Functional Grading Between Soft-Magnetic Fe-Co/Fe-Ni Alloys and the Effect on Magnetic and Microstructural Properties.

Producing soft magnetic alloys by additive manufacturing has the potential to overcome cracking and brittle fracture issues associated with conventional thermomechanical processing. Fe-Co alloys exhibit high magnetic saturation but low ductility that makes them difficult to process by commercial methods. Ni-Fe alloys have good ductility and high permeability in comparison to Fe-Co, but they suffer from low magnetic saturation. Functional grading between Fe-Co and Ni-Fe alloys through blown powder directed energy deposition can produce soft magnetic materials that combine and enhance properties beyond the strengths of the individual magnetic materials. This work focuses on the microstructure, crystal structure, and magnetic properties of functionally graded Fe49Co49V2/Ni80Fe16Mo4 coupons. The grading between the two materials is found to refine the microstructure, thereby improving the mechanical hardness without the use of a nonmagnetic element. Postbuild thermal treatments are found to recrystallize the microstructure and increase the grain size, leading to improved magnetic properties. Analysis of crystal structures provides an understanding of the solubility limits and phase equilibria between the BCC (Fe-Co) and FCC (Ni-Fe) structures. Success in functional grading of soft magnets may provide a pathway toward improving energy conversion efficiency through strategic combinations of high saturation and high strength materials.

Nursing students' learning flow, self-efficacy and satisfaction in virtual clinical simulation and clinical case seminar.

BACKGROUND: Virtual clinical simulations and clinical case seminar become widely utilized to address these constraints and help nursing students acquire clinical competencies as the limitations on practicum opportunities have been intensified by the COVID-19 pandemic. The purpose of this study was to examine learning flow, self-efficacy and satisfaction in virtual clinical simulation and clinical case seminar among nursing students. METHODS: A descriptive cross-sectional study was used. Forty-two junior nursing students completed survey questionnaires after participating in computer-based virtual clinical simulation and clinical case seminar, which aimed at acquiring knowledge and care skills in geriatric nursing. RESULTS: Significant differences in two methods were found in learning flow which included challenge-skill balance (t = -2.24, p < .05) and action-awareness merge (t = -3.32, p < .01). There was no significant difference in learning self-efficacy (t=-1.52, p = .137) and learning satisfaction (t=-0.92, p = .365). CONCLUSIONS: When there's a mismatch between the perceived challenge and the students' skill levels, it can hinder the learning process. Therefore, instructors should evaluate the clinical skill levels of their students and make necessary adjustments to the difficulty levels of simulation and clinical case seminar accordingly.

Effects of Physical Exercise Program for Older Family Caregivers of Persons With Dementia.

Self-efficacy plays a major role in improving health behaviors. The purpose of this study was to examine the effects of a physical activity program that utilized four self-efficacy resources in older family caregivers of persons with dementia. Quasi-experimental pretest-posttest design with control group was used. Study participants were 64 family caregivers aged 60 years or older. The intervention included a 60-minute group session per week for 8 weeks along with individual counseling and text messages. The experimental group showed significantly higher self-efficacy than the control group. In addition, physical function, quality of life related to health, caregiving burden, and depressive symptoms were significantly improved in the experimental group in comparison with those of control group. These findings suggest that a physical activity program with a focus on the resources of self-efficacy may be not only feasible but also effective for older family caregivers of persons with dementia.

Nurses' Perceptions About Smart Beds in Hospitals.

The purpose of this study was to examine nurses' perceptions of the smart mattress equipped with Internet of things, which are incorporated into patients' beds. In addition, their concerns and suggestions about smart mattress were explored. A total of 349 nurses in a tertiary hospital participated in a cross-sectional survey. Data were collected using questionnaires. Descriptive statistical analysis was used for survey data, whereas content analysis was used for qualitative data from open-ended questions. The participants' intention to accept the smart mattresses was 12.5 (SD, 1.73) on average, indicating a high level of acceptance. The participants expected the smart mattresses to decrease their physical work burden, improve work efficiency, and prevent pressure ulcers. However, they were concerned about an increase in other aspects of their workload and in patient safety problems due to false alarms, inaccuracies, and malfunctions of the device. Nurses suggested various features that can be integrated into smart mattress. It is critical to address nurses' perceptions, expectations, and concerns during the conceptual and developmental stage of new technology in order to improve the usability, acceptance, and adoption of smart mattresses and other new innovations in hospital settings.

Nurses' behavioral intention in using virtual clinical simulation training: By structural equation modeling.

