Crowns, Composite Resin And Ceramics Color Associated Performance Study

Color determination of natural and artificial teeth by the practicing dentist is of everyday importance, but it is difficult. Based on the previous investigation of teeth color, the present study designed and produced 72 color cards, of which were controlled by a HITACHI 307 Spetrocolorimeter, according to the characteristic of Chinese teeth crown and precision of human eyes. 690 natural maxillary anterior teeth of 115 men and womem were measured. Data included the frequencies of CIE 1976 L" a" b" color system readings in nature and their distribution in the color space; effects of site on the teeth; and age and sex demographics.56 colors of 10 brand of the representative anterior composite resins were selected to test from home and abroad. Colorimetric evaluation on these composite resins were made and the influence of the VLC-1 resin thinkness and background to their surface color were described using infinite optical thickness(IOP) which is a concept evaluating composite resin translucency.42 anterior restorative resins were chosen to test the change in color under two conditions :kept a year and half without light, and irradiated with sun light and ultraviolet rays. The factors of effecting the hiding ability of composite resin opaque were evaluated by color difference which was measured with white and black background. Three types of light-cured opaque materials were developed base on the result. Studies on the properties and mechanisms of their ability bonding to human enamel in vitro and two kinds of dental casting alloys were carried out. clinical practice of color dealing method on restoration of discolor teeth was summed up though above experiences.The color change of two kinds of porcelain restoration VITA and KC-1 which was developed by both Baoji Nonferrous Metal Institute and our department were compared due to repeated firings. The effects of superficial colorant, glaze, and autoglaze on the surface texture were evaluated by SEM.The optical properties and translucency of American product DICOR and LIKO which was...