The Effect of Intermittent Resistance Activity for Interrupting Prolonged Sitting on Vascular Function and Postprandial Metabolism after a High-fat Meal / 대한스포츠의학회지

Purpose@#Numerous studies have reported the effects of interrupting prolonged sitting with aerobic exercise on vascular and postprandial function, but the effects of resistance exercise for interrupting prolonged sitting remain unclear. We tested the hypothesis that intermittent resistance activity breaks would attenuate prolonged sittinginduced vascular and postprandial metabolic dysfunction. @*Methods@#Fourteen healthy adults (age, 24±2 years; body mass index, 22.0±2.4 kg/m2 ) completed two trials in a randomized cross-over design. During a 4-hour sitting after a high-fat meal, the participants underwent either resistance activity (RA) with 10 repetitions of five exercises every hour or uninterrupted sitting as a control trial (SIT). Plasma glucose, triglycerides, and brachial artery blood pressure, along with blood flow and shear rate in the superficial femoral artery and carotid artery were measured at baseline and every hour during the 4-hour sitting period. Brachial artery flow-mediated dilation (FMD) was measured at baseline, 2 hours, and 4 hours after the start of the sitting. @*Results@#Plasma glucose and triglycerides increased after a high-fat meal in both RA and SIT groups without a significant interaction effect. In addition, while SIT group decreased brachial artery FMD (7.2%±2.0% to 6.5%±2.7% to 5.1%±2.6%), RA did not attenuate a decrease in FMD (7.6%±3.4% to 7.3%±3.1% to 6.7%±2.7%, interaction p=0.581). @*Conclusion@#Our findings indicate that interrupting prolonged sitting with intermittent RA did not attenuate the negative effects of sitting on vascular function and postprandial metabolism in young healthy adults.

Acute Effects of Virtual Reality Exergame on Vascular Function in Children and Adolescents with Congenital Heart Disease: A Single-Arm Trial / 대한스포츠의학회지

Purpose@#Regular aerobic exercise improves exercise capacity and quality of life in children with congenital heart disease (CHD), but it remains unclear whether aerobic exercise would improve vascular function in children with CHD. We tested the hypothesis that acute bout of virtual reality (VR) exergame would improve vascular function in children with CHD. @*Methods@#In a single-arm study, eight children (age, 9±1 years; five males) with CHD participated in VR exergame (30 minutes at 40% of heart rate reserve) using a stationary cycle ergometer with a head mount display. Endothelial function and arterial stiffness as surrogate markers of vascular function were assessed via reactive hyperemia index (RHI) and augmentation index (AIx) using peripheral arterial tonometry at baseline and 30 minutes after VR exergame. @*Results@#Compared to baseline, VR exergame improved in RHI (1.08 [0.96–1.30] to 1.16 [1.09–1.36], p＜ 0.05) and natural log transformed RHI (0.07 [−0.04–0.26] to 0.15 [0.09–0.31], p＜ 0.05). However, no significant changes were observed for decrease AIx (−1.00 [−9.00–9.50] to −7.00 [−14.00–8.75], p=0.547) and AIx@75 (−6.50 [9.75–3.50] to −4.50 [−13.00–4.50], p=0.735) (all index values are reported as median [interquartile range]). @*Conclusion@#These findings suggest that a single bout of VR exergame has the potential to improve vascular endothelial function in children with CHD.

Association between masticatory function and cognitive impairment in the elderly / 대한구강보건학회지

Objectives@#With the surge in the elderly population, a growing interest in the prevention and treatment of geriatric diseases has been observed, along with awareness of the severity of problems associated with dementia, a cognitive impairment. The purpose of this study was to investigate the correlation between chewing ability and cognitive function among elderly people residing in a rural area. @*Methods@#A total of 162 elderly individuals, aged between 65 and 97 years, were surveyed. Trained examiners conducted interviews and assessments of chewing ability, on the basis of the number of remaining teeth, denture status, masticatory performance evaluating gum, ShadeEye-NCC measuring overall change in color of the gum (ΔE), and T-Scan® III analyzing distribution of occlusion patterns. Cognitive function was assessed using the Korean version of the Mini-Mental State Examination-Dementia Screening (MMSE-DS) tool. @*Results@#Participants with a low score in the MMSE-DS were found to have distinguishably lower denture need, smaller number of remaining teeth, and lesser color change in the masticatory performance evaluating gum. In the cognitive impairment group, a tendency of having unilateral and anterior occlusion led to occlusal discomfort and chewing difficulties. @*Conclusions@#The study highlights important associations between chewing ability and cognitive function. The finding corroborates that tooth loss may be a predictive risk factor for cognitive impairment.

