OBJECTIVE To test the null hypothesis that the aging process in self-ligating brackets is not higher than in conventional brackets. METHODS Twenty-five conventional (GN-3M/Unitek; GE-GAC; VE-Aditek) and 25 self-ligating (SCs-3M/Unitek; INs-GAC; ECs-Aditek) metal brackets from three manufacturers (n = 150) were submitted to aging process in 0.9% NaCl solution at a constant temperature of 37 ± ...

OBJECTIVES The aim of the present study was to investigate the composition, morphology, bulk structure and ionic release of two brands of titanium orthodontic brackets: Orthos2 (Ormco, USA) and Rematitan (Dentaurum, Germany). METHODS Five specimens of each group were examined with computerized X-ray microtomography, to reveal the morphology and structure of brackets, whilst resin-embedded and...

BACKGROUND The objective of this study was to compare the frictional forces generated by three types of monocrystalline ceramic brackets coupled with conventional elastomeric ligatures (CEL) and nonconventional elastomeric ligatures (NCEL) during the alignment of apically displaced teeth at the maxillary arch. METHODS All tests (a total of 480 tests) were carried out in a dry state on a unive...

OBJECTIVE To compare the frictional resistance between self-ligating and conventional brackets tied to different types of wire. MATERIAL AND METHODS Abzil Kirium Capelozza (Pattern I) and Easy Clip (Roth prescription) incisor brackets were used. An elastomeric ligature or a 0.10-in ligating wire was used to ligate the wire to the Abzil bracket. Three types of orthodontic archwire alloys were ...

Although bracket pools in the NCAA Men’s Basketball Tournament are a game, practice most players do not compete strategically. Instead, they more likely to choose brackets as though playing lottery. When faced with such unsophisticated opponents, game simplifies finance problem where you must an optimal portfolio of brackets. The that pay highest return modal which higher seeds always...

We present a translation of the Lambek calculus with brackets and the unit constant, Lb∗1, into the Lambek calculus with brackets allowing empty antecedents, but without the unit constant, Lb∗. Using this translation, we extend previously known results for Lb∗ to Lb∗1: (1) languages generated by categorial grammars based on the Lambek calculus with brackets are context-free (Kanazawa 2017); (2)...

OBJECTIVE This study evaluated the glass transition temperature (Tg) and degree of conversion (DC) of a light-cured (Fill Magic) versus a chemically cured (Concise) orthodontic composite. MATERIAL AND METHODS Anelastic relaxation spectroscopy was used for the first time to determine the Tg of a dental composite, while the DC was evaluated by infrared spectroscopy. The light-cured composite sp...

The aim of this laboratory-based study was to investigate the effects of different combinations of tip and torque upon friction between an orthodontic bracket and archwire using a specially made jig. Victory Twin Series upper premolar brackets (3M Unitek) were mounted on a jig, which allowed tip and torque values in the slot to be varied without altering the centre of rotation. The jig was moun...

For redundant second-class constraints the Dirac brackets cannot be defined and new brackets must be introduced. We prove here that the Jacobi identity for the new brackets must hold on the surface of the second-class constraints. In order to illustrate our proof we work out explicitly the cases of a fractional spin particle in 2 + 1 dimensions and the original Brink-Schwarz massless superparti...