Purpose: This study aimed to evaluate the accuracy of bite registration using intraoral scanner based on data trimming strategy for fremitus teeth. Materials and Methods: A reference model was designed by Medit Model Builder software (MEDIT Corp., Seoul). Tooth number 24 and 25 were separated as dies and tooth number 26 was prepared for full-coverage crown. Those were printed using a 3D printer (NextDent 5100). The scanning procedure was performed by a single trained operator with one intraoral scanner (i700; MEDIT Corp.). The scanning groups were divided as follows: group 1 (G1), no fremitus; group 2 (G2), 0.5 mm buccal fremitus in the maxillary left first and second premolar; and group 3 (G3), 1.5 mm buccal fremitus in the maxillary left first and second premolar. Each group was scanned 10 times and were analyzed using the reference model data. Surface-based occlusal clearance was analyzed at the prepared tooth to evaluate accuracy.Result: Mean values of control group (G1) were 1.587±0.021 mm. G2 showed similar values to those from the control group (1.580±0.024 mm before trimming strategy and 1.588±0.052 mm after trimming strategy). G3 showed significantly greater values (1.627±0.025 mm before trimming strategy and 1.590±0.024 mm after trimming strategy) and the differences were found between trimming strategy (P=0.004). Conclusion Bite trimming strategy for fremitus teeth is a reliable technique to reduce inaccuracies caused by the mobility at maximum intercuspation.

Objective: To investigate the association between thyroidectomy and suicide attempt. Methods: A nationwide population-based electronic medical records database of South Korea between January 1, 2009 and June 30, 2016 was used to investigate incidence rate ratios (IRRs) of suicide attempts and probable suicide attempts before and after thyroidectomy using a self-controlled case series design. Results: In 2,986 patients who attempted suicide or probable suicide, the IRRs of suicidal behaviors during risk periods one year before and after thyroidectomy were investigated. Generally, after thyroidectomy, there was no increase in IRR compared to the non-risk period. When data were analyzed according to thyroidectomy type, after partial thyroidectomy, IRR increased up to 1.43 (95% CI: 1.03–1.98, p=0.032) in the days 91–181 period. In the subgroup with major depressive disorder (MDD), the IRR increased up to 1.74 (95% CI: 1.21–2.51, p=0.003) before thyroidectomy, and increased up to 1.67 (95% CI: 1.16–2.41, p=0.006) after thyroidectomy. Conclusion Although the general risk of suicide attempt was not increased after thyroidectomy, patients with MDD showed increased risk of suicide attempt before and after thyroidectomy. These results suggest that suicidality should be evaluated when depressive symptoms are present in patients who have undergone thyroidectomy.

OBJECTIVE: To determine the feasibility of labeling human mesenchymal stem cells (hMSCs) with bifunctional nanoparticles and assessing their potential as imaging probes in the monitoring of hMSC transplantation. MATERIALS AND METHODS: The T1 and T2 relaxivities of the nanoparticles (MNP@SiO2[RITC]-PEG) were measured at 1.5T and 3T magnetic resonance scanner. Using hMSCs and the nanoparticles, labeling efficiency, toxicity, and proliferation were assessed. Confocal laser scanning microscopy and transmission electron microscopy were used to specify the intracellular localization of the endocytosed iron nanoparticles. We also observed in vitro and in vivo visualization of the labeled hMSCs with a 3T MR scanner and optical imaging. RESULTS: MNP@SiO2(RITC)-PEG showed both superparamagnetic and fluorescent properties. The r1 and r2 relaxivity values of the MNP@SiO2(RITC)-PEG were 0.33 and 398 mM-1 s-1 at 1.5T, respectively, and 0.29 and 453 mM-1 s-1 at 3T, respectively. The effective internalization of MNP@SiO2(RITC)-PEG into hMSCs was observed by confocal laser scanning fluorescence microscopy. The transmission electron microscopy images showed that MNP@SiO2(RITC)-PEG was internalized into the cells and mainly resided in the cytoplasm. The viability and proliferation of MNP@SiO2(RITC)-PEG-labeled hMSCs were not significantly different from the control cells. MNP@SiO2(RITC)-PEG-labeled hMSCs were observed in vitro and in vivo with optical and MR imaging. CONCLUSION: MNP@SiO2(RITC)-PEG can be a useful contrast agent for stem cell imaging, which is suitable for a bimodal detection by MRI and optical imaging.
Animals ; Biocompatible Materials ; Cells, Cultured ; Cobalt ; Feasibility Studies ; Ferric Compounds ; Humans ; Magnetic Resonance Imaging/*methods ; *Mesenchymal Stem Cells ; Mice ; Mice, Nude ; Microscopy, Confocal ; Microscopy, Electron ; Nanoparticles/*chemistry ; Phantoms, Imaging ; Polyethylene Glycols ; Rats ; Rhodamines ; Silicon Dioxide ; Staining and Labeling/methods