AIM: To examine the relationship between the nurses' behavioral intention to use virtual clinical simulation training and study variables, including perceived usefulness, perceived ease of use, self-efficacy, technology anxiety, perceived enjoyment and personal innovativeness. BACKGROUND: Little is known about the nurses' behavioral intentions behind using virtual clinical simulation training. DESIGN: A cross-sectional study. METHODS: A total of 206 registered nurses participated in this survey. Data were collected through online survey from March 20, 2021, to April 2, 2021, since entry into the hospital was strictly controlled due to the COVID-19 outbreak. RESULTS: Structural equation modeling identified that both perceived usefulness and perceived ease of use were the predictors which influenced behavioral intention. Additionally, perceived enjoyment indirectly affected behavioral intention by influencing both perceived usefulness and perceived ease of use. CONCLUSION: The successful introduction of virtual clinical simulation training depends on nurses' willingness and acceptance of its use. The findings of this study show that virtual clinical simulation training should be perceived as useful, easy to use and enjoyable to be accepted by nurses. Virtual clinical simulation programs may have the potential to help improve nurses' clinical skills and competencies in patient care. TWEETABLE ABSTRACT: This study revealed that the usefulness of its contents, ease of use and enjoyment are important to increase nurses' behavioral intention to use virtual clinical simulation training.

COVID-19 and related social distancing measures induce significant metabolic complications without prominent weight gain in Korean adults.

Background: This study using multi-center health examination data from Korean adults was conducted to confirm changes in weight, and their related cardiometabolic parameters, before and after strengthening of social distancing regulations. Methods: A retrospective cohort study was conducted using health check-up data from 13 university hospitals. The study period was from January 2018 to July 2020. To examine the effect of systematic social distancing measures, participants who underwent a health check-up (Visit 3) between July 2020 and July 2021 (during full scale social distancing), and had undergone two previous health check-ups (Visits 1 and 2) between January 2018 and June 2020 (before social distancing), were selected. In total, data from 7,875 participants were analyzed. Linear mixed-effect models were used to calculate estimates of anthropometric indices and metabolic markers measured on Visits 2 and 3, compared with measurements from Visit 1. Results: There were no significant differences in body weight, body mass index, waist circumference, and body composition on Visit 3 than on Visits 1 and 2. However, the odds of metabolic syndrome and its components, including hypertension, high glucose, diabetes, hypercholesterolemia, hypertriglyceridemia, hyper-non-high-density lipoprotein cholesterolemia, and dyslipidemia were significantly higher on Visit 3 than on Visits 1 and 2. The increase in metabolic complications was marked, particularly in relatively young adults who visited health check-up centers located in the capital area. Conclusion: Metabolic syndrome and its components were significantly worse after high level social distancing, although there were no significant increases in anthropometric indices and body fat levels. Healthcare providers need to prevent and manage worsening of metabolic parameters in subpopulations prone to be more sedentary and eat unhealthy food during the COVID-19 pandemic and associated social distancing measures.

Fatty Liver Change in Korean Adults in a Systematic Social Distancing System Amid the COVID-19 Pandemic: A Multicenter Analysis.

In response to the COVID-19 pandemic, the Korean government implemented policies including the systematic social distancing (SSD) system which started on 28 June 2020. The present study investigated the development and aggravation of fatty liver measured using ultrasonography during the transition period (from pre-SSD to SSD) compared to the fatty liver changes during the pre-SSD period. Changes in fatty liver and liver enzymes were assessed in different groups stratified by alcohol consumption. Our retrospective cohort analysis included 5668 participants who underwent health checkups at 13 university hospitals during the SSD period and two or more checkups before the SSD period. Fatty liver developed and aggravated more in the transition period (13.6% development and 12.0% aggravation) than in the pre-SSD period (10.8% development and 10.1% aggravation) in the alcohol consumption group. This finding was more prominent in women than in men. Abnormal alanine transaminase levels were more often developed in the transition period than in the pre-SSD period, especially in men (11.1% vs. 8.6% in each period). In conclusion, the SSD system may contribute to fatty liver changes in individuals who regularly consume alcohol. Further research of the post-pandemic period is needed to assess long-term changes in fatty liver disease.

Prediction of Cardiovascular Risk Using Nonalcoholic Fatty Liver Disease Scoring Systems.

