RESUMEN
OBJECTIVES: This study aimed to evaluate the surface gloss, surface roughness, and color change of restorative materials after a three-body wear abrasion. METHODS AND MATERIALS: Four resin composites with different filler particle size (Gracefil Flo [GFF, 0.7 µm], Gracefil LoFlo [GFL, 0.25 µm], Gracefil ZeroFlo [GFZ, 0.15 µm], and Gracefil Putty [GFP, 0.3 µm]), two CAD/CAM resin composite blocks with different filler particle size (Cerasmart 300 [CS3, 0.7 µm] and Cerasmart Prime [CSP, 0.3 µm], GC), and one CAD/CAM lithium disilicate glass-ceramic block (Initial LiSi Block [ILS], GC) as a control were evaluated. Twenty slab-shaped specimens were obtained from each material. Ten specimens were subjected to 80,000 toothbrushing strokes and measured for surface gloss (Gloss Unit, GU), surface roughness (Ra, µm), and color (L*, a*, and b* values) before toothbrushing and at every 20,000 strokes. Color differences (ΔL*, Δa*, Δb*, and ΔE00) before and after toothbrushing were calculated. After 80,000 strokes, abraded surfaces were observed using scanning electron microscopy. The other 10 specimens were measured for Vickers microhardness (VHN). RESULTS: After 80,000 toothbrushing strokes, the mean GU ranged from 60.43 to 16.12 (the highest for ILS and lowest for GFL), and the mean Ra ranged from 0.079 to 4.085 (the lowest for ILS and highest for GFL). At all measuring stages, the calculated ΔE00 values ranged from 0.31 to 0.92 for all materials. The mean VHN ranged from 632.34 to 39.08 (the highest for ILS and lowest for GFZ). The resin composite containing the largest filler particle (GFF) showed significantly lower Ra and higher VHN than other resin composites (GFL, GFZ, and GFP). The CAD/CAM resin composite block containing a smaller filler particle (CSP) retained significantly higher GU than that containing a larger filler particle (CS3). A negative correlation between GU and Ra was detected. CONCLUSIONS: Based on the findings, toothbrush abrasion induced a decrease in GU and an increase in Ra for all resin-based materials tested. Resin-based materials with larger filler size tended to show lower Ra, while resin-based materials with smaller filler size tended to show a smaller reduction in GU. These were more pronounced for light-cure resin composites than for resin composite blocks for CAD/CAM.
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Accidente Cerebrovascular , Cepillado Dental , Humanos , Resinas Compuestas , Materiales Dentales , Propiedades de SuperficieRESUMEN
The study aimed to histologically evaluate wound healing of exposed human pulp on direct pulp capping using super-pulsed CO2 laser preirradiation. In this single-blind clinical trial, 28 third molar teeth of 17 volunteers were randomly capped with either CO2 laser irradiation (n=14) or Dycal (calcium hydroxide cement; n=14) and restored using resin composite. The laser was operated in super-pulsed mode (pulse duration, 0.2 ms; interval, 5.8 ms; 0.003 J/pulse). The irradiation conditions were a power output of 0.5 W, an irradiation time of 15 seconds, repeat mode (10-ms irradiation and 10-ms intervals, for a total beam exposure time of 7.5 seconds), total applied energy of 3.75 J, and an activated air-cooling system. Each tooth was extracted at six or 12 months posttreatment and prepared for histological evaluation. We evaluated the parameters of pulp tissue disorganization, inflammatory cell infiltration, reparative dentin formation (RDF), and bacterial penetration. There were no significant differences between groups for all parameters at each postoperative period (Mann-Whitney U-test, p>0.05). CO2 laser irradiation completely controlled bleeding and exudate from the exposed pulp. The CO2 laser group had a tendency to delay RDF compared with the Dycal group, but 4 of 7 teeth from the CO2 laser group showed a complete dentin bridge at 12 months posttreatment.
