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1.
Biochem Biophys Res Commun ; 694: 149407, 2024 Jan 29.
Artículo en Inglés | MEDLINE | ID: mdl-38154209

RESUMEN

Interleukin-38 (IL-38), a member of the IL-1 family, is known for its anti-inflammatory properties mediated through ligand signaling in various disease models. It plays a significant role in atherosclerosis development, forming a theoretical basis for therapeutic strategies. However, the direct effects of IL-38 on atherogenic responses in the vascular endothelium and monocytes remain unclear. In this investigation, IL-38 treatment reduced THP-1 monocyte adhesion to HUVECs, decreased the expression of vascular adhesion molecules, and mitigated inflammation in the presence of palmitate. IL-38 treatment upregulated SIRT6 expression and enhanced autophagy markers such as LC3 conversion and p62 degradation. The effects of IL-38 were nullified by siRNA-mediated suppression of SIRT6 or heme oxygenase-1 (HO-1) in HUVECs and palmitate-treated THP-1 cells. These findings reveal that IL-38 mitigates inflammation through the SIRT6/HO-1 pathway, offering a potential therapeutic approach for addressing obesity-related atherosclerosis.


Asunto(s)
Aterosclerosis , Sirtuinas , Humanos , Aterosclerosis/metabolismo , Hemo-Oxigenasa 1/genética , Hemo-Oxigenasa 1/metabolismo , Inflamación/metabolismo , Interleucinas , Obesidad/complicaciones , Palmitatos , Sirtuinas/genética , Sirtuinas/metabolismo
2.
J Adhes Dent ; 18(4): 303-9, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27419239

RESUMEN

PURPOSE: To determine the influence of aging in artificial saliva compared to distilled water on the dentin microtensile bond strength (µTBS) of different adhesive systems. MATERIALS AND METHODS: Occlusal enamel and superficial dentin of 42 teeth were removed and roots were sectioned to expose the pulp chamber for connecting the tooth segments to an intrapulpal pressure assembly. According to the tested adhesives, tooth segments were allocated to three groups (n = 14): an etch-and-rinse adhesive (Adper Scotchbond Multi-Purpose, SBMP), a two-step self-etching adhesive (Clearfil SE Bond, CSE), and a singlestep self-etching adhesive (Clearfil S3 Bond, S3). Each adhesive system was applied to the dentin surface according to its manufacturer's instructions, while intrapulpal pressure was simulated. Resin composite (3M ESPE) was built up in two increments of 2 mm each. Each bonded specimen was sectioned to obtain eight sticks (0.8 ± 0.01 mm2). Sticks of each group were divided equally (n = 56) according to the storage solution, either distilled water or artificial saliva. For each storage solution, half of the sticks of each subgroup (n = 28) was stored for 24 h at 37°C and the other half was thermocycled for 10,000 cycles between 5°C and 55°C. Sticks were then subjected to µTBS testing. Data were statistically analyzed using multifactor ANOVA with repeated measures and Bonferroni's post-hoc test (p < 0.05). Student's t-test was used for pairwise comparison. Failure modes were determined for all tested sticks using scanning electron microscopy. RESULTS: The decrease in bond strength of the three adhesives was significantly higher in distilled water than in artificial saliva. The predominant failure modes were adhesive and mixed. CONCLUSION: The decrease in bond strength was more pronounced for specimens stored in distilled water than in artificial saliva.


Asunto(s)
Recubrimiento Dental Adhesivo , Recubrimientos Dentinarios/química , Saliva Artificial/química , Agua/química , Adhesividad , Resinas Compuestas/química , Materiales Dentales/química , Pulpa Dental/fisiología , Humanos , Técnicas In Vitro , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Presión , Cementos de Resina/química , Estrés Mecánico , Propiedades de Superficie , Temperatura , Resistencia a la Tracción , Factores de Tiempo
3.
J Adhes Dent ; 17(2): 163-8, 2015 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-25830163