This study aimed to determine whether nonalcoholic fatty liver disease (NAFLD) is an independent risk factor for CVD and to identify the most useful NAFLD diagnostic tool for predicting CVD. Data from a total of 23,376 Korean adults without established CVD were analyzed. Cardiovascular risk was calculated using the Framingham Risk Score (FRS) 2008. The presence of NAFLD was defined as moderate-to-severe fatty liver disease diagnosed by ultrasonography. Scores for fatty liver were calculated using four NAFLD scoring systems (Fatty Liver Index, FLI; Hepatic Steatosis Index, HSI; Simple NAFLD Score, SNS; Comprehensive NAFLD Score, CNS), and were compared and analyzed according to cardiovascular risk group. Using the FRS, 67.4% of participants were considered to be at low risk of CVD, 21.5% at intermediate risk, and 11.1% at high risk. As the risk of CVD increased, both the prevalence of NAFLD and the score from each NAFLD scoring system increased significantly (p < 0.001). In the unadjusted analysis, the CNS had the strongest association with high CVD risk; in the adjusted analysis, the FLI score was most strongly associated with high CVD risk. Fatty liver is an important independent risk factor for CVD. Therefore, the available NAFLD scoring systems could be utilized to predict CVD.

Safety and Effectiveness of an In-Hospital Screening Station for Coronavirus Disease 2019 in Response to the Massive Community Outbreak.

PURPOSE: To evaluate the results of operating an in-hospital coronavirus disease 2019 screening station on an outpatient basis and to identify the effectiveness and necessity of such a screening station. PATIENTS AND METHODS: This cross-sectional study included 1345 individuals who were tested for COVID-19 using real-time reverse transcription polymerase chain reaction (RT-PCR) at an in-hospital screening station on an outpatient basis. The subjects were healthcare workers (HCWs) with suspected COVID-19 symptoms or exposure to patients with confirmed COVID-19, caregivers at the hospital for complete enumeration, and patients who were scheduled to be admitted to a nonrestricted area in the hospital or to visit for outpatient treatment, but had suspected COVID-19 symptoms. The subjects were divided and compared as follows: HCW versus non-HCW groups and RT-PCR positive versus negative groups. RESULTS: A total of 140 had symptoms, 291 wanted to be tested, and 664 were asymptomatic but were screened. Seven subjects had positive results for COVID-19. Compared with the non-HCWs, the HCWs were younger and had a lower rate of underlying medical conditions. In addition, there were more women, individuals with exposure to confirmed cases, and individuals with symptoms or those who just wanted to be tested. The frequency of all symptoms was high among the HCWs. The results of the logistic regression analysis showed that the HCWs were significantly associated with the presence of symptoms, having an odds ratio of 23.317 (confidence interval, 15.142-35.907L; P < 0.001). The positive group had a high rate of exposure to patients with confirmed COVID-19 and had more subjects with symptoms or those who wanted to be tested. CONCLUSION: In-hospital screening stations are a relatively safe way to protect and support HCWs and to reduce and manage the spread of infection within the hospital effectively during an outbreak in the community.

Extracellular Vesicles Derived from Kefir Grain Lactobacillus Ameliorate Intestinal Inflammation via Regulation of Proinflammatory Pathway and Tight Junction Integrity.

The aim of this study was to demonstrate the anti-inflammatory effect of Lactobacillus kefirgranum PRCC-1301-derived extracellular vesicles (PRCC-1301 EVs) on intestinal inflammation and intestinal barrier function. Human intestinal epithelial cells (IECs) Caco-2 were treated with PRCC-1301 EVs and then stimulated with dextran sulfate sodium (DSS). Real-time RT-PCR revealed that PRCC-1301 EVs inhibited the expression of pro-inflammatory cytokines in Caco-2 cells. PRCC-1301 EVs enhanced intestinal barrier function by maintaining intestinal cell integrity and the tight junction. Loss of Zo-1, claudin-1, and occludin in Caco-2 cells and the colitis tissues was recovered after PRCC-1301 EVs treatment, as evidenced by immunofluorescence analysis. Acute murine colitis was induced using 4% DSS and chronic colitis was generated in piroxicam-treated IL-10-/- mice. PRCC-1301 EVs attenuated body weight loss, colon shortening, and histological damage in acute and chronic colitis models in mice. Immunohistochemistry revealed that phosphorylated NF-κB p65 and IκBα were reduced in the colon tissue sections treated with PRCC-1301 EVs. Our results suggest that PRCC-1301 EVs may have an anti-inflammatory effect on colitis by inhibiting the NF-κB pathway and improving intestinal barrier function.

Association between Breakfast Skipping and the Metabolic Syndrome: The Korea National Health and Nutrition Examination Survey, 2017.

