Purpose: Recently, deep learning techniques have been introduced for age estimation, with automated methods based on radiographic analysis demonstrating high accuracy. In this study, we applied convolutional neural network (CNN) techniques to the lower dentition area on orthopantomograms (OPGs) of children to develop an automated age estimation model and evaluate its accuracy for use in forensic dentistry. Methods: In this study, OPGs of 2,856 subjects aged 3-14 years were analyzed. The You Only Look Once (YOLO) V8 object detection technique was applied to extract the mandibular dentition area on OPGs, designating it as the region of interest (ROI). First, 200 radiographs were randomly selected, and were used to train a model for extracting the ROI. The trained model was then applied to the entire dataset. For the CNN image classification task, 80% of OPGs were allocated to the training set, while the remaining 20% were used as the test set. A transfer learning approach was employed using the ResNet50 and VGG19 backbone models, with an ensemble technique combining these models to improve performance. The mean absolute error (MAE) on the test set was used as the validation metric, and the model with the lowest MAE was selected. Results: In this study, the age estimation model developed using mandibular dentition region from OPGs achieved MAE and root mean squared error (RMSE) values of 0.501 and 0.742, respectively, on the test set, and MAE and RMSE values of 0.273 and 0.354, respectively, on the training set. Conclusions The automated age estimation model developed in this study demonstrated accuracy comparable to that of previous research and shows potential for applications in forensic investigations. Increasing the sample size and incorporating diverse deep learning techniques are expected to further enhance the accuracy of future age estimation models.

BACKGROUND: Despite the necessity of job retention in achieving return-to-work (RTW) goals, many workers leave their jobs after returning to work. The objective of this study was to examine the impacts of RTW type and period on job retention in Korean workers with occupational injuries and diseases. METHODS: Data were derived from the Panel Study of Worker's Compensation Insurance, including data from 2,000 systemically sampled workers who had finished recuperation in 2012; three waves of survey data were included in the analyses. Workers who returned to work (n = 1,610) were included in the analysis of the relationship between RTW type and job retention, and 664 workers who returned to their original workplaces were included in the analysis of the relationship between RTW period and job retention. The participants completed a questionnaire, and administrative data were provided by workers' compensation insurance. RESULTS: A Cox proportional-hazards regression analysis showed an increased hazard ratio (HR) for non-retention of 2.66 (95% confidence interval, 2.11–3.35) in reemployed workers compared to that in workers returning to their original workplaces. Among workers returning to their original workplaces, HRs for non-retention were increased in workers with a RTW period of 13–24 months (3.03 [1.52–6.04]) and > 24 months (5.33 [2.14–13.25]) compared to workers with a RTW period of ≤ 3 months. CONCLUSION: RTW type and period were significantly related to job retention, suggesting that policies for promoting job retention rate should be implemented.
Insurance ; Occupational Diseases ; Occupational Health ; Occupational Injuries ; Return to Work ; Workers' Compensation

OBJECTIVES: The purpose of this study was to investigate the effects of low-level laser therapy (LLLT) with a diode gallium-aluminum-arsenide (Ga-Al-As) low-level laser device on the healing and attachment of titanium implants in bone. MATERIALS AND METHODS: Thirteen New Zealand white male rabbits weighing 3.0+/-0.5 kg were used for this study. Dental titanium implants (3.75 mm in diameter and 8.5 mm in length, US II RBM plus fixture; Osstem, Seoul, Korea) were implanted into both femurs of each rabbit. The rabbits were randomly divided into a LLLT group and a control group. The LLLT was initiated immediately after surgery and then repeated daily for 7 consecutive days in the LLLT group. Six weeks and 12 weeks after implantation, we evaluated and compared the osseointegration of the LLLT group and control group, using histomorphometric analysis, removal torque testing, and resonance frequency analysis (RFA). The results were statistically significant when the level of probability was 0.05 or less based on a non-parametric Mann-Whitney U-test. RESULTS: The implant survival rate was about 96%. Histologically and histomorphometrically, we observed that the titanium implants were more strongly attached in LLLT group than in control group. However, there was no significant difference between the LLLT group and control group in removal torque or RFA. CONCLUSION: Histologically, LLLT might promote cell-level osseointegration of titanium implants, but there was no statistically significant effects.
Animal Experimentation ; Bone Density ; Dental Implants ; Femur ; Humans ; Low-Level Light Therapy* ; Male ; New Zealand ; Osseointegration* ; Rabbits* ; Seoul ; Survival Rate ; Titanium* ; Torque*

