No abstract

No abstract

No abstract

No abstract

\10 6 Pa s − 1 ) for stresses B 20 Pa. Between 100 and SUMMARY Tooth bleaching materials need to flow easily on insertion but should have high viscosity at 200 Pa stress, all three materials showed a large low stresses to stay in place on the teeth. Some drop in viscosity and flowed readily. The recovery degree of elasticity may also aid retention on the portion of the data showed a marked difference teeth thereby maximizing efficacy. The present where the elasticity of the gels was nearly two work was undertaken to study the comparative orders of magnitude higher than that of the paste. rheology of three tooth bleaching systems: two gels It was concluded that all materials would flow readily on insertion into the mouth and all have (Opalescence ® , Ultradent; Perfecta Trio ® , American Dental Hygienics) and a paste (Colgate Platinum ® , desirable high viscosity at low stress, but the paste Colgate). A dynamic stress rheometer (Rheometrics material had the lowest elasticity. The effect of Scientific) with cone and plate geometry was used, elasticity on performance needs to be determined clinically. with the materials maintained at 37·0 90·1°C with a vapour hood to minimize volatilization. Stress creep and recovery experiments were carried out. KEYWORDS: bleach, carbamide peroxide, rheology, viscosity Steady shear viscosity for all three systems was high