RESUMO
A novel lotion formulation of fluticasone propionate 0.05% has recently become available. Two large, randomized, placebo-controlled, double-blind studies involving 438 subjects demonstrated its efficacy and safety when applied once daily in the treatment of atopic dermatitis in subjects from 3 months to 87 years of age. The studies were limited to 4 weeks duration of use of fluticasone lotion and did not assess longer term efficacy or side effects.
Assuntos
Androstadienos/administração & dosagem , Antialérgicos/administração & dosagem , Dermatite Atópica/tratamento farmacológico , Fármacos Dermatológicos/administração & dosagem , Administração Tópica , Adolescente , Androstadienos/efeitos adversos , Antialérgicos/efeitos adversos , Criança , Pré-Escolar , Fármacos Dermatológicos/efeitos adversos , Método Duplo-Cego , Fluticasona , Humanos , Lactente , PomadasRESUMO
Pancreatic endocrine function was studied in forty dogs after ligation or free i.p. drainage of the pancreatic duct, with or without simultaneous partial pancreatectomy. Shrinkage and fibrosis of the pancreas occurred in all dogs, with equal severity in the open duct and duct-tied groups. Fasting blood sugars remained within the normal range but fasting levels of plasma insulin and glucagon were reduced. Dynamic tests of endocrine function indicated that partial pancreatectomy reduced the insulin response to i.v. injection of dextrose or glucagon and delayed the reestablishment of glucose homeostasis. Glucose tolerance was normal in dogs with intact pancreases, but duct ligation was associated with deteriorating recovery after glucagon injection. The precise coordination of circulating glucose, insulin, and glucagon levels seen in normal dogs was lost in both partial and intact pancreas groups and these disturbances were attributed to the fibrotic changes arising from interference with the ductal drainage. Both ligation and free i.p. drainage of the pancreatic duct therefore resulted in abnormalities of islet function. When combined with partial pancreatectomy, both techniques were associated with significant pancreatic endocrine insufficiency.
Assuntos
Ilhotas Pancreáticas/fisiopatologia , Pancreatopatias/fisiopatologia , Ductos Pancreáticos/cirurgia , Animais , Glicemia/análise , Cães , Feminino , Glucagon/sangue , Teste de Tolerância a Glucose , Insulina/sangue , Ligadura , Masculino , Pancreatectomia , Pancreatopatias/etiologia , Pancreatopatias/patologiaRESUMO
BACKGROUND: The ability of Mycobacterium tuberculosis to survive and replicate in macrophages is crucial for the mycobacterium's ability to infect the host and cause tuberculosis. To identify Mycobacterium tuberculosis genes involved in survival in macrophages, a library of non-pathogenic Mycobacterium smegmatis bacteria, each carrying an individual integrated cosmid containing M. tuberculosis H37Rv genomic DNA, was passed through THP-1 human macrophages three times. RESULTS: Two of the clones recovered from this enrichment process, sur2 and sur3, exhibited significantly increased survival relative to wild-type bacteria. In coinfection experiments, the ratio of sur2 colonies to wild-type colonies was 1:1 at 0 hours but increased to 20:1 at 24 hours post phagocytosis. The ratio of sur3 colonies to wild-type colonies was 1:1 at 0 hours and 5:1 at 24 hours. The M. tuberculosis ORFs responsible for increased survival were shown to be Rv0365c for the sur2 clone and Rv2235 for the sur3 clone. These ORFs encode proteins with as-of-yet unknown functions. CONCLUSIONS: We identified two M. tuberculosis ORFs which may be involved in the ability of tubercle bacilli to survive in macrophages.
