three bulk-fill composites- SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), and one conventional composite resin G-ænial POSTERIOR (GP) were used as the control group. The samples were obtained at room temperature (24°C) and at 55°C in T2 mode after being placed in a heating device for 10 minutes. The samples were divided into eight groups (n=10) according to the type of material and heating process that was utilized (preheated and nonheated). All samples were tested with a Vickers microhardness (VHN) tester on the bottom and top surfaces. The first measurements were obtained at baseline; the second set of measurements was performed after the samples were stored in distilled water at 37°C for 24 hours. The depth of cure was calculated using a bottom/top hardness ratio of measurements. Statistical analysis was performed utilizing the SPSS V23 and Shapiro-Wilk tests. Lastly, the Duncan test was used for multiple comparisons (p<0.05). While the VHN increased after the preheating procedure in bulk-fill composites, it decreased in GP. There was no difference between the baseline and the 24-hour VHN values in SDR and GP. After 24 hours, while the VHN of EST increased, the VHN of AFX decreased. There was no difference between the hardness ratios of the AFX and EST samples (p<0.001) and hardness ratios were greater than GP and SDR. When comparing the baseline and the 24- hour values, the VHN depended on the type of materials. Sufficient curing depth was obtained in all groups with a thickness of 2mm.

Resumen El objetivo fue investigar el efecto del precalentamiento de tres resinas Bulk-fill, una resina compuesta convencional sobre la microdureza Vickers y la profundidad de curado de estas resinas. Se utilizaron tres composites Bulk-Fill-SDR Plus (SDR), Estelite BULK FILL Flow (EST), Admira® Fusion x-tra (AFX), y una resina compuesta convencional G-ænial POSTERIOR (GP) como grupo de control. Las muestras se obtuvieron a temperatura ambiente (24°C) y a 55°C en modo T2 después de haber sido colocadas en un dispositivo de calentamiento durante 10 minutos. Se dividieron en ocho grupos (n=10) según el tipo de material y el proceso de calentamiento que se utilizó (precalentado y no calentado). Se probaron con un medidor de microdureza Vickers (VHN) en las superficies inferior y superior. Las primeras mediciones se obtuvieron en la línea de base; la segunda se realizó después de que las muestras se almacenaran en agua destilada a 37°C durante 24 horas. La profundidad de curado se calculó utilizando una relación de dureza inferior/ superior de las mediciones. El análisis estadístico se realizó utilizando el SPSS V23 y las pruebas de Shapiro-Wilk. Por último, se utilizó la prueba de Duncan para las comparaciones múltiples (p<0,05). VHN aumentó tras el procedimiento de precalentamiento en las resina Bulk-Fill, disminuyó en los GP. No hubo diferencias entre los valores de VHN de referencia y de 24 horas en SDR y GP. Después de 24 horas, mientras que el VHN de EST aumentó, el VHN de AFX disminuyó. No hubo diferencias entre los ratios de dureza de las muestras de AFX y EST (p<0,001) y los ratios de dureza fueron mayores que los de GP y SDR. Al comparar los valores de referencia y los de 24 horas, el VHN dependió del tipo de materiales. Se obtuvo una profundidad de curado suficiente en todos los grupos con un grosor de 2mm.

The effect of storage temperature and application temperature on the properties of adhesives and resin composites / 口腔疾病防治

@#The properties of adhesives and light-cured resin composites are closely related to the repair of dental defects. Therefore, improving the properties of adhesives and resins composite to increase the success rate of filling has been the focus of research in the field of prosthodontics in recent years. Current studies have confirmed that temperature can change the properties of adhesives and light-cured resin composites, affecting their repair effect. A proper storage temperature ensures the good performance of materials: the self-etching adhesive system should be refrigerated, and the light-cured resin composite should be refrigerated or stored at room temperature according to its composition, proportion and other properties; however, the appropriate storage temperature for the etch-and-rinse adhesive system is not clear. The appropriate application temperature could improve the fluidity, monomer conversion, bonding strength, compressive strength and other properties of the materials to improve the quality of filling restoration. However, there is a wide variety of adhesives and resin composites, and the effect of temperature on each material is different. Thus, it is still necessary to explore the temperature range for material storage, precooling and preheating. Few studies have been performed in vivo, and the clinical restorative effects of adhesives and resin composites stored and used at different temperatures need to be further studied.