RESUMEN

PURPOSE: To investigate the effect of pre-repair aging periods and intermediate adhesive systems based on different monomers on the repair bond strength of silorane-based resin composite. MATERIALS AND METHODS: A total of 32 Filtek P90 (3M ESPE) substrate specimens (4 mm diameter and 4 mm height) were made. Substrate specimens were grouped according to the pre-repair time periods into four groups (n = 8/group): 15 to 30 min, 24 h, 1 month, and 3 months. All substrate specimens were ground flat using a diamond stone and were etched using Scotchbond phosphoric acid etchant (3M ESPE). The specimens of each pre-repair time period were equally distributed among the two repair groups, using either silorane-based (P90 System Adhesive) or acrylamide-based (AdheSE One F, Ivoclar Vivadent) intermediate adhesive systems. Specimens of P90 System adhesive received Filtek P90 as the repair resin composite, and Tetric N-Ceram (Ivoclar Vivadent) was used with AdheSE One F specimens. Additional specimens were made from the repair resin composite materials to study the cohesive strength. Specimens were sliced into sticks (0.6 ± 0.01 mm2) for microtensile bond strength testing (µTBS). Modes of failure were determined. RESULTS: Two-way ANOVA with repeated measures revealed no significant effect for the pre-repair aging periods, intermediate adhesive systems based on different monomers, or their interaction on repair bond strength of silorane-based resin composite. CONCLUSION: Up to 3 months of pre-aging the repaired silorane-based resin composite had no negative effect on its repair bond strength, even when an intermediate adhesive system based on a different monomer (acrylamide) was used.


Asunto(s)
Resinas Compuestas/química , Recubrimiento Dental Adhesivo , Cementos Dentales/química , Resinas de Silorano/química , Grabado Ácido Dental/métodos , Resinas Acrílicas/química , Análisis del Estrés Dental/instrumentación , Diamante/química , Humanos , Ensayo de Materiales , Organofosfonatos/química , Saliva Artificial/química , Estrés Mecánico , Propiedades de Superficie , Resistencia a la Tracción , Factores de Tiempo
4.
J Pharm Pharmacol ; 76(7): 834-841, 2024 Jul 05.
Artículo en Inglés | MEDLINE | ID: mdl-38588466

RESUMEN

OBJECTIVES: Madecassoside (MA) is a triterpene derived from Centella asiatica that has been recognized for its antioxidant and anti-inflammatory properties in various disease models. However, its direct impact on cultured white adipocytes and the underlying mechanisms, mainly through gene knockdown, have not been thoroughly explored. METHODS: Western blot analysis was utilized to assess the expression levels of various proteins, while oil red O staining was used to measure lipid deposition. The adipocyte shapes were confirmed using H&E staining. KEY FINDINGS: MA treatment enhanced browning and lipolysis in 3T3-L1 adipocytes and adipose tissue from experimental mice while suppressing lipogenesis. Furthermore, MA treatment increased the expression of PPARα and FGF21 in 3T3-L1 adipocytes as well as the secretion of FGF21 into the culture medium. Knockdown of PPARα or FGF21 using siRNA diminished the effects of MA on lipid metabolism in cultured adipocytes. CONCLUSIONS: These findings demonstrate that MA promotes thermogenic browning and lipolysis while inhibiting adipocyte lipogenesis, thus showing the potential for attenuating obesity. The study suggested that MA could be a viable therapeutic approach for treating obesity.


Asunto(s)
Células 3T3-L1 , Factores de Crecimiento de Fibroblastos , Lipogénesis , Lipólisis , Obesidad , PPAR alfa , Triterpenos , Animales , Ratones , Lipólisis/efectos de los fármacos , Triterpenos/farmacología , Lipogénesis/efectos de los fármacos , Factores de Crecimiento de Fibroblastos/metabolismo , PPAR alfa/metabolismo , Obesidad/metabolismo , Obesidad/tratamiento farmacológico , Masculino , Metabolismo de los Lípidos/efectos de los fármacos , Ratones Endogámicos C57BL , Adipocitos/metabolismo , Adipocitos/efectos de los fármacos , Termogénesis/efectos de los fármacos , Adipocitos Blancos/efectos de los fármacos , Adipocitos Blancos/metabolismo
5.
Obes Facts ; : 1-11, 2024 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-39102791