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Recubrimiento de la Pulpa Dental , Dentina Secundaria , Dióxido de Carbono , Pulpa Dental , Humanos , Cementos de Resina , Método Simple CiegoRESUMEN
BACKGROUND: The complex interplay between ethnicity, Fitzpatrick skin type (FST), and hirsutism in patients with polycystic ovarian syndrome (PCOS) is poorly understood. OBJECTIVE: In this cross-sectional, retrospective analysis, we examined the prevalence, severity, and distribution of hirsutism with clinician-rated site-specific and total modified Ferriman-Gallwey (mFG) visual scoring in a diverse cohort of American patients with PCOS. METHODS: Independent analyses were conducted on the basis of patient-reported FST ratings and ethnicity. RESULTS: In this PCOS cohort, a correlation was found between hirsutism and ethnicity and the highest prevalence of hirsutism and total mFG scores was observed in Hispanic, Middle Eastern, African American, and South Asian patients. A positive correlation between hirsutism and FST was also observed with an increasing prevalence of hirsutism in the group of patients with higher FSTs. Significant trends in the anatomic distribution of hirsutism were observed between ethnic groups as well. A higher facial mFG score was found in African American patients but higher mFG scores in the truncal and extremity regions were observed in Middle Eastern patients. Truncal hirsutism was also associated with higher FSTs. CONCLUSIONS: Ethnicity and FST may be important variables in both the quantitative and qualitative presentations of hirsutism in women with PCOS and should be considered in the diagnostic evaluation of any patient who is suspected of having the condition. Previously published studies that examined ethnicity, FST, and hirsutism in homogeneous cohorts limited comparison and generalizability but the strength of this study lies in its detailed analysis within a single large and diverse PCOS cohort. Validated studies are needed to determine whether clinical criteria for hirsutism should be adjusted for ethnicity and FST in the PCOS population and particularly within diverse cohorts and patients of mixed ancestry.
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Hormone-based therapies including combined oral contraceptive medications and spironolactone are considered effective therapies to treat adult acne in women. Our objective is to provide a concise and comprehensive overview of the types of hormonal therapy that are available to treat acne and comment on their efficacy and safety profiles for clinical practice. A systematic search using the PubMed Database was conducted to yield 36 relevant studies for inclusion in the review and several conclusions were drawn from the literature. Treatment with oral contraceptive pills leads to significant reductions in lesion counts across all lesion types compared with placebo. There were no consistent differences in efficacy between the different combined oral contraceptive formulations. In terms of risk, oral contraceptive pill users had three-times increased odds of venous thromboembolism versus non-users according to a recent meta-analysis (95% confidence interval 2.46-2.59). Data on oral contraceptive pill use and breast cancer risk are conflicting but individual patient risk factors and histories should be discussed and considered when prescribing these medications. However, use of these medications does confer measurable protection from endometrial and ovarian cancer. Spironolactone was also shown to be an effective alternative treatment with good tolerability. Combined oral contraceptive medications and spironolactone as adjuvant and monotherapies are safe and effective to treat women with adult acne. However, appropriate clinical examinations, screening, and individual risk assessments particularly for venous thromboembolism risk must be conducted prior to initiating therapy.
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Carcinoma de Células Escamosas/etiología , Enfermedades del Oído/etiología , Trasplante de Riñón/efectos adversos , Trasplante de Páncreas/efectos adversos , Neoplasias Cutáneas/etiología , Carcinoma de Células Escamosas/cirugía , Enfermedades del Oído/cirugía , Educación Médica Continua , Humanos , Masculino , Persona de Mediana Edad , Pronóstico , Neoplasias Cutáneas/cirugíaAsunto(s)
Exantema/etiología , Fiebre/etiología , Trasplante de Hígado/efectos adversos , Adulto , Educación Continua , Femenino , HumanosRESUMEN
Autoinflammatory syndromes are a distinct class of inherited diseases of cytokine dysregulation with important cutaneous features. Several disorders, including familial cold autoinflammatory syndrome (FCAS), Muckle-Wells syndrome and neonatal onset multisystem inflammatory disorder (NOMID), are associated with mutations in a common gene, CIAS-1. These disorders are now believed to represent related conditions along a spectrum of disease severity, in which FCAS is the mildest and NOMID is the most severe phenotype. Patients typically present with lifelong atypical urticaria with systemic symptoms, with potential for developing end-organ damage due to chronic inflammation. Advances in the understanding of the genetic basis of these syndromes have also revealed cytokine signalling molecules that are critical to normal regulation of inflammatory pathways. The dramatic response of these syndromes to anakinra, an interleukin (IL)-1 antagonist, highlights the important role of IL-1 cytokine signalling in the pathogenesis of this rare but fascinating class of diseases.
