Micrometric measurements by scanning electron microscope (SEM) for dental age estimation in adults.

Determining age from dental structure is a well documented forensic procedure and the data may be used as auxiliary information in identification. In this study 20 measurements of different variables in incisor teeth were obtained using a SEM micrometric scaler and the results were stastically correlated with age by the multiple regression method. A formula was then derived from the calculations for age estimation which gave statistically acceptable results. Gender differences were also investigated and when separated delivered even stronger correlation.

Corrosion behaviour of dental metals and alloys in different media.

The corrosion tendencies of metals are related with their position in the electromotive series. These electrode potential degrees may change due to the compositions of the alloys, the surrounding media, or due to alterations in the composition because of recurrent casting. Therefore in this research, the electrode potentials and their changes over a period of time were measured in different pH media simulating the oral electrochemical conditions in vitro. The surface structure of the first and second castings of 29 different dental metals and alloys were examined under a scanning electron microscope and their composition in percentage weight was calculated by the Energy-dispersive X-ray Analysor system. Further the current-potential curves of the dental alloys were found by the potentiodynamic method in three different solutions and, in addition, the changes of corrosion potentials over time were also determined. The corrosion rates, corrosion potentials, their changes over time and their cathodic Tafel slopes were determined. All alloys tested showed ion leakage in corrosive media. Titanium exhibited the least, but alloys with tin and cobalt content displayed the greatest corrosion tendencies. Alloys with iron and copper corroded in the acid media, conversely alloys containing chromium, nichel and molybdenum proved to be resistant to corrosion. The recurrent castings were also corrosion resistant.

Human dentinal structure as an indicator of age.

Odontological data can constitute essential evidence for age estimation in forensic work. In this research the structural differentiation of dentine was correlated with chronological aging after SEM and EDXA examinations were performed on extracted human teeth ranging in ages between 25 and 74 years. EDXA showed that the spherical structures within the dentine observed were comprised of calcium phosphate. They were then counted and their state of fusion noted and the statistical "Z" test applied to the different age groups. The results demonstrated a correlation between the fusion of calcospherites and age in all layers of the dentine.

Bitemarks in forensic odontology.

Person identification is important in criminology, and forensic odontologists are key personnel for identifying a highly individual dentition which could cause a bitemark and which could be used to convict or exculpate a suspect. Bitemarks may be observed in skin, wax, from a dental model indirectly from a photograph, a scanned image of a dental model or food. This paper shows that bitemarks constitute reliable evidence for person identification and that a tolerance of approximately 1mm existed between measurements of a wax bite, dental model, photograph and computer scanned image.