Prediction of learning curves of wired and wireless intraoral scanners.

This clinical study aimed to predict the learning curve of wireless and wired intraoral scanners (IOSs) and to compare the reduction patterns of working time. Overall, 14 participants were enrolled in the study. The intraoral scanning procedure was repeated four times, each using wireless and wired IOSs (i700; MEDIT). The work time from the first to the 600th iterations was predicted using the Wright model. Regarding statistical analysis, the Mann-Whitney U-test was performed for comparison between wireless and wired IOSs and between groups with and without an IOS usage experience, and the Friedman test was performed to evaluate the time reduction (α = 0.05). There was a significant difference between wireless and wired IOSs in the first (P = 0.008) and the third (P = 0.035) iterations. Moreover, the time for 600 iterations was statistically significantly different between wireless and wired IOSs (P < 0.05); however, there was no significant difference after the sixth iteration (e.g., seventh iteration: P = 0.062). In wireless IOS, no significant difference was found between participants with and without an IOS usage experience after the 34th iteration (P = 0.053). The difference in the learning effect between wireless and wired IOSs can be overcome by initial learning; however, an IOS usage experience can affect the learning time of wireless IOSs.

Three-dimensional morphometric analysis of facial units in virtual smiling facial images with different smile expressions.

PURPOSE: Accuracy of image matching between resting and smiling facial models is affected by the stability of the reference surfaces. This study aimed to investigate the morphometric variations in subdivided facial units during resting, posed and spontaneous smiling. MATERIALS AND METHODS: The posed and spontaneous smiling faces of 33 adults were digitized and registered to the resting faces. The morphological changes of subdivided facial units at the forehead (upper and lower central, upper and lower lateral, and temple), nasal (dorsum, tip, lateral wall, and alar lobules), and chin (central and lateral) regions were assessed by measuring the 3D mesh deviations between the smiling and resting facial models. The one-way analysis of variance, Duncan post hoc tests, and Student's t-test were used to determine the differences among the groups (α = .05). RESULTS: The smallest morphometric changes were observed at the upper and central forehead and nasal dorsum; meanwhile, the largest deviation was found at the nasal alar lobules in both the posed and spontaneous smiles (P < .001). The spontaneous smile generally resulted in larger facial unit changes than the posed smile, and significant difference was observed at the alar lobules, central chin, and lateral chin units (P < .001). CONCLUSION: The upper and central forehead and nasal dorsum are reliable areas for image matching between resting and smiling 3D facial images. The central chin area can be considered an additional reference area for posed smiles; however, special cautions should be taken when selecting this area as references for spontaneous smiles.

Flattening of Lithium Plating in Carbonate Electrolytes Enabled by All-In-One Separator.

The uncontrollable dendritic growth of metallic lithium during repeated cycling in carbonate electrolytes is a crucial obstacle hindering the practical use of Li-metal batteries (LMBs). Among numerous approaches proposed to mitigate the intrinsic constraints of Li metal, the design of a functional separator is an attractive approach to effectively suppress the growth of Li dendrites because direct contact with both the Li metal surface and the electrolyte is maintained. Here, a newly designed all-in-one separator containing bifunctional CaCO3 nanoparticles (CPP separator) is proposed to achieve the flattening of Li deposits on the Li electrode. Strong interactions between the highly polar CaCO3 nanoparticles and the polar solvent reduces the ionic radius of the Li+ -solvent complex, thus increasing the Li+ transference number and leading to a reduced concentration overpotential in the electrolyte-filled separator. Furthermore, the integration of CaCO3 nanoparticles into the separator induces the spontaneous formation of mechanically-strong and lithiophilic CaLi2 at the Li/separator interface, which effectively decreases the nucleation overpotential toward Li plating. As a result, the Li deposits exhibit dendrite-free planar morphologies, thus enabling excellent cycling performance in LMBs configured with a high-Ni cathode in a carbonate electrolyte under practical operating conditions.

Dental diagnosis for inlay restoration using an intraoral optical coherence tomography system: A case report.

