RESUMO
The aim of the present study was to evaluate the effect of composite resin contamination with powdered and unpowdered latex gloves on the shear bond strength of etch-and-rinse and two-step self-etch adhesive systems. Standard flat dentin surfaces were prepared on the facial aspect of 120 bovine incisors and randomly assigned into two (n=60) groups: group 1: Single Bond (SB), group 2: Clearfil SE Bond (CSE). Furthermore, each group was randomly subdivided into three (n=20) based on the type of composite contamination (without contamination, contamination with powdered latex gloves, and contamination with unpowdered latex gloves). The adhesives were applied and resin composite bonded to the dentin. After thermocycling, the specimens were subjected to a shear bond strength test. Two-way analysis of variance (ANOVA) and a post hoc Bonferroni test were used for statistical analysis. One-way ANOVA was used to compare shear bond strength values in each group. Statistical significance was set at p < 0.02. Two-way ANOVA showed that the shear bond strength was significantly influenced by the type of composite surface contamination (p=0.001). In the SB group there were no significant differences between different surface treatments (p=0.08). In the CSE group a significant difference was observed between the subgroup without contamination and the subgroup with powdered latex glove contamination (p=0.01); however, no significant differences were observed between the other subgroups.
Assuntos
Resinas Compostas/química , Colagem Dentária , Materiais Dentários/química , Dentina/ultraestrutura , Luvas Cirúrgicas , Látex/química , Amido/química , Condicionamento Ácido do Dente/métodos , Animais , Bis-Fenol A-Glicidil Metacrilato/química , Bovinos , Análise do Estresse Dentário/instrumentação , Adesivos Dentinários/química , Contaminação de Medicamentos , Ácidos Fosfóricos/química , Proteínas de Plantas/química , Pós , Distribuição Aleatória , Cimentos de Resina/química , Resistência ao Cisalhamento , Estresse Mecânico , Temperatura , Fatores de Tempo , Água/químicaRESUMO
A limitation in the use of hydrophilic polymers as implantable devices is their inherently poor mechanical strength. Using interpenetrating polymer networks (IPNs) consisting of both hydrophilic and hydrophobic networks is an effective method of strengthening these polymers. In this work, a series of poly(dimethyl siloxane) (PDMS)/poly(acrylic acid) (PAAc) sequential IPNs were synthesized and their properties, including swelling, morphology, and mechanical strength, were investigated. A reinforcing effect of the addition of PAAc to PDMS was observed at a concentration of 20 wt%, where this component had a bimodal size distribution. All of the IPNs exhibited rubbery behavior in the swollen state. Phase inversion in the IPNs occurred at about 60 wt% of PAAc. However, the swelling data showed that the phase inversion in the swollen state occurred at PAAc contents lower than those for dry IPNs. The improved cell behavior, reported in previous works for PDMS/PAAc IPNs with about 20 wt% PAAc, can, in addition to the increased surface wettability, be attributed to the bimodality of PAAc particles size distribution in the IPN.
Assuntos
Resinas Acrílicas/química , Dimetilpolisiloxanos/química , Fenômenos Mecânicos , Água/química , Acrilatos/química , Microscopia Eletrônica de Varredura , Estresse MecânicoRESUMO
We determined the carriage rate of Neisseria meningitidis before and after hajj pilgrimage among a group (1) of 674 randomly selected Iranian pilgrims, and the effect of 500 mg of ciprofloxacin given 24 hours before return on the reduction of meningococcal carriers among another group (2) of 123 randomly selected Iranian pilgrims. Throat specimens taken 1 hour before departure on the hajj and immediately on return were cultured. Carriage rates of N. meningitidis in group 1 were 5.2% before and 4.6% after pilgrimage (P = 0.65); 3 new serogroups (Z, Z and A) were identified on return. In group 2, the carriage rate decreased from 8.1% to zero before and after pilgrimage.
Assuntos
Anti-Infecciosos/uso terapêutico , Portador Sadio/epidemiologia , Ciprofloxacina/uso terapêutico , Islamismo , Infecções Meningocócicas/epidemiologia , Viagem , Portador Sadio/tratamento farmacológico , Portador Sadio/microbiologia , Distribuição de Qui-Quadrado , Feminino , Humanos , Irã (Geográfico)/epidemiologia , Masculino , Infecções Meningocócicas/tratamento farmacológico , Infecções Meningocócicas/etiologia , Pessoa de Meia-Idade , Neisseria meningitidis/classificação , Neisseria meningitidis/efeitos dos fármacos , Vigilância da População , Fatores de Risco , Arábia Saudita , Sorotipagem , Fatores de Tempo , Viagem/estatística & dados numéricos , Resultado do TratamentoRESUMO
We determined the carriage rate of Neisseria meningitidis before and after hajj pilgrimage among a group [1] of 674 randomly selected Iranian pilgrims, and the effect of 500 mg of ciprofloxacin given 24 hours before return on the reduction of meningococcal carriers among another group [2] of 123 randomly selected Iranian pilgrims. Throat specimens taken 1 hour before departure on the hajj and immediately on return were cultured. Carriage rates of N. meningitidis in group 1 were 5.2% before and 4.6% after pilgrimage [P = 0.65]; 3 new serogroups [Z, Z' and A] were identified on return. In group 2, the carriage rate decreased from 8.1% to zero before and after pilgrimage