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Antirreumáticos/uso terapéutico , Enfermedades Autoinmunes/genética , Proteínas Portadoras/genética , Inflamación/genética , Periodicidad , Urticaria/genética , Edad de Inicio , Enfermedades Autoinmunes/patología , Enfermedades Autoinmunes/terapia , Enfermedad Crónica , Predisposición Genética a la Enfermedad , Humanos , Recién Nacido , Inflamación/tratamiento farmacológico , Inflamación/patología , Proteína Antagonista del Receptor de Interleucina 1/uso terapéutico , Mutación , Proteína con Dominio Pirina 3 de la Familia NLR , Fenotipo , Índice de Severidad de la Enfermedad , Síndrome , Urticaria/tratamiento farmacológico , Urticaria/patologíaRESUMEN
OBJECTIVE: To investigate the effect of valproic acid on plasma levels of risperidone and its active metabolite, 9-hydroxyrisperidone under steady state conditions in 12 schizophrenic patients. METHODS: The efficacy and tolerability for the combination treatment of valproic acid and risperidone were examined. RESULTS: The addition of valproic acid to risperidone significantly reduced total scores of PANSS positive symptoms, especially excitement and hostility scores, but did not change SAS scores. Addition of valproic acid did not alter plasma concentrations of risperidone or 9-hydroxyrisperidone or active moiety, and the risperidone/9-hydroxyrisperidone ratio. The combination of valproic acid with risperidone decreased plasma levels of HVA, but not those of MHPG; additionally, treatment with this combination was found to reduce dopaminergic activity. CONCLUSION: These results suggest that the addition of valproic acid to risperidone is both effective and well tolerated for treating excitement and impulsiveness in schizophrenic patients without influencing the metabolism of risperidone, and treatment with valproic acid and risperidone.
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Antimaníacos/uso terapéutico , Antipsicóticos/sangre , Agitación Psicomotora/tratamiento farmacológico , Risperidona/sangre , Esquizofrenia/complicaciones , Ácido Valproico/uso terapéutico , Adulto , Antimaníacos/efectos adversos , Antipsicóticos/efectos adversos , Antipsicóticos/uso terapéutico , Interacciones Farmacológicas , Femenino , Ácido Homovanílico/sangre , Humanos , Isoxazoles/sangre , Masculino , Metoxihidroxifenilglicol/sangre , Persona de Mediana Edad , Palmitato de Paliperidona , Escalas de Valoración Psiquiátrica , Agitación Psicomotora/complicaciones , Pirimidinas/sangre , Risperidona/efectos adversos , Risperidona/uso terapéutico , Esquizofrenia/tratamiento farmacológico , Psicología del Esquizofrénico , Ácido Valproico/efectos adversosRESUMEN
Two patients with bipolar I disorder were successfully treated with a combination of risperidone and lithium in their acute manic states and maintenance periods. Although lithium monotherapy alone could not prevent relapse in these patients, the addition of a low dose of risperidone was well tolerated and effective for preventing recurrence over the long term. Plasma levels of HVA and MHPG were found to be elevated during the manic episodes and gradually decreased after the risperidone treatment. These results indicate that a low dose of risperidone to the lithium regimen was an effective and well tolerated means for treatment in the acute manic state and the later maintenance period in parallel with decreasing plasma levels of HVA and MHPG.
