OBJECTIVE: To investigate the resistance to sliding (RS) in self-ligating and conventional ligation bracket systems at 5 different second-order bracket angulations by using low-stiffness alignment wires in a 3-bracket experimental model and to verify the performance of the main RS components in both systems when these wires are used. METHODS: Interactive self-ligating brackets with closed and open slides were used for the self-ligating (SL) and conventional ligation (CL) groups, respectively; elastomeric ligatures (1 mm inner diameter) were used in the latter system. The alignment wire used was 0.014 inch heat-activated NiTi (austenitic finish temperature set at 36degrees C by the manufacturer). A custom-made testing machine was used to measure frictional resistance. Tests were repeated 5 times at every angulation simulated. All data were analyzed statistically. RESULTS: The RS increased significantly with increasing angulation in both SL and CL groups (p < 0.0001). However, the RS values were significantly higher at every angulation (p < 0.0001) in the CL group. CONCLUSIONS: Despite the relevance of the binding phenomenon, ligation forces predominantly affect the RS when low-stiffness alignment wires are used.
Elastomers ; Friction ; Ligation ; Models, Theoretical ; Polymers

Objective: The frequency of various disasters has become a 21st century global crisis. The biological-disaster of the coronavirus disease of 2019 (COVID-19) gave rise to a multi-dimensional global impact. The 25 items of Societal Influences Survey Questionnaire (SISQ) was developed to assess various categories of social influence during the pandemic. This study compares the SISQ scores of Taiwan, Republic of Korea (Korea) and Japan. Methods: Persons living in Korea, Japan, and Taiwan were recruited and evaluated through an SISQ online survey. The SISQ is composed of 25 items each with a 4-point Likert scale. The SISQ assesses the following six factors: self-restraint, social impact, government policy, social cost, concern of infection, and awareness of information. A principal factor analysis and reliability (Cronbach’s alpha) were performed to validate the SISQ. The analysis of variance (ANOVA) and post-hoc analysis was conducted to explore the differences between groups. Results: The SISQ had acceptable reliabilities, and accounted for 58.86% of the variance. The significance for ANOVA with post-hoc analysis showed that scores of self-restraints ranked highest in Japan followed by Taiwan and Korea. Taiwanese scored lower than other nations regarding the concern of infection. Koreans scored higher in awareness of information than the other two nations. The effect of age and marital status were also estimated. Conclusion The SISQ comprehensively evaluate multiple domains of social influence, and it manifests the divergence of social impacts across the three nations.