RESUMO
AIM: To investigate the effects of combinations of several irrigants on the roughness and wettability of dentine, adhesion of Enterococcus faecalis and Candida albicans and adsorption of chlorhexidine (CHX) to the dentine. METHODOLOGY: Bovine dentine samples were prepared and their surface roughness standardized. The samples were distributed in groups (n = 10) and subjected to one of the following irrigation protocols: G1 - saline solution; G2 - sodium hypochlorite (NaOCl); G3 - NaOCl + ethylenediaminetetraacetic acid (EDTA); G4 - NaOCl + peracetic acid (PAA); G5 - NaOCl + 1-hydroxyethylidene-1,1-diphosphonic acid (HEDP); G6 - NaOCl + EDTA + CHX; G7 - NaOCl + PAA + CHX; G8 - NaOCl + HEDP + CHX; and G9 - mixture of NaOCl + HEDP. After treatments, roughness and wettability were measured. In order to evaluate the adhesion of microorganisms to dentine, new dentine samples were prepared and after 2 h of contact with the microorganisms, were analysed using a confocal laser scanning microscope and the number of microorganisms adhering to the surfaces were determined. Absorption spectra were collected by attenuated total reflectance of Fourier-transform infrared spectroscopy before and after immersion of other dentine samples in each solution of G6, G7 and G8 and in a solution of 2% CHX at various time intervals. The areas of the band associated with CHX with the peak at 1492 cm-1 were calculated between 1479 and 1500 cm-1 of the spectral range. The data obtained in all experiments were subjected to one-way ANOVA (α < 0.05). The values of the CHX band were also subjected to one-way repeated measures ANOVA (α < 0.05). RESULTS: Saline solution, NaOCl, HEDP and CHX did not alter the roughness of the dentine (P > 0.05), whilst EDTA and PAA did (P < 0.05). Dentine surface wettability increased after the use of all irrigants compared to saline solution (P < 0.05), with HEDP causing the greatest increases (P < 0.05). The adhesion of E. faecalis was favoured on surfaces treated with only saline solution and NaOCl, and on samples that had decalcifying agents as the final irrigant (P < 0.05). The adhesion of C. albicans was highest on surfaces treated with only saline solution and on surfaces that had NaOCl used as the last irrigant (P < 0.05). The use of CHX as a final irrigant reduced the adhesion of both microorganisms. The roughness and wettability did not influence the adhesion of the microorganisms tested. The adsorption of CHX to the dentine was significant after 1 min of immersion of the mineralized samples in the irrigant (P < 0.05), and the use of chelating agents prior to CHX potentiated this adsorption. CONCLUSIONS: The irrigation solutions had a variable effect on the properties of dentine, on the adhesion of E. faecalis and C. albicans and the adsorption of CHX to the dentine surface.
Assuntos
Aderência Bacteriana/efeitos dos fármacos , Clorexidina/farmacologia , Dentina/efeitos dos fármacos , Dentina/microbiologia , Dentina/patologia , Irrigantes do Canal Radicular/farmacologia , Adsorção/efeitos dos fármacos , Animais , Candida albicans/efeitos dos fármacos , Bovinos , Quelantes/farmacologia , Ácido Edético/farmacologia , Enterococcus faecalis/efeitos dos fármacos , Ácido Etidrônico/farmacologia , Teste de Materiais , Ácido Peracético/farmacologia , Hipoclorito de Sódio/farmacologia , Propriedades de Superfície/efeitos dos fármacosRESUMO
AIM: To evaluate mineral trioxide aggregate (MTA), Biodentine and several formulations of calcium aluminate cements (CACb) in terms of their ability to release calcium ions (Ca2+ ) and form apatite-like precipitates after short-term immersion in phosphate-buffered saline (PBS) and its influence on the bond strength to the root-end cavity. METHODOLOGY: Ten samples of MTA, Biodentine, CACb and calcium-enriched aluminate cement (CACb+) were placed in contact with PBS or deionized water for 14 days. The cement surfaces were analysed using SEM, EDS-X and FTIR. Eighty standardized root-end cavities filled with the cements (ten samples of each cement) were immersed in PBS or deionized water for 14 days, and the bond strengths were measured. Data from the push-out test were analysed using two-way ANOVA and Tukey's tests (α = 0.05). RESULTS: A gradual decrease was observed in Ca2+ concentrations and pH of all solutions. FTIR bands of different phases of hydroxyapatite were identified. Crystalline formation was observed on the surface of all cements after immersion in PBS. No significant difference was observed in the bond strength of the test materials (P > 0.05); however, all cements without contact with the solution revealed significantly lower bond strength values than those in contact with the solution (P < 0.05). CONCLUSION: MTA, Biodentine, CACb e CACb+ were associated with precipitation of crystals after being in contact with PBS for 14 days, indicated by different phases of hydroxyapatite crystalline formation, which also increased dislodgment resistance of the material from root-end cavities. The CACb+ had similar bond strengths and precipitation of crystals to existing materials.