Assuntos
Macrófagos/fisiologia , Oxigenases de Função Mista/fisiologia , Mycobacterium tuberculosis/metabolismo , Fagocitose/fisiologia , Humanos , Macrófagos/microbiologia , Mycobacterium tuberculosis/fisiologia , Fases de Leitura AbertaRESUMO
STUDY OBJECTIVE: The presence of pleural adhesions may render video-assisted thoracoscopic surgery (VATS) difficult or impossible. The aim of this study was to assess the value of chest CT in the detection of pleural adhesions prior to VATS. DESIGN: Prospective study of the accuracy of chest CT in detecting pleural adhesions prior to VATS. SETTING: Tertiary-referra; teaching hospital and Veterans Administration hospital. PATIENTS: Between July 1994 and March 1995, 63 consecutive patients undergoing 64 VATS procedures were evaluated with chest CT prior to surgery. MEASUREMENTS AND RESULTS: Preoperative scans were interpreted by consensus of two pulmonary radiologists prior to surgery. Suspected pleural adhesions and other findings related to the pleura were recorded on a form given to the surgeon prior to VATS. The surgeon confirmed or excluded each suspected adhesion during VATS, and documented any other lesions not identified preoperatively. Patient-by-patient and lesion-by-lesion analyses were performed. Pleural adhesions were correctly identified by CT in 28 of 39 cases (sensitivity, 71%) and excluded in 18 of 25 cases (specificity, 72%). On a lesion-by-lesion basis, 73 adhesions were identified during VATS, of which only 28 were identified prospectively at CT. There were 45 missed adhesions and 20 adhesions that were suggested falsely (sensitivity, 38%; specificity, 46%). Eighteen pleural spaces were correctly identified as being free of pleural adhesions. CONCLUSIONS: CT is moderately sensitive and specific for preoperative identification of pleural adhesions in patients undergoing VATS but its accuracy is poorer for individual lesions.
Assuntos
Doenças Pleurais/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto , Idoso , Idoso de 80 Anos ou mais , Endoscopia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Doenças Pleurais/cirurgia , Estudos Prospectivos , Sensibilidade e Especificidade , Toracoscopia , Aderências Teciduais/diagnóstico por imagem , Gravação em VídeoRESUMO
Insulin-like growth factor-I (IGF-I) is thought to play a role in the onset of reproductive ability at puberty and the control of reproductive function throughout adult life. It is believed that these effects are mediated at least in part by the activation of gonadotropin releasing hormone (GnRH) neurones by IGF-I, but the interactions of IGF-I with GnRH neurones in vivo are largely unknown. We first examined the anatomical relationship between GnRH and IGF-I cells in neuroendocrine regions. Using double-label immunocytochemistry, we observed that in the preoptic area-anterior hypothalamus (POA-AH), the site of GnRH perikarya, the majority (78%) of GnRH cell bodies expressed IGF-I immunoreactivity. IGF-I immunoreactivity was also high in the median eminence, the site of GnRH release, and GnRH neuroterminals were seen to interweave among IGF-I-immunopositive cells. Due to this substantial overlap of GnRH and IGF-I immunoreactive elements, we then tested the hypothesis that changes in IGF-I may regulate the GnRH system. Animals were examined at the two important reproductive life transitions: puberty and reproductive senescence. IGF-I mRNA levels were measured in POA-AH and medial basal hypothalamus-median eminence (MBH-ME) and effects of IGF-I treatment on GnRH mRNA levels were quantified by RNase protection assay. Although IGF-I treatment did not alter GnRH gene expression, there were significant alterations in hypothalamic IGF-I gene expression at both puberty and reproductive senescence. During puberty, IGF-I mRNA levels in the MBH-ME of rats increased from the juvenile stage (P25) to the day of vaginal opening (P35), and from the day of vaginal opening to young adulthood (P45) in the POA-AH. During reproductive ageing, IGF-I mRNA levels were significantly lower in middle-aged than young rats, particularly in the MBH-ME. At all ages, IGF-I expression was greater in the MBH-ME than in the POA-AH. These experiments demonstrate that: (i) the majority of adult GnRH neurones are immunopositive for the IGF-I protein; (ii) hypothalamic IGF-I levels increase at the onset of reproductive function and decrease at reproductive senescence in a regionally specific manner; and (iii) despite the presence of IGF-I in GnRH perikarya, IGF-I does not affect GnRH gene expression, suggesting that IGF-I may act at the level of GnRH release rather than gene expression.