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Antimaníacos/uso terapéutico , Antipsicóticos/uso terapéutico , Trastorno Bipolar/tratamiento farmacológico , Carbonato de Litio/uso terapéutico , Risperidona/uso terapéutico , Adulto , Antimaníacos/administración & dosificación , Antimaníacos/efectos adversos , Antipsicóticos/administración & dosificación , Antipsicóticos/efectos adversos , Trastorno Bipolar/psicología , Femenino , Ácido Homovanílico/sangre , Humanos , Carbonato de Litio/administración & dosificación , Carbonato de Litio/efectos adversos , Masculino , Metoxihidroxifenilglicol/sangre , Escalas de Valoración Psiquiátrica , Risperidona/administración & dosificación , Risperidona/efectos adversosRESUMEN
INTRODUCTION: Repetitive transcranial magnetic stimulation (rTMS) is a non-invasive and easily tolerated method of altering cortical physiology. To date, numerous open and sham controlled clinical trials have explored the antidepressant potential of rTMS. In the present study, we investigated clinical trials of high-frequency rTMS (20 Hz) for treatment of refractory depression, and also examined the effect of rTMS on plasma levels of catecholamine metabolites and brain-derived neurotropic factor (BDNF). METHODS: Twenty-six depressed inpatients who met the DSM-IV criteria for major depressive disorder and had failed to respond to treatment with at least two antidepressant drugs given at adequate doses (above 150 mg/day in an equivalent dose of imipramine) and durations (at least 4 weeks for each drug) were enrolled in this study. Eleven were males, 15 females. The ages of the subjects ranged from 19 to 78 years old (mean +/- SD = 52.9 +/- 17.8). All patients were administered left prefrontal 20 Hz rTMS at 80 % MT (total 800 pulses a day) over ten daily sessions. The plasma levels of 3-methoxy-4-hydroxyphenylglycol (MHPG) and homovanillic acid (HVA) were analyzed by high-performance liquid chromatography. The plasma levels of BDNF were also measured with the sandwich ELISA method. RESULTS: The mean 17-item Hamilton Rating Scale for Depression (Ham-D) score of 20.5 +/- 5.2 before rTMS was significantly decreased to 15.6 +/- 7.3 after rTMS. Nine of 26 patients (35 %) demonstrated some improvement (Ham-D > or = 25 %) by rTMS. The levels of plasma MHPG, but not those of HVA, were significantly reduced after rTMS treatment, and a negative correlation was observed between the change in plasma MHPG levels and the change in scores of agitation. In addition, the plasma levels of BDNF were significantly increased by 23 % in responders and partial responders, but not in nonresponders, after rTMS treatment, and a trend for association was found between the changes in Ham-D scores and changes in plasma BDNF levels in all patients after rTMS treatment. CONCLUSION: These results suggest that rTMS treatment brings about some improvement in refractory depression, especially for symptoms such as agitation, by influencing MHPG and BDNF, which is in accordance with previous reports showing that BDNF was increased by various antidepressants treatments.
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Factor Neurotrófico Derivado del Encéfalo/sangre , Encéfalo/metabolismo , Catecolaminas/sangre , Trastorno Depresivo Mayor/terapia , Periodicidad , Estimulación Magnética Transcraneal , Adulto , Antidepresivos Tricíclicos/uso terapéutico , Cromatografía Líquida de Alta Presión , Terapia Combinada , Trastorno Depresivo Mayor/tratamiento farmacológico , Ensayo de Inmunoadsorción Enzimática , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
In the present study, we investigated the effects of levomepromazine on plasma risperidone concentrations in a steady state. Twenty patients taking risperidone at a stable dose for more than 2 weeks who were considered to require levomepromazine coadministration were selected. The scores of excitement in BPRS significantly decreased 2 weeks after the coadministration of levomepromazine. Plasma risperidone concentrations and the ratio of risperidone and 9-hydroxyrisperidone (risperidone/9-hydroxyrisperidone) did not change between before and 2 weeks after the coadministration of levomepromazine. The extrapyramidal symptoms were not worsened by the coadministration of levomepromazine. These results suggest that a low dosage of levomepromazine, use as a sedative adjuvant to risperidone treatment, have no statistically significant effect on the trough plasma concentrations of risperidone.