Background and Objectives: Recently, the prevalence of metabolic syndrome in Korea has increased rapidly. Current knowledge reflects the importance of dietary control in relation to the metabolic syndrome. The objective of this study was to evaluate the influence of skipping breakfast on the metabolic syndrome. Materials and Methods: We conducted a cross-sectional study using data from the Korea National Health and Nutrition Examination Survey 2017 for the second year. A total of 3864 adults aged 20 to 64 were included in the study. We stratified the study population into three groups, based on breakfast patterns: the regular group, irregular group, and skipping group. Multiple logistic regression analysis was used to analyze the association between skipping breakfast and the presence of metabolic syndrome. Results: We noted an increase in the proportion of metabolic syndrome cases as follows: skipping group (3.3%), irregular group (5.4%), and regular group (8.5%) (p < 0.001). The multivariate-adjusted odds ratios of metabolic syndrome in the skipping and irregular groups compared with the regular group were 0.68 (95% CI; 0.35 to 1.35) and 0.81 (95% CI; 0.51 to 1.28), respectively. In the 40-65-year-old age group, which had a high prevalence of metabolic syndrome, the multivariate-adjusted odds ratios of metabolic syndrome in the skipping group compared with regular group were 0.78 (95%CI, 0.39 to 1.62). Conclusions: There was no significant correlation between skipping breakfast and risk factors of metabolic syndrome (after adjusting for risk factors), but a tendency of skipping breakfast to lower the risk of metabolic syndrome was observed. A rationale for these results is proposed through the association between skipping breakfast and intermittent fasting.

Inflammatory markers for predicting overall survival in gastric cancer patients: A systematic review and meta-analysis.

Systemic inflammatory biomarkers have begun to be used in clinical practice to predict prognosis and survival of cancer patients, but the approach remains controversial. We conducted a meta-analysis to determine the predictive value of the c-reactive protein (CRP), neutrophil-to-lymphocyte ratio (NLR), and Glasgow prognostic score (GPS)/modified Glasgow prognostic score (mGPS) in the clinical outcome of gastric cancer (GC) patients. We searched literature databases to identify relevant studies. All articles identified in the search were independently reviewed based on predetermined selection criteria. Meta-analysis was conducted to calculate the hazard ratio (HR) and 95% confidence intervals (CI) of overall survival of the included studies. A total of 41 eligible cohort studies, involving a total of 18,348 patients meeting the inclusion criteria, were considered for meta-analysis. Increases in CRP (HR = 1.654, 95% CI: 1.272-2.151), NLR (HR = 1.605, 95% CI: 1.449-1.779), and GPS/mGPS (HR = 1.648, 95% CI: 1.351-2.011) were significantly associated with poorer survival in patients with GC. Substantial heterogeneities were noted in all three markers (I2 = 86.479%, 50.799%, 69.774%, in CRP, NLR, and GPS/mGPS, respectively). Subgroup analysis revealed a significant positive correlation between each marker and poor survival, regardless of country, study quality, cancer stage, study design, or the inclusion of patients undergoing chemotherapy. This meta-analysis demonstrates that CRP, NLR, and GPS/mGPS are associated with poor survival in patients with GC. Further prospective studies using standardized measurements are warranted to conclude the prognostic value of various inflammatory markers.

Association between Bone Mineral Density and Serum Iron Indices in Premenopausal Women in South Korea.

BACKGROUND: Osteoporosis is characterized by a decrease in bone mineral density (BMD) and increased risk of fragility fractures. Serum iron level may interact with bone health status. This study investigated the correlations of BMD with serum iron level, hemoglobin level, and total iron-binding capacity (TIBC). METHODS: We performed a retrospective analysis of data from the medical records of premenopausal women in South Korea. The women's BMDs and the Z scores of the BMDs were verified using dual-energy X-ray absorption. The participants were stratified into quartiles for analyses of the associations of BMD with serum iron level, TIBC, and hemoglobin level. RESULTS: A simple linear regression analysis revealed associations of changes in BMD with iron level (ß=-0.001, standard error [SE]=0.001, P<0.001), hemoglobin level (ß=0.015, SE=0.003, P<0.001), and TIBC (ß=0.001, SE=0.001, P<0.001). This pattern was also observed in a multiple linear regression analysis. A multivariate logistic regression analysis of iron level and TIBC for low BMD revealed odds ratios of 1.005 (P<0.001) and 0.995 (P<0.001), respectively. CONCLUSION: This study demonstrated clear relationships of changes in BMD with serum iron level and TIBC, and thus confirms the usefulness of these markers in the clinical evaluation of iron storage and BMD in younger women.