Assuntos
Compostos de Alumínio/química , Compostos de Cálcio/química , Colagem Dentária , Cimentos Dentários/química , Óxidos/química , Silicatos/química , Análise do Estresse Dentário , Dentina , Combinação de Medicamentos , Humanos , Teste de Materiais , Raiz DentáriaRESUMO
AIM: To investigate the effects of several decalcifying agents alone and in combination with sodium hypochlorite (NaOCl) on the organic and inorganic components of dentine using attenuated total reflectance in Fourier transform infrared spectroscopy (ATR-FTIR). METHODOLOGY: Dentine slices from bovine teeth were submitted to (n = 5) the following: 0.9% saline, 9% and 18% etidronic acid (HEDP), 5% and 10% tetrasodium EDTA (EDTANa4 ), 17% trisodium EDTA (EDTAHNa3 ), and 0.5% and 2.0% peracetic acid (PAA) for 0.5-10 min; and to the combinations: G1 - mixture 5% NaOCl + 18% HEDP (5 and 10 min); G2 - mixture 5% NaOCl + 10% EDTANa4 (5 and 10 min); G2 - 2.5% NaOCl (5 min) + 17% EDTAHNa3 (1 min); G3 - 2.5% NaOCl (5 min) + 0.5% PAA (1 min); G4 - 2.5% NaOCl (5 min) + 9% HEDP (5 min). Specimens of G2, G3 and G4 received final flushes with 2.5% NaOCl for 0.5-10 min. Amide III/phosphate and carbonate/phosphate ratios of the spectra collected from the dentine specimens before and after immersion in the solutions were determined. Data were submitted to one-way repeated measures and one-way anova. RESULTS: For the same decalcifying agent, the higher the concentration and immersion time the greater the removal of phosphate, exposure of collagen matrix and consequently the increases in amide III/phosphate ratio. However, significant differences were found only between the two concentrations of PAA (P < 0.05). PAA caused greater increases in this ratio, followed by EDTAHNa3 , EDTANa4 and HEDP, and this order was retained in the combinations with NaOCl. This ratio was significantly reduced in G1 (P < 0.05) and not altered in G2 (P > 0.05). Due to collagen degradation, the amide III/phosphate ratio reduced significantly after the use of NaOCl in G3, G4 and G5 (P < 0.05). NaOCl required approximately 0.5 s to deproteinate the collagen matrix exposed after phosphate removal by EDTAHNa3 and PAA. The carbonate of dentine was removed more rapidly than phosphate by all decalcifying agents alone and in G3, G4 and G5. In the combinations with NaOCl, the last irrigant used defined the dentine amide III/phosphate and carbonate/phosphate ratios. CONCLUSIONS: HEDP and EDTANa4 caused minor whilst EDTAHNa3 and PAA caused greater demineralization of dentine; both effects were time and concentration dependent. NaOCl degraded the dentine organic matrix more rapidly when it was exposed. Combinations of NaOCl and decalcifying agents can be used to create dentine surfaces with varying compositions for interaction with endodontic sealers.