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Antipsicóticos/sangre , Metotrimeprazina/farmacología , Metotrimeprazina/uso terapéutico , Trastornos Psicóticos/tratamiento farmacológico , Risperidona/sangre , Adolescente , Adulto , Antipsicóticos/metabolismo , Escalas de Valoración Psiquiátrica Breve , Relación Dosis-Respuesta a Droga , Femenino , Humanos , Masculino , Metotrimeprazina/administración & dosificación , Persona de Mediana Edad , Risperidona/metabolismoRESUMEN
We investigated the relationships between the changes in plasma catecholamine metabolites obtained from depressed patients before and after administration of sulpiride, a benzamide compound, or fluvoxamine, a selective serotonin reuptake inhibitor (SSRI), and between clinical responses to treatment with each of these drugs. Responders to sulpiride had significantly lower plasma homovanillic acid (pHVA) levels before administration of sulpiride than did non-responders or controls (responders: 4.5 +/- 3.1 ng/ml, non-responders: 11.1 +/- 5.9 ng/ml, controls: 10.9 +/- 5.3 ng/ml). Positive relationships were observed between changes in pHVA levels and improvement rates in the 17-item Hamilton Depression Rating Scale (Ham-D). In contrast, responders to fluvoxamine had significantly higher plasma free 3-methoxy-4-hydroxyphenylglycol (pMHPG) levels before administration of fluvoxamine than did non-responders or controls (responders: 8.5 +/- 1.8 ng/ml, non-responders: 5.9 +/- 2.I ng/ml, controls: 5.2 +/- 2.9 ng/ml). Negative relationships were observed between changes in pMHPG levels and improvement rates in Ham-D. These results suggest that lower pretreatment pHVA levels and higher pretreatment levels of pMHPG might be predictors of response to sulpiride and fluvoxamine, respectively, and that sulpiride might produce a functional increase in the dopaminergic system, resulting in improvement in some depressive symptoms; fluvoxamine, on the other hand, might produce a functional decrease in the noradrenergic system via serotonergic neurons, resulting in improvement of those symptoms.
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Antidepresivos de Segunda Generación/uso terapéutico , Trastorno Depresivo Mayor/sangre , Antagonistas de Dopamina/uso terapéutico , Fluvoxamina/uso terapéutico , Ácido Homovanílico/sangre , Metoxihidroxifenilglicol/sangre , Inhibidores Selectivos de la Recaptación de Serotonina/uso terapéutico , Sulpirida/uso terapéutico , Adulto , Anciano , Biomarcadores/sangre , Trastorno Depresivo Mayor/tratamiento farmacológico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Resultado del TratamientoRESUMEN
We investigated the association between fluvoxamine and nausea from various viewpoints. The incidence of nausea induced by fluvoxamine was 29% (12/41). Plasma 5-hydroxyindoleacetic acid (p5-HIAA) levels after fluvoxamine administration were significantly higher in patients with nausea (6.6+/-3.4 ng/ml) than in those without nausea (3.5+/-2.7 ng/ml). On the other hand, no significant differences were found between patients with and patients without nausea in terms of sex, age, initial and maximum dosages of fluvoxamine and its plasma concentrations, and clinical response to fluvoxamine. However, the incidence of nausea in patients who were initially administered fluvoxamine at under 50 mg/day was significantly lower than in those who were started at above 50 mg/day. In addition, mosapride, a member of the benzamide family, was effective in alleviating fluvoxamine-induced nausea. These results suggest that fluvoxamine-induced nausea is associated with hyperactivity in serotonergic neurons.