Association between masticatory function and cognitive impairment in the elderly / 대한구강보건학회지

Objectives@#With the surge in the elderly population, a growing interest in the prevention and treatment of geriatric diseases has been observed, along with awareness of the severity of problems associated with dementia, a cognitive impairment. The purpose of this study was to investigate the correlation between chewing ability and cognitive function among elderly people residing in a rural area. @*Methods@#A total of 162 elderly individuals, aged between 65 and 97 years, were surveyed. Trained examiners conducted interviews and assessments of chewing ability, on the basis of the number of remaining teeth, denture status, masticatory performance evaluating gum, ShadeEye-NCC measuring overall change in color of the gum (ΔE), and T-Scan® III analyzing distribution of occlusion patterns. Cognitive function was assessed using the Korean version of the Mini-Mental State Examination-Dementia Screening (MMSE-DS) tool. @*Results@#Participants with a low score in the MMSE-DS were found to have distinguishably lower denture need, smaller number of remaining teeth, and lesser color change in the masticatory performance evaluating gum. In the cognitive impairment group, a tendency of having unilateral and anterior occlusion led to occlusal discomfort and chewing difficulties. @*Conclusions@#The study highlights important associations between chewing ability and cognitive function. The finding corroborates that tooth loss may be a predictive risk factor for cognitive impairment.

Acute Effects of Postexercise Cigarette Smoking on Central Hemodynamics and Endothelial Function in Young Men / 대한스포츠의학회지

Purpose@#Recovery from exercise is a vulnerable phase that has been linked to increased susceptibility to sudden cardiovascular events. Cigarette smoking increases the risk of cardiovascular mortality and morbidity. We tested the hypothesis that postexercise cigarette smoking would attenuate hemodynamics and vascular function during recovery from exercise in young men. @*Methods@#Thirteen habitual smokers (age, 22±3 years; body mass index, 25.1±3.6 kg/m 2 ) participated in (1) cigarette smoking (0.6 mg nicotine) and (2) sham smoking (SHAM) immediately postexercise (30 minutes on a treadmill;40% to 60% of heart rate [HR] reserve) in a randomized order. Assessments were hemodynamics (HR, rate-pressure product [RPP], brachial and central artery blood pressures) and vascular function (arterial stiffness via carotid-femoral pulse wave velocity [PWV]; conduit vessel function via brachial artery flow-mediated dilation [FMD]). All variables were assessed at baseline, 10 minutes, and 30 minutes postexercise, except for FMD (baseline and 30 minutes postexercise). @*Results@#Compared with the SHAM trial, cigarette smoking increased HR, RPP, and brachial and central blood pressures postexercise (interaction, p＜ 0.05). PWV reduced and FMD increased postexercise in the SHAM trial, while cigarette smoking attenuated exercise-induced improvements (interaction, p＜ 0.05). @*Conclusion@#Cigarette smoking attenuated hemodynamic recovery and an improvement in arterial stiffness and conduit vessel function in young habitual smokers, thereby providing evidence for the negative effects of cigarette smoking during recovery from exercise.

Comparison of Effects of Acute Tabata-Styled and Moderate Intensity Continuous Exercise on Vascular Function in Healthy Young Men / 대한스포츠의학회지

