Validity of a combination of periodontal pathogens and salivary biomarkers as predictors of periodontitis.

OBJECTIVE: Chronic periodontitis is caused by multiple risk factors. To predict chronic periodontitis in older people, we evaluated the association between a combination of major periodontal pathogens and salivary biomarkers and the presence of periodontitis. METHODS: Stimulated saliva samples were collected to analyze the prevalence of Porphyromonas gingivalis, Treponema denticola, Tannerella forsythia, and Prevotella intermedia, as well as four biomarkers: interleukin (IL)-1ß, IL-6, tumor necrosis factor-α (TNF-α), and prostaglandin E2 (PGE2). A total of 201 Japanese patients were recruited. Oral examinations ware performed to determine chronic periodontitis as measured by Community Periodontal Index. The sociodemographic and behavioral characteristics were also obtained, and the parameters were adjusted as potential confounders to employ statistical models. RESULTS: The odds ratio (OR) for the presence of P. gingivalis and the third tertile level of IL-1ß as compared with the absence of P. gingivalis and the lowest tertile of IL-1ß was highest in individuals with periodontitis (OR = 13.98; 95% confidence interval [CI] 3.87-50.52) with the best level (0.79) of area under the curve (AUC) based on the receiver operating characteristic curve. The OR for the presence of P. gingivalis and the third tertile of PGE2 was 7.76 (CI 1.89-31.91) with an AUC of 0.78. The coexistence of more than two periodontal bacteria and the third tertile of PGE2 was also strongly associated with chronic periodontitis (OR = 9.23, 95% CI 2.38-35.79) with an AUC of 0.76. CONCLUSIONS: The combined information of the presence of P. gingivalis in stimulated saliva, and higher levels of salivary IL-1ß may play a vital role in the detection and prediction of chronic periodontitis in older adults.

Association between mastication-related factors and the prevalence of dementia in Korean elderly women visiting senior centres.

OBJECTIVE: The purpose of this study was to evaluate the mastication ability of elderly women by assessing the number of their remaining teeth, subjective mastication comfort, subjective chewing ability of five food items, relative occlusion balance and mastication performance involving in chewing gum. BACKGROUND: Korea has already entered an aged society, issues related to the elderly are also growing; for example, dementia is emerging as a social problem. In addition, oral health of the elderly is very important because it is directly related to nutrient intake. A total of 101 subjects aged ≥65 who attended senior citizen centres in Daegu city provided consent and were included in this study. MATERIALS AND METHODS: The Korean version of the Mini-Mental State Examination (MMSE-DS) was used to evaluate cognitive function. To assess the degree of objective mastication, we measured colour changes using a chewing gum and posterior occlusion force using a T-scan Ⅲ® system. RESULTS: There was an association between mastication ability and cognitive function, indicated by the colour changes in the chewing gum (P < .05). The participants with greater relative posterior occlusion forces had higher MMSE-DS scores than those with stronger relative anterior occlusion forces. There was a positive correlation between cognitive function and posterior occlusion force. CONCLUSION: The elderly having more occlusion force of posterior teeth rather than anterior teeth were associated with better cognitive ability. Therefore, it may be important for the elderly to restore the masticatory function for the posterior part to prevent against deterioration of cognitive function.

In vivo and in vitro assessment of the bleaching effectiveness of a brush-off patch containing 3.0% hydrogen peroxide.

OBJECTIVES: To evaluate the efficacy of a brush-off patch containing 3.0% hydrogen peroxide, which is a new over-the-counter (OTC) product for tooth whitening, and determine the optimal protocol for use. MATERIALS AND METHODS: We performed an in vitro study using hydroxyapatite specimens and a clinical trial involving 140 volunteers. The brush-off patch was applied to the specimens (in vitro) or the maxillary anterior teeth (in vivo; 14 days) for 10 min twice daily (case 10 group) or 30 min once daily (case 30 group). We also included control groups in both experiments. Lightness (L*), redness (a*), and yellowness (b*) values were measured using a colorimeter. In the in vivo study, color changes were measured at baseline and 7 and 14 days after the start of patch application. The overall color change (ΔE) was statistically analyzed. RESULTS: In the in vitro study, the color change (ΔE*) after the experiment was significantly different between the two case groups and the control group (p < 0.001). In the in vivo study, the case groups showed color changes at both 7 and 14 days after patch application. In particular, the change in the case 30 group was significantly more prominent on day 14 than on day 7 (p < 0.05). CONCLUSION: Our findings suggest that brush-off patches containing 3.0% hydrogen peroxide are effective OTC products for tooth whitening. CLINICAL RELEVANCE: For best results, brush-off patches containing 3.0% hydrogen peroxide can be applied once daily for 30 min.

