Heat Induced Changes to Dental Resin Composites: A Reference in Forensic Investigations?

• NCJ Number: 219260
• Journal: Journal of Forensic Sciences Volume: 52 Issue: 4 Dated: July 2007 Pages: 913-919
• Author(s): Renata B. Brandao M.Sc.; Carmen C.S. Martin Ph.D.; Alma B.C.E.B. Catirse Ph.D.; Marcio de Castro e Silva Ph.D.; Martin P. Evison Ph.D.; Marco A. Guimaraes M.D., Ph.D.
• Date Published: July 2007
• Length: 7 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

This study examined color change and surface damage in two dental resin composites--the materials most often used for aesthetic dental restorations--that were exposed to high temperatures over different time intervals.

Abstract

The composite resins underwent a two-phase pattern of color and brightness change compared to the original characteristics, initially becoming darker and then lighter when temperatures and exposure times increased. The two-phase pattern began and developed at different rates for different resins. For forensic purposes, brightness was a more reliable feature than color in examining the heat-induced changes to composite resins. The hybrid resin Z100 (R1) presented more intense color and brightness changes, but showed less intense superficial damage than the microhybrid resin Charisma (R2), which reached melting point first. Procedures for investigating burnt human remains should contain protocols for the recovery and careful handling of fragile and fragmented dental materials. Other standardized investigation of temperature and time exposure for dental restorative materials will provide additional findings relevant to comparative forensic applications. Samples were prepared using two resins: Z100 (R1) and Charisma (R2). These were selected for testing because they are commonly used, are significantly different in composition, have been reported on in other scientific publications and databases, and offer a foundation upon which comparative analysis of other resins can be based. A total of 208 cylindrical samples (104 of each resin) were prepared for the experiment. They were heated at the following temperatures: 200 degrees centigrade (C), 400 degrees C, 600 degrees C, and 1000 degrees C for 15, 30, and 45 minutes. Color and brightness changes were analyzed by spectrophotometry, and surface changes were identified by scanning electron microscopy. 2 tables, 4 figures, and 29 references