Purpose@#Regular moderate-intensity aerobic exercise confers immense vascular benefits, yet the lack of time remains the most common barrier to a regular exercise routine. A Tabata exercise is a type of high-intensity interval training exercise that is time efficient and has recently been demonstrated to improve cardiorespiratory fitness and metabolic profiles, but its benefits on vascular function still remain unclear. We tested the hypothesis that the Tabata-styled exercise would be as effective as moderate-intensity continuous exercise (MICE) in improving vascular function in young healthy adults. @*Methods@#Using a randomized, cross-over design, fourteen healthy men (age, 23.8±2.3 years; body mass index, 23.7±2.2 kg/m2 ) performed two acute exercise trials, separated at least by 72 hours: a modified Tabata-styled exercise (eight sets of 20-second exercise at 120% of maximal power output using a bike and 10-second rest, total 4 minutes) or a MICE for 30 minutes at a heart rate reserve of 40%–60%. Vascular function was assessed via brachial artery flow-mediated dilation and arterial stiffness (pulse wave velocity and augmentation index) at baseline and again at 60 minutes and 120 minutes after exercise. @*Results@#Compared with MICE, a Tabata-styled exercise increased heart rate at 60 minutes (p＜ 0.05). Both exercises improved vascular function to a similar extent, as evidenced by an increase in flow-mediated dilation and a reduction in arterial stiffness at 60 minutes and 120 minutes (p＜ 0.05). @*Conclusion@#These findings demonstrate that the Tabata-styled exercise is a time-efficient exercise strategy that is as effective as MICE in enhancing vascular function in healthy young men.

Job satisfaction level of dental staff at oral health centers for people with special needs / 대한구강보건학회지

OBJECTIVES: The purpose of this study was to investigate the job satisfaction level of the dental staff working at oral health centers for people with disabilities. METHODS: A questionnaire survey was conducted with 73 dentists and dental hygienists working at seven regional oral health centers for people with special needs and dental hospitals for people with disabilities in Seoul. The questionnaire consisted of seven questions across two subscales: general satisfaction (4 questions) and satisfaction with wage and welfare (3 questions). The internal consistency of the questionnaire items was assessed using Cronbach's alpha (0.80). The responses were analyzed using a t-test with SPSS (version 23.0). RESULTS: Of the 73 dental staff members, 50% were dentists, 64% were women, and participants' average age was 30 years. In total, 58% of the participants had up to five years of experience working with people with disabilities, 42% of them worked full-time, and each participant treated an average of 200 patients with disabilities per month. The participants reported that their salary was relatively low. Dental hygienists had higher satisfaction level than dentists in the institution's welfare work. The more full-time workers answered, the more suitable they are for their work. CONCLUSIONS: The job satisfaction level of most professionals working in oral health centers for people with disabilities was not very high but they felt rewarded by their welfare work. It was inferred that it is necessary to examine and improve institutional support aspects such as human resource support. Increasing the number of centers in the central region is also needed.

Association between the management of oral health and experience of oral health education and an investigation of influential factors of the PHP index in university students / 대한구강보건학회지

OBJECTIVES: The aims of this study were to determine the association between the management of oral health and experiences of oral health education and to investigate the influential factors of the Patient Hygiene Performance (PHP) index in an area's university students. In addition, we explored the factors that influence the PHP index and how to effectively promote oral health. METHODS: All collected data were analyzed using the χ2 test, the t-test, and multiple regression using SPSS version 23.0 for Microsoft Windows. The statistical significance level was set at 5%. RESULTS: The total age of 380 participants ranged from 18 to 39 years (mean 22.22±2.43). No significant differences were found in oral health status and experiences of oral health education. CONCLUSIONS: Active national-based policies to develop regular and systematic national oral health education programs are needed.

Association of Sleep Duration and Depression with Periodontitis in Older People Aged 65 Years and Older / 치위생과학회지

BACKGROUND: Sleep disorder is a precursor to depression, which is one of the psychological factors associated with periodontal disease that, in turn, affects general and periodontal health. This study aimed to investigate the relationship between sleep duration, depression, and periodontitis in older people aged over 65 years. METHODS: A total of 2,002 older adults aged 65 years or older were included in the study. Their general and health aspects, including smoking, drinking, diabetes, hypertension, and depression, were investigated. Periodontitis was examined using the Community Periodontal Index (CPI). Data were analyzed through a complex sampling design method. Frequency and crossover analyses were conducted to investigate the relationship between depression and periodontitis. To investigate the effect of depression on periodontitis, a logistic regression analysis was performed. RESULTS: Regarding depression and participants' general characteristics, statistically significant differences were found in sex, economic activity, smoking habit, and CPI (p<0.05). In the presence of depression, the odds ratio for periodontitis was 1.84, and the adjusted odds ratio for age, sex, economic activity, residence type, household income, education level, smoking habit, drinking, hypertension, and diabetes was 1.72, representing a significant difference (p<0.05). CONCLUSION: This study examined the relationship between depression and periodontitis in older persons and confirmed a significant correlation. As the population of older adults increases, we should pay attention to their mental and oral health as well as systemic diseases. Various programs for the health promotion of older persons need to be implemented to improve the quality of life of older people.