PATIENTS: The patient was a 32-year-old man who underwent amalgam restoration of the mandibular right second molar. An amalgam restoration fracture was diagnosed by intraoral optical coherence tomography (OCT), and pulp exposure was examined during cavity preparation. Subsequently, a definitive ceramic restoration was fabricated, and the marginal fit in the oral cavity was evaluated using the OCT system. DISCUSSION: The existing OCT system cannot acquire images inside the oral cavity because of the large probe size. However, the proposed intraoral OCT system can access the prostheses in the mandibular right second molar. Therefore, dental diagnosis for restoration treatment with dental prosthesis fracture, marginal gap, and pulp exposure after tooth preparation is possible using the proposed intraoral OCT system. CONCLUSIONS: The use of the intraoral OCT system improved dental diagnosis by allowing the dentist to confirm quantitative values through cross-sectional images, rather than that by determining a treatment plan after visual dental diagnosis.

Comparison of Wear of Interim Crowns in Accordance with the Build Angle of Digital Light Processing 3D Printing: A Preliminary In Vivo Study.

The aim of this study is to evaluate the wear volume of interim crowns fabricated using digital light processing 3D printing according to the printing angle. A total of five patients undergoing the placement of a single crown on the mandibular molar were included. Interim crowns were fabricated directly in the oral cavity using the conventional method. A digital light processing 3D printer was then used to fabricate crowns with build angles of 0, 45, and 90 degrees. Therefore, four fabricated interim crowns were randomly delivered to the patients, and each was used for one week. Before and after use, the intaglio surfaces of the interim crowns were scanned using a 3D scanner. The volume changes before and after use were measured, and changes in the height of the occlusal surface were evaluated using the root mean square value. Data normality was verified by statistical analysis, and the wear volume in each group was evaluated using a one-way analysis of variance and Tukey's honestly significant difference test (α = 0.05). Compared with the RMS values of the conventional method (11.88 ± 2.69 µm) and the 3D-printing method at 0 degrees (12.14 ± 2.38 µm), the RMS values were significantly high at 90 degrees (16.46 ± 2.39 µm) (p < 0.05). Likewise, there was a significant difference in the change in volume between the groups (p = 0.002), with a significantly higher volume change value at 90 degrees (1.74 ± 0.41 mm3) than in the conventional method (0.70 ± 0.15 mm3) (p < 0.05). A printing angle of 90 degrees is not recommended when interim crowns are fabricated using digital light processing 3D printing.

Long-term impact of psychological factors and social interactions on obesity of female nationals in the United Arab Emirates.

OBJECTIVE: Along with rapid economic growth, the United Arab Emirates (UAE) has undergone enormous sociocultural changes. Consequently, sociocultural and psychological factors, along with malnutrition and physical inactivity, have contributed to the high obesity rate. The objective of this study is to assess the long-term impact of these new emerging factors on obesity among women in the UAE via mathematical modeling. METHODS: A differential equation model was developed considering psychological/social factors in population dynamics. It predicts the long-term prevalence of obesity among women in the UAE under these factors by 2070. Computer simulations and a sensitivity analysis of the model were conducted to measure the impact of these factors on obesity. RESULTS: The model predicts the following: 80.07% of female UAE nationals will become overweight or have obesity and 60.19% will have obesity by 2070, and the population with abnormal eating behavior will increase to 15% by 2070. Psychological/social factors aggravate the obesity problems and can cause abnormal eating behavior to develop with little effect on weight reduction. CONCLUSIONS: The obesity rate of female UAE nationals will continue to rise by 2070. Rising abnormal eating behavior caused by psychological/social factors is an emerging issue and should be recognized as a sign of escalating obesity problems in the UAE.

The Relationship Between Workplace Burnout and Male Depression Symptom Assessed by the Korean Version of the Gotland Male Depression Scale.

