RESUMO
PURPOSE: This study aimed to assess the impact of battery levels in single-peak and multi-peak light-curing units (LCUs) on irradiance, and their effects on glass fiber post push-out bond strength to root dentin and the degree of conversion of dual-cure universal resin cement. METHODS AND MATERIALS: Sixty bovine roots underwent endodontic treatment and were randomly distributed into 6 groups (n=10), formed by combining two LCUs (single-peak and multipeak) and three battery levels (100%, 50%, and 10%). A spectrophotometer measured irradiance (mW/ cm2) and spectral irradiance (mW/cm2/nm). Push-out bond strength (PBS) tests occurred at three root regions (cervical, middle, and apical), with optical and scanning electron microscopy for failure mode analysis. Degree of conversion (DC) was evaluated across the root regions. Data were analyzed using two-way repeated measures ANOVA and the Tukey HSD test. The Fisher exact test verified failure modes (α=0.05). RESULTS: As multipeak LCU battery levels decreased, emitted irradiance also diminished, with notable PBS reductions in the apical thirds. Failure modes were influenced by different conditions, primarily exhibiting mixed modes. Battery levels significantly impacted DC in the multipeak LCU, particularly in the cervical region, while the single-peak LCU exhibited DC reduction at the 10% battery level in the cervical region. CONCLUSIONS: Emitted irradiance, resin cement DC, and glass fiber post bond strength to root dentin may be influenced by varying cordless LCUs and battery levels.
Assuntos
Lâmpadas de Polimerização Dentária , Vidro , Técnica para Retentor Intrarradicular , Cimentos de Resina , Cimentos de Resina/química , Bovinos , Técnica para Retentor Intrarradicular/instrumentação , Animais , Teste de Materiais , Microscopia Eletrônica de Varredura , Colagem Dentária/métodos , Análise do Estresse Dentário , Cura Luminosa de Adesivos Dentários/métodos , Técnicas In Vitro , DentinaRESUMO
AIM: To investigate ex vivo the influence of gamma irradiation therapy and restorative material on fracture resistance, fracture mode and strain of root filled human premolars. METHODOLOGY: Sixty extracted human maxillary premolar teeth were randomly divided into six groups (n = 10) determined by two study factors: (i) restorative materials: sound teeth, root filled teeth restored with composite resin, root filled teeth restored with amalgam; (ii) gamma irradiation: irradiated (subjected to 60 Gy of gamma irradiation in daily increments of 2 Gy) and nonirradiated. For the strain gauge test, two strain gauges per sample were attached on the buccal and palatal cusp surfaces (n = 5). Strain values were recorded during loading of 0-150 N. Fracture resistance (N) was assessed in a mechanical testing machine (n = 10). Strain gauge for each cusp and fracture resistance data were analysed by two-way anova (3 × 2) followed by the Tukey's honestly significant difference test (α = 0.05). The failure mode was evaluated using an optical stereomicroscope and classified according to the location of the failure. RESULTS: Gamma radiation therapy significantly reduced the fracture resistance of intact teeth. The strain was higher for teeth restored with amalgam than for those restored with composite resin. The teeth restored with composite resin had similar strain values to sound teeth. Nonirradiated teeth had more restorable failures than irradiated teeth. CONCLUSIONS: Gamma irradiation significantly reduced fracture resistance and increased cusp strain. The use of composite resin resulted in better biomechanical behaviour than amalgam for restoring root filled teeth whether or not they were submitted to radiotherapy.