Presence of Metabolic Syndrome Components Is Associated with Tooth Loss in Middle-Aged Adults

PURPOSE: In general, the prevalence of metabolic syndrome (MS) and tooth loss increases with age. We investigated the relationship between the presence of MS, its elements, and tooth loss in middle-aged Korean adults. MATERIALS AND METHODS: This study included Korean adults between 30 and 64 years of age who resided in the capital area of Seoul. From January to June 2014, individuals interested in participating in the oral health survey among those who visited the university hospital's cardiovascular center and provided informed consent were selected. Among 748 subjects who responded to the oral health questionnaires, 30 were excluded due to unclear responses; therefore, a total of 718 were included in the final analysis. RESULTS: The crude odds ratio (OR) of ≥one MS component affecting tooth loss was 1.45 [95% confidence interval (CI), 1.06–2.00]. After adjusting for sex, age, education, income level, occupation, smoking status, kidney disease, chronic obstructive pulmonary disease, and rheumatic disease, the adjusted OR was 1.47 (95% CI, 1.06–2.05), which was statistically significant (p<0.05). The OR for tooth loss was higher in the presence of ≥one component of MS (50–64 years of age) in females. CONCLUSION: This study suggests that female aged 50–64 years may have higher likelihood of tooth loss upon the presence of at least one MS component. Prevention against MS among female of older age could contribute to maintenance of remaining teeth. Further well-designed studies are needed.

Can the number of functional teeth potentially affect cognitive function? / 대한구강보건학회지

OBJECTIVES: With the growing elderly population, there is an increasing interest in the oral and general health of elderly individuals. Loss of teeth is representative of oral disease in elderly individuals and is associated with medical and dental problems. The purpose of this study was to investigate the relationship between the number of remaining functional teeth and cognitive function. METHODS: A total of 456 (111 public health centers, 261 senior centers, 84 sanatoriums) older adults (aged ≥65 years) residing in Korea were included. A mental health nurse examined the cognitive function using the Korean version of the Mini-Mental State Examination. A dentist examined the number of functional teeth and denture status through an oral examination, while a dental hygienist surveyed the subjective masticatory level using a questionnaire. RESULTS: The mean age of the participants was 79.5 years (range 65–97 years), and 76.1% of them were women. Participants with a small number of functional teeth had lower cognitive function. In these participants, the odds ratio with poor cognitive function was 2.30 times higher; it was 2.74 times higher after adjusting for age, sex, residence, education, and denture use, and was statistically significant. CONCLUSIONS: Our study suggested that the number of functional teeth was associated with cognitive function in the Korean elderly population.

The Relationship between Oral Health and Stroke in Adults Based on the 6th (2015) Korea National Health and Nutrition Examination Survey / 치위생과학회지

Stroke is the second cause of death worldwide, although the survival period is increasing after the occurrence of stroke, severe physical disability is caused with aftereffect. Oral inflammation is not limited to the oral cavity, it can cause malignant changes in other tissues and organs. In previous studies, we confirmed the relationship between tooth loss and stroke due to periodontal inflammation. The purpose of this study was to investigate the relationship between oral health and stroke such as oral hygiene behavior, tooth loss and periodontal disease among Korean adults over 40 years of age. This study was analyzed using the 6th Korea National Health and Nutrition Examination Survey (KNHANES) data. A total of 3,389 adults over 40 years of age were analyzed as final subjects. Socioeconomic statuses and oral health status was analyzed using a complex sample analysis technique. Logistic regression was used to analyze the relationship of oral health and stroke, and 95% confidence intervals were computed using SPSS. When the prevalence of stroke according to oral hygiene behavior was checked, the prevalence of strokes was lower in subjects who had a lot of brushings per day and subjects who used oral hygiene products (p 0.05). Loss of teeth was found to be associated with the risk factor of stroke. Therefore, loss of teeth due to periodontal disease is an additional issue that should be considered as a risk factor for stroke.