Lead exposure may affect gingival health in children.

BACKGROUND: Several studies have reported the harmful effects of lead poisoning. However, the relationship between lead exposure and oral health of children has not been well defined. The aim of this study was to investigate the relationship between blood lead level (BLL) and oral health status of children. METHODS: A total of 351 children (aged 7-15 years) were recruited from the pilot data of the Korean Environmental Health Survey in Children and Adolescents, which was designed to examine environmental exposure and children's health status in South Korea. Blood samples were taken to determine BLLs and oral examinations were performed to assess oral health parameters, including community periodontal index (CPI), gingival index (GI), and plaque index (PI). Information regarding socioeconomic status, oral hygiene behavior, and dietary habits was collected from parents and guardians. RESULTS: The participants were divided equally into four quartiles, with quartile I comprised of children with the lowest BLLs. There were significant differences for PI (p < 0.05) among the quartile groups. Using logistic regression models, we found a significant relationship between BLL and oral health parameters. The crude odds ratios for CPI, GI, and PI in the third quartile were 5.24 (95% CI: 1.48-18.56), 4.35 (95% CI: 1.36-13.9), and 4.17 (95% CI: 1.50-11.54), respectively, while the age and gender-adjusted odds ratios were 7.66 (95% CI: 1.84-31.91), 6.80 (95% CI: 1.80-25.68), and 3.41 (95% CI: 1.12-10.40), respectively. After adjustments for age, gender, parent education level, and frequency of tooth brushing, the adjusted odds ratios were 7.21 (95% CI: 1.72-30.19), 6.13 (95% CI: 1.62-23.19), and 3.37 (95% CI: 1.10-10.34), respectively. CONCLUSIONS: A high BLL might be associated with oral health problems in children, including plaque deposition and gingival diseases.

Metabolic syndrome parameters in adolescents may be determinants for the future periodontal diseases.

AIM: The prevalence of metabolic syndrome (MetS) increases even in adolescents. The evidence that MetS is associated with the periodontal diseases in adolescents has been understudied. Therefore, our aim was to assess the association between MetS parameters and gingivitis in adolescents. MATERIAL AND METHODS: A total of 941 participants (590 boys, 351 girls), aged 12-18 years was selected from the Fourth Korea National Health and Nutrition Examination Survey, a cross-sectional and nationally representative survey, which had had information on waist circumference, blood pressure, serum triglyceride, high-density lipoprotein (HDL) cholesterol, and the fasting blood sugar and community periodontal Index (CPI). RESULTS: The number of positive parameters of MetS showed significant positive correlation with gingivitis; adjusted and crude ORs with one positive parameters of MetS were 1.92 (95% CI: 1.21-3.04) and 1.88(95% CI: 1.28-2.76), respectively. And adjusted OR with three or more positive parameters of MetS was 3.29 (95% CI: 1.24-8.71). Among five parameters of MetS, Low HDL-cholesterol showed significant association with gingivitis (crude OR 2.12, 95% CI 1.20-3.73; adjusted OR 1.96, 95% CI 1.24-3.12). CONCLUSIONS: Having more positive parameters of MetS and low HDL-cholesterol parameter had an independent relationship with the prevalence of gingivitis, which may be determinants for the future periodontal diseases even in adolescents.

Burnout and its related factors in Korean dentists.

