Comparison of CBCT radiation doses with conventional radiographs in TMJ imaging using Monte Carlo simulations.

Three-dimensional imaging methods are widely used for evaluation of bony changes of temporomandibular joint (TMJ). Besides, lateral and posterio-anterior TMJ projections in both closed- and open-jaw positions for each temporomandibular joint are used as two-dimensional diagnostic tools. The purpose of the present study was to compare effective and mean organ absorbed doses of plain radiography techniques with those of different modalities of cone beam computed tomography (CBCT) scanning of an adult's temporomandibular joint. PCXMC 2.0 software was used to calculate mean organ and effective doses. A NewTom CBCT device (Newtom 5G XL; QR systems; Verona, Italy) was simulated at 360° rotation using a 6 × 6 cm2 FOV in standard and high-resolution modes. Lateral and posterio-anterior TMJ plain projections were simulated according to recommendations of the manufacturer of the Planmeca ProMax® 2D S3 device. Doses for both projections were simulated with Monte Carlo methods and the International Commission on radiological protection adult reference computational phantoms. The highest mean organ absorbed doses occurred in bone surfaces, salivary glands, and skull for posterio-anterior TMJ and lateral TMJ, and for CBCT scanning in all examinations. The effective doses of posterio-anterior and lateral TMJ plain radiographs were found to be higher than those of the Standard Mode-Eco Scan CBCT. Therefore, the lowest effective dose was calculated in Standard Mode-Eco Scan CBCT. It is concluded that NewTom 5G XL Standard Mode-Eco Scan CBCT can be used instead of plain radiographs (lateral and posterio-anterior TMJ) in temporomandibular joint imaging as it allows visualizing the three-dimensional structure of the temporomandibular joint as an advantage.

Evaluation of the differences in the localization of the lingula mandibulae according to pubertal development in children: A new anthropological and forensic approach.

OBJECTIVE: This study aims to investigate changes in lingula mandibulae localization before and after puberty and sex differences. DESIGN: 288 panoramic radiographs evaluated retrospectively were divided into four groups according to pubertal development: under and over 10 years old for females and under and over 11 years old for males. Four anatomic sites were used as reference points: (a) the anterior border of the ramus; (b) the posterior border of the ramus; (c) the deepest point of mandibular notch; and (d) the angulus mandibulae. The ratio of the distances from the lingula mandibulae to points (a) and (b) and the ratio of the distances from the lingula mandibulae to points (c) and (d) were determined. Two-way ANOVA was performed to assess differences between subgroups based on sex and puberty, and a Bonferroni post-hoc test was performed for multiple comparisons. RESULTS: Puberty and sex has a significant interaction effect on the vertical location of the lingula mandibulae. Postpubertal lingula mandibulae is positioned proportionally more anteriorly by prepubertal localization. In addition, the lingula mandibulae is situated more posteriorly in females compared to males. A significant interaction effect of puberty and sex was observed in relation to the vertical positioning of the lingula mandibulae. CONCLUSIONS: The spatial localization of the lingula mandibulae and its spatial displacement with age can be used both in estimating sex and the onset of puberty. Changes in the localization of lingula mandibulae according to pubertal development and sex can be used in forensic and anthropological contexts.

Comparison of Dental and Skeletal Age Estimating Methods in Children.

Objectives: Estimating age is a crucial determinant of forensic science. Various methods have been used to estimate dental age (DA) and skeletal age (SA).The aim of the current study was to compare the Cameriere's DA method with the Cameriere's SA method in estimating CA in children. Materials and methods: A total of 216 radiographs of 130 females and 86 males (between 9 to 14.99 years of age) were evaluated in northwestern Turkey. DA was calculated on the panoramic images using Cameriere's open-apex method. SA was determined on the lateral cephalograms using the fourth cervical vertebrae method by Cameriere. The DA, SA, and CA data were compared using a paired t-test and Wilcoxon test. Results: The mean CA of all groups was calculated as 12.96±0.30, the mean DA of 12.74±0.68 and the mean SA of 12.89±0.89. In males, the DA method presented an underestimation between ages of 14.00 and 14.99 (p<0.05) and an overestimation between ages 9.00 and 11.99 (p<0.05). In females, the DA method showed an underestimation in the 13.00- and 14.99-year-old age groups (p<0.05) and an overestimation in the 10.00- and 11.99-year-old age groups (p<0.05). The SA method revealed a significant underestimation in females between the ages of 13.00 and 14.99 and in males between the ages of 14.00 and 14.99 (p<0.05). Conclusions: The SA estimation method may provide more accurate results compared to the DA method with children of both sexes aged between 9.00 to 12.99 in the determination of CA.

Effects of direct therapeutic radiation on pulpal surface of root dentin: an in vitro study.

The aims of the study were to analyze the effects of therapeutic radiation on human root dentin samples from the aspect of possible alterations in crystallinity, micro-morphology, and composition. Fifty-six root dentin specimens were divided into seven groups (0, 10, 20, 30, 40, 50, and 60 Gy). Scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD) analyses were performed on pulpal surfaces of root dentin after being irradiated by 6MV photon energy. Mineral compositions, Ca/P, P/N, Ca/N ratios, and hydroxyapatite pikes were calculated. Some deuteriations on the dentin surface were observed in SEM images after 30 Gy and subsequent doses. One-way ANOVA revealed that there was no significant alteration in weight percentages of C, O, Mg, Ca, P, and N between groups. Radiation did not influence stoichiometric Ca/P, Ca/N, and P/N molar ratios. XRD analysis did not show a remarkable decline in hydroxyapatite pikes by the increasing doses. Radiotherapy changes the micromorphology of circumpulpal dentin but does not affect elemental composition and crystallinity.