Relationship between stress and subjective oral dryness in the elderly in a rural region: a pilot study / 대한구강보건학회지

OBJECTIVES: Stress is a psychological reaction to stimuli such as anxiety or threat felt by a person either physically or mentally when placed in a difficult situation. Although a relationship between stress and dry mouth has been reported, it remains understudied. The purpose of this study was to investigate the association between stress and subjective dry mouth among the elderly living in a rural region. METHODS: A total of 214 people aged ≥60 years living in a rural area were recruited with an informed consent for a cross-sectional analysis. Information about stress and subjective dry mouth was obtained by an interview survey with a constructed questionnaire. Data on other potential confounding factors (including oral factors) such as socio-demographic data, health-related behaviors, the number of remaining teeth, and subjective chewing ability were also gathered at the same time. Logistic regression models were used to analyze the relationship of stress and dry mouth using SPSS. RESULTS: The Crude odds ratio (OR) of stress awareness affecting subjective dry mouth was 2.59 (95% confidence interval: 1.43–4.68). After adjusting for sex, education, income, smoking, and alcohol intake, the adjusted OR was 2.52 (95% confidence interval: 1.30–4.87) which was statistically significant. CONCLUSIONS: Elderly people who were stressed had an approximately 2-fold increase in experiencing subjective dry mouth when compared to their stress-free counterparts.

Relationship between the Subjective-Objective Oral Health Status and Oral Health Related Quality of Life in the Elderly / 치위생과학회지

The purpose of this study was to analyze the relationship between objective oral health status determined by dentists, self-perceived subjective oral health status, and oral health related quality of life (OHRQoL) in the elderly. The related factors affecting OHRQoL in the elderly were also surveyed. Four hundred and thirty elderly individuals who visited the three public health centers and four dental clinics in Busan were selected by convenience sampling. Twelve dental hygienists investigated the subjective oral health status and OHRQoL using the 14-item Oral Health Impact Profile (OHIP-14) and twentyone dentists examined the objective oral health status, including healthy remaining teeth, treated remaining teeth, functional remaining teeth, missing teeth, and non-treated missing teeth. Data were analyzed using SPSS ver. 12.0. OHRQoL was higher when oral and periodontal status was perceived as healthy, when there was no toothache, no interference in mastication, and when study subjects had the ability of food softening. It was also higher when study subjects had ≥20 remaining teeth and <9 missing teeth, and were wearing denture. The related factors affecting OHRQoL of the elderly were the type of medical insurance, toothache, ability of food softening, perception of periodontal status, and the number of healthy remaining teeth. There was a significant relationship between the subjective-objective oral health status and OHRQoL in the elderly. A continuous oral health care system aimed at retaining ≥20 healthy remaining teeth is needed to improve oral health and OHRQoL for the elderly, especially for the elderly receiving medical aid.

Effective Management Interval Focused on Professional Mechanical Tooth Cleaning / 치위생과학회지

This study was conducted to investigate the optimal management interval in 33 healthy adults by observing changes in oral health on the basis of the plaque control index and gingival index. When plaque control score was compared according to the period, it was found that oral hygiene management was the best in the fourth visit (p0.05). The questionnaire survey showed, that the optimal management interval was 1, 3, and 6 months. As a result, with the effective management interval for the preventive management program focused on professional mechanical tooth cleaning, which was administered weekly, the maximum ability for oral hygiene management was attained at the fourth visit. The effective management period was 1 month. The use of a phase contrast microscope and the calculation of the evaluation index for oral hygiene management could influence the motivation to improve oral hygiene management.

Relationship between cancer and oral health in Korean adults determined using data from the 6th (2013-2014) Korea National Health and Nutritional Examination Survey / 대한구강보건학회지

OBJECTIVES: Dental caries and periodontitis are major oral bacterial infections associated with dental plaque. Infection and inflammation play a role in carcinogenesis, and a significant link has been found between some highly prevalent oral and dental diseases and some types of cancer. Therefore, the aim of this study was to evaluate the relationship between cancer and oral health among Korean adults. METHODS: Data from the 6th Korea National Health and Nutrition Examination Survey were used to analyze the incidence of cancer according to oral health. Demographic and socioeconomic statuses and oral behavior of the participants was analyzed using complex chi-square tests. Logistic regression was used to analyze the relationship between a high DMFT index and cancer by calculating the 95% confidence intervals. RESULTS: In total, 6,450 case-control subjects were included. Significant difference was observed in the DMFT index, but not in periodontal diseases, between the cases and controls. The odds ratio for cancer was 1.80 (95% confidence interval: 1.18 to 2.73) in the high-risk group. However, no significant difference was observed after adjusting for age, education level, and income. CONCLUSIONS: The results provide potential evidence of a significant association between cancer and oral disease.

