On the forensic relevance of tattoos: distinguishing black inks with energy dispersive spectroscopy and backscattered scanning electron microscopy.

PURPOSE: This study aimed to analyze black tattoo inks by means of energy dispersive spectroscopy and backscattered scanning electron microscopy. METHODS: The sample consisted of five types of commercial tattoo pigments of the black colour (Easy Glow™, Electric Ink™, Iron Works™, Master Ink™, and Viper™). An Energy Dispersive Spectroscopy (EDS) detector (Silicon Drift Detector - SDD - type) attached to a Scanning Electron Microscope (SEM) device (Tescan Vega3 LMU, Libusina, Czech Republic) was used. X-ray characteristic signs were detected for each tattoo ink in an interval between 0 and 2.5 keV. The electron acceleration potential in the microscope was 15 keV. Two regions were analyzed for each sample (n = 10). On each region, a micrography of backscattered electrons (BSE) was obtained. Means and standard deviations (SD) of the weight percentages (Wt%) were calculated. RESULTS: C and O were predominant, with a mean O/C ratio between 2.69 and 2.74 Wt%. Electric Ink and Master Ink were the most similar pigments, while Easy Glow was the most distinctive - with agglomerates of Al that had a concentration 25 × higher than other specimens. Other compounds detected in the sample were Cl and Cu. CONCLUSION: EDS and SEM were efficient to distinguish black tattoo inks. These are our preliminary outcomes on the use of EDS and SEM to analyze black tattoo inks. Thus, careful interpretation is necessary to avoid rash applications in human identification practice.

Conformational and constitutional analysis of dental caries following radiotherapy for head and neck cancer.

BACKGROUND: This study aimed to investigate the morphology and chemical composition of dental caries related to ionizing radiation (DCIR), an aggressive and progressive disease that affects dental hard tissues. MATERIALS AND METHODS: Eight human teeth with DCIR were paired with sixteen control teeth (8 teeth with conventional caries and 8 without caries) and included in this study. An analysis of the morphology of the lesions was performed using the following techniques: periapical radiography, cone beam computed tomography, computed microtomography, and scanning electron microscopy. The chemical composition was assessed using X-ray dispersive spectroscopy. RESULTS: There was more demineralization in DCIR lesions when compared to conventional dental caries, even though there was no cavitation in the cervical region of the teeth. The superficial roughness and topography of DCIR lesions were similar to those of healthy teeth. On the other hand, lesions of conventional dental caries showed greater surface and topographic irregularity when compared to DCIR and healthy teeth (p = 0.001). Calcium (Ca) and phosphorus (P) levels were lower in DCIR lesions when compared to controls. However, higher levels of carbon (C) have been observed in DCIR lesions. There was a greater loss of the mineral matrix in DCIR followed by conventional caries. The reduction in the mineral matrix (Ca and P) was compatible with the imaging patterns observed in teeth with DCIR and conventional caries. CONCLUSION: Despite their rapid evolution, DCIR presents an irregular, apparently intact surface with significant changes in the amount of Ca, P, and C.

Morphologic, Structural, and Chemical Properties of Pulp Stones in Extracted Human Teeth.

INTRODUCTION: Pulp stones are mineral structures that develop in the pulp tissue triggered by several clinical conditions. The exact biochemical process behind the occurrence of pulp stones is uncertain. This study aimed to perform a structural and crystallographic characterization of pulp stones and dentin from extracted human teeth. METHODS: The sample consisted of 13 erupted and unerupted permanent human teeth diagnosed with pulp stones. The teeth were analyzed with scanning electron microscopy with secondary and backscattered electrons, energy-dispersive spectroscopy, micro-Raman spectroscopy, micro-X-ray diffraction, and inductively coupled plasma atomic emission spectroscopy. RESULTS: The pulp stones revealed a heterogeneous morphology and structure compared with each other. Compared with the adjacent dentin, the pulp stones had a similar structure. From a chemical point of view, oxygen, calcium, carbon, and phosphorus were the most prevalent chemical elements in the inner part of the stones, whereas on the surface carbon, nitrogen, sulfur, chlorine, aluminum, potassium, zinc, copper, and lead were the most prevalent. Copper, iron, and zinc were higher in the stones than the dentin (P < .05). Statistically significant differences between the chemical structure of stones from erupted and unerupted teeth were not detected (P > .05). CONCLUSIONS: Pulp stones have structural and chemical properties that are similar to dentin. Variations in morphology are common.