NCJ Number
226546
Journal
Journal of Forensic Sciences Volume: 54 Issue: 2 Dated: March 2009 Pages: 263-266
Date Published
March 2009
Length
4 pages
Annotation
A new method was developed for characterizing postmortem crack propagation patterns in teeth.
Abstract
The study found that patterns of postmortem heat-induced crack propagation differed from perimortem and antemortem trauma-induced crack propagation patterns. Dental material of the postmortem tooth undergoes dehydration, which leads to a shrinking and more brittle dentin material and a weaker dentin-enamel junction. Dentin invertible tensile stresses are magnified by the presence of the pulp cavity, initiating crack propagation from the internal dentin through the dentin-enamel junction and lastly the enamel. In contrast, “in vivo” perimortem and antemortem trauma-induced crack propagation initiates cracking from the external surface of the enamel toward the dentin-enamel junction where the majority of the energy of the crack is dissipated, eliminating the crack’s progress into the dentin. These unique patterns of crack propagation can be used to distinguish postmortem taphonomy-induced damage from antemortem and perimortem trauma in teeth. A total of 36 permanent mandibular first, second, and third incisors and first premolars from fresh pigs aged 6 months were removed from the bone. The 36 teeth were separated into 3 groups, with a representative number of each tooth type in the 3 groups. The groups were each exposed to a temperature range of 41-49 degrees C for 9 hours each day for 14 days. Teeth were examined with a low-powered microscope at 3-hour intervals during their exposure to heat. Observations of the presence and propagation pattern of cracks were recorded. Microscopic methods are described. 1 table, 4 figures, and 17 references