Assuntos
Envelhecimento/fisiologia , Hormônio Liberador de Gonadotropina/análise , Fator de Crescimento Insulin-Like I/genética , Neurônios/fisiologia , Área Pré-Óptica/fisiologia , Maturidade Sexual/fisiologia , Animais , Contagem de Células , Estrogênios/sangue , Feminino , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Hormônio Liberador de Gonadotropina/metabolismo , Imuno-Histoquímica , Fator de Crescimento Insulin-Like I/análise , Eminência Mediana/química , Eminência Mediana/crescimento & desenvolvimento , Eminência Mediana/fisiologia , Neurônios/química , Neurônios/citologia , Ovariectomia , Área Pré-Óptica/citologia , Área Pré-Óptica/crescimento & desenvolvimento , Terminações Pré-Sinápticas/química , RNA Mensageiro/análise , Ratos , Ratos Sprague-DawleyRESUMO
Over a three year period, 22 diabetic and 87 non-diabetic patients received 120 cadaver kidney transplants at Dulwich Hospital. Horse antilymphocyte globulin (ALG), azathioprine and low-dose intra-muscular methyl prednisolone were used as immunosuppressive agents. A control group of 98 non-diabetic patients (113 transplants) at Guy's Hospital during the same period were treated with a standard azathioprine and oral steroid regime. Four main findings emerged: Firstly, survival rates for first grafts in the non-diabetic patients were similar in both centers. This suggests that neither the ALG or more conventional immunosuppressive regime holds any advantage in this patient group. Secondly, the first grafts in diabetic patients did significantly worse than similar grafts in the non-diabetics. Thirdly, in patients receiving the more conventional regime, second grafts did significantly worse than first grafts. Fourthly, and in contrast, the ALG regime gave similar survival figures for both first and second grafts. Thus, ALG had no apparent advantage over conventional steroid regimes on the survival of first grafts but it did produce a marked improvement in the outcome of subsequent grafts.
Assuntos
Soro Antilinfocitário/farmacologia , Sobrevivência de Enxerto/efeitos dos fármacos , Transplante de Rim , Adulto , Animais , Azatioprina/farmacologia , Nefropatias Diabéticas/cirurgia , Feminino , Cavalos/imunologia , Humanos , Terapia de Imunossupressão , Masculino , Metilprednisolona/farmacologia , Pessoa de Meia-Idade , Prednisolona/farmacologia , ReoperaçãoRESUMO
This in vitro study quantified the marginal discrepancy of the implant-to-prosthetic-crown interface on nonsubmerged dental implants restored with either a cemented or a screw-retained approach. Metal-ceramic crowns were fabricated for 20 ITI 4.1 x 10 mm solid-screw titanium implants. Ten implants received octa abutments and screw-retained crowns fabricated on premachined gold cylinders. The remaining 10 implants were restored with 5.5-mm solid abutments and metal-ceramic crowns cemented alternately with a glass-ionomer or a zinc phosphate luting agent. Inspection of the implant-crown interface was conducted using light microscopy under x 50 magnification at selected stages in the process of crown fabrication. Statistical analysis revealed a significant difference (P < .001) in the mean marginal fit between screw-retained (8.5 +/- 5.7 microns) and luted implant-supported crowns. This difference was observed both before (54.4 +/- 18.1 microns) and after cementation with glass-ionomer (57.4 +/- 20.2 microns) or zinc phosphate (67.4 +/- 15.9 microns).