A new preheating thermoviscous composite for restoration of non-carious cervical lesions: a 6-month randomized clinical trial / Um novo compósito termoviscoso de pré-aquecimento para restauração de lesões cervicais não cariosas: ensaio clínico randomizado de 6 meses

Objetivo: Este ensaio clínico randomizado, duplo-cego e boca dividida avaliou o desempenho clínico de um novo compósito termoviscoso com pré-aquecimento (PHT) em comparação com uma resina composta sem aquecimento (NHT) em restaurações de lesões cervicais não cariosas (LCNCs) durante um período de 6 meses. Material e Métodos: 120 restaurações foram realizadas em LCNCs com dois materiais restauradores (n = 60). Após a profilaxia, os dentes foram isolados com isolamento de fio retrator/rolos de algodão e um adesivo universal foi aplicado na estratégia de condicionamento seletivo do esmalte. Para o grupo PHT o aquecimento foi realizado a 68°C usando um aquecidor de bancada por 3 min. Por outro lado, para o grupo NHT, nenhum aquecimento foi aplicado. Ambos os materiais restauradores foram colocados no dispensador de cápsulas e inseridos nas LCNCs. Após 6 meses, o desempenho clínico das restaurações foi avaliado de acordo com os critérios FDI. A análise estatística foi realizada com teste Qui-quadrado para todos parâmetros da FDI (α = 0,05). Resultados: Apenas três restaurações no grupo NHT foram perdidas/fraturadas após seis meses de acompanhamento. As taxas de retenção (intervalo confiança 95%) por seis meses foram de 97,5% (88,6% - 99,0%) para o grupo NHT e 100% (93,9% - 100%) para o grupo PHT (p > 0,05). Vinte e duas restaurações (8 para NHT e 14 para PHT) apresentaram pequenos defeitos de adaptação marginal aos seis meses de acompanhamento (p > 0,05). Vinte e seis restaurações apresentaram alguma retenção de biofilme aos seis meses de acompanhamento (11 para NHT e 15 para PHT; p > 0,05). Em relação a todos os outros parâmetros de FDI avaliados, todas as restaurações foram consideradas clinicamente aceitáveis. Conclusão: O desempenho clínico do novo compósito termoviscoso de pré-aquecimento mostrou-se promissor após 6 meses de avaliação clínica quando aplicado em LCNCs.(AU)

Objective: This double-blind, split-mouth randomized clinical trial evaluate the clinical performance of a new preheating (PHT) thermoviscous composite compared to a non-heating (NHT) composite resin in restorations of non-carious cervical lesions (NCCLs) over a period of 6-month. Material and Methods: 120 restorations were performed on NCCLs with two restorative materials (n = 60). After prophylaxis, the teeth were isolated with retraction cord isolation/cotton rolls and one universal adhesive was applied in the selective enamel etching strategy. For the PHT group heating was carried out at 68°C using a heater bench for 3 min. On the other side, for the NHT group, no heating was applied. Both restorative materials were placed in the caps dispenser and inserted in the NCCLs. The restorations were evaluated after 6-month of clinical performance according to the FDI criteria. Statistical analysis was performed with Chi-square test for all FDI parameters (α = 0.05). Results: Three restorations only in the NHT group were lost/fractured after six months follow-up. The retention rates (confidential interval 95%) for six months were 97.5% (88.6% - 99.0%) for the NHT group and 100% (93.9% - 100%) for the PHT group (p > 0.05). Twenty-two restorations (8 for NHT and 14 for PHT) presented small marginal adaptation defects at the six-months follow-up (p > 0.05). Twenty-six restorations were found to have biofilm retention in the six-month recall (11 for NHT and 15 for PHT; p > 0.05). Regarding all others FDI parameters evaluated, all restorations were considered clinically acceptable. Conclusion: The clinical performance of the new preheating thermoviscous was found to be promise after 6-month of clinical evaluation when applied in NCCLs (AU)

In Vitro Effect of Temperature on Dentin Bond Strength of Universal Adhesive Systems / Efecto In Vitro de la temperatura sobre la resistencia de unión de los sistemas adhesivos universales a la dentina

ABSTRACT The aim of this study was to evaluate the shear bond strength (SBS) of two universal adhesives (Universal Single Bond and All Bond Universal) and a two- step self-etch adhesive system (Clearfil SE Bond) to dentine at various temperatures. Materials and Methods: One hundred and twenty dentin specimens were divided randomly to 12 groups, according to adhesive systems (Universal Single Bond and All Bond Universal, Clearfil SE Bond) and temperature ( 4ºC, 20 ºC, 36ºC, 55ºC) used. Dentin specimens were prepared (n :10, adhesives were applied, and composite cylinders were polymerized. Statistical analysis of the SBS data was performed using Two-way analysis of variance (ANOVA) and Tukey's Honestly Significant Differences post-hoc test. Results: The Clearfil SE Bond was shown to have higher SBS than the universal adhesives at all temperatures; however, there was no statistically significant difference (P>0.05). In both groups, the lowest SBS values were observed in the samples at 4°C while the highest SBS values were observed in the samples at 55°C. In this case, there was a statistically significant difference (P<0.05). Conclusions: The results suggest that the effectiveness of an adhesive may increase if it is preheated at 36°C or above before use instead of being used immediately after removal from the refrigerator or at room temperature.