Effect of Prognosis Awareness on the Survival and Quality of Life of Terminally Ill Cancer Patients: A Prospective Cohort Study.

BACKGROUND: Physicians and caregivers are conflicted over whether to inform patients that their disease is terminal. Studies examining the effect of awareness of prognosis on the survival and quality of life of terminally ill cancer patients report conflicting results. This study aimed to assess the effects of prognosis awareness on the survival time and psychological health of terminally ill cancer patients. METHODS: Patients in the hospice wards of two general hospitals were asked to complete a questionnaire. All were mentally alert and could express themselves clearly. Awareness of prognosis was defined as knowing both the diagnosis and exact prognosis. Survival time was defined as the time from hospital admission to death. Multiple psychological examinations were conducted to verify the effect of prognosis awareness on psychological health. RESULTS: Of the 98 subjects who met the inclusion criteria, 65 (66.3%) were aware of their terminal status. The patients' awareness was significantly related to survival time after adjusting for clinical variables with a hazard ratio of 1.70 (95% confidence interval [CI], 1.01-2.86). Furthermore, the unaware group had a higher risk of cognitive impairment (Mini-Mental State Examination <24; adjusted odds ratio [aOR], 3.65; 95% CI, 1.26-10.59) and a poorer quality of life (physical component summary of the Short Form 36-item Health Survey <20; aOR, 3.61; 95% CI, 1.12- 11.60) than the aware group. CONCLUSION: Knowledge of the exact prognosis might have a positive effect on the survival and quality of life of terminally ill cancer patients.

Shikimic acid, a mannose bioisostere, promotes hair growth with the induction of anagen hair cycle.

Shikimic acid (SA) has recently been found to be a major component of plant stem cells. The exact effects of SA on human hair follicles (HFs) is unknown. The purpose of this study was to examine the effects of SA on hair growth. We investigated the effect of SA on an in vivo C57BL/6 mouse model. We examined the expression of mannose receptor (MR), which is a known receptor of SA, in human HFs and the effect of SA on human dermal papilla cells (hDPCs), outer root sheath cells (hORSCs), and on ex vivo human hair organ culture. SA significantly prolonged anagen hair growth in the in vivo mouse model. We confirmed expression of the MR in human HFs, and that SA increased the proliferation of hDPCs and hORSCs. It was found that SA enhanced hair shaft elongation in an ex vivo human hair organ culture. SA treatment of hDPCs led to increased c-myc, hepatocyte growth factor, keratinocyte growth factor and vascular endothelial growth factor levels and upregulation of p38 MAPK and cAMP response element-binding protein levels. Our results show that SA promotes hair growth and may serve as a new therapeutic agent in the treatment of alopecia.

Effects of Pet Insects on Cognitive Function among the Elderly: An fMRI Study.

Animal-assisted therapy has positive effects on cognitive function, depression, performance ability, and social functioning in elderly patients. The aim of this study was to evaluate the effects of rearing pet insects on the cognitive function of healthy elderly participants, with fMRI (functional magnetic resonance imaging) being used for this purpose. Community-dwelling right-handed elderly women (≥60 years) with normal cognitive function were enrolled and randomized at a 1:1 ratio into two groups: insect-rearing and control (n = 16) groups, with the insect-rearing group being further classified into two groups for analysis according to the subjects' scores in the Wisconsin Card Sorting Test, WCST) at the baseline fMRI: Insect-rearing group I with a relatively high score (n = 13), and insect-rearing group II with a relatively low score (n = 6). The insect-rearing groups received and reared crickets as pet insects for 8 weeks. The WCST consisted of two variations, a high level baseline (HLB) and semi-WCST version. There was a significant difference accuracy of the HLB-semi-WCST (p < 0.05) in insect-rearing group II after 8 weeks from the baseline test. In the fMRI analysis involving the WCST reaction test, increased activation was observed in the right dorsal lateral prefrontal cortex and parietal cortex in insect-rearing group II when the semi-WCST, rather than the HLB, was performed. Rearing pet insects showed positive effects on executive functions and performance improvement in elderly women. Further larger studies on the effects of pet insects on cognitive function are warranted.

The Association between Mineral and Trace Element Concentrations in Hair and the 10-Year Risk of Atherosclerotic Cardiovascular Disease in Healthy Community-Dwelling Elderly Individuals.

