New Improved Method of Setting the Jaw's Coordinate System

Precise and reproducible alignment of the coordinate system plays a key role in the processes of monitoring geometric parameters. In cases of long-term processes, which are executed in multiple phases, errors in setting the coordinate system can lead to wrong conclusions and mismanagement of these processes. Orthodontic therapy, ie teeth leveling, lasts for one year with controls every month. The geometric parameters (teeth positions) are monitored by the dental arch equations. During each control, the current state is compared with previous control. Conditio sine qua non is precisely and repeatably setting of the jaw's coordinate system. The ABO method (American Board of Orthodontics; digital model orientation) does not provide repeatability in successive controls. In this study, a new method of setting the coordinate system of the jaw is presented. To ensure as user-friendly procedure as possible a simple algorithm is listed. A case study on digital dental model analyses for dental arch curve mathematical definition is presented at the end of the study. This is an example of the application of engineering methods in non-engineering areas

Tactical voting and party preferences : a test of cognitive dissonance theory

Studying the development of stable political attitudes, political scientists have argued that repeated voting for a political party reinforces initial party preferences, in a seemingly mechanistic process of habit-formation. However, the empirical evidence is scarce and the theoretical framework underdeveloped. Does the act of voting for a party improve an individual’s evaluation of this party? If so, is this effect simply due to habit-formation, or a more complex psychological mechanism? Drawing on cognitive dissonance theory, we examine the act of voting as a choice inducing dissonance reduction. We go beyond existing research, by focusing on tactical voters—a group for which the notion of habitual reinforcement does not predict an effect. The analyses reveal a positive effect of the act of voting tactically on the preferences for the parties voted for and may thus call for a revision of the traditional understanding of the role of voting in shaping party preferences