The aim of this study was to investigate the effects of low-level laser (LLL) irradiation on the turnover of fibronectin and collagen type I in periodontal tissue during tooth movement in rats by immunohistochemistry. Thirty male Sprague-Dawley rats aged 15 weeks were assigned to either an experimental group (n = 15) that underwent LLL irradiation during tooth movement, or a control group (n = 15). In the experimental group, the gallium-aluminum-arsenide (Ga-Al-As) diode LLL (wavelength 808 nm; output 96 mW) was used to irradiate three areas on both the palatal side and the labial side of the maxillary incisor. The radiation was administered by the contact method for 10 s at 0.83 J/cm(2) energy dose, once a day for 7 days. Total energy dose over the complete schedule was 34.86 J/cm(2). The animals were killed on days 1, 3, 7, 14 and 21. There was no difference between the two groups in the amount of tooth movement. The immunohistochemistry results showed that the expression of fibronectin and collagen type I in the experimental group had significantly increased from day 1, with a more even distribution than in the control group, and that this difference was maintained until the end of the experiment. These results suggest that LLL irradiation facilitates the reorganization of the connective tissues during tooth movement in rats.

The objective of this study is to estimate the relationship between amalgam removal and urinary mercury levels. To measure urinary mercury concentration, urine of participants was collected at baseline, immediately, 24 hours and 48 hours after removal of amalgam restorations. The statistical analysis was performed using IBM SPSS Statistics ver. 20.0. The overall mean urinary mercury concentration at baseline, immediately, 24 hours and 48 hours after removal of amalgam restorations was 2.77, 2.75, 2.95 and 4.00 g/g creatinine, respectively. Logistic regression model shows that the gender leads to increased odds of high urinary mercury concentration in children (odds ratio, OR=1.99), even after adjusting for high amalgam surfaces (OR=1.23) and fish consumption (OR=1.26) at the baseline. Our findings suggest that mercury exposure from dental amalgam adversely impact health and therefore are a health risk.

The purpose of this study was to determine the effects of dental hygienists' leader-member exchange (LMX) and empowerment on organizational performance, improve human resource management in their organization and their job satisfaction and organizational commitment, and provide basic data that could help improve organizational performance. A survey was conducted in 324 dental hygienists at dental care institutions in Ulsan, Busan, and Daegu from March 2 to 31, 2015 and the following results were obtained: Dental hygienists at dental hospitals had higher levels of LMX than those at dental clinics; those who were at higher positions, who were older, and who were more educated showed higher levels of empowerment. There was significant, positive correlation between LMX and empowerment and job satisfaction and organizational commitment: dental hygienists with better LMX and higher levels of empowerment showed higher levels of job satisfaction and organizational commitment. For dental hygienists, significance (=0.325, p＜0.001) exerted the greatest impact on job satisfaction, followed by organizational commitment (=0.264, p＜0.001) and competence (=0.164, p＜0.01) and LMX (=0.321, p＜0.001) had the greatest impact on organizational commitment, followed by job satisfaction (=0.275, p＜0.001) and significance (=0.210, p＜0.001).To put the results together, dental hygienists in dental care practice had their job satisfaction and organizational commitment affected by LMX and empowerment; therefore, it is necessary to develop diverse education programs with the objective of promoting mutual exchange between a manager of dental hygienists' team and members and improving empowerment.

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