Influence of radiopaque fillers on physicochemical properties of a model epoxy resin-based root canal sealer

Objective: To verify the influence of radiopaque fillers on an epoxy resin-based sealer. Material and Methods: Experimental sealers were formulated by adding 20%, 40%, 60%, 80%, 100% and 120% of calcium tungstate, ytterbium trifluoride or barium sulphate by weight to an epoxy-resin-base. Setting time, flow, film thickness, radiopacity, sorption, solubility, pH and push-out bond strength were evaluated. Results: The setting time ranged from 373 to 612.66 min, the flow varied from 13.81±0.49 to 22.49±0.37 mm, and the film thickness ranged from 16.67±5.77 to 33.33±11.54 µm. The lowest pH was 5.47±0.53, and the highest was 6.99±0.03. Radiopacity varied from 0.38±0.04 to 2.57±0.21 mmAl and increased with the amount of filler. Calcium tungstate sealers had a higher sorption and solubility than other sealers. There was no significant difference in the push-out bond strength among the fillers at the 120% concentration. CONCLUSION: The inorganic fillers evaluated and their concentrations affect the physicochemical properties of an epoxy resin-based root canal sealer. .

Hardness evaluation of prosthetic silicones containing opacifiers following chemical disinfection and accelerated aging

We evaluated the effects of disinfection and aging on the hardness of silicones containing opacifiers and intended for use in facial prosthetics. A total of 90 samples were produced using a cylindrical metal mold 3 mm in height and 30 mm in diameter. The samples were fabricated from Silastic MDX 4-4210 silicone in three groups: GI contained no opacifier, GII contained barium sulfate (Ba), and GIII contained titanium dioxide (Ti). The samples were disinfected using effervescent tablets (Ef), neutral soap (Ns), or 4 percent chlorhexidine (Cl) 3 times a week for 60 days. After this period the samples underwent 1,008 hours of accelerated aging. The hardness was measured using a durometer immediately following the disinfection period and after 252, 504, and 1,008 hours of aging. The data were statistically analyzed using 3-way ANOVA and the Tukey test (p < .05). The GIII group exhibited the greatest variation in hardness regardless of elapsed time. All groups displayed greater hardness after 1,008 hours of accelerated aging independent of disinfectant type. All of the hardness values were within the clinically acceptable range.

Viscosities reproductive patterns for use in videofluoroscopy and rehabilitation therapy of dysphagic patients / Padrões reprodutíveis de viscosidade para uso em videofluoroscopia e na terapia de reabilitação de pacientes disfágicos

BACKGROUND: Usually the suitable consistence identified and indicated as safe by videofluoroscopic method has been empirically obtained by association of barium sulfate solution with meals. However, it has been evidenced to be very difficult to reproduce this consistence in nutritional rehabilitation therapy from subjective information. AIM: To build two reproductive similar crescent viscosities series of solutions, with and without barium sulfate, to be used, the first, as radiological contrasted mean and the second, as base to reproduce the defined safer consistence, in the oral diet rehabilitation of dysphagic patients. METHODS: Two viscosity solutions series were obtained from starch and distilled water with and without 100 percent barium sulfate solution. The viscosity levels were defined step by step with digital viscosimeter (Brookfield, model LVTD-II) and with infrared thermometer Icel TD - 960. The fluids viscosity was register in centipoises, with their inferior and superior values followed by complimentary information about spindle kind, rotation speed and temperature. RESULTS: The two series of solutions, with and without barium sulfate, could be defined as aqueous (>1-143,5 cP), fine liquid (428 - 551 cP), thick liquid (4.284 -7.346,5 cP)), pasty (7.346,4 - 13.035 cP), pasty thick (19.260 - 34.320 cP) and creamy (163.500 - 255.300 cP). CONCLUSION: The study could offer reproductive formulas, with and without contrast mean, to be follow for obtaining the desirable viscosity to be used, each of them, in radiological evaluation and in nutritional diet minimizing the gaps fails between evaluation and therapy.

RACIONAL: Com freqüência, a consistência identificada e indicada pelo exame videofluoroscópico como segura, para uso nos pacientes disfágicos, tem sido empiricamente produzida pela mistura de alimentos com a solução de sulfato de bário. É expressiva a dificuldade observada quando se busca reproduzir esta consistência, subjetivamente indicada, para usá-la na terapia de reabilitação. OBJETIVO: Construir duas series de soluções, com valores reprodutíveis de viscosidade, uma com e outra sem a adição de sulfato de bário, a serem utilizadas a primeira, como meio de contraste radiológico, e a segunda, como base para reprodução da consistência definida como segura na reabilitação do paciente disfágico. MÉTODOS: As duas séries com viscosidades padrão foram buscadas com uso de amido, água destilada e solução de sulfato de bário a 100 por cento. Os níveis de viscosidade foram definidos passo à passo com o uso de um viscosímetro digital (Brookfield, model LVTD-II) e um termômetro de infravermelho Icel TD-960. As viscosidades foram registradas em centipoise (cP) e os limites superior e inferior de cada nível foi complementado pela informação do tipo e velocidade do "spindle" necessário e da temperatura da solução. RESULTADOS: As duas series de soluções, com e sem sulfato de bário, puderam ser definidas como aquosa (>1-143,5 cP), líquido fino (428-551 cp), liquido espesso (4.284-7.346,5 cp), pastosa (7.346,4-13.035 cP), pastosa espessa (19.260-34.320 cP) e cremosa (163.500-255.300 cP). CONCLUSÕES: Podem-se oferecer fórmulas com viscosidades reprodutíveis, com e sem adição de meio de contraste, a serem utilizadas, cada uma delas, na avaliação radiológica e na terapia nutricional, minimizando as falhas de reprodução entre a avaliação e a terapia.