Evaluation of relationship between cognitive function and occlusal status in elderly individuals using the T-scan III® system / 대한구강보건학회지

OBJECTIVES: The aim of this study was to investigate the relationship between cognitive function and occlusal status in elderly individuals. METHODS: A total of 162 individuals aged 65 years and older, who attended the senior citizen center in Daegu city, were included after consent for participation in the study was obtained. The Korean version of the Mini-Mental State Examination (MMSE-K) was used to evaluate the level of cognitive function. Occlusal status was determined using the T-scan III® system. All collected data were analyzed by χ² test, t-test, one way ANOVA, and linear regression analysis using SPSS version 23.0 for Windows. RESULTS: There was a significant relationship between the cognitive function and the use of dentures. Individuals with posterior occlusal status had higher MMSE-K scores than those with anterior occlusal status. There was a positive correlation between the cognitive function and posterior occlusal force. CONCLUSIONS: These results suggest that occlusal status was associated with cognitive function in the elderly individuals. Active national policies to improve occlusal condition in the elderly population are needed.

A Study of Oral Health Status and Oral Health Promotion Activities according to the Snack Intake Frequency Change of Some Soldiers Compare to before and after Military Service / 치위생과학회지

The purpose of this study was to find the attitude change for snack by military soldiers before and after entering military service. To investigate oral health status and improving activities, this survey was done for 318 soldiers at Gyeong-gi province Paju city and the results were as follows. After entering military service, the soldiers take more snacks than before and take snacks 2 or more times a day. Both smokers and non-smokers take more snacks after entering military service than before entering. The soldiers did not go dental clinic regularly. But they have lots of interests about oral health. As higher position and older, soldiers restrain themselves to taking sugar contained food, and the elder soldiers showed higher practical character for nutrition intake than younger soldiers. Private soldiers were least practical for brushing after meal and showed the highest level of fulfill for using fluoride contained toothpaste, regular scaling and checkup at dental clinic and flossing.

Effect of health behaviors on oral health in Korean adolescents / 대한구강보건학회지

OBJECTIVES: Adolescence is a time during which health behaviors and attitudes that significantly affect the quality of life are formed. The aim of this study was to analyze data from a large national survey to determine the effect of health behaviors and the DMFT index as well as oral and general health behavior patterns on oral health in adolescents. METHODS: Data from the Fifth Korea National Health and Nutrition Examination Survey were used to analyze the association between health behaviors and the DMFT index in Korean adolescents. The data were analyzed using SAS version 19.3. Multiple regression analysis was used to assess the relationship between the variables, and 95% confidence intervals were computed. RESULTS: Sex, age, private medical insurance coverage, usage of oral-hygiene-assistance products, lack of dental treatment, and the status of self-recognition of oral health were the factors that had a significant influence on oral health among adolescents. CONCLUSIONS: The study findings provided further evidence supporting the promotion of school-based oral health programs and highlighting the need of oral health education for adolescents.

Effect of preference drinks on tooth color reduction after tooth bleaching: A 12-momth follow-up study / 대한구강보건학회지

OBJECTIVES: This study aimed to observe the decrease in tooth color after home and office bleaching due to consumption of juice, soda, and coffee over a period of one year. METHODS: We obtained written consent from 30 subjects, who were divided into two groups i.e., home bleaching and office bleaching groups. They were treated with opalessence® and Zoom2 whitening gel, and the color of their teeth was assessed using shade Eye-NCC over a one-year period. A self-describing questionnaire was used to determine the frequency of juice, soda, and coffee consumption. RESULTS: The changes in color were measured before and after 1 day, 1 month, 3 months, 6 months, and 12 months. Although the tooth color slightly changed after 12 months, the teeth were brighter than the original color. Consumption of juices, sodas, and coffee is thought to be associated with decrease in tooth color, although the change was not statistically significant. CONCLUSIONS: The ΔE* values showed that the tooth bleaching effect remained for 12 months. Consuming a normal amount of juice, sodas, and coffee does not significantly reduce tooth color after tooth bleaching.