Assuntos
Materiais Dentários/efeitos da radiação , Raios gama/efeitos adversos , Radioterapia/efeitos adversos , Tratamento do Canal Radicular , Fraturas dos Dentes/etiologia , Dente não Vital/complicações , Análise de Variância , Dente Pré-Molar/patologia , Dente Pré-Molar/efeitos da radiação , Fenômenos Biomecânicos , Estudos de Casos e Controles , Resinas Compostas/efeitos da radiação , Amálgama Dentário/efeitos da radiação , Falha de Restauração Dentária , Restauração Dentária Permanente , Análise do Estresse Dentário , Humanos , Maxila , Dosagem Radioterapêutica , Valores de Referência , Estatísticas não Paramétricas , Fraturas dos Dentes/patologiaRESUMO
AIM: To test the hypothesis that the presence of an anti-rotation device (ARD) and its location can influence the biomechanical behaviour of root filled teeth restored with cast post-and-cores and metallic crowns. METHODOLOGY: Fifth two bovine incisor roots were selected and divided into four groups (n = 13): Nd- without ARD; Bd- buccal ARD; Ld- lingual ARD; BLd- buccal and lingual ARD. The specimens were restored with cast post-and-cores and metallic crowns. After a fatigue process (3 x 10(5) 50 N), three strain gauges were attached on the buccal, lingual and proximal surfaces and the samples of each group (n = 3) were submitted to a 0-100 N load. Fracture resistance was assessed in a mechanical testing machine (n = 10). Strain values and fracture resistance data were analysed by one-way anova and Tukey Honestly Significant Difference (HSD) test (alpha = 0.05). The failure mode was then evaluated under an optical stereomicroscope. Bidimensional models of each group were generated for finite element analysis (FEA) and analysed using the von Mises criteria. RESULTS: No significant difference in fracture resistance values and fracture modes occurred between the four groups. The BLd group had higher stress concentrations in the buccal dentine and higher strain values on the proximal surfaces. CONCLUSIONS: The anti-rotation devices did not influence significantly the fracture resistance and fracture mode. However, the stress-strain values were increased when the anti-rotation device was prepared on the buccal and lingual faces concomitantly.
Assuntos
Análise do Estresse Dentário , Técnica para Retentor Intrarradicular/instrumentação , Dente não Vital/fisiopatologia , Animais , Fenômenos Biomecânicos , Bovinos , Coroas , Análise do Estresse Dentário/métodos , Análise de Elementos Finitos , Rotação , Fraturas dos Dentes/prevenção & controleRESUMO
The functional effect of the A>G transition at position 2756 on the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase), involved in folate metabolism, may be a risk factor for head and neck squamous cell carcinoma (HNSCC). The frequency of MTR A2756G (rs1805087) polymorphism was compared between HNSCC patients and individuals without history of neoplasias. The association of this polymorphism with clinical histopathological parameters was evaluated. A total of 705 individuals were included in the study. The polymerase chain reaction-restriction fragment length polymorphism technique was used to genotype the polymorphism. For statistical analysis, the chi-square test (univariate analysis) was used for comparisons between groups and multiple logistic regression (multivariate analysis) was used for interactions between the polymorphism and risk factors and clinical histopathological parameters. Using univariate analysis, the results did not show significant differences in allelic or genotypic distributions. Multivariable analysis showed that tobacco and alcohol consumption (P < 0.05), AG genotype (P = 0.019) and G allele (P = 0.028) may be predictors of the disease and a higher frequency of the G polymorphic allele was detected in men with HNSCC compared to male controls (P = 0.008). The analysis of polymorphism regarding clinical histopathological parameters did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. In conclusion, our data provide evidence that supports an association between the polymorphism and the risk of HNSCC.
Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/genética , Carcinoma de Células Escamosas/genética , Neoplasias de Cabeça e Pescoço/genética , Polimorfismo Genético/genética , Carcinoma de Células Escamosas/enzimologia , Estudos de Casos e Controles , Feminino , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Neoplasias de Cabeça e Pescoço/enzimologia , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Fatores de RiscoRESUMO
The functional effect of the A>G transition at position 2756 on the MTR gene (5-methyltetrahydrofolate-homocysteine methyltransferase), involved in folate metabolism, may be a risk factor for head and neck squamous cell carcinoma (HNSCC). The frequency of MTR A2756G (rs1805087) polymorphism was compared between HNSCC patients and individuals without history of neoplasias. The association of this polymorphism with clinical histopathological parameters was evaluated. A total of 705 individuals were included in the study. The polymerase chain reaction-restriction fragment length polymorphism technique was used to genotype the polymorphism. For statistical analysis, the chi-square test (univariate analysis) was used for comparisons between groups and multiple logistic regression (multivariate analysis) was used for interactions between the polymorphism and risk factors and clinical histopathological parameters. Using univariate analysis, the results did not show significant differences in allelic or genotypic distributions. Multivariable analysis showed that tobacco and alcohol consumption (P < 0.05), AG genotype (P = 0.019) and G allele (P = 0.028) may be predictors of the disease and a higher frequency of the G polymorphic allele was detected in men with HNSCC compared to male controls (P = 0.008). The analysis of polymorphism regarding clinical histopathological parameters did not show any association with the primary site, aggressiveness, lymph node involvement or extension of the tumor. In conclusion, our data provide evidence that supports an association between the polymorphism and the risk of HNSCC.
Assuntos
Feminino , Humanos , Masculino , Pessoa de Meia-Idade , /genética , Carcinoma de Células Escamosas/genética , Neoplasias de Cabeça e Pescoço/genética , Polimorfismo Genético/genética , Estudos de Casos e Controles , Carcinoma de Células Escamosas/enzimologia , Frequência do Gene , Predisposição Genética para Doença , Genótipo , Neoplasias de Cabeça e Pescoço/enzimologia , Reação em Cadeia da Polimerase , Polimorfismo de Fragmento de Restrição , Fatores de RiscoRESUMO
The authors report a confirmed case of hantavirus pulmonary syndrome in the rural area of the municipality of Anajatuba, state of Maranhão. Two other suspected cases from the same region are also described. The confirmed case involved a previously healthy young woman who died with signs and symptoms of acute respiratory insufficiency 5 days after presenting fever, myalgia and a dry cough. The patient was a student who was helping her parents with work in the fields; it was a habit of the family to store rice inside the house. The suspected cases involved two first-degree relatives working as field hands who died of acute respiratory insufficiency 24 and 48 hours, respectively, after presenting fever, myalgia and a dry cough. Both stored rice and corn inside their home. People living in the region reported massive infestations with rats in the woods and fields.
Assuntos
Síndrome Pulmonar por Hantavirus/diagnóstico , Adulto , Animais , Brasil , Evolução Fatal , Feminino , Humanos , Masculino , Ratos , População RuralAssuntos
Anemia Macrocítica/etiologia , Anemia Megaloblástica/etiologia , Difilobotríase/complicações , Enteropatias Parasitárias/complicações , Adolescente , Anemia Megaloblástica/tratamento farmacológico , Difilobotríase/tratamento farmacológico , Comportamento Alimentar , Humanos , Masculino , Niclosamida/uso terapêutico , Vitamina B 12/uso terapêuticoAssuntos
Arritmias Cardíacas , Doenças do Recém-Nascido , Arritmias Cardíacas/tratamento farmacológico , Arritmias Cardíacas/etiologia , Digoxina/uso terapêutico , Quimioterapia Combinada , Eletrocardiografia , Feminino , Frequência Cardíaca , Humanos , Recém-Nascido , Masculino , Propranolol/uso terapêuticoRESUMO
Os autores relatam a experiencia inicial no reconhecimento e manuseio de disritmias cardiacas diagnosticadas no bercario de um hospital geral. Apos discussao de possibilidades etiologicas, demonstraram a preponderancia de disritmias supraventriculares no grupo etario e o efeito terapeutico com o uso do esquema digoxina e/ou propranolol. A ocorrencia na serie analidada de dois casos de parassistolia atrial e realcada, levantando a questao da real frequencia desta rara disritmia no recem-nascido e seus aspectos evoluativos