OBJECTIVES: Dentistry has been identified as one of the most stressful work environments. Knowledge of modifiable work-environment factors related to job stress could lead to a strategy and policy to provide a better work environment for dentists. The aims of this study were to examine the degree and distribution of burnout and to determine the factors associated with burnout subscale of Korean dentists. METHODS: A cross-sectional survey of Korean dentists was conducted using a custom-designed and validated questionnaire that incorporated the Maslach Burnout Inventory Human Services Survey (MBI-HSS) as well as questions regarding sociodemographic and job-related characteristics. A random sample of 1,000 dentists was selected from 13,207 registered dentists in the Korean Dental Association. The MBI-HSS scores were summarised in the three dimensions of emotional exhaustion, depersonalisation, and personal sense of accomplishment. Bivariate and multivariate analyses were conducted to assess the prevalence of burnout and its related factors. RESULTS: The adjusted response rate was 45.9% (444/967). In the subscales of burnout, 41.2%, 55.9%, and 41.4% of respondents scored highly in emotional exhaustion and depersonalisation and poorly for personal sense of accomplishment, respectively. High burnout seems to be more likely to occur in association with some of the sociodemographic and job-related characteristics, especially younger age, male gender, without occupational calling, and unwilling to reselect a dentistry as a job. CONCLUSIONS: This study suggests that burnout is a common problem in Korean dentists and that occupational calling and willing to reselect a dentistry as a job are important factors for managing burnout.

Association of Adiposity with Periodontitis and Metabolic Syndrome: From the Third National Health and Nutrition Examination Survey of United States.

This study explored the epidemiological role of central adiposity and body mass index (BMI) in terms of clinical attachment loss (CAL)/pocket depth (PD) and metabolic syndrome components. This study included data from the National Health and Nutrition Examination Survey III of America on 12,254 adults aged 20 years of age or older with a blood sample, anthropometric measurements, and a periodontal examination. Clinical periodontitis measurements, including CAL and PD, were classified into quintiles or quartiles and compared. CAL was positively associated with central adiposity, hypertension, and hyperglycemia; the relationship between CAL and diabetes was stronger when central adiposity was absent (odds ratio [OR] and 95% confidence interval: 6.33, 2.14-18.72 vs. 3.14, 1.78-5.56). The relationship between CAL and impaired fasting glucose (IFG) differed slightly with BMI. The IFG ORs for normal, overweight, and obese patients were 1.63 (1.08-2.45), 1.76 (1.05-2.97), and 1.43 (0.88-2.30), respectively. CAL was positively correlated with all metabolic syndrome components except hypertriglyceridemia. Associations between CAL, diabetes, and IFG significantly varied with BMI. Periodontitis in individuals without central obesity or with normal bodyweight may independently indicate diabetes and IFG. Therefore, preventive measures against periodontitis without obesity are necessary to improve general and oral health.

Dental composite fillings and bisphenol A among children: a survey in South Korea.

AIMS: Bisphenol A (BPA)-based dental composites have commonly been used to fill dental cavities or seal pits and fissures on teeth. However, epidemiological evidence with regard to the BPA exposure from dental composites among children has rarely been reported. This study investigated whether there is a relationship between the BPA concentration in urine and the presence of composite restorations and sealants among South Korean children. METHODS: Oral examinations and urine sample analyses were conducted on a total of 495 children aged 8-9 years. We classified the participants into four groups by the number of resin composites and sealant surfaces (0, 1-5, 6-10 and 11+). RESULTS: BPA concentrations in urine were higher in children with 11 or more surfaces restored with sealants and resin composites than in those with zero restored surfaces, although no difference was seen in the group with 1-10 surfaces. After adjusting for gender and age, the urinary BPA concentration in children with 11 or more resin composite surfaces was 2.67 µg/g creatinine, which was higher than the concentration found in those with no filling surfaces (P < 0.01). CONCLUSIONS: Having many dental composite filling surfaces on teeth may increase the urinary BPA concentration in children.

Effect of Molar Occlusal Balance on Cognitive Function in the Elderly.

BACKGROUND: Elderly people with dementia, who are increasing at a rate comparable to the rate at which theelderly population is growing, are becoming a serious social problem in Korea. Therefore, the purpose of this study was to investigate the association between molar occlusal balance and cognitive function among Koreans aged 65 years and older. METHODS: A total of 308 participants aged 65 years and older who attended a senior center were recruited for the study with their consent. The Korean version of the Mini-Mental State Examination (MMSE-DS) was used to assess cognitive function, and masticatory ability was measured according to the ability to chew food, the number of remaining teeth, and the self-perceived perceived masticatory function. Relative molar occlusal balance was measured using the T-scan Ⅲ system. All collected data were analysed using SPSS version 23.0. RESULTS: There was a significant association between cognitive function and molar masticatory ability (P < .05). The participants with relative molar occlusal balance had a higher MMSE-DS score when compared to those with relative incision occlusal balance, adjusted for sociodemographic factors and number of remaining teeth, subjective masticatory ability, chewing ability, occlusion time, and denture use. Cognitive function was higher when relative molar occlusion was greater compared to anterior occlusion in anterior-posterior teeth balance. CONCLUSIONS: Cognitive function in elderly people was higher when the relative molar occlusal balance was greater. Mastication with posterior teeth may have a more important effect on stimulation of cognitive function. Therefore, oral health care focusing on maintenance of molar teeth may be crucial for elderly persons.

