Forenzic significance of composite restorations radiopacity: Assessment by dental students

In order to forensic use, dental materials should be sufficiently radiopaque to be detected against enamel/dentin, resulting in correct evaluation of restorations contours, detection of secondary caries, marginal defects, etc. Radiopacity of contemporary composites has been improved by inserting of filler-particles containing heavy metals: aluminum, barium, strontium, zirconium, ytterbium. Tetric composite group (Te-econom, Ceram, EvoCeram) has the most suitable radiopacity; T-econom has highest radiopacity (4.78mm aluminum when exposure-0.6'). The aim of this study was to comparison of MOD composite restorations (T-Econom, Ivoclar, Vivadent) radiographs in molar models and to assess their role in forensic identification, by dental students. Two sets of identical radiographs of molars models (that were previously filled with cement base and composite) were made by standardized technique (exposure-time 0.2ms, amperage-10mA, voltage-70kV). One of the sets consists a few radiographs that did not have their pairs in the second set. Equality of composite restorations on the 'ante-mortem' and 'post-mortem' radiographs were assessed by dental students. Statistical analysis was performed using the kappa test. Results showed (k.t.=0.82) that there is a high correlation of correct answers although estimates are made by students who have no experience in forensic identification and forensic evidence, neither enough knowledge in dental radiology. Although the forensic identification should not be based only on the appearance of the one restoration, or the assessment of non-professional forensic scientists, this study indicates that radiopacity of composites may have a major forensic importance, because 'ante-mortem' and 'post-mortem' radiographs were showed exactly match certain morphological characteristics of composite restorations.