Screening for depression in males is important because their symptoms differ from those of females, ranging from indications of aggression to attempts at suicide. Men and women differ in their responses to job stress. There are no tools that have been verified, developed, or translated for screening male depression in Korea. Our team translated the Gotland Male Depression Scale (GMDS) into Korean. The Korean version of GMDS (K-GMDS) and Maslach Burnout Inventory-General Survey (MBI-GS) were administered to 277 office workers in one public institution. Gender differences in each scale score were measured along with the correlation between the K-GMDS and the MBI-GS. There was no significant difference in the K-GMDS score between males and females, whereas females scored significantly higher on the MBI-GS (p < .001). The correlation between the K-GMDS total score and the MBI total score (male: r = .702, p < .001, female: r = .375, p < .001) and MBI subscale scores were higher in males than females. Gender moderated the relationship between total K-GMDS and total MBI scores (p < .001). The Korean version of the GMDS is suitable for screening male depression symptoms in the workplace. The results of the K-GMDS demonstrated a strong correlation between depressive symptoms and work-related burnout among men. This study can be used as a basis for studying male depression symptoms in Korea, which has not been studied extensively. This will prove beneficial for work environments.

Nanoarchitectonics of the cathode to improve the reversibility of Li-O2 batteries.

The strategic design of the cathode is a critical feature for high-performance and long-lasting reversibility of an energy storage system. In particular, the round-trip efficiency and cycling performance of nonaqueous lithium-oxygen batteries are governed by minimizing the discharge products, such as Li2O and Li2O2. Recently, a metal-organic framework has been directly pyrolyzed into a carbon frame with controllable pore volume and size. Furthermore, selective metallic catalysts can also be obtained by adjusting metal ions for outstanding electrochemical reactions. In this study, various bimetallic zeolitic imidazolate framework (ZIF)-derived carbons were designed by varying the ratio of Zn to Co ions. Moreover, carbon nanotubes (CNTs) are added to improve the electrical conductivity further, ultimately leading to better electrochemical stability in the cathode. As a result, the optimized bimetallic ZIF-carbon/CNT composite exhibits a high discharge capacity of 16,000 mAh·g-1, with a stable cycling performance of up to 137 cycles. This feature is also beneficial for lowering the overpotential of the cathode during cycling, even at the high current density of 2,000 mA·g-1.

Tailoring the Surface of Natural Graphite with Functional Metal Oxides via Facile Crystallization for Lithium-Ion Batteries.

Graphite is the most popular anode material for lithium-ion batteries (LIBs) owing to its high reversibility and stable cycling performance. With the rapid growth of the global electric vehicle (EV) market, it has become necessary to improve the quick-charge performance of graphite to reduce the charging time of LIBs. Therefore, from a structural viewpoint, it is crucial to control interfacial reactions and stabilize the surface of graphite to improve the sluggish interfacial kinetics. Herein, we propose a facile approach for integrating functional metal oxides on the surface of natural graphite (NG) via a surface-coating technique in combination with a facile-crystallization process. The functionality of the metal oxides, i.e., MoO2 and Fe3O4, on the surface of NG was thoroughly investigated based on various structural and electrochemical analyses. The results demonstrate that the metal oxides play critical roles in stabilizing the surface of NG and facilitating faster Li+ migration at the interface between NG and the electrolyte during cycling. In particular, the full cell configured with the c-Fe3O4-NG anode shows remarkably improved charging behavior (3 C charging-1 C discharging) without any significant loss of reversible capacity during 300 cycles. This study has conclusively established that tailoring the surface of NG with functional metal oxides would be a utilitarian way to improve the charging capability of NG. We are confident that the study results would provide utilitarian insights into the development of advanced LIBs for successful implementation in EV applications in the future.

Impact of scanning strategy on the accuracy of complete-arch intraoral scans: a preliminary study on segmental scans and merge methods.

PURPOSE: This study investigated the accuracy of full-arch intraoral scans obtained by various scan strategies with the segmental scan and merge methods. MATERIALS AND METHODS: Seventy intraoral scans (seven scans per group) were performed using 10 scan strategies that differed in the segmental scan (1, 2, or 3 segments) and the scanning motion (straight, zigzag, or combined). The three-dimensional (3D) geometric accuracy of scan images was evaluated by comparison with a reference image in an image analysis software program, in terms of the arch shape discrepancies. Measurement parameters were the intermolar distance, interpremolar distance, anteroposterior distance, and global surface deviation. One-way analysis of variance and Tukey honestly significance difference post hoc tests were carried out to compare differences among the scan strategy groups (α = .05). RESULTS: The linear discrepancy values of intraoral scans were not different among scan strategies performed with the single scan and segmental scan methods. In general, differences in the scan motion did not show different accuracies, except for the intermolar distance measured under the scan conditions of a 3-segmental scan and zigzag motion. The global surface deviations were not different among all scan strategies. CONCLUSION: The segmental scan and merge methods using two scan parts appear to be reliable as an alternative to the single scan method for full-arch intraoral scans. When three segmental scans are involved, the accuracy of complete arch scan can be negatively affected.