RESUMEN

INTRODUCTION: Previous research has shown that an aqueous extract of Humulus japonicus (EH) can ameliorate hypertension, nonalcoholic fatty liver disease, and oxidative stress in adipocytes by activating the thermogenic pathway. However, the effects of an ethanol (30%) extract of EH on obesity are unknown. METHODS: Various protein expression levels in fully differentiated 3T3-L1 adipocytes were assessed by Western blotting. Lipid deposition in 3T3-L1 adipocytes was examined by oil red O staining. The MTT assay was used to evaluate adipocyte viability. Caspase 3 activity and glycerol release were determined using commercial assay kits. RESULTS: In this study, we discovered that EH treatment inhibited lipogenesis and promoted lipolysis in both differentiated 3T3-L1 adipocytes and adipose tissue of mice fed a high-fat diet. EH treatment also increased phosphorylated protein kinase A (PKA) levels while reducing p38 phosphorylation. When H89, a PKA inhibitor, was used, the effects of EH on lipogenic lipid accumulation and lipolysis in 3T3-L1 adipocytes were eliminated. Treatment with luteolin 7-O-ß-d-glucoside (LU), the major active compound in EH, also suppressed lipid deposition and p38 phosphorylation but enhanced lipolysis in 3T3-L1 adipocytes. These changes were abrogated by H89. CONCLUSION: These findings indicate that EH containing LU reduces lipogenesis and stimulates lipolysis via the PKA/p38 signaling pathway, leading to an improvement in obesity in mice. Therefore, our study suggested that EH could be a promising therapeutic agent for treating obesity.

6.
J Adhes Dent ; 15(6): 519-26, 2013 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-23700580

RESUMEN

PURPOSE: To evaluate the effect of three different liquids used for intrapulpal pressure (IPP) simulation on the microtensile bond strength (µTBS) of three adhesive systems to dentin. MATERIALS AND METHODS: The occlusal surfaces of sound human molars were ground flat down to mid-dentin depth. The teeth were bonded under 15 mmHg simulated IPP using distilled water, phosphate buffered saline, or human plasma as a simulating liquid. Three adhesive systems were tested: a single-bottle etch-and-rinse adhesive (SingleBond, 3M ESPE), and two single-step self-etching adhesives (G-Bond, GC) and (iBond, Heraeus Kulzer). Resin composite (Tetric EvoCeram, Ivoclar Vivadent) buildups were made in 2 increments, each 2 mm in height. Specimens were stored in artificial saliva under 20 mmHg IPP at 37°C for 24 h prior to testing. µTBS (n = 15) was tested using a universal testing machine, and failure modes were determined. Data were statistically analyzed using ANOVA and Bonferroni post-hoc tests at p <= 0.05. RESULTS: With SingleBond adhesive, distilled water showed significantly higher µTBS compared to plasma and phosphate buffered saline. With G-Bond, no significant difference was found between distilled water and phosphate buffered saline, whereas plasma showed significantly lower µTBS values. In contrast, no significant difference was encountered between the three IPP liquids for iBond adhesive. Predominant modes of failure were adhesive and mixed. CONCLUSION: A difference in intrapulpal pressure simulating liquids influences the bonding of adhesives to dentin. Etch-and-rinse adhesives are more sensitive to intrapulpal simulating liquids than are self-etching adhesives. Adhesives containing protein-coagulating components perform better with plasma perfusion than those lacking such components.


