br Discussion The aim of this study

Discussion The aim of this study was to establish staining protocols to enhance the visualization of a dental filling or its remaining in forensic dentistry. Teeth and dental materials resist to most of environmental and disaster conditions, therefore the forensic odontology exam is essential in the process of identification of victims. The evaluation of the teeth characteristics and of dental treatments, which are exclusive of a person, is one of the most effective procedures in the process of identification of one individual to the exclusion of others [16]. In disaster victim identification (DVI) scenarios, victims can be identified by three primary characteristics: dental status, fingerprints and DNA. Consequently, during postmortem examinations the cadaver will be inspected by a multidisciplinary team - fingerprint and DNA experts, police officers, pathologists, and odontologists [17,18]. The work of the forensic odontologist is to perform the postmortem oral examination and fill in the pink INTERPOL form for later match [19]. The work has to be done as fast and as precise as possible. The application of our protocols lasts 80 s, with possibility of staining the buccal and the occlusal surfaces of both arches concomitantly and in less than 3 min. Our protocols were designed to be easily applied and the substances effortlessly transported to different scenarios where the identification of the dead may be necessary. Some of these scenarios may not have appropriate conditions such as good illumination and dental X-ray equipment to help the clinical examination. These conditions may lead to mistakes when completing dental charts, and result in errors in identification of the deceased. Whilst it Fluorouracil is known that radiographs are important in forensic dentistry, a previous study [20] found that 40% of aesthetical restorations could not be detected on dental radiographs [12]. In addition, the practice of removing the jaws has been discouraged because the family has the rights to view the body and the absence of the jaws can be of psychological impact [16]. This emphasizes the importance of finding non- or less invasive adjunct methods to improve the forensic dental examination. Previously, the difference in fluorescence between the filling and the tooth under ultraviolet light has been suggested as an adjunct method [21,22]. However, the industry has tried to match their fluorescence, impairing the detection of the materials by ultraviolet lights [23]. Bux et al. [24] demonstrated that high quality aesthetic restorations may be overlooked even by an experienced dentist. The author suggested that phosphoric acid could be used to modify the optical properties of the tooth surface, by changing its ionic characteristic [24]. The interaction between tissues and dyes can be physical or chemical. In physical staining, the dye must be adsorbed on the surface of the tissue or precipitated within the tissue. In contrast, chemical interactions are more common in histology and imply a tissue-dye binding. Ionic bonding involves electrostatic attraction between opposite charges between the dye and the tissue [13]. The dyes proposed in this study require a chemical interaction, and since they are not embedded in the tissue, they can be removed. In fact, the removal of the staining can be performed with gauze and 70% ethanol. However, if the margins of the restoration are not adapted, the staining can remain. Therefore, it is recommended to apply any staining protocol after clearance from the pathologist in charge. The visualization of the composite fillings was improved when darker dyes were used. The choice between a luminescent or a conventional dye is strongly dependent on the nature and color of the substrate, with luminescent dyes being more sensitive to light and storage conditions compared to non-luminescent ones [25,26]. In our study, the use of non-luminescent dyes was preferred to avoid an extra concern with the staining solution storage, considering the diversity of scenarios the postmortem exams are usually done.