Comprehensive Study on Color Changes of Glass-ionomer Cement Family Dental Materials

2003 Fiscal Year Final Research Report Summary

• Project/Area Number: 14571820
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Conservative dentistry
• Research Institution: Iwate Medical University
• Principal Investigator: KAWASHIMA Toshihiro Iwate Medical University, School of Dentistry, Instructor, 歯学部, 助手 (80204717)
• Co-Investigator(Kenkyū-buntansha): KUBOTA Minoru Iwate Medical University, School of Dentistry, Professor, 歯学部, 教授 (10005100)
• Project Period (FY): 2002 – 2003
• Keywords: glass ionomer cement / color / color difference / water sorption / rheometer / electrical resistance / dental material

Research Abstract

The color change of the glass ionomer cement Is time-dependent. However, there were few research reported the mechanism of the color change of the glass ionomer cement. The purpose of this study was to Investigate the physicochemical changes of glass ionomer cement concerning color change. The period of this study was divided into 3 groups; an hour, a month and a year. There was no relevance between the color change and the value of amplitude by means of rheometer in an hour. Then, the amount of change of color difference between every minute was calculated from the values of CIEIAB system. This study indicated the possibility of the relevance between amount of change of color difference and value of the amplitude. There was the high correlation between color change and change of amount of water sorption of the glass ionomer cement in a month. There was hardly the color change In a year from a month, also there was hardly the change of amount of water sorption of the cement. However, it seemed to have to pass through over about 6 months to become stable of the color.Though the resin modified glass ionomer cement used for the comparison showed the slight color change during 1 month, there was hardly the color change for 1 year. However, amount of water sorption of the resin modified glass ionomer cement was larger than other materials used in this study, and It was about 5% as a weight ratio for 1 year. In case of the resin modified glass ionomer cement, there was no relevance between color change and amount of water sorption. In the composite resin used as a control, the color change and the amount of water sorption were smaller than glass ionomer cement.