Preliminary Animal Study on Bone Formation Ability of Commercialized Particle-Type Bone Graft with Increased Operability by Hydrogel.

The purpose of this study was to evaluate the bone-generating ability of a new bovine-derived xenograft (S1-XB) containing hydrogel. For control purposes, we used Bio-Oss and Bone-XB bovine-derived xenografts. S1-XB was produced by mixing Bone-XB and hydrogel. Cell proliferation and differentiation studies were performed to assess cytotoxicities and cell responses. For in vivo study, 8 mm-sized cranial defects were formed in 16 rats, and then the bone substitutes were transplanted into defect sites in the four study groups, that is, a Bio-Oss group, a Bone-XB group, an S1-XB group, and a control (all n = 4); in the control group defects were left empty. Eight weeks after surgery, new bone formation areas were measured histomorphometrically. In the cell study, extracts of Bio-Oss, Bone-XB, and S1-XB showed good results in terms of the osteogenic differentiation of human mesenchymal stem cells (hMSCs) and no cytotoxic reaction was evident. No significant difference was observed between mean new bone areas in the Bio-Oss (36.93 ± 4.27%), Bone-XB (35.07 ± 3.23%), and S1-XB (30.80 ± 6.41%) groups, but new bone area was significantly smaller in the control group (18.73 ± 5.59%) (p < 0.05). Bovine-derived bone graft material containing hydrogel (S1-XB) had a better cellular response and an osteogenic effect similar to Bio-Oss.

Effects of Gamma Radiation-Induced Crosslinking of Collagen Type I Coated Dental Titanium Implants on Osseointegration and Bone Regeneration.

This study aimed to compare two methods of crosslinking collagen type I on implanted titanium surfaces, that is, using glutaraldehyde (GA) or gamma-rays (GRs), in a beagle dog model. For in vivo experiments, implants were allocated to three groups and applied to mandibular bone defects in beagle dogs; Group SLA; non-treated Sandblasted, large grit, acid-etched (SLA) implants, Group GA; SLA implants coated with GA crosslinked collagen type I, Group GR; SLA surface implants coated with collagen type I and crosslinked using 25 kGy of 60Co gamma radiation. New bone µCT volumes were obtained, and histologic and histometric analyses were performed in regions of interest. The GR group had significantly better new bone areas (NBAs) and bone to implant contact (BIC) results than the SLA group (p < 0.05), but the GA and GR groups were similar in this respect. New bone volumes and inter-thread bone densities (ITBD) were non-significantly different in the three groups (p > 0.05). Within the limits of this study, gamma-ray collagen crosslinking on titanium implants can be considered a substitute for glutaraldehyde crosslinking.

Synthesis of freestanding binder- and additive-free carbon nanofiber with graphene-wrapped Nb2O5composite anode for lithium-ion batteries.

Niobium pentoxide (Nb2O5)-based materials have attracted significant interest for application in diverse fields. Unfortunately, the employment of these materials as electrodes of lithium-ion batteries (LIBs) is limited by several inherent drawbacks. The present study demonstrated the synthesis of composites comprising homogeneous graphene-wrapped niobium pentoxide (GNbO) encapsulated in carbon nanofibers (CNFs) for utilization as binder- and additive-free anodes in LIBs. The composites were synthesized via electrospinning and subsequent carbonization; the presence of graphene (G) ensured the homogenous dispersion of the Nb2O5particles in the CNF matrix. The CNFs formed a highly conductive network that resulted in high physical flexibility, electrical conductivity, and structural stability during charge-discharge cycles, thereby facilitating rapid ion/electron transmission. Consequently, the CNF/GNbO composite anodes exhibited outstanding electrochemical performances. CNF/GNbO_5 (one of the synthesized composites with an Nb2O5concentration of 5 wt% relative to GO) delivered a specific capacity of 361 mAh g-1after 100 cycles, corresponding to a capacity retention of 58.3%. In addition, it exhibited an excellent rate capability with a capacity of 317 mAh g-1at 10 C. The outcomes of the present study will facilitate the extensive application of the synthesized composites as high-performance anodes in next-generation LIBs.

