Gravimetric and spectrophotometric analysis of water sorption in composite restoratives

Forty samples of two composite resin restoratives were prepared to study the water sorption using gravimetric and Spectrophotometric methods. Arco-Dent composite showed significant water sorption value either by weight or volumetric methods. Quayle Dental composite showed insignificant water sorption. The water sorption values and rate of Arco Dent had a direct relation to the time of immersion till the equilibrium state. The recent volumetric as well as the gravimetric methods are valid and give nearly comparable results. The authors advice using double beam Spectrophotometric to study volumetric changes of the materials as a function of water sorption as it is a recent and an accurate method

comparative study on the shear bond strength of some resinous dentin adhesives

The shear bond strength between composite and dentine after using adhesive of different modes of actions was evaluated in this study. Freshly extracted sound human molars were selected, embedded in steel rings using improved dental stone. The buccal surfaces of 180 specimen were cut to expose dentine using a milling machine. The denuded dentine surface were either untreated or treated by EDTA or ferric oxalate. Two different adhesive systems bonding either to the organic or inorganic portions of dentine were used. A combination of both the organic and inorganic dentine adhesive was also used. A light cured composite resin was placed on the treated dentine surface by a teflon ring. The specimen were divided into nine equal groups and tested for shear bond strength using a universal testing machine. The results revealed that the highest mean shear bond strength scores were obtained with the use of the combination of dentine adhesive followed by the adhesive bonding to the organic component of dentine. Furthermore, the use of EDTA for the surface treatment of dentine was found to greatly improve the shear bond strength values of the dentine bonding agents to dentine surface

Scanning electron microscopic study of argon laser-induced morphologic changes on human dental enamel and dentin

Thirty two human posterior teeth were used in this study to investigate the effect of pulsed Argon laser of different densities [40, 50 and 60 J/ cm[2]] on the surface topography of human enamel and dentin. The S.E.M. results showed apparent alterations on the surface topography of both tissues. Increasing the energy density from 40 to 60 J/Cm [2] showed worse, and destructive changes. Moreover, the effect of Argon laser on dentin was more pronounced when compared with that of enamel irrespective of the energy dentisty used

Durability of cermet ionomer cement conditioned in different media

The glass ionomer cement has exhibited significant adhesion to hard tooth structures and good cariostatic properties. The sintering of the silver alloy powder and glass ionomer cement "cermet cement" has provided additional improvement in the physical properties of the restorative material. These were flexural resistance, wear resistance, increased radio-opacity, hardness, and porosity. The improvement in the physical properties of the cermet glass cements has provided an extension in their clinical use as core build up, lining for inlays, amalgam and composite restorative, fissure filling, restoration of primary teeth, class II tunnel preparation, treatment of root caries and repair of defective metal margins in crown and inlays