Assuntos
Coroas , Dente Suporte , Implantes Dentários , Retenção em Prótese Dentária/métodos , Cimentação , Pinos Dentários , Planejamento de Prótese Dentária , Retenção em Prótese Dentária/instrumentação , Cimentos de Ionômeros de Vidro , Ligas de Ouro , Humanos , Ligas Metalo-Cerâmicas , Cimento de Fosfato de ZincoRESUMO
OBJECTIVES: Adhesive cements used with metal endodontic posts may decrease fracture in non-vital teeth. Results from studies that evaluate cements for post retention by pulling posts out of extracted teeth are difficult to interpret owing to the number of interfaces where fracture might occur. The objective of this study was to isolate the metal/cement interface for tensile bond strength testing and microscopic observation. METHODS: Three metals and seven cement treatments were examined for bond strength by using a truncated cone tensile test. The bond strength data were analyzed by a two-way ANOVA and Scheffé's multiple comparison test at p = 0.05. Specimens were examined at 50x magnification to determine the failure mode and with scanning electron microscopy (500x) to observe the surfaces after debonding. RESULTS: Significant differences in tensile bond strengths were found among cements compared within two of the metal groups. One of the metal groups had no significant differences among cement bonds. When comparing within cement treatment groups, two groups had significant differences in bond strength among the metals. Microscopic observations revealed adhesive, cohesive and mixed failure modes that varied with cement treatment and metal combination. The interaction between metal and cement was a critical determinant of the strength and characteristic fracture mode of the bond achieved. SIGNIFICANCE: Some of the cement treatments performed better (i.e., higher bond strength) with some metals than with others. Other cements had similar bond strengths with all three metals. Because of this interaction, careful consideration of the materials combination should help to maximize the bond at the metal/cement interface.
Assuntos
Ligas Dentárias , Colagem Dentária , Adesivos Dentinários , Técnica para Retentor Intrarradicular/instrumentação , Adesividade , Análise de Variância , Teste de Materiais , Microscopia Eletrônica de Varredura , Paládio , Aço Inoxidável , Estatísticas não Paramétricas , Resistência à Tração , Titânio , Dente não VitalRESUMO
The handling characteristics of a gallium alloy (Gallium Alloy GF) were compared to those of a spherical high-copper amalgam (Tytin). Ten dentists each restored four identical MO preparations in acrylic typodont teeth (no. 30), two with amalgam and two with gallium alloy. Each restoration was evaluated immediately following completion by the operator for six clinically relevant criteria. Each criterion was scored between 1 and 5, where 1 = very poor, 2 = poor, 3 = fair, 4 = good, and 5 = very good. Three two-sided Mann-Whitney tests were used to compare the median scores for significant differences (P < 0.05). The first test indicated no significant difference between scores for the first- and second-placed restorations, within criteria and within alloy type (n = 10). The second test indicated a significant difference between amalgam and gallium alloy, within criteria and within restoration sequence (n = 10), for each criterion except resistance to fracture during removal of the matrix band. The third test indicated a significant difference between amalgam and gallium alloy, within each criteria, combining scores for first- and second-placed restorations (n = 20). During simulated clinical placement, amalgam was rated significantly higher than gallium alloy in each handling characteristic evaluated.
Assuntos
Ligas Dentárias , Amálgama Dentário , Gálio , Restauração Dentária Permanente/métodos , Estudos de Avaliação como Assunto , Teste de MateriaisRESUMO
This study investigated the relationship between race, finding meaning (as a positive psychological resource variable), and the outcomes of caregiver depression and global role strain among 77 African American and 138 White spouse caregivers of persons with dementia. Finding provisional meaning had a direct negative relationship with depression and global role strain. Although African American caregivers were less likely to report depression and role strain, there was no interaction by race in the process influencing caregiver distress.
Assuntos
Atitude , Negro ou Afro-Americano , Cuidadores , Depressão , População Branca , Negro ou Afro-Americano/psicologia , Cuidadores/psicologia , Efeitos Psicossociais da Doença , Feminino , Humanos , Masculino , Transtornos Mentais , Fatores de Risco , Cônjuges/psicologia , População Branca/psicologiaRESUMO
Adapalene gel 0.1% is approved for use in the treatment of acne vulgaris. A new cream formulation, adapalene cream 0.1%, has been developed. Our objective was to evaluate the efficacy and tolerability of adapalene cream 0.1% in comparison with its cream vehicle, applied once daily for 12 weeks to patients with facial acne vulgaris. We used a 12-week, multicenter, randomized, double-blind, vehicle-controlled, comparative phase 3 study of adapalene cream 0.1% and cream vehicle. The study enrolled 237 patients (125 males and 112 females), aged 12 through 30 years, with mild-to-moderate acne vulgaris. Adapalene cream 0.1% demonstrated superior efficacy compared with its cream vehicle. Significantly lower numbers of total inflammatory and noninflammatory lesion counts were observed at the end of the study period in patients using adapalene cream 0.1% as opposed to those using cream vehicle (P<.05 compared with baseline, for all 3 parameters). Adapalene cream 0.1% caused more cutaneous side effects than the cream vehicle, but these were tolerated in most patients. In summary, the results of this study indicate that adapalene cream 0.1% demonstrates superior efficacy over cream vehicle for the treatment of acne vulgaris. Adapalene cream 0.1% also has excellent tolerability and is associated with a low incidence of cutaneous adverse events.
