The color stability of direct denture reline resins / 대한치과보철학회지

STATEMENT OF PROBLEM: Direct denture reline resins tend to discolor during service in the oral environment by intrinsic and extrinsic factor. PURPOSE: This study was designed to evaluate the color stability of direct denture reline resins. MATERIAL AND METHODS: Mild Rebaron(GC Corp., Japan), Meta Base M(Sun medical Co., Japan), Mild Rebaron LC(GC Corp., Japan) and as a control group, Vertex SC(Dentimex Zeist, Holland) were chosen for this study. Ten specimens of each direct denture reline resins were fabricated. Treatment methods designed for this study were the coffee staining test(7days) and the accelerated aging test(100hours). The color changes before and after treatment were measured by Tristimulous colorimeter(Yasuda seiki seisakusho, Ltd. Japan) and analyzed. RESULTS: All the direct denture reline resins subjected to the coffee staining test and the accelerated aging test showed noticible difference in color change. After coffee staining test, Meta Base M showed the highest color change followed by Vertex SC, Mild Rebaron LC and Mild Rebaron. There were no statistical differences between Meta Base M and Vertex SC and between Mild Rebaron LC and Mild Rebaron(p>0.05). After accelerated aging test, Mild Rebaron LC showed the highest color change followed by Vertex SC, Meta Base M and Mild Rebaron. There were no statistical differences only between Mild Rebaron and Mata Base M(p>0.05) but among the others, there were statistical differences(p<0.05). CONCLUSION: Within the limitation of this study, all the direct denture reline resins subjected to the extrinsic and intrinsic factors showed noticible difference in color change, and there were differences among manufacturers.

Color stability of current prosthetic composites under accelerated aging and Immersion in a coffee solution / 대한치과보철학회지

The color stability of current prosthetic composites is unknown, even though the quality of com-posite materials has been improving. This study examined the intrinsic color stability of various current prosthetic resins (ceramic-polymers) after an accelerated aging process and the extrinsic color stability after immersion in a coffee solution. By comparing the amount of dis-coloration after aging with that without aging, the effect of the accelerated aging process on external discoloration could be evaluated. Three current prosthetic composites (Artglass, Targis, Sculpture), one light polymerized direct composite (Z100) and one dental porcelain control (Ceramco) were assessed. The col-or changes (delta E) of all the specimens were determined using the CIE L*a*b* color order system with a reflected spectrophotometer. The results were as follows: 1. The prosthetic composite materials subjected to the accelerated aging test showed no sig-nificant difference in color changes (p> .05). 2. In the coffee solution immersion test after the aging process, the color changes of the Targis and Artglass groups were not different from that of the Z100 group, which showed the highest color change. 3. In the immersion only test, a significantly high color change was observed in the sculpture glazing group. 4. The aging process influenced on the color changes more in the Targis, Artglass and Z100 groups than in the Sculpture and Ceramco groups.