Bilateral sagittal split ramus osteotomy is considered a standard technique in mandibular orthognathic surgeries to reduce unexpected bilateral stress in the temporomandibular joints. Unilateral sagittal split ramus osteotomy (USSO) was recently introduced to correct facial asymmetry caused by asymmetric mandibular prognathism and has shown favorable outcomes. If unilateral surgery could guarantee long-term postoperative stability as well as favorable results, operation time and the incidence of postoperative complications could be reduced compared to those in bilateral surgery. This report highlights three consecutive cases with long-term follow-up in which USSO was used to correct asymmetric mandibular prognathism. Long-term postoperative changes in the condylar contour and ramus and condylar head length were analyzed using routine radiography and computed tomography. In addition, prior USSO studies were reviewed to outline clear criteria for applying this technique. In conclusion, patients showing functional-type asymmetry with predicted unilateral mandibular movement of less than 7 mm can be considered suitable candidates for USSO-based correction of asymmetric mandibular prognathism with or without maxillary arch surgeries.
Facial Asymmetry* ; Follow-Up Studies ; Head ; Humans ; Incidence ; Orthognathic Surgery ; Osteotomy, Sagittal Split Ramus* ; Postoperative Complications ; Prognathism ; Radiography ; Temporomandibular Joint

OBJECTIVES: This study aimed to find the prevalence and occupational risk factors for major psychiatric disorders among subway drivers in South Korea. METHODS: Of all 998 current subway drivers, 995 participated in this study. The Korean version of the Composite International Diagnostic Interview (K-CIDI 2.1) was administered by trained interviewers to diagnose psychiatric disorders in all participants. The questions on socio-demographic characteristics and working conditions included some questions related to a person under train (PUT) experience and work-related problems. One-year prevalence and lifetime prevalence of major depressive disorder (MDD), post-traumatic stress disorder (PTSD), and panic disorder were diagnosed through the interview. The standardized prevalence ratios (SPRs) of these three disorders were calculated in the sample of subway drivers using the 2011 Korean National Epidemiologic Survey data as a basis. Multiple logistic regressions were performed to determine the association between work-related factors and the prevalence of the psychiatric disorders. RESULTS: The standardized prevalence ratios (SPRs) for a 1-year prevalence of MDD and PTSD among subway drivers were 1.1 (95% CI 0.7-1.7) and 5.6 (95% CI 3.1-8.8), respectively. Conflict with passengers was significantly associated with an increased risk for both MDD and PTSD in 1-year and in lifetime prevalence. Experiencing a sudden stop due to an emergency bell increased the risk of the lifetime prevalence of MDD (OR 2.61, 95% CI 1.14-6.97) and PTSD (OR 7.53, 95% CI 1.77-32.02). The risk of PTSD significantly increased among drivers who once experienced a near accident in terms of both the 1-year prevalence (OR 8.81, 95% CI 1.96-39.3) and the lifetime prevalence (OR 6.36, 95% CI 2.40-16.90). CONCLUSIONS: PTSD and panic disorder were more prevalent among subway drivers than in the general population. We found that having a conflict with passengers, a near accident, and a breakdown while driving can be risk factors for psychiatric disorders among subway drivers. Therefore, a prompt and sensitive approach should be introduced for these high risk groups within the subway company.
Depressive Disorder, Major ; Emergencies ; Humans ; Korea* ; Logistic Models ; Panic Disorder ; Prevalence ; Railroads* ; Risk Factors ; Stress Disorders, Post-Traumatic