Assuntos
Acne Vulgar/tratamento farmacológico , Anti-Inflamatórios não Esteroides/uso terapêutico , Fármacos Dermatológicos/uso terapêutico , Naftalenos/uso terapêutico , Adapaleno , Administração Tópica , Adolescente , Adulto , Criança , Método Duplo-Cego , Feminino , Humanos , Masculino , Veículos Farmacêuticos/administração & dosagem , Sensibilidade e Especificidade , Resultado do TratamentoRESUMO
Retinoids reverse the abnormal pattern of keratinization seen in acne vulgaris. Tazarotene is the first of a novel family of topical receptor-selective acetylenic retinoids. This study evaluates the safety and efficacy of topical tazarotene 0.1% and 0.05% gels, in comparison to vehicle gel, applied once daily for 12 weeks, in the treatment of mild-to-moderate facial acne vulgaris. A total of 446 patients with facial acne vulgaris were enrolled, and 375 patients, ranging in age from 14 to 44 years, were evaluable in this multicenter, double-blind, randomized study. In comparison to vehicle gel, treatment with tazarotene 0.1% gel resulted in significantly greater reductions in noninflammatory and total lesion counts at all follow-up visits, and inflammatory lesion counts at Week 12. Tazarotene 0.05% gel resulted in significantly greater reductions in noninflammatory and total lesion counts than vehicle gel at Weeks 8 and 12. At Week 12, treatment success rates were 68% and 51% for tazarotene 0.1% and 0.05%, respectively (40% for vehicle gel). Tazarotene gel was an effective, safe, and generally well-tolerated therapy for the treatment of acne vulgaris.
Assuntos
Acne Vulgar/tratamento farmacológico , Ceratolíticos/administração & dosagem , Ácidos Nicotínicos/administração & dosagem , Retinoides/administração & dosagem , Adolescente , Adulto , Método Duplo-Cego , Feminino , Géis/administração & dosagem , Géis/efeitos adversos , Humanos , Ceratolíticos/efeitos adversos , Masculino , Ácidos Nicotínicos/efeitos adversos , Ácidos Nicotínicos/farmacocinética , Satisfação do Paciente , Retinoides/efeitos adversos , Fatores de Tempo , Resultado do TratamentoRESUMO
Twelve prefabricated posts were cemented in extracted teeth with zinc phosphate cement, 14 with resin cement after the canals were acid etched and 14 with zinc phosphate cement after acid etching. After thermocycling, specimens were subjected to a straight-line tensile force. The posts cemented with resin cement had significantly higher tensile strength than those cemented with the two zinc phosphate cement treatments.
Assuntos
Cimentação , Ligas Dentárias , Cimentos Dentários , Retenção em Prótese Dentária , Técnica para Retentor Intrarradicular , Condicionamento Ácido do Dente , Análise de Variância , Ligas Dentárias/química , Cimentos Dentários/química , Planejamento de Prótese Dentária , Cavidade Pulpar/ultraestrutura , Adesivos Dentinários/química , Humanos , Dente Molar , Fosfatos/química , Cimentos de Resina/química , Aço Inoxidável/química , Resistência à Tração , Termodinâmica , Cimento de Fosfato de Zinco/químicaRESUMO
Currently there is no "standard" finishing and polishing procedure for dental amalgam restorations. This investigation evaluated the effect of four different finishing techniques on the durability of dental amalgam restorations as determined by the marginal breakdown. Burnishing immediately before carving or as part of the condensation process seems to improve the carving characteristics of the amalgam.