RESUMEN El objetivo de este estudio fue evaluar la resistencia al cizallamiento (SBS) de dos adhesivos universales (Universal Single Bond y All Bond Universal) y un sistema de adhesivo de autograbado de dos pasos (Clearfil SE Bond) a la dentina en diferentes temperaturas. Materiales y métodos: Ciento veinte muestras de dentina se dividieron aleatoriamente en 12 grupos, de acuerdo con los sistemas adhesivos (Universal Single Bond y All Bond Universal, Clearfil SE Bond) y la temperatura (4ºC, 20ºC, 36ºC, 55ºC) utilizada. Se prepararon muestras de dentina (n: 10), se aplicaron los sistemas adhesivos y se polimerizaron los cilindros compuestos. El análisis estadístico de los datos de SBS se realizó utilizando el análisis de varianza de dos vías (ANOVA) y la prueba post-hoc de Tukey's. Resultados: El Clearfil SE Bond mostró tener un SBS más alto que los adhesivos universales en todas las temperaturas evaluadas; sin embargo, no hubo una diferencia estadísticamente significativa (P> 0.05). En todos los grupos, los valores más bajos de SBS se observaron en las muestras a 4°C, mientras que los valores de SBS más altos fueron obtenidos en las muestras a 55°C (P <0.05). Conclusiones: Los resultados sugieren que la efectividad de un adhesivo puede aumentar si se precalienta a 36°C o superior, antes de usarlo inmediatamente después de sacarlo del refrigerador o a temperatura ambiente.

Effect Of Preheating On Surface Roughness And Microhardness Of A Nanohybrid Composite Resin - An In Vitro Study

Introduction: The success of dental composites in restorative dentistry stems from their good aesthetic properties andadequate durability. The clinical performance of composite resins is directly related to the degree of monomer conversion afterphoto polymerization. Placing composites at an elevated temperature reduce their viscosity and increase the efficiency ofpolymerization. Heating the composite prior to placement in the cavity increases monomer conversion rate and therefore theduration of the irradiation period may be reduced.Purpose of Study: Evaluate and compare effect of pre-heating on surface roughness and microhardness of nanohybrid compositeresin subjected to two different temperatures and two different durations using light emitting diode curing unit (LED LCU).Methods: Nanohybrid composite resin was tested at two temperatures (37°C and 55°C) and pre-heating of composite wasdone using incubator at two durations (10 and 20 minutes) respectively. Samples were injected into cylindrical Teflon molds andthe top surface of the specimens were polymerized using LED LCU for 40 s. After preservation for 24 h, specimens checkedfor surface roughness and Vickers hardness measurements. Statistical analysis were performed using one-way analysis ofvariance and Tukey post hoc test at a level of significance of P < 0.05 for both surface roughness and microhardness.Results: Pre-heating of composite affect on microhardness and did not influence on surface roughness.Conclusion: Pre-heating of resin composite increases microhardness and no significant effect on roughness.

Clinical study on preheating of substitution fluid to prevent hypothermia in patients with continuous renal replacement therapy / 中国实用护理杂志