OBJECTIVES: The most common occupational disease that is compensated by Industrial Accident Compensation Insurance (IACI) in Korea is musculoskeletal disease (MSD). Although complaints about the workers' compensation system have been raised by injured workers with MSD, studies that examine workers' experiences with the Korean system are rare. This paper is a qualitative study designed to examine injured workers' experiences with the workers' compensation system in Korea. The aim of this study is to explore the drawbacks of the workers' compensation system and to suggest ways to improve this system. METHODS: All workers from an automobile parts factory in Anseong, GyeongGi province who were compensated for MSD by IACI from January 2003 to August 2013 were invited to participate. Among these 153 workers, 142 workers completed the study. Semi-structured open-ended interviews and questionnaires were administered by occupational physicians. The responses of 131 workers were analyzed after excluding 11 workers, 7 of whom provided incomplete answers and 4 of whom were compensated by accidental injury. Based on their age, disease, department of employment, and compensation time, 16 of these 131 workers were invited to participate in an individual in-depth interview. In-depth interviews were conducted by one of 3 occupational physicians until the interview contents were saturated. RESULTS: Injured workers with MSD reported that the workers' compensation system was intimidating. These workers suffered more emotional distress than physical illness due to the workers' compensation system. Injured workers reported that they were treated inadequately and remained isolated for most of the recuperation period. The compensation period was terminated without ample guidance or a plan for an appropriate rehabilitation process. CONCLUSIONS: Interventions to alleviate the negative experiences of injured workers, including quality control of the medical care institutions and provisions for mental and psychological care for injured workers, are needed to help injured workers return to work earlier and more healthy.
Accidents, Occupational ; Automobiles ; Compensation and Redress ; Employment ; Gyeonggi-do ; Insurance ; Korea ; Musculoskeletal Diseases ; Occupational Diseases ; Occupational Injuries ; Qualitative Research ; Quality Control ; Rehabilitation ; Return to Work ; Sick Leave* ; Workers' Compensation

Follow-Up Studies ; Humans ; Jaw ; Orthognathic Surgery

0.05). Amnesia during local injection was observed in eight patients (34.8%). Compared with the preoperative anxiety score, the intraoperative anxiety score was decreased.CONCLUSION: In this study, we found cardiovascular and respiratory stability in intravenous sedation using dexmedetomidine with pethidine, in plate and screw removal, after orthognathic surgery. Furthemore, intravenous sedation using dexmedetomidine with pethidine shows adequate analgesic and sedative effects.]]>
Amnesia ; Anxiety ; Arterial Pressure ; Blood Pressure ; Dexmedetomidine ; Heart Rate ; Humans ; Hypnotics and Sedatives ; Meperidine ; Orthognathic Surgery ; Oxygen

Anesthesia, General ; Animals ; Azaperone ; Durapatite ; Humans ; Osteoblasts ; Osteogenesis ; Polyethylenes ; Polypropylenes ; Seeds ; Swine

Phosphatidylinositol phosphates (PtdInsPs) are ubiquitous membrane phospholipids that play diverse roles in cell growth and differentiation. To clarify the regulation mechanism acting on neurofilament light chain (NF-L) self assembly, we examined the effects of various PtdInsPs on this process. We found that PtdInsPs, including PI(4,5)P2, directly bind to the positively charged Arg54 of murine NF-L, and this binding promotes NF-L self assembly in vitro. Mutant NF-L (R53A/R54A) proteins lacking binding affinity to PtdInsPs did not have the same effect, but the mutant NF-L proteins showed greater self assembly than the wild-type in the absence of any PtdInsP. These results collectively suggest that Arg54 plays a pivotal role in NF-L self assembly by binding with PtdInsPs.
Animals ; Fluorescent Antibody Technique ; Mice ; Mutation/genetics ; Neurofilament Proteins/genetics/*metabolism ; Phosphatidylinositol Phosphates/*metabolism ; Phospholipase C gamma/metabolism ; *Protein Multimerization