Assuntos
Amálgama Dentário , Polimento Dentário/métodos , Ligas Dentárias , Infiltração Dentária/prevenção & controle , Oclusão Dentária , Humanos , Microscopia Eletrônica de Varredura , Propriedades de SuperfícieRESUMO
A two-year-old domestic cat was admitted with dyspnea and coughing. Unilateral pleural effusion with characteristics of an eosinophilic exudate was demonstrated. A direct fecal smear was positive for Aelurostrongylus abstrussus larvae. Treatment with levamisole and fenbendazole was curative. Aelurostrongylosis should be suspected in any cat with dyspnea, coughing, or pleural effusion.
Assuntos
Doenças do Gato , Infecções por Nematoides/veterinária , Derrame Pleural/veterinária , Animais , Doenças do Gato/tratamento farmacológico , Doenças do Gato/parasitologia , Gatos , Levamisol/uso terapêutico , Masculino , Metastrongyloidea , Infecções por Nematoides/complicações , Infecções por Nematoides/tratamento farmacológico , Derrame Pleural/etiologiaRESUMO
PURPOSE: To examine the effect of mixing techniques (hand-mixing vs. trituration) on fluoride release from chemically-cured (Fuji II) and resin-modified (Fuji II LC) glass ionomer products. MATERIALS AND METHODS: Fluoride measurements were determined and comparisons made between hand-mixed-type materials that were both hand-mixed (60 seconds) and triturated (10 seconds). Hand-mixed specimens were made using the manufacturer's recommended powder/liquid ratio. Triturated specimens of the same material were made using the same powder/liquid ratio. Disk specimens (8.5 mm diameter, 2 mm thickness; n = 6) were stored in deionized water for 23 hours to obtain Day 1 solutions. Solutions were also obtained at 2, 3, 4, 5, 6, 7, 14, 21, and 28 days after fabrication and were changed 24 hours before fluoride concentration was determined using a fluoride ion selective electrode. Daily rates of fluoride release and 28-day cumulative fluoride totals were calculated. Cumulative data were analyzed by two-way ANOVA and Scheffé's test (alpha = 0.05). Daily results were analyzed by the Mann-Whitney U-test. RESULTS: A significant difference was observed between materials (P < 0.001). Depending on the kind of material used, the method of manipulation affected the fluoride release. Data analysis revealed that: (1) Fuji II LC released significantly more fluoride than Fuji II for both triturated (P = 0.005) and hand-mixed (P < 0.005); (2) the triturated Fuji II released significantly more fluoride than the hand-mixed (P = 0.02); and (3) the hand-mixed Fuji II LC released more fluoride than the triturated, but was not statistically significant (P = 0.16).
Assuntos
Cariostáticos/administração & dosagem , Restauração Dentária Permanente/métodos , Fluoretos/administração & dosagem , Cimentos de Ionômeros de Vidro/química , Análise de Variância , Restauração Dentária Permanente/instrumentação , Composição de Medicamentos/instrumentação , Composição de Medicamentos/métodos , Estudos de Avaliação como Assunto , Fluoretos/química , Cimentos de Resina/química , Resinas Sintéticas/química , Estatísticas não ParamétricasRESUMO
PURPOSE: To determine the amount of fluoride released from several glass ionomer products [Fuji Cap II, Fuji Ionomer Type II, Ketac-Silver, Chelon-Silver, and Miracle Mix (hand-mixed and encapsulated)], and to compare them between triturated (5, 10, 15 seconds) encapsulated and hand-mixed glass ionomers. MATERIALS AND METHODS: The amount of fluoride released at 1, 2, 3, 7, 14, 21 and 28 days after the start of immersion in deionized-distilled water at 37 degrees C was determined with a fluoride ion selective electrode. Rates of fluoride release and cumulative amounts of fluoride release were calculated. RESULTS: Each glass ionomer released the greatest amount of fluoride during the first 24-hour period. Although there was some variation between products, generally the hand-mixed specimens released significantly (P < 0.05) less fluoride than those prepared by mechanical trituration (10 and 15 seconds). The cumulative amounts of fluoride released from the mechanically triturated glass ionomers were significantly (P < 0.05) greater than the amounts released from the hand-mixed glass ionomers. No significant differences in the cumulative amounts of fluoride released from triturated materials were found among the different trituration times.