Longitudinal profiling of oligomeric Aß in human nasal discharge reflecting cognitive decline in probable Alzheimer's disease.

Despite clinical evidence indicating a close relationship between olfactory dysfunction and Alzheimer's disease (AD), further investigations are warranted to determine the diagnostic potential of nasal surrogate biomarkers for AD. In this study, we first identified soluble amyloid-ß (Aß), the key biomarker of AD, in patient nasal discharge using proteomic analysis. Then, we profiled the significant differences in Aß oligomers level between patient groups with mild or moderate cognitive decline (n = 39) and an age-matched normal control group (n = 21) by immunoblot analysis and comparing the levels of Aß by a self-standard method with interdigitated microelectrode sensor systems. All subjects received the Mini-Mental State Examination (MMSE), Clinical Dementia Rating (CDR), and the Global Deterioration Scale (GDS) for grouping. We observed higher levels of Aß oligomers in probable AD subjects with lower MMSE, higher CDR, and higher GDS compared to the normal control group. Moreover, mild and moderate subject groups could be distinguished based on the increased composition of two oligomers, 12-mer Aß*56 and 15-mer AßO, respectively. The longitudinal cohort study confirmed that the cognitive decline of mild AD patients with high nasal discharge Aß*56 levels advanced to the moderate stage within three years. Our clinical evidence strongly supports the view that the presence of oligomeric Aß proteins in nasal discharge is a potential surrogate biomarker of AD and an indicator of cognitive decline progression.

The effect of a mental health promotion program on Korean firefighters.

BACKGROUND: There is worldwide interest in the mental health of firefighters, since they are more prone to exposure to traumatic stress and psychiatric disorders. AIMS: This study aimed to assess their mental health and provide individualized support to local firefighters through a mental health promotion program. METHOD: Eighteen hundred and fifty-nine active Korean firefighters in 2015 and 2017 (502 and 1,357, respectively) participated in the 'Visiting Counselling Centre for Firefighters' program commissioned by the National Fire Agency. The program consisted of self-administered questionnaires, a group education session, an individual counseling session for every participant, four counseling sessions for certain participants and additional brief intensive counseling (BIC). We administered the Post-traumatic stress disorder Checklist (PCL), Beck's Depression Inventory (BDI), Beck's Anxiety Inventory (BAI), Beck Scale for Suicidal ideation (BSS), Insomnia Severity Index (ISI), Korean version of the Alcohol Use Disorders Identification Test (AUDIT-K) and the abbreviated World Health Organization Quality of Life (WHOQOL-BREF) before and after the program. Additional analysis was performed to determine whether BIC participation further improved the psychopathological outcome. RESULTS: The participants showed meaningful improvement in all psychopathological scales; the PCL, BDI, BAI, BSS, ISI, AUDIT-K and WHOQOL-BREF scores all significantly improved. Meanwhile, BIC participation improved certain psychopathological symptoms at a higher degree; the BDI, BAI, BSS and AUDIT-K scores significantly improved. CONCLUSION: The mental health promotion program improved the mental health of the participating active firefighters in Korea. Meanwhile, BIC participation improved certain psychopathological symptoms at a higher degree. A comprehensive approach for supporting the mental health of firefighters should be considered.

Possibility of Recycling SiOx Particles Collected at Silicon Ingot Production Process as an Anode Material for Lithium Ion Batteries.

