Different Types Of Brackets Research Articles

Improvement in adhesion of the brackets to the tooth by sandblasting treatment

In oral orthodontic treatments, achievement of a good adhesion between brackets and teeth surfaces is essential. One way to increase adhesion is to apply a surface treatment of teeth facing surfaces through the projection of abrasive particles to produce a surface roughness which improves adhesion of the bracket to the tooth, because of the significantly increased contact between the two surfaces. The effect on adhesion through the use of this technique in different types of brackets, as well as through the use of different blasting particles, however, is yet not well described. In this study we have included three types of brackets which are commonly used in orthodontic therapies (two of them a mesh-type and the third one a micro-milled type) with a contact surface area of 11.16, 8.85 and 6.89 mm(2) respectively. These brackets were used combined with a sandblasting treatment with two different types of abrasive particles, alumina (Al(2)O(3)) and silicon carbide (SiC) and applied to natural teeth in vitro. The abrasive particles used are bio-compatible and usually used in achieving increased roughness for improved adherence in biomedical materials. Sandblasting was performed at 2 bars for 2 s; three particle sizes were used: 80, 200 and 600 μm. Non-blasted samples were used as control. Each of the pieces were cemented to natural teeth with a self-curing composite. Samples were stored in physiologic serum at 5°C temperature. Tensile tests were performed with a universal testing machine. Brackets treated with sandblasted particles were measured to have an increased adhesion as compared to the control sample. The highest bond strength was measured for samples sandblasted with alumina particles of 80 and 200 μm combined with micro-milled brackets. The recorded stresses did not exceed the tensile strength of tooth enamel.

Experimental evaluation of modal damping in automotive components with different constraint conditions

The selection of reliable damping values for mechanical components of complex shape is very difficult from a theoretical point of view, above all in the case of complex constraint conditions. This work presents an example of experimental procedure for estimating the modal damping in a family of mechanical components. An Experimental Modal Analysis (EMA) program has been carried out on different types of brackets used on diesel engines, and in different constraint conditions with the aim of collecting the damping values in a database. In particular, the EMA has been carried out on brackets in the freely-supported condition and in the clamped condition actually used in the engine, highlighting the variations in modal damping with the different constraint conditions. The results of the experimental measurements have been processed with different modal analysis algorithms in order to increase the robustness of the solution. The resulting damping plots represent very useful data in the field of numerical analysis.

Wire load-deflection characteristics relative to different types of brackets

To test the hypothesis that the dimension of the bracket, both in labial and in lingual orthodontics, is a relevant parameter to determine the forces acting on the teeth, and that some wires commonly used in labial orthodontics (0.016"-diameter SS, TMA and Nitinol) are not suitable for the first phase of lingual treatment. An ideal dental cast was bonded with eight different brackets (Damon 3MX, Ovation, Time 2, Innovation and Smart Clip Clarity on the vestibular face; STB, Adenta Time and Innovation-L on the lingual). After photographic documentation, the interbracket distance was calculated for each type of bracket, using ImageJ software. The mean elasticity modulus of the tested wires was obtained from the review of the available literature. The theoretical wire load on every tooth was calculated mathematically at three different levels of deflection (0.5mm; 1.0mm and 1.5mm), on both the labial and lingual sides, for all types of bracket. The lingual arch in the anterior segment is always shorter than the vestibular arch. The different brackets, having different dimensions, have an influence on the interbracket distance, and, consequently, on the wire load. At large deflections, superelastic NiTi expresses light and continuous forces, which are significantly lower than the other examined alloys. The initial hypothesis was supported. Because of the reduced interbracket distance, the adoption of superelastic wires is required in lingual mechanics and with smaller diameter compared to labial mechanotherapy, in particular during the first phases of treatment. The use of a bracket with reduced mesiodistal dimensions can contribute to reduce the load on the teeth.

