introduction: the aim of this study was to compare the microleakage of beneath the orthodontic brackets bonded with 3 different bonding techniques and evaluate the effect of thermocycling. methods: one hundred and twenty premolars were randomly divided into 6 groups, received the following treatment: group 1: 37% phosphoric acid gel+unite primer+unite adhesive, group 2: 37% phosphoric acid gel+...

In earlier work the Kauffman bracket polynomial was extended to an invariant of marked graphs, i.e., looped graphs whose vertices have been partitioned into two classes (marked and not marked). The marked-graph bracket polynomial is readily modified to handle graphs with weighted vertices. We present formulas that simplify the computation of this weighted bracket for graphs that contain twin ve...

This paper defines a new invariant of virtual knots and flat virtual knots. We study this invariant in two forms: the extended bracket invariant and the arrow polyomial. The extended bracket polynomial takes the form of a sum of virtual graphs with polynomial coefficients. The arrow polynomial is a polynomial with a finite number of variables for any given virtual knot or link. We show how the ...

Definition 1.1. A Poisson algebra is an associative algebra A over a field K (fixed, of characteristic zero), equipped with a Lie bracket {−,−} such that {x,−} is a derivation for any x ∈ A, i.e. {x, yz} = {x, y}z + y{x, z}. Definition 1.2. A Poisson structure on a manifold M is a Poisson bracket {−,−} on the algebra C∞(M). Example 1.3. On T ∗Rn with position coordinates q1, ..., qn and momentu...

OBJECTIVE The coefficients of friction (COFs) of aesthetic ceramic and stainless steel brackets used in conjunction with stainless steel archwires were investigated using a modified linear tribometer and special computer software, and the effects of the bracket slot size (0.018 inches [in] or 0.022 in) and materials (ceramic or metal) on the COF were determined. METHODS Four types of ceramic ...

OBJECTIVES The aim of this study was to evaluate the effect of conventional and high-power light emitting diode (LED) light curing units on shear bond strength (SBS) of metal and ceramic brackets to tooth surface. MATERIALS AND METHODS Forty sound bovine maxillary central incisors were used for the study. The teeth were divided into four groups (n=10). Teeth surfaces were etched with 37% phos...

OBJECTIVE To compare the galvanic coupling of conventional and metal injection molded (MIM) brackets with commonly used orthodontic archwires. MATERIALS AND METHODS Six of each type of bracket were suspended in lactic acid along with a sample of orthodontic wire (three nickel-titanium and three copper-nickel-titanium) for 28 days at 37 degrees C. The potential differences between the wires an...

INTRODUCTION Polymer brackets still have some disadvantages because of decreased wear resistance and hardness. The aim of this study was to investigate the mechanical properties of alternative bracket polymers; urethane-dimethacrylate, high-density polyethylene, and an experimental bracket polymer (EBP) consisting of polyethylene and a copolymer were tested. Polycarbonate and polyoxymethylene b...

BACKGROUND Orthodontic treatment with fixed appliances requires - among others - the correct clinical expression of torque, which depends on the precise fitting of archwire and slot. Especially in the lingual technique torque problems become clinically more evident than in labial appliances also with respect to the vertical alignment of teeth due to different distances from the center of resist...

Different techniques have been introduced for the removal of ceramic brackets. Since the early 1990s, lasers have been used experimentally for debonding ceramic brackets. The goal of this study is to give a comprehensive literature review on laser-aided ceramic bracket debonding. PubMed and Google Scholar databases were used to identify dental articles with the following combination of key word...