Influence of Chewing Ability on Elderly Adults' Cognitive Functioning: The Mediating Effects of the Ability to Perform Daily Life Activities and Nutritional Status.

Chewing ability is also related to activities of daily living (ADLs) and nutritional status; however, these associations have not been firmly established. We examined chewing ability as a predictor variable and explored its relationship with cognitive functioning as mediated by ADLs and nutritional status data were collected by face-to-face interviews. Patients were receiving home healthcare service in Mun-gyeong city, Gyung-buk, Korea. Participants comprised 295 patients aged 81.35 ± 6.70 years. Structural equation modeling (SEM) was performed using AMOS 18.0 (SPSS Inc., Chicago, IL, USA). The model fit was based on absolute fit index and incremental fit index. Data were collected to assess cognitive functioning (using the Korean version of the Mini-Mental Status Examination for dementia screening (MMSE-DS)), ADL, a mini-nutritional assessment (MNA) questionnaire, and a chewing ability test. Participants with better chewing ability had significantly better cognitive functioning, ADLs, and nutritional status (p < 0.001). Chewing ability directly affected cognitive functioning and indirectly affected how ADLs and MNA affected MMSE-DS. Chewing ability is an important factor influencing the cognitive functioning of elderly adults in Korea, both directly and indirectly through mediating variables such as nutritional status and ADLs. Efforts to help older adults maintain their chewing ability are necessary for preventing cognitive impairment.

Estimation and change of edentulism among the Korean population: Korea National Health and Nutrition Examination Survey 2007-2018.

OBJECTIVES: To estimate the prevalence of edentulism according to the socio-demographic variables of Korean adults between 2007 and 2018 and to analyze the trends. METHODS: This study was conducted using raw data from the Korea National Health and Nutrition Examination Survey (KNHANES) from 2007 to 2018. Edentulism was defined as the absence of upper and lower teeth or the retained root of the missing teeth. To obtain the prevalence of edentulism, complex sample frequency analysis and regression analysis were performed according to the socio-demographic variables to represent the national population. The Korean population structure in 2005 was exploited as a standard population to calculate age-standardized edentulism. RESULTS: The prevalence of edentulism in 2016-2018 was 9.7% in the Korean elderly, and the change of age-standardized edentulism steadily declined over time from 2007, 12.8%. In particular, it decreased by approximately 20% in the period between 2016 and 2018 compared to that in 2007 for those in their 80s. The trend of the prevalence according to gender decreased significantly in women. According to the level of education, the greatest decrease was seen in the group with the lowest education, although the prevalence itself was higher than that seen in those who were more educated. CONCLUSIONS: The prevalence of edentulism among the older Korean population has decreased over time. However, the concern is on those with lower education and men as these groups are still at higher risk for edentulism.

More Teeth and Posterior Balanced Occlusion Are a Key Determinant for Cognitive Function in the Elderly.

Age-related decline in cognitive function is a major challenge in geriatric healthcare. A possible explanation is that the tooth loss or low chewing ability is at cause of cognitive impairment or dementia. The study aimed to investigate the potential relationship between chewing ability and cognitive function in the elderly. A total of 563 participants aged 65 years or over residing in urban and rural areas of South Korea were surveyed. The chewing ability was measured by objectively measurable indications such as the number of remaining teeth, denture status, color-changeable gum, and occlusal balance using T-Scan III®. The cognitive function was measured by the Korean version of Mini-Mental State Examination-Dementia Screening (MMSE-DS) and a score of 24 or more (out of 30) indicates a normal cognition, below 23 indicates cognitive impairment. The association between socio-demographic factors, chewing ability factors, and cognitive function demonstrated statistically significant results. When comparing the denture status and chewing ability, the proportion of need denture group had fewer remaining teeth and anterior balanced occlusion. The average number of remaining teeth in anterior balanced occlusion with cognitive impairment was 11.2 compared to posterior balanced occlusion with the normal cognition 19.2. A multiple linear regression analysis declared a significant correlation between number of remaining teeth, denture status, occlusal balance, and cognitive function. Results of the present study revealed objectively measurable indications are suitable for chewing ability assessment and correlated with cognitive function.