Asunto(s)
Recubrimiento Dental Adhesivo , Pulpa Dental/fisiología , Recubrimientos Dentinarios/química , Dentina/ultraestructura , Adhesividad , Adolescente , Bisfenol A Glicidil Metacrilato/química , Tampones (Química) , Resinas Compuestas/química , Análisis del Estrés Dental/instrumentación , Líquido de la Dentina/fisiología , Humanos , Ensayo de Materiales , Metacrilatos/química , Microscopía Electrónica de Rastreo , Plasma/fisiología , Presión , Cementos de Resina/química , Saliva Artificial/química , Cloruro de Sodio/química , Estrés Mecánico , Propiedades de Superficie , Resistencia a la Tracción , Agua/química , Adulto Joven
7.
J Adhes Dent ; 14(3): 245-50, 2012 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-22282743

RESUMEN

PURPOSE: The aim of this study was to compare microshear bond strength (µSBS) of different adhesives to normal dentin (ND) and caries-affected dentin (AD) as differentiated using the dye permeability test. MATERIALS AND METHODS: One hundred freshly extracted carious teeth were ground to expose normal and cariesaffected dentin. Differentiation between both substrates was carried out using microhardness and a new dye permeability method. Ground teeth were divided into 5 groups according to the adhesive tested; Clearfil SE Bond (SE), Clearfil DC Bond (DC) (Kuraray), Bond Force (BF) (Tokuyama), AdheseOne (AH) (Ivoclar), Adper Prompt-L-pop (PR) (3M ESPE). Adhesives were applied to selected substrate, and composite cylinders (0.9 mm diameter x 0.7 mm length) were formed. After 24 h, specimens were subjected to microshear testing at a crosshead speed of 0.5 mm/min. Failure modes were determined using a stereomicroscope at 40X magnification. Data were analyzed using Kruskal-Wallis and Mann-Whitney U-tests. RESULTS: Normal dentin was permeable for the dye, while caries-affected dentin was impermeable. Vickers hardness numbers (VHN) for normal and caries-affected dentin were 63.98 ± 3.24 and 62.40 ± 3.49 respectively, which were not significantly different (p > 0.05). µSBS values were: SE-ND = 22.34 ± 6.4, SE-AD = 18.70 ± 4.0, BF-ND = 24.52 ± 4.9, BF-AD = 18.31 ± 4.9, DC-ND = 24.49 ± 8.0, DC-AD = 18.97 ± 9.4, AH-ND = 17.21 ± 6.8, AH-AD = 17.03 ± 10.3, PR-ND = 13.67 ± 4.4, PR-AD = 7.31 ± 2.4 MPa. A statistically significant difference was found among the adhesive systems to both normal (p < 0.01) and caries-affected dentin (p < 0.001). However, µSBS of SE, DC, and AH adhesives to normal dentin were not significantly different from those of caries-affected dentin (p > 0.05). CONCLUSIONS: The permeability test was an effective tool to differentiate between normal and caries-affected dentin. Some adhesive systems showed no significant difference in their bond to normal or affected dentin.


Asunto(s)
Recubrimiento Dental Adhesivo , Permeabilidad de la Dentina , Recubrimientos Dentinarios , Dentina , Cementos de Resina , Grabado Ácido Dental/métodos , Colorantes , Caries Dental/diagnóstico , Caries Dental/patología , Análisis del Estrés Dental , Dentina/patología , Dureza , Humanos , Ensayo de Materiales , Azul de Metileno , Resistencia al Corte , Estadísticas no Paramétricas
8.
Am J Dent ; 23(4): 217-22, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-21250573

RESUMEN

PURPOSE: To evaluate the effect of different chlorhexidine concentrations on bond strength of resin composite to normal and caries-affected dentin using a self-etch primer adhesive. METHODS: Thirty carious human molars were ground to expose flat dentin surfaces containing caries-affected surrounded by normal dentin. The teeth were divided into three groups. One group received no chlorhexidine pretreatment (control). The second and third groups received 2% or 5% chlorhexidine pretreatments, respectively before applying the self-etch primer adhesive (Clearfil SE Bond). Resin composite was applied to caries-affected dentin and to normal dentin on the same tooth with the aid of polyethylene tubes (0.9 mm diameter and 0.7 mm height). For micro-shear bond strength testing, each tooth was secured in a specially designed attachment jig to hold the specimens to the universal testing machine. Load was applied by the testing machine through a wire loop adjusted to the bonded interface at a crosshead speed of 0.5 mm/minute. Micro-shear bond strength was calculated and mode of failure was examined with a x40 stereomicroscope. RESULTS: Statistical analysis revealed insignificant differences between control, 2% and 5% chlorhexidine pretreatment for normal as well as for caries-affected dentin groups. Also, there were insignificant differences in bond strength values between normal and caries-affected dentin for each treatment modality. Adhesive failure was the most common mode of failure.