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Trastorno Depresivo Mayor/tratamiento farmacológico , Fluvoxamina/efectos adversos , Náusea/inducido químicamente , Náusea/diagnóstico , Inhibidores Selectivos de la Recaptación de Serotonina/efectos adversos , Adulto , Anciano , Anciano de 80 o más Años , Antieméticos/uso terapéutico , Benzamidas/uso terapéutico , Relación Dosis-Respuesta a Droga , Femenino , Fluvoxamina/administración & dosificación , Humanos , Ácido Hidroxiindolacético/sangre , Masculino , Persona de Mediana Edad , Morfolinas/uso terapéutico , Náusea/tratamiento farmacológico , Índice de Severidad de la EnfermedadRESUMEN
We demonstrated the effect of clonazepam (2 mg/day) on Meige syndrome in two schizophrenic patients under continuous treatment with antipsychotic drugs, and changes in the plasma levels of gamma-aminobutyric acid (GABA), homovanillic acid (HVA), and 3-methoxy-4-hydroxyphenylglycol (MHPG) in these cases. The plasma levels of HVA and MHPG during treatment with clonazepam were decreased in the responder, while not changed in the non-responder to clonazepam. A difference between the responder and the non-responder was not found in the plasma GABA levels. These results suggest that hyperactivities of the central dopaminergic and noradrenergic neurones are involved in the pathophysiology of Meige syndrome.
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Antipsicóticos/efectos adversos , Clonazepam/uso terapéutico , Ácido Homovanílico/sangre , Síndrome de Meige/inducido químicamente , Metoxihidroxifenilglicol/sangre , Ácido gamma-Aminobutírico/sangre , Adulto , Antipsicóticos/uso terapéutico , Clonazepam/efectos adversos , Femenino , Humanos , Síndrome de Meige/sangre , Síndrome de Meige/tratamiento farmacológico , Esquizofrenia Hebefrénica/sangre , Esquizofrenia Hebefrénica/tratamiento farmacológico , Esquizofrenia Paranoide/sangre , Esquizofrenia Paranoide/tratamiento farmacológicoRESUMEN
Mechanisms that underlie the patterning of cytokine expression in T helper (T(H)) cell subsets remain incompletely defined. An evolutionarily conserved approximately 400-bp noncoding sequence in the intergenic region between the genes Il4 and Il13, designated conserved noncoding sequence 1 (CNS-1), was deleted in mice. The capacity to develop T(H)2 cells was compromised in vitro and in vivo in the absence of CNS-1. Despite the profound effect in T cells, mast cells from CNS-1(-/-) mice maintained their capacity to produce interleukin 4. A T cell-specific element critical for the optimal expression of type 2 cytokines may represent the evolution of a regulatory sequence exploited by adaptive immunity.
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Citocinas/genética , ADN Intergénico/fisiología , Células Th2/inmunología , Animales , Aspergilosis/inmunología , Células Cultivadas , Secuencia Conservada , Citocinas/biosíntesis , ADN Intergénico/genética , Marcación de Gen , Interleucina-4/biosíntesis , Interleucina-4/genética , Leishmaniasis Cutánea/inmunología , Mastocitos/inmunología , Ratones , Ratones Noqueados , ARN Mensajero/biosíntesis , Eliminación de Secuencia , Infecciones por Strongylida/inmunologíaRESUMEN
Effector T cells mediate adaptive immunity and immunopathology, but methods for tracking such cells in vivo are limited. We engineered knockin mice expressing IL-4 linked via a viral IRES element with enhanced green fluorescent protein (EGFP). Reporter T cells primed under Th2 conditions showed sensitive and faithful EGFP expression and maintained endogenous IL-4. After Nippostrongylus infection, reporter expression demonstrated the evolution of type 2 immunity from tissue lymphocytes and thence to lymph node CD4(+) T cells, which subsequently migrated into tissue. The appearance of EGFP(+) CD4(+) T cells in tissue, but not in lymph nodes, was Stat6-dependent. Transferred EGFP(+) CD4(+) T cells from infected animals conferred protection against Nippostrongylus to immunodeficient mice. These mice will provide a valuable reagent for assessing immunity in vivo.