This cross-sectional analysis included 137 Korean subjects aged 60⁻79 years. All subjects underwent anthropometric measurements and laboratory tests. Scalp hair samples were obtained from each individual, the concentrations of 36 minerals and trace elements were analyzed, and 16 ratios of elements were calculated. ASCVD risk was estimated using pooled cohort ASCVD risk assessment equations for 10-year risk profiles. The 137 subjects were divided into three risk groups: low (<5%, n = 28), intermediate (5% to <7.5%, n = 21), and high (≥7.5%, n = 88) risk groups. After adjusting for obesity (BMI ≥ 25 kg/m²) and sex, Na concentration (mg%) in hair was significantly lower in the low-risk (13.91 ± 7.02) than in the intermediate-risk (47.18 ± 8.08) and high-risk (36.76 ± 3.95) groups (p for trend = 0.024). The concentration of K (mg%) in hair was also positively associated with the severity of ASCVD risk (10.50 ± 8.37, 23.62 ± 9.63, 33.31 ± 4.71, respectively; p for trend = 0.017), but their differences were not statistically significant (p = 0.059). By contrast, the levels of Co, U, and Hg, and the Ca/P and Ca/Mg ratios, were negatively correlated with the severity of ASCVD risk (p for trend < 0.05). Mean Na concentration in hair was significantly lower in the low-risk than in the other risk groups. By contrast, Co, U, and Hg concentrations showed significant negative associations with risk severity. Further studies are needed to assess whether dietary modification for trace elements could lower the risk of ASCVD.

Novel effect of sildenafil on hair growth.

BACKGROUND: Sildenafil, a phosphodiesterase 5 (PDE5) inhibitor, is known to increase the intracellular level of cyclic guanosine monophosphate (cGMP), which causes vasodilation. However, the effect of sildenafil on human hair follicles (hHFs) is unknown. OBJECTIVE: The purpose of this study was to determine the role of sildenafil in hair growth. METHODS: We investigated the expression of PDE5 in human dermal papilla cells (hDPCs) and hHFs. The effects of sildenafil on hDPC proliferation were evaluated using BrdU assays. The mRNA expression of growth factors and extracellular signal-regulated kinase (ERK) phosphorylation were investigated using real-time PCR and western blotting, respectively. Additionally, anagen induction and perifollicular vessel formation were evaluated using an in vivo mice model. RESULTS: We confirmed high expression of PDE5 in hDPCs and hHFs. Sildenafil enhances proliferation of hDPCs and up-regulates the mRNA expression of vascular endothelial growth factor (VEGF) and platelet-derived growth factor (PDGF), which are responsible for hair growth. Additionally, sildenafil up-regulates the levels of phosphorylated ERK and accelerates anagen induction by stimulating perifollicular vessel formation after topical application in mice. CONCLUSION: Our study demonstrates for the first time, the significant therapeutic potential of sildenafil on hair growth and its potential use in treatment of alopecia.

Biomechanical effect of mandibular advancement device with different protrusion positions for treatment of obstructive sleep apnoea on tooth and facial bone: A finite element study.

BACKGROUND: The mandibular advancement device (MAD) is widely used for obstructive sleep apnoea (OSA) treatment, and several studies have demonstrated its effectiveness. However, no comprehensive studies have yet examined the biomechanical safety of the MAD. OBJECTIVES: The objective of this study was to analyse the biomechanical effect of different protrusion positions of a MAD on the teeth and facial bones. METHODS: The posterior restorative forces due to the stretched mandibular muscles were measured by pressure sensors attached to the experimental mandibular advancement device for mandibular protrusions of 10-70% of the maximum protrusion of the subject. A detailed three-dimensional biomechanical model of the study subject, constructed from computed tomography scans, was used in finite element analysis, with loading conditions calculated from the measured posterior restorative forces. The outcome measures were the principal stresses on the periodontal ligaments (PDL) and cancellous bone, and the pressure at the PDL surfaces. The measurements were used to analyse the risk of the tooth movement, tooth root resorption, and bone resorption. RESULTS: The lowest and highest restorative forces occurred at 40% and 70% of maximum protrusion, respectively. The highest risk of tooth movement occurred at the mandibular molar teeth. The mandibular second molar teeth had the highest risks of root and bone resorption. CONCLUSIONS: Mandibular advancement at 70% of maximum protrusion induces risks of tooth root resorption and bone resorption. The mandibular second molars were subjected to the highest stresses. Stress on the teeth and facial bones was the lowest at 40% of maximum mandibular advancement.