Objective To explore the effect of preheating of substitution fluid on the incidence of hypothermia in patients with continuous renal replacement therapy (CRRT). Methods Use SPSS software to generate random Numbers, 98 cases were numbered in advance, and then randomly divided into control group and experimental group with 49 cases in each group. Control group based on the conventional way in the process of CRRT heating, experimental group preheating the substitution fluid to 37℃in constant temperature box on the basis of conventional heating. The CRRT parameters of the two groups, the hourly body temperature of the patients and the arteriovenous temperature of the blood filtration catheter were recorded,and the laboratory indicators related to hemolysis before and after treatment were compared between the two groups. Results In the control group, the incidence of hypothermia at 6h, 12h, 18h, 24h, 48h and 72h was 20.41% (10/49), 32.65% (16/49), 40.82% (20/49), 48.98%(24/49), 55.10%(27/49), 59.18%(29/49),while the incidence of hypothermia in the experimental group at 6h, 12h, 18h, 24h, 48h and 72h was 6.12% (3/49), 14.29% (7/49), 20.41% (10/49), 28.57% (14/49), 34.69% (17/49), 38.78% (19/49), the incidence of hypothermia between the two groups was statistically significant ( χ2=4.083-4.804, P<0.05). The difference of arteriovenous terminal temperature in the control group at 6h, 12h, 24h, 48h and 72h was (0.15±0.21), (0.16±0.12), (0.17±0.10), (0.15±0.12), (0.17±0.11)℃, while the difference of arteriovenous terminal temperature in the experimental group at 6h, 12h, 24h, 48h and 72h was (0.15±0.21), (0.16±0.12), (0.17±0.10), (0.15±0.12), (0.17±0.11)℃, there were statistically significant differences between the two groups (Z=2.524-3.458, P < 0.05). When the rate of substitution fluid was ＜1 000ml/h, the incidence of hypothermia in the control group was 3/10, the incidence of hypothermia in the experimental group was 4/6 ,there was no statistically significant difference in body temperature between the two groups (P > 0.05). While the substitution fluid rate in 1 000-3 000 ml/h, the incidence of hypothermia in the control group was 50.00% (12/24), the incidence of hypothermia in the experimental group was 19.05% (4/21) ,the incidence of hypothermia in the experimental group was significantly lower than that in the control group (χ2=4.683, P< 0.05), When the rate of substitution fluid was > 3000ml/h, the incidence of hypothermia in the control group was 93.33%(14/15), and that in the experimental group was 50.00% (11/22). The difference in the incidence of hypothermia between the two groups was statistically significant (P<0.05).There was no significant difference between the two groups in hemolysis related laboratory indicators before and after CRRT treatment (P > 0.05). Conclusions Preheating of substitution fluid can safely and effectively reduce the incidence of hypothermia in CRRT patients, and when the rate of substitution fluid was>1 000ml/h, the effect of preventing hypothermia is more significant.

Clinical study on preheating of substitution fluid to prevent hypothermia in patients with continuous renal replacement therapy / 中国实用护理杂志

Objective@#To explore the effect of preheating of substitution fluid on the incidence of hypothermia in patients with continuous renal replacement therapy (CRRT).@*Methods@#Use SPSS software to generate random Numbers, 98 cases were numbered in advance, and then randomly divided into control group and experimental group with 49 cases in each group. Control group based on the conventional way in the process of CRRT heating, experimental group preheating the substitution fluid to 37℃ in constant temperature box on the basis of conventional heating. The CRRT parameters of the two groups, the hourly body temperature of the patients and the arteriovenous temperature of the blood filtration catheter were recorded, and the laboratory indicators related to hemolysis before and after treatment were compared between the two groups.@*Results@#In the control group, the incidence of hypothermia at 6h, 12h, 18h, 24h, 48h and 72h was 20.41% (10/49), 32.65%(16/49), 40.82%(20/49), 48.98%(24/49), 55.10%(27/49), 59.18%(29/49), while the incidence of hypothermia in the experimental group at 6h, 12h, 18h, 24h, 48h and 72h was 6.12% (3/49), 14.29% (7/49), 20.41% (10/49), 28.57% (14/49), 34.69% (17/49), 38.78% (19/49), the incidence of hypothermia between the two groups was statistically significant (χ2=4.083-4.804, P < 0.05). The difference of arteriovenous terminal temperature in the control group at 6h, 12h, 24h, 48h and 72h was (0.15±0.21), (0.16±0.12), (0.17±0.10), (0.15±0.12), (0.17±0.11)℃, while the difference of arteriovenous terminal temperature in the experimental group at 6h, 12h, 24h, 48h and 72h was (0.15±0.21), (0.16±0.12), (0.17±0.10), (0.15±0.12), (0.17±0.11)℃, there were statistically significant differences between the two groups (Z=2.524-3.458, P < 0.05). When the rate of substitution fluid was <1 000ml/h, the incidence of hypothermia in the control group was 3/10, the incidence of hypothermia in the experimental group was 4/6, there was no statistically significant difference in body temperature between the two groups (P > 0.05). While the substitution fluid rate in 1 000-3 000 ml/h, the incidence of hypothermia in the control group was 50.00% (12/24), the incidence of hypothermia in the experimental group was 19.05% (4/21), the incidence of hypothermia in the experimental group was significantly lower than that in the control group (χ2=4.683, P< 0.05), When the rate of substitution fluid was > 3000ml/h, the incidence of hypothermia in the control group was 93.33%(14/15), and that in the experimental group was 50.00%(11/22). The difference in the incidence of hypothermia between the two groups was statistically significant (P < 0.05).There was no significant difference between the two groups in hemolysis related laboratory indicators before and after CRRT treatment (P > 0.05).@*Conclusions@#Preheating of substitution fluid can safely and effectively reduce the incidence of hypothermia in CRRT patients, and when the rate of substitution fluid was > 1 000ml/h, the effect of preventing hypothermia is more significant.