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Genes Reporteros/genética , Interleucina-4/genética , Nippostrongylus/inmunología , Infecciones por Strongylida/inmunología , Animales , Inmunidad , Interleucina-4/biosíntesis , Ratones , Ratones MutantesRESUMEN
This study's objectives were: 1) to determine the combination of bonding procedures (with or without acid etching, moist or dry substrate, one or two applications of primer/adhesive) that would produce the highest shear bond strength of Prime & Bond and Dyract AP and 2) to characterize the resin-dentin/enamel interface produced by these bonding procedures. Ninety-six bovine incisors were randomly assigned to eight groups for shear bond testing to enamel (n = 6) and dentin (n = 6). Prime & Bond and Dyract AP were applied and cured following manufacturers' instructions. Shear bond testing was conducted in a Universal Testing Machine. Thirty-two bovine incisors were sectioned to produce blocks with enamel and dentin, then bonded in pairs for evaluation of interfacial morphology. They were polished and argon ion-etched using a high-speed argon ion-etching machine and examined by SEM. The groups where enamel was etched, kept moist or dry and received a single application of Prime & Bond produced the highest shear bond strength. Dentin bond strengths were high in the groups where dentin was etched and kept moist. The number of Prime & Bond applications had no effect on dentin bond strength. Acid etching results in better adaptation of Prime & Bond to enamel and dentin regardless of whether moisture is present.
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Bisfenol A Glicidil Metacrilato , Recubrimiento Dental Adhesivo/métodos , Recubrimientos Dentinarios , Ácidos Polimetacrílicos , Grabado Ácido Dental , Análisis de Varianza , Animales , Bovinos , Compómeros , Permeabilidad del Esmalte Dental , Permeabilidad de la Dentina , Metacrilatos , Microscopía Electrónica de Rastreo , Distribución Aleatoria , Silicatos , Estadísticas no Paramétricas , Propiedades de SuperficieRESUMEN
The rapid decrease in the size of dental restorations has increased the demand for the smallest rotary cutting instrument possible. The width of cavities prepared with two experimental diamond points and the smallest commercial diamond point were compared and significant differences found. SEM observation of the head surfaces of the three diamond points revealed that the experimental points had comparable cutting characteristics with the commercial diamond point.
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Preparación de la Cavidad Dental/instrumentación , Diamante , Análisis de Varianza , Diente Premolar/ultraestructura , Preparación de la Cavidad Dental/métodos , Diseño de Equipo , Humanos , Ensayo de Materiales , Microscopía Electrónica de Rastreo , Propiedades de SuperficieAsunto(s)
Trastorno Depresivo Mayor/psicología , Miastenia Gravis/psicología , Adulto , Comorbilidad , Trastorno Depresivo Mayor/diagnóstico , Humanos , Masculino , Miastenia Gravis/diagnóstico , Examen Neurológico , Grupo de Atención al Paciente , Inventario de Personalidad , Timoma/diagnóstico , Timoma/psicología , Neoplasias del Timo/diagnóstico , Neoplasias del Timo/psicologíaRESUMEN
The purpose of this study was to evaluate the effect of filler size on the wear of resin cements. Materials tested included four experimental dual-cure resin cements (Kuraray) consisting of different-sized filler particles. A rectangular box cavity was prepared on the flattened occlusal surface of extracted human molars. Ceramic inlays for the cavities were fabricated using the Cerec 2 system. The Cerec inlays were cemented with the respective cements and adhesive systems according to the manufacturer's directions. The restored surface was finished by wet-grinding with an 800-grit silicon carbide paper. Six specimens were prepared for each resin cement. Half of the specimens were subjected to a three-body wear test for 200,000 cycles, and the others were subjected to a toothbrush abrasion test for 30,000 cycles. The worn surface of each restoration was scanned by a profilometer (Surfcom 475 A) at eight different points for each restoration. The wear value was determined by measuring the vertical gap depth on the profilometric tracings. The data were statistically analyzed by one-way analysis of variance (ANOVA) and Scheffe's test. The results showed that, with increase of filler size, the wear value decreased in the toothbrush test and increased in the three-body wear test. The cement with 0.04-microm filler exhibited the lowest wear value among the materials in the three-body wear test, and the same wear value as the cement with 0.97-microm filler in the toothbrush test. Based upon the results of this study, it is concluded that the wear of resin cements was affected by the filler size as well as the mode of wear test.