Morphological changes in Streptococcus mutans after chewing gum containing xylitol for twelve months.

Few studies have been conducted to evaluate the effect of xylitol on the virulence and morphology of Streptococcus mutans (S. mutans). This study was conducted to evaluate changes in the morphology and virulence of S. mutans in response to long-term consumption of gum containing xylitol. Participants were voluntarily recruited for a women's oral health prevention program, classified into two groups (a control and a xylitol group), and then followed for 1 year. Ten salivary samples were randomly selected from each group. Colony count, field emission scanning electron microscopy, and real-time reverse transcription polymerase chain reaction were used to analyze the characteristics of S. mutans. In the xylitol group, the colony counts of S. mutans decreased steadily over time. In addition, the adherence of the colonies in the xylitol group became weak, and the size of the colonies decreased compared to the control. The secretion of sticky substances from the surface of S. mutans colonies and gtfB gene expression also decreased in the xylitol group. These findings indicate that regular chewing of xylitol gum over a long period may lead to decreased gtfB expression, which can negatively affect the synthesis of extracellular polysaccharides by S. mutans, which could reduce the size and growth of S. mutans colonies and change their morphology as a result.

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.

Factors affecting use of word-of-mouth by dental patients.

OBJECTIVES: Word-of-mouth (WOM) refers to communication among consumers, which greatly influences the marketing strategies of dental clinics. This study aimed to explore factors that affect use of WOM by dental patients and to analyse their pathways. METHODS: The participants were 520 outpatients from four private dental clinics. Data were obtained from a survey using self-reported questionnaires, which included questions regarding seven latent variables: five exogenous variables, including medical service quality (physical environment, customer service, patient relationship quality) and individual characteristic variables (opinion leader tendency, social hub tendency); and two endogenous variables (intention to recommend, WOM experience). Statistical analysis was performed using structural equation modelling. RESULTS: Significant associations were found in the pathways between relationship quality and intention to recommend, intention to recommend and WOM, and opinion leader tendency and WOM (P < 0.001). Higher patient relationship quality and higher intention to recommend were related to positive WOM, as was higher opinion leader tendency. CONCLUSIONS: Improving patient relationship quality can promote positive WOM for dental clinics. Strategies are needed to promote a positive perception of dental clinics by effectively responding to the views of patients with strong opinion leader tendencies.

Relationship between the activities of daily living, oral health-related quality of life and dementia.

AIM: The aim of the present study was to investigate the association between the activities of daily living and the oral health-related quality of life and dementia in older adults. METHODS: Over a period of 18 months, we visited 12 elderly care facilities and recruited 375 participants, 345 of whom were selected to undergo oral health examinations and oral health-related surveys. Each investigation was carried out face-to-face by a professional worker. RESULTS: Cognitive ability was found to be good when the results of the activities of daily living and the oral health-related quality of life examinations were good. If the results of the activities of daily living examination were bad, the odds ratio of dementia was 2.66, and adjusted odds ratio for age, sex, residence type, education level and denture was 2.99, representing a significant difference (P < 0.05). CONCLUSIONS: Most oral problems are not simply the outcome of aging, with oral hygiene management being the most important determining factor. Oral health problems can be prevented, and in order to improve the quality of life of older adults, attention must be paid to oral healthcare. Geriatr Gerontol Int 2018; 18: 943-949.

Scheduling mammography screening for the early detection of breast cancer in Korean women.