The impact of remineralization agents on dental bleaching efficacy and mineral loss in bleached enamel.

This study evaluated the effect of remineralization agents on bleaching efficiency, enamel mineral changes, and post-bleaching color stability. A total of 112 enamel-dentin blocks were prepared from bovine teeth. Following initial color measurements, separate treatment regimens were carried out as follows: negative control (no treatment); positive control (bleaching only); bleaching, then NaF; bleaching + NaF (mix); bleaching, then CPP-ACPF; bleaching + CPP-ACPF (mix); bleaching, then nHAP+F; bleaching + nHAP+F (mix). Color measurements were repeated after immersion in distilled water for 7 days, and again after staining with coffee solution for 14 days. The CIELAB-based whiteness index was used to evaluate bleaching efficiency, and the CIEDE2000 color difference formula for color stability. Chemical investigation was performed using scanning electron microscopy with energy dispersive spectroscopy and X-ray diffraction analyses. The experimental groups showed significant increases in whiteness compared to the negative control, and the staining after bleaching did not result in statistically significant differences between the groups. Energy dispersive spectroscopic analysis revealed that bleaching protocols had no impact on elemental levels as well as the ratio of Ca/P. The combined use of bleaching agents with remineralization agents did not affect bleaching effectiveness but also did not provide an additional contribution.

Effects of radiotherapeutic X-ray irradiation on cervical enamel.

PURPOSE: Therapeutic radiation used for head and neck cancers mainly affects the cervical region of the tooth. To better understand the impact of therapeutic radiation on tooth, we aimed to examine the crystallinity, micro-morphology, and elemental composition of the cervical inner enamel located adjacent to the dento-enamel junction. MATERIALS AND METHODS: Ninety-one specimens obtained from 16 impacted third mandibular molars were randomly divided into seven groups (0, 10, 20, 30, 40, 50, and 60 Gy irradiation groups). Energy-dispersive X-ray spectroscopy (EDX) and scanning electron microscopy (SEM) were performed after the irradiation by 6 MV photon energy. The X-ray diffraction (XRD) were conducted in every group before and after irradiation. Elemental compositions, and Ca/P, P/N, Ca/N atomic ratios were subjected to the Shapiro-Wilk normality test. All of the elements except Mg showed a normal distribution and were compared by the one-way ANOVA. The non-normally distributed Mg data and Ca/P, P/N, and Ca/N ratios were compared by the Kruskal-Wallis test. RESULTS: The results showed that widening in the interprismatic spaces were observed in the experimental groups subjected to 30 Gy and the following increased doses. In addition, there were no significant differences in C, O, Ca, P, N percentages between irradiated and non-irradiated groups (p > .05). An increase in atomic ratio of the Mg was detected after samples conducted by 60 Gy radiation dose (p < .05). The stoichiometric Ca/P, Ca/N, and P/N atomic ratios did not change by irradiation (p > .05). The XRD peaks of the inner enamel crystalline phase showed a slight decline in the 60 Gy radiation dose group. CONCLUSION: Radiation effects begin to be seen after 30 Gy radiation dose groups. The widen interprismatic spaces seen obviously in 50 Gy and 60 Gy dose groups. Besides Mg ratio showed an increase in the 60 Gy dose group. But it should be thought that radiation caries is a multi-factorial disease that is in collaboration with various radiation-induced side effects.

Effects of high temperature on dental restorative materials for forensic purposes.

This study aimed to observe the effects of high temperature on different restorative dental materials by detecting changes in their microstructural and elemental composition. Disk shaped samples (10 mm diameter, 2 mm depth) were prepared from 8 dental materials (compomer, glass carbomer, ormocer, giomer, zinc reinforced glass ionomer (GI), silver-alloy reinforced GI, zirconia reinforced GI, and conventional GI). Scanning electron microscopy/Energy dispersive X-ray spectroscopy (SEM/EDS) was used to characterize sample surface structures and elemental composition. The same samples were also analyzed using X-ray fluorescence (XRF) to determine the trace element content. Each sample was placed in a porcelain furnace and exposed to 900 °C for 30 min. Observations of macroscopic changes in samples after exposure high temperature were recorded. The microstructural changes in sample surfaces after incineration were detected by SEM. The elemental compositions obtained before and after the incineration were compared after repeating the XRF and EDS analyses. Dental materials demonstrated specific macroscopic changes and microstructural deteriorations detected by SEM images after exposure to high temperature. While several changes occurred in the elemental content of materials in terms of amount, the original elemental composition was preserved. The ability to distinguish dental materials by elemental analyses has had an important impact on the identification process.

Determination and classification of intraoral phosphor storage plate artifacts and errors.

PURPOSE: The aim of this study was to determine the reasons and solutions for intraoral phosphor storage plate (PSP) image artifacts and errors, and to develop an appropriate classification of the artifacts. MATERIALS AND METHODS: This study involved the retrospective examination of 5,000 intraoral images that had been obtained using a phosphor plate system. Image artifacts were examined on the radiographs and classified according to possible causative factors. RESULTS: Artifacts were observed in 1,822 of the 5,000 images. After examination of the images, the errors were divided into 6 groups based on their causes, as follows: images with operator errors, superposition of undesirable structures, ambient light errors, plate artifacts (physical deformations and contamination), scanner artifacts, and software artifacts. The groups were then re-examined and divided into 45 subheadings. CONCLUSION: Identification of image artifacts can help to improve the quality of the radiographic image and control the radiation dose. Knowledge of the basic physics and technology of PSP systems could aid to reduce the need for repeated radiography.