The aim of the study was to investigate the influence of cross section, edge geometry and structural hardness on torque transmission between square wire and bracket. For this purpose, 5 different brands of stainless steel square wire in 3 dimensions (0.016" x 0.016", 0.016" x 0.022" and 0.017" x 0.025") were inserted into edgewise brackets with a slot size of 0.018" and loaded with different torques (1 and 3 Ncm). The slot and wire geometries were analyzed by computer on ground specimens before and after loading. In addition, the Vickers hardness and micro-hardness of the unstressed and stressed metal surfaces were determined. While the slot size was very accurately maintained, the wire dimensions deviated downwards by an average of 10%. Torque transmission led to notching and bending-up phenomena on the bracket slot flanks. A torque loading of 3 Ncm increased the torque play of 0.016" x 0.022" wires by 3.6 degrees, and of 0.017" x 0.025" wires by 3.7 degrees. In the case of 0.016" x 0.016" wires, an effective torque transmission was no longer possible. The average Vickers hardness of the wires was 533 kp/mm2, and that of the brackets 145 kp/mm2. The micro-hardness in the deformation area of stressed internal slot walls increased with increasing load transmission from 204 to 338 kp/mm2. As a result of excessively small wire dimensions and plastic deformation of the brackets, a relatively large torque play occurs. Deformation and notching in the area of the internal slot walls are inconsistent with demands for recycling brackets. A standardization of bracket wire systems stating the actual torque play would be desirable.

No abstract

The fully automatic determination of the cephalometric landmarks has led to relevant errors up to now, so that it is mandatory to check all automatically set landmarks and to correct them if required. In the case of the semiautomatic method, all relevant angles can be determined with the same reliability as hand drawing.

Basically information means selection within a domain (value or definition set) of possibilities. For objectifiable, comparable and precise information the domain should be the same for all. Therefore the global (online) definition of the domain is proposed here. It is advantageous to define an ordered domain, because this allows using numbers for addressing the elements and because nature is ordered in many respects. The original data can be ordered in multiple independent ways. We can define a domain with multiple independent numeric dimensions to reflect this. Because we want to search information in the domain, for quantification of similarity we define a distance function or metric. Therefore we propose "Domain Spaces" (DSs) which are online defined nestable metric spaces. Their elements are called "Domain Vectors" (DVs) and have the simple form:URL (of common DS definition) plus sequence of numbers At this the sequence must be given so that the mapping of numbers to the DS dimensions is clear. By help of appropriate software DVs can be represented e.g. as words and numbers. Compared to words, however, DVs have (as original information) important objectifiable advantages (clear definition, objectivity, information content, range, resolution, efficiency, searchability). Using DSs users can define which information they make searchable and how it is searchable. DSs can be also used to make quantitative (numeric) data as uniform DVs interoperable, comparable and searchable. The approach is demonstrated in an online database with search engine (http://NumericSearch.com). The search procedure is called "Numeric Search". It consists of two systematic steps:1. Selection of the appropriate DS e.g. by conventional word based search within the DS definitions. 2. Range and/or similarity search of DVs in the selected DS.

Our skeletal malocclusion questionnaire provides useful additional information on specific aspects of skeletal malocclusion patients, mapping in a detailed fashion aspects of function, esthetics, psychological condition, and social interactions. OHIP-G14 scores correlated negatively with OHRQoL.