Asunto(s)
Antiinfecciosos Locales/química , Clorhexidina/química , Recubrimiento Dental Adhesivo , Caries Dental/patología , Dentina/ultraestructura , Cementos de Resina/química , Adhesividad , Resinas Compuestas/química , Materiales Dentales/química , Análisis del Estrés Dental/instrumentación , Humanos , Curación por Luz de Adhesivos Dentales , Ensayo de Materiales , Resistencia al Corte , Estrés Mecánico , Propiedades de Superficie
9.
J Prosthet Dent ; 104(2): 92-7, 2010 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-20654765

RESUMEN

STATEMENT OF PROBLEM: It is becoming increasingly difficult to obtain sufficient freshly extracted human teeth to utilize in in vitro studies, particularly for bonding investigations. PURPOSE: The purpose of this study was to investigate the effect of different storage conditions for human extracted teeth prior to their use in microtensile bond strength (microTBS) testing. MATERIAL AND METHODS: Thirty incisors were divided into groups according to their storage time and condition. The first group consisted of freshly extracted teeth. Teeth of the second group were stored in chloramine-T at 4 degrees C for 2 years +/-1 month. The last group was stored dry for up to 2 years +/-2 months, after which teeth were rehydrated in distilled water for 2 weeks before use. All teeth were disinfected using 0.5% chloramine-T. Dentin surfaces were exposed and then bonded using Scotchbond Multi-Purpose or Clearfil SE Bond to composite resin foundations (Esthet-X). Following 24-hour storage, bonded teeth (n=30) were sectioned into beams with a cross-section of 0.9 +/-0.1 mm(2) and subjected to microTBS testing using a microtensile testing machine (Micro Tensile Tester). Data were calculated and statistically analyzed using Kruskal-Wallis and Mann-Whitney tests (alpha=.05). Failure modes were determined using a stereomicroscope at x40 magnification. RESULTS: Statistical analysis revealed no significant difference between the different storage conditions nor between the 2 adhesive systems for each storage condition (P>.05). Modes of failure for all tested groups were predominantly adhesive followed by mixed. CONCLUSIONS: Within the limitations of this study, it was concluded that aging of teeth and storage conditions had no significant effect on dentin microtensile bond strength to composite resin.


Asunto(s)
Recubrimiento Dental Adhesivo/métodos , Análisis del Estrés Dental/métodos , Recubrimientos Dentinarios/química , Dentina/química , Manejo de Especímenes/métodos , Fracaso de la Restauración Dental , Humanos , Cementos de Resina/química , Manejo de Especímenes/efectos adversos , Resistencia a la Tracción , Diente/química
10.
J Adv Res ; 17: 117-123, 2019 May.
Artículo en Inglés | MEDLINE | ID: mdl-31193330