Recently, some studies have utilized silicon (Si) as an anode material of lithium ion battery by recycling Si from the slurry of wafer slicing dust. The filtration of Si particles condensed from Si vapors that were exhausted from the ingot growing furnace could propose another method of Si recycling. In this study, we investigated the possibility of using such collected silicon oxides (SiOx) particles as an anode material. After collecting SiOx particles, FE-SEM, TEM, EDS, XRD, XPS analysis, and charge/discharge test were carried out to investigate characteristics and usability of these particles. FE-SEM and FE-TEM images showed that these particles mainly consisted of spherical primary particles with a diameter of 10 nm or less. Agglomerates of these primary particles were larger than 300 nm in diameter. In TEM image and EDS analysis, crystalline particles were observed along with amorphous particles. As a result of XRD analysis, amorphous silica (SiO2) and crystalline Si were observed. Charge/discharge tests were carried out to determine the feasibility of using these particles as an anode material for lithium ion batteries. A cycle efficiency of 40.6% was obtained in the test in which the total number of charge/discharge cycle was 100 under the condition of C-rate 0.2 for the first three times and C-rate 1.0 for the remaining 97 times. Results showed that these collected particles could be used as an anode material for lithium ion batteries.

Bone Regeneration Using a Three-Dimensional Hexahedron Channeled BCP Block Combined with Bone Morphogenic Protein-2 in Rat Calvarial Defects.

It is important to obtain sufficient bone mass before implant placement on alveolar bone, and synthetic bone such as biphasic calcium phosphate (BCP) has been studied to secure this. This study used a BCP block bone with a specific structure of the three-dimensional (3D) hexahedron channel and coating with recombinant human bone morphogenetic protein-2 (rhBMP-2) impregnated carboxymethyl cellulose (CMC) was used to examine the enhancement of bone regeneration of this biomaterial in rat calvarial defect. After the preparation of critical-size calvarial defects in fifteen rats, defects were divided into three groups and were implanted with the assigned specimen (n = 5): Boneplant (untreated 3D hexahedron channeled BCP block), Boneplant/CMC (3D hexahedron channeled BCP block coated with CMC), and Boneplant/CMC/BMP (3D hexahedron channeled BCP block coated with CMC containing rhBMP-2). After 4 weeks, the volumetric, histologic, and histometric analyses were conducted to measure the newly formed bone. Histologically, defects in the Boneplant/CMC/BMP group were almost completely filled with new bone compared to the Boneplant and Boneplant/CMC groups. The new bone volume (P < 0.05) and area (P < 0.001) in the Boneplant/CMC/BMP group (20.12% ± 2.17, 33.79% ± 3.66) were much greater than those in the Boneplant (10.77% ± 4.8, 16.48% ± 9.11) and Boneplant/CMC (10.72% ± 3.29, 16.57% ± 8.94) groups, respectively. In conclusion, the 3D hexahedron channeled BCP block adapted rhBMP-2 with carrier CMC showed high possibility as an effective bone graft material.

Physical activity levels and social interactions of preschoolers with and without disabilities.

This study examined differences of physical activity levels and social interactions among preschoolers with/without disabilities and those at risk for a developmental delay (DD). Sixty preschoolers (20 in each group) were film during their designated large gross motor time. Their physical activity levels and social interaction were examined using the physical activity level screening. Regarding physical activity levels, the result of a two-way analysis of variance indicated significant main effects for groups, F(2,54)=4.192, P=0.02; preschoolers at risk for a DD were more active than preschoolers without disabilities, P=0.02. For social interaction, a significant main effect for groups, F(2,54)=8.994, P<0.001 was found; Preschoolers at risk for a DD were more interactive than preschoolers with/without disabilities, P=0.001 and P=0.002, respectively. There were no significant gender differences across three groups on physical activity levels and social interactions. Although preschoolers at risk for a DD was more active and interactive than the other groups, preschoolers across three groups engaged in light physical activity levels, and had limited social interactions with peers.

Magnetically actuated microrobots as a platform for stem cell transplantation.

Magnetic microrobots were developed for three-dimensional culture and the precise delivery of stem cells in vitro, ex vivo, and in vivo. Hippocampal neural stem cells attached to the microrobots proliferated and differentiated into astrocytes, oligodendrocytes, and neurons. Moreover, microrobots were used to transport colorectal carcinoma cancer cells to tumor microtissue in a body-on-a-chip, which comprised an in vitro liver-tumor microorgan network. The microrobots were also controlled in a mouse brain slice and rat brain blood vessel. Last, microrobots carrying mesenchymal stem cells derived from human nose were manipulated inside the intraperitoneal cavity of a nude mouse. The results indicate the potential of microrobots for the culture and delivery of stem cells.