OBJECTIVE: To propose an efficient screening schedule for breast cancer among Korean women using the stochastic model in which the age-specific incidence rate was considered. SETTING: Female breast cancer data in the Korea Central Cancer Registry 2002. METHODS: The stochastic model was based on the threshold method, in which the schedule is determined by a pre-specified threshold value. The threshold value was defined as the probability of being in a preclinical state of breast cancer at age 40 years. The sensitivity of the mammography was specified as 0.7. Two models for mean sojourn time (MST) in the preclinical state were considered; MSTs for Model I were 2 (ages < 50 years), 3 (ages 50-59 years), and 4 years (ages > or = 60 years), and MSTs for Model II were 3, 4, and 5 years for the corresponding age groups. RESULTS: The threshold method for Model I generated 19 examinations within the screening ages of 40-69 years. Each screening time was determined at ages 40.0, 41.6, 43.2, 44.8, 46.0, 47.2, 48.4, 49.6, 50.7, 51.7, 52.7, 53.7, 54.7, 56.2, 57.8, 59.4, 61.3, 63.1, and 64.9 years. The schedule sensitivity of Model I was 64.2%, which was higher than that (57.5%) of the biennial periodic schedule. Model II included 11 screenings between the ages of 40 and 69 years and also showed a higher schedule sensitivity, especially for women aged 40 years as compared with the biennial screening. CONCLUSIONS: This finding suggests that the threshold screening schedule for breast cancer increase the schedule sensitivity by reflecting the age-specific incidence rate of a population.

Xenon light has effectiveness on the detection of incipient carious lesions on bovine enamel in vitro.

OBJECTIVE: Filtered 325-nm xenon light was used to test its effectiveness in the detection of incipient carious lesions on bovine enamel by measuring the fluorescence spectrum. BACKGROUND DATA: The combination of early detection with new interventional methodology and caries management will be the preferred dental practice in the future. METHODS: Specimens of bovine tooth enamel were embedded in resin, polished, exposed to a lactate carbopol buffer system for 71 hours, and randomly divided into one control and three test groups of 10 specimens each, with Vickers hardness number (VHN) stratification. The surface changes were characterized by atomic force microscopy. All specimens were irradiated with xenon light, and a fluorescence spectrum was produced. Characteristics of fluorescence among the demineralized tooth groups were measured using an optical multichannel analyzer and a confocal laser scanning microscope. RESULTS: The VHNs were significantly different among the four groups (p < 0.05). The fluorescence had a peak intensity of approximately 425 nm, and the slope value between 450 and 550 nm was significantly decreased in all test groups (groups II-IV) compared to the control group (group I), as the VHN decreased (p < 0.05). Demineralized lesion depth gradually increased to 30-40 microm in groups II-IV. CONCLUSIONS: The 325-nm xenon light resulted in high efficacy for detecting incipient carious lesions. By evaluating the highest peak and slope value, the incipient carious lesion may be detected.

Factors related to job satisfaction among South Korean dentists.

OBJECTIVES: The purposes of this study were to investigate the level and distribution of job satisfaction and to explore work environment factors associated with job satisfaction of South Korean dentists. METHODS: A stratified systematic random sample of 1029 dentists was selected from the 10 357 registered dentists in the Korean Dental Association. They were surveyed via a self-administered mail questionnaire. Job satisfaction was measured by a modified version of the Dentist Satisfaction Survey. RESULTS: The response rate was 62.2%. The mean score of overall job satisfaction among South Korean dentists was 3.2 out of 5. In terms of work environment factors, the most satisfying aspect was patient relations (3.7) and the least satisfying aspect was personal time (2.8). Multiple regression analysis identified a model including patient relations, perception of income, personal time, staff, and specialty training that accounted for 35% of variation in overall job satisfaction. The majority of the variance was explained by patient relations. CONCLUSIONS: This study suggests that patient relations, perception of income, personal time, staff, and specialty training are important work environment factors for job satisfaction among South Korean dentists. The findings of this study will be helpful to policy makers to design plans to increase the level of job satisfaction among South Korean dentists.

Surface change of dental amalgam after treatment with 10% carbamide peroxide.

The aim of this study was to explore the effect of bleaching agents on the release of metal ions and change in physical and chemical characteristics of amalgams. Amalgam surface changes resulting from bleaching on amalgam were assessed with inductively coupled plasma atomic emission spectrophotometer, an automatic mercury analyzer, a colorimeter, and atomic force microscopy. Analysis of the release of metal ions indicated that the bleaching agent caused more copper, tin, and mercury ions to be released into the immersion solution. Furthermore, metal ion release increased progressively as immersion time was increased from 42 to 84 hours. Morphological examination revealed no significant effects of the 10% carbamide peroxide bleaching agent on the surface morphology of any of the amalgams tested. These results demonstrated that bleaching using 10% carbamide peroxide did not adversely affect the two types of amalgam tested. In other words, a 10% carbamide peroxide bleaching agent can be safely used on a short-term basis in dentist-monitored bleaching of the dental amalgam.