RESUMEN

The study question was whether the use of high-viscosity glass-ionomer with chlorhexidine (HVGIC/CHX) for the Atraumatic Restorative Treatment (ART) prepared cavities could achieve a higher restoration survival percentage and be more effective for preventing dentine carious lesions adjacent to the restoration than the use of HVGIC without CHX. The study followed a split-mouth, quadruple-blind, randomized controlled clinical design and lasted 2 years. Patients with at least two small- to medium-sized occlusal cavities were included. The occlusal cavities were prepared according to the ART method and restored with HVGIC/CHX (test) and HVGIC (control). A replica of all restorations available and digital photographs were fabricated at baseline and after 0.5, 1, 1.5 and 2 years and evaluated by two examiners using the ART and Federation Dentaire International (FDI) restoration assessment criteria. Survival curves were constructed using the Kaplan-Meier method, and the log-rank test was used to test for significance between the survival percentages. A total of 100 subjects with an average age of 14.4 years participated. According to the ART restoration assessment criteria, the 2-year survival percentages of ART/HVGIC/CHX (96.8%) and ART/HVGIC (94.8%) did not differ significantly and no significant difference was found between the test (97.9%) and control (96.9%) groups according to the FDI restoration assessment criteria. Eight and five occlusal restorations failed according to the ART and FDI restoration criteria, respectively. No dentine carious lesions along the restoration margin were observed. The 2-year survival of ART restorations in both groups was high. The development of carious dentine lesions adjacent to the restoration was not observed in either treatment group. There is no evidence for modifying HVGIC by incorporating chlorhexidine in order to prevent dentine carious lesion development or to improve the survival of ART restorations in occlusal surfaces in permanent teeth. HVGIC without chlorhexidine can be used successfully to restore occlusal 'ART-prepared' cavities in permanent teeth.

11.
J Egypt Public Health Assoc ; 83(5-6): 435-50, 2008.
Artículo en Inglés | MEDLINE | ID: mdl-19493511

RESUMEN

UNLABELLED: This study was conducted to evaluate different regimens of 0.12% chlohexidine (CHX) rinse on the salivary parameters and Mutans Streptococci (MS) for a group of Egyptians. Twenty one females were recruited based on inclusive exclusive criteria. They were assigned to three different groups according to the CHX regimen specified. Salivary parameters (unstimulated salivary flow rate, stimulated salivary flow rate, pH and buffering capacity) and salivary mutans streptococci were evaluated at base line for all participants. Diet recording was done for 4 days in a supplied chart. DMFS and DS scores were also determined. This was followed by the use of 0.12% CHX mouth rinse once daily for 60 seconds before bedtime for either 3,7 or 14 days. Salivary parameters were re-evaluated in the early morning after the use of the mouth rinse, after 1 month and 3months. Mutans Streptococci (MS) were also evaluated at the same intervals. The salivary parameters did not show any difference throughout the study. The majority of the participants belonged to the moderate low fermentable CHO diet content category and they consumed five meals of cariogenic intake per day. Their DMFS scores ranged between 2 and 50 whereas the DS scores ranged between 2 and 10. The 3 day regimen was not statistically significantly different from the 7 and 14 days regimens and the maximum efficacy of CHX was obtained immediately after its use and lasted throughout the first week after stopping it. The effect of the CHX disappeared after 1 month and gradually reached the base line and surpassed this level sometimes. CONCLUSION AND RECOMMENDATIONS: A regimen of once daily use of 15 ml of 0.12% CHX mouth rinse for 3 days is effective in reducing MS below critical values. It is recommended to reuse the CHX rinse after 1 month owing to the cessation of its effect. Patients who start using CHX should not discontinue it.

12.
J Adv Res ; 7(2): 263-9, 2016 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-26966567

RESUMEN

The reparability of dual-cured resin composite core buildup materials using a light-cured one following one week or three months storage, prior to repair was evaluated. Two different dual-cured resin composites; Cosmecore™ DC automix and Clearfil™ DC automix core buildup materials and a light-cured nanofilled resin composite; Filtek™ Z350 XT were used. Substrate specimens were prepared (n = 12/each substrate material) and stored in artificial saliva at 37 °C either for one week or three months. Afterward, all specimens were ground flat, etched using Scotchbond™ phosphoric acid etchant and received Single Bond Universal adhesive system according to the manufacturers' instructions. The light-cured nanofilled resin composite (Filtek™ Z350 XT) was used as a repair material buildup. To determine the cohesive strength of each solid substrate material, additional specimens from each core material (n = 12) were prepared and stored for the same periods. Five sticks (0.8 ± 0.01 mm(2)) were obtained from each specimen (30 sticks/group) for microtensile bond strength (µTBS) testing. Modes of failure were also determined. Two-way ANOVA revealed a significant effect for the core materials but not for the storage periods or their interaction. After one week, dual-cured resin composite core buildup materials (Cosmecore™ DC and Clearfil™ DC) achieved significantly higher repair µTBS than the light-cured nanofilled resin composite (Filtek™ Z350 XT). However, Clearfil™ DC revealed the highest value, then Cosmecore™ DC and Filtek™ Z350 XT, following storage for 3-month. Repair strength values recovered 64-86% of the cohesive strengths of solid substrate materials. The predominant mode of failure was the mixed type. Dual-cured resin composite core buildup materials revealed acceptable repair bond strength values even after 3-month storage.