Effect of preheating on the properties of resin composite / 华西口腔医学杂志

Resin composite, which is commonly used as a dental filling material, has some problems, such as poor wear resistance, polymerization shrinkage, and poor dentin marginal adaptability. Preheating of resin composite improves its pro-perties. This paper reviewed the effects of resin composite preheating on its monomer conversion, marginal microleakage, mechanical properties, and irritation on dental pulp.

Effect of Preheating on Microstructure and Tensile Properties of Friction Stir Welded AA7075 Aluminium Alloy Joints

ABSTRACT The high strength AA7075 aluminum alloy is commonly used in the aerospace components due to its exclusive mechanical properties like lightweight and high strength. This alloy cannot be welded by fusion welding techniques due to solidification cracking which severely degrade the mechanical properties of the joint. In contrast, through friction stir welding (FSW) process solidification relate defects can be eliminated. Anyhow, the strength of friction stir welded joint is influenced by process parameters and tool parameters. These parameters govern the heat input, metal flow, microstructure evolution and mechanical properties of the weld. In normal welding condition, (without preheating) heat is generated by friction force which is produced between tool and workpiece. In this paper an added heat input through preheating the metal before weld. This preheating temperature effects on microstructure, microhardness and tensile properties of the joints were investigated. From this study the following conclusions are derived. Sufficient heat input should be given to obtain defect free and quality joint. The results showed that, preheating the base metal to 100 °C prior to welding improved the tensile strength and joint efficiency compared to the joints made without preheating.

Research on effects of preheating on the mechnical properties of two resin composites / 中国医学装备

Objective:To investigate the effect of preheating on the microhardness and compressive strength of two resin composites. Methods: Specimens were fabricated from one microhybrid composite resin(Filtek Z250, 3M ESPE, St. Paul, MN, USA)and one nanohybrid composite resin (Filtek Z350, 3M ESPE, St. Paul, MN, USA), and stored at two different temperature(23℃, 40℃). The microhardness and compressive strength were tested after cured. Data obtained were analyzed using two-way analysis of variance. Results:For two composites, the preheated specimens have higher microhardness and compressive strength value than that stored at room temperature. Conclusion:Preheating can improve the mechnical properties of resin composite.

One case of XG501A X-ray machine breakdown repair / 中国医学装备

It reports the E02 breakdown after XG501A program controller starting. The experiences and solutions of the E02 breakdown. According to the breakdown prompt, we carry on the analysis and the overhaul to the gastrointestinal filament preheating circuit. It is able to find the breakdown surely to be at, if you carried on the analysis search according to electric circuit's work flow. You must consider that comprehensive and gradually metrical data in the overhaul process. You cannot take for granted and only then may avoid detouring and equipment's damage.

Effect of pre-heating on some physical properties of composite resin / 대한치과보존학회지

The purpose of this study was to evaluate the effect of pre-heating on some physical properties of composite resin. Eighty extracted, noncarious human molars were used in the present study. Four different temperatures of composite resin were used: 4degrees C, 17degrees C, 48degrees C, and 56degrees C. The 4degrees C and 17degrees C values represented the refrigerator storage temperature and room temperature respectively. For 48degrees C and 56degrees C, composite resin was heated to the temperatures. As physical properties of composite resin, shear bond strength, microhardness, and degree of conversion were measured. The data for each group were subjected to one-way ANOVAs followed by the Tukey's HSD test at 95% confidence level. Both in enamel and dentin, among composite resin of 4degrees C, 17degrees C, 48degrees C, and 56degrees C, the pre-heated composite resin up to 56degrees C revealed the highest shear bond strength, and pre-heated composite resin to the higher temperature revealed higher shear bond strength. Microhardness value was also higher with composite resin of higher temperature. Degree of conversion was also higher with composite resin of the higher temperature. In this study, it seems that pre-heating composite resin up to the higher temperature may show higher shear bond strength, higher microhardness value, and higher degree of conversion. Therefore, when using composite resin in the clinic, preheating the composite resin could be recommended to have enhanced physical properties of it.