OBJECTIVE To test the null hypothesis that there is no color change when enamel porcelain thickness is changed and to evaluate the ability of a shade guide to prescribe chroma. METHODS Three shades (3M1, 3M2 and 3M3) were selected from a Vitapan 3D master shade guide. Five disk specimens were prepared for each shade, consisting of three layers (opacious dentin, dentin and enamel) at thickness...

To investigate the influence of post length and amount of remaining root tissue on the fracture resistance of roots restored with fibre posts relined with resin composite. Ninety upper canine teeth were divided into nine groups (n = 10). The post spaces were prepared resulting in different lengths, as follows: group 2/3, preparations with lengths of 10 mm; group 1/2, preparations with lengths o...

objective: selection of an appropriate shade of composite is critical in achieving an esthetic restoration. different systems are used to assess and describe color parameters. this study aimed to assess the effect of color and thickness of filtek supreme (fs) and premise (p) composite resins on correction of tooth discoloration.   methods: in this in vitro experimental study, 10 anterior teeth ...

OBJECTIVES This study evaluated the effect of errors commonly made in using total-etch adhesives, on the resulting bond strength, fluid movement and nanoleakage of resin dentin bonds. METHODS Two total-etch adhesives were used for bonding to dentin according to the manufacturers' recommendations, with meticulous solvent evaporation (control), or with the introduction of common bonding errors-...

this research investigates the effect of the post-cure time on the residual stresses in laminated composites. laminated composites were made of t300 carbon fibers and epoxy resin. the post-cure process was carried out at the constant temperature of 120 °c for 6 and 12 hours for two specimens. the slitting method was employed to determine through-thickness residual stress distribution of the com...

The aim of this study was to determine the effect of different ceramic thickness on heat generation during resin cement photo-activation by QTH (quartz-tungsten-halogen), LED (light emitting diode), and PAC (plasma arc-curing) LCUs (light curing units). The resin cement used was Rely X ARC (3M-ESPE), and the ceramic was IPS Empress Esthetic (Ivoclar-Vivadent), of which 0.7-, 1.4- and 2.0-mm thi...

Piezoelectric properties of three sol-gel derived Pb Zr0.53Ti0.47 O3 thin film specimens of different thicknesses integrated onto Pt/Ti/SiO2 Si substrates are investigated to delineate the influence of residual stress on the strain-field response characteristics from other thickness related effects. Residual tensile stresses are determined from wafer curvature measurements for films ranging in ...