13.
J Adv Res ; 6(6): 805-10, 2015 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-26644916

RESUMEN

This study was conducted to evaluate the effect of ultrasound application on the surface microhardness (VHN) and diametral tensile strength (DTS) of three high viscous glass-ionomer restorative materials (HVGIRMs). For each test (VHN and DTS), a total of 180 specimens were prepared from three HVGIRMs (Ketac-Molar Aplicap, Fuji IX GP Fast, and ChemFil Rock). Specimens of each material (n = 60) were further subdivided into three subgroups (n = 20) according to the setting modality whether ultrasound (20 or 40 s) was applied during setting or not (control). Specimens within each subgroup were then equally divided (n = 10) and tested at 24 h or 28 days. For the VHN measurement, five indentations, with a 200 g load and a dwell time for 20 s, were made on the top surface of each specimen. The DTS test was done using Lloyd Testing machine at a cross-head speed of 0.5 mm/min. Ultrasound application had no significant effect on the VHN. Fuji IX GP Fast revealed the highest VHN value, followed by Ketac-Molar Aplicap, and the least was recorded for ChemFil Rock. Fuji IX GP Fast and Ketac-Molar Aplicap VHN values were significantly increased by time. ChemFil Rock recorded the highest DTS value at 24 h and was the only material that showed significant improvement with both US application times. However, this improvement did not sustain till 28 days. The ultrasound did not enhance the surface microhardness, but its positive effect on the diametral tensile strength values was material and time dependent.

14.
J Adv Res ; 6(3): 471-8, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-26257945

RESUMEN

The effect of preheating of the silorane-based resin composite on intrapulpal temperature (IPT) and dentin microtensile bond strength (µTBS) was evaluated. For the IPT, teeth (n = 15) were sectioned to obtain discs of 0.5 mm thickness (2 discs/tooth). The discs were divided into three groups (n = 10/group) according to the temperature of the Filtek LS™ silorane-based resin composite during its placement, either at room temperature (23 ± 1 °C) or preheated to 54 °C or 68 °C using a commercial Calset™ device. Discs were subjected to a simulated intrapulpal pressure (IPP) and placed inside a specially constructed incubator adjusted at 37 °C. IPT was measured before, during and after placement and curing of the resin composite using K-type thermocouple. For µTBS testing, flat occlusal middentin surfaces (n = 24) were obtained. P90 System Adhesive was applied according to manufacturer's instructions then Filtek LS was placed at the tested temperatures (n = 6). Restorative procedures were done while the specimens were connected to IPP simulation. IPP was maintained and the specimens were immersed in artificial saliva at 37 °C for 24 h before testing. Each specimen was sectioned into sticks (0.9 ± 0.01 mm(2)). The sticks (24/group) were subjected to µTBS test and their modes of failure were determined using scanning electron microscope (SEM). For both preheated groups, IPT increased equally by 1.5-2 °C upon application of the composite. After light curing, IPT increased by 4-5 °C in all tested groups. Nevertheless, the IPT of the preheated groups required a longer time to return to the baseline temperature. One-way ANOVA revealed no significant difference between the µTBS values of all groups. SEM revealed predominately mixed mode of failure. Preheating of silorane-based resin composite increased the IPT but not to the critical level and had no effect on dentin µTBS.

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