Assuntos
Dentina/química , Irrigantes do Canal Radicular/farmacologia , Hipoclorito de Sódio/farmacologia , Animais , Bovinos , Dentina/efeitos dos fármacos , Espectroscopia de Infravermelho com Transformada de Fourier , Desmineralização do Dente/induzido quimicamenteRESUMO
This study surveyed the mitochondrial haplotype diversity of nine freshwater fish species and two estuarine-marine species from the coastal basins and drainages of the highland plateaus of Paraná, Brazil. Portions of the cytochrome b gene or the control region were sequenced. The demographic history of each species was inferred using the Bayesian skyline method, mismatch distribution analysis and statistical neutrality tests. Demographic reconstruction analyses revealed a single pattern of variation in the effective population size (Ne ) among species. No dramatic changes in Ne were detected in upland species. By contrast, evidence of population expansion over the past 200 000 years was detected in all coastal plain and estuarine species. These findings correspond to periods of low sea-level (regressions) followed by a rapid increase in the sea-level by >100 m. The resulting reconnections and subsequent fragmentation and isolation between the estuarine and freshwater bodies were putatively relevant to the historical demography of the fish species in these areas.
Assuntos
Estuários , Peixes/genética , Variação Genética , Filogeografia , Animais , Oceano Atlântico , Sequência de Bases , Teorema de Bayes , Brasil , Citocromos b/genética , DNA Mitocondrial/genética , Água Doce , Haplótipos , Dinâmica PopulacionalRESUMO
The aim of this study is to evaluate the temperature change on specimens of primary enamel irradiated with different pulse duration of Nd:YAG laser. Fifteen sound primary molars were sectioned mesiodistally, resulting in 30 specimens (3.5 × 3.5 × 2.0 mm). Two small holes were made on the dentin surface in which K-type thermocouples were installed to evaluate thermal changes. Specimens were randomly assigned in 3 groups (n = 10): A = EL (extra long pulse, 10.000 µs), B = LP (long pulse, 700 µs), and C = SP (short pulse, 350 µs). Nd:YAG laser (λ = 1.064 µm) was applied at contact mode (10 Hz, 0.8 W, 80 mJ) and energy density of 0.637 mJ/mm(2). Analysis of variance (ANOVA) was performed for the statistical analysis (P = 0.46). Nd:YAG laser pulse duration provided no difference on the temperature changes on primary enamel, in which the following means were observed: A = EL (23.15°C ± 7.75), B = LP (27.33°C ± 11.32), and C = SP (26.91°C ± 12.85). It can be concluded that the duration of the laser pulse Nd:YAG increased the temperature of the primary enamel but was not influenced by different pulse durations used in the irradiation.
Assuntos
Esmalte Dentário/fisiologia , Lasers de Estado Sólido , Temperatura , Humanos , Lasers de Estado Sólido/normas , Fatores de TempoRESUMO
Expanded access to antiretroviral therapy (ART) offers opportunities to strengthen HIV prevention in resource-limited settings. We invited 27 ART programmes from urban settings in Africa, Asia and South America to participate in a survey, with the aim to examine what preventive services had been integrated in ART programmes. Twenty-two programmes participated; eight (36%) from South Africa, two from Brazil, two from Zambia and one each from Argentina, India, Thailand, Botswana, Ivory Coast, Malawi, Morocco, Uganda and Zimbabwe and one occupational programme of a brewery company included five countries (Nigeria, Republic of Congo, Democratic Republic of Congo, Rwanda and Burundi). Twenty-one sites (96%) provided health education and social support, and 18 (82%) provided HIV testing and counselling. All sites encouraged disclosure of HIV infection to spouses and partners, but only 11 (50%) had a protocol for partner notification. Twenty-one sites (96%) supplied male condoms, seven (32%) female condoms and 20 (91%) provided prophylactic ART for the prevention of mother-to child transmission. Seven sites (33%) regularly screened for sexually transmitted infections (STI). Twelve sites (55%) were involved in activities aimed at women or adolescents, and 10 sites (46%) in activities aimed at serodiscordant couples. Stigma and discrimination, gender roles and funding constraints were perceived as the main obstacles to effective prevention in ART programmes. We conclude that preventive services in ART programmes in lower income countries focus on health education and the provision of social support and male condoms. Strategies that might be equally or more important in this setting, including partner notification, prompt diagnosis and treatment of STI and reduction of stigma in the community, have not been implemented widely.