Microbial Adhesion on Different Bracket Types in vitro

To test the hypothesis that there are differences in total bacterial counts and capacity for biofilm formation between seven different bracket types. By means of an in vitro experiment, seven commercially available bracket systems (Damon [A], Clarity [B], Mystique [C], Speed [D], Victory MBT [E], Micro-loc [F], and Generus [G]) were compared. A total of 25 premolar brackets of each bracket system were incubated in brain heart infusion medium containing the saliva and bacteria of two orthodontic patients. After 72 hours, the amounts of aerobe and anaerobe bacteria were determined by counting the colony-forming units (CFU). The CFU ratio (aerobe/anaerobe) also was calculated, and the black pigmented bacteria were analyzed. Significant differences between the different bracket types in terms of biofilm formation were found. Bracket types can be arbitrarily divided into low, intermediate, and high plaque-retaining brackets. The group with low adhesion consists of bracket types E, F, and G; the group with high adhesion of bracket types A, B, and C; and type D exhibits intermediate adhesion. The group with high microbial adhesion (A, B, and C) did present significantly lower CFU ratios (aerobe/anaerobe) than were exhibited by the other bracket systems (P < .05). The hypothesis is accepted. Orthodontic brackets serve as different loci for biofilm formation; in this in vitro study, significant differences were noted between the different types of brackets.

Analyse des biomechanischen Verhaltens von kieferorthopädischen Brackets mit unterschiedlichen Verschlussmechanismen / Biomechanical analysis of orthodontic brackets with different closing mechanisms

The aim of the present study was to investigate the biomechanical characteristics of orthodontic bracket systems made of metal, ceramics or plastics. Six different types of brackets were studied, including the Hanson Speed- and Damon 2-Brackets, both of which are equipped with specialised closing mechanisms. In addition, two conventional metal brackets (Ultratrimm), Discovery, the ceramics bracket Fascination 2 and the polycarbonate bracket Brillant were investigated. Stainless steel wires with the dimensions 0.40 mmx0.56 mm, 0.46 mmx0.56 mm, 0.46 mmx0.64 mm and 0.48 mmx0.64 mm were used with each bracket type simulating the clinical rotational movement of an upper central incisor in a biomechanical set-up. A buccal crown torque of 20 degrees was applied and the correction of the malposition was simulated experimentally. Each bracket/wire combination was analysed five times. The following parameters were analysed: maximum torquing moment, torque angle correction, and moment/torque ratio. Combining a 0.48 mmx0.64 mm steel wire with the ceramics brackets (Fascination 2) delivered the highest torquing moment (35 Nmm). The best torque correction was achieved with plastic brackets (17 degrees ). The lowest moments were approximately 5.2 Nmm (Damon) 2, 0.40 mmx0.56 mm steel wire), being in the range of the recommended minimum torquing moment (5 Nmm). Discovery brackets delivered similar low moments. Overall, only minor differences exist between the various bracket systems with regard to their efficiency in torque correction. Clinically, the wire/slot play seems to be more important than differences in the bracket designs.

The influence of size and structure of metal orthodontic bracket base on bond strength on tooth enamel

The factors which may influence the bond strength of the applied orthodontic brackets on the tooth surface are the size and structure of the bracket base. The aim of the paper was to investigate the influence of size and shape of different types of brackets on bond strength on the enamel and analyze the remaining quality of adhesive material on the tooth surface after debonding of orthodontic brackets (adhesive remnant index - ARI). In this study, three types of metal brackets of different sizes and shapes of Dentaurum manufacturer were used (Utratrimm, Equilibrium 2, Discovery, Dentaurum, Inspringen, Germany). The brackets were applied onto the middle part of the anatomic crowns of buccal surfaces of 30 premolars extracted for orthodontic reasons. In addition, the pre-treatment of teeth by 37% orthophosphoric acid and adhesive material System1+ (Dentaurum, Germany) were used. The mean value of the bonded brackets bond strength of Discovery type after debonding was 8.67 +/- 0.32 MPa, while the value of the bonded brackets bond strength of Equilibrium 2 type amounted to 8.62 +/- 0.22 MPa. The value of the bonded brackets bond strength of Ultratrimm type after debonding was 8.22 +/- 0.49 MPa. There were no statistical differences in the values of bond strength regarding all three groups of the investigated orthodontic brackets (F = 4.56; p < 0.05). The base size and design of metal orthodontic brackets did not play a significant role in bond strength, while the values of ARI index were identical in all three investigated groups.

Adhesion of Streptococcus mutans to Different Types of Brackets

To examine the difference in the adhesion of Streptococcus mutans to three different types of orthodontic brackets and the effect of the presence of an early salivary pellicle and Streptococcus sanguis on adhesion. Three adhesion experiments were performed using stainless steel, ceramic, and plastic orthodontic brackets. In the first experiment a clinical strain of S mutans adhered to the three different types of brackets (n = 6 for each). For the second, the brackets were treated with saliva before adhesion of S mutans (n = 6 per type of bracket). Finally, the third experiment concerned saliva coated brackets (n = 6 per type