Assuntos
Fluoretos/química , Cimentos de Ionômeros de Vidro/química , Análise de Variância , Cimentos Cermet/química , Composição de Medicamentos , Microscopia Eletrônica de Varredura , Compostos de Prata/química , Propriedades de Superfície , Fatores de TempoRESUMO
This study evaluated the bond strength of four restorative materials to dentin using Amalgambond. Two high-copper amalgams [Tytin; spherical, (T) and Epoque 80; lathe-cute, (E)], a gallium alloy [Gallium Alloy GF (G) and a resin composite [P-50 (P)] were tested. The polished dentin surface was treated with dentin-enamel activator (10 seconds), washed, dried, and adhesive agent was applied (30 seconds). In group A, the dentin adhesive was placed onto the dentin and while still wet, T, E, or G was condensed in cylinders (4 mm diameter) with condensation forces suggested by the manufacturer for a clinical situation. In group B, the cylindrical specimens of restorative material were allowed to set and then adhered to the treated dentin using the adhesive system. For the composite (control), the adhesive was applied to the treated dentin and while still wet, P was layered into the cylinder and cured for a total of 90 seconds. After storage in water (37 degrees C) for 24 hours, all the specimens were tested for tensile bond strength. This study revealed that the bond strength of P was significantly higher than the other materials tested and also that amalgam allowed to set for 1, 6 or 24 hours before adhesion to dentin had a significantly greater bond strength than freshly condensed amalgam. Although the desired high bond strength did not develop in the bonding of the metallic restorative materials, signs of bonding were found.
Assuntos
Colagem Dentária , Adesivos Dentinários/química , Metacrilatos/química , Análise de Variância , Resinas Compostas , Ligas Dentárias/química , Amálgama Dentário , Dentina , Gálio , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Propriedades de Superfície , Resistência à Tração , Fatores de TempoRESUMO
PURPOSE: To assess the handling characteristics of a gallium alloy triturated with one drop (10 microL) of ethyl alcohol and compare them to those of a high-copper amalgam. MATERIALS AND METHODS: A commercial gallium alloy (Gallium Alloy GFII) and a high-copper amalgam (Tytin) were used. Ten dentists each restored four identical MO preparations in acrylic typodont teeth (two for each material). Each restoration was immediately evaluated by the operator for placement, condensation, proximal contact, carving, and resistance to fracture during matrix removal and overall quality according to a method used previously. The rating scale for each criterion ranged from 1 (very poor) to 5 (very good). Scores for each criterion for the amalgam and gallium alloy restorations were statistically compared. RESULTS: The gallium alloy tested was still rated significantly worse (P < or = 0.05) than amalgam for placement, condensation and carving but there were no significant differences in scores for other criteria. The dentists judged the handling of the gallium alloy in all criteria as fair to good and evaluated it as better in placement, condensation and establishment of proximal contact compared to a previous study, mainly because the pre-set material was no longer sticky.
Assuntos
Ligas Dentárias/química , Etanol/química , Gálio/química , Amálgama Dentário/química , Adaptação Marginal Dentária , Restauração Dentária Permanente/métodos , Restauração Dentária Permanente/estatística & dados numéricos , Humanos , Modelos Dentários , Variações Dependentes do Observador , Fatores de TempoRESUMO
This study investigated the physical and mechanical properties and the microstructure of four different gallium alloys. For all gallium alloys, the compressive strengths measured at one hour (86-223 MPa) and 24 hours (265-286 MPa) after specimen preparation were found to be well within the range exhibited by many high-copper amalgams. The creep values and dimensional change of the gallium alloys were comparable to those of leading amalgams, except for the dimensional change value of one alloy. The set gallium alloys consisted of a multi-phase structure including beta-Sn, CuGa2, In4Ag9, Ag72Ga28, and Ga5Pd (except for one product that did not contain Pd) that was more complicated than the structure of dental amalgams. Although the gallium alloys had physical and mechanical properties comparable to those of high-copper amalgams, the microstructure, coupled with the instability of the element gallium itself, could make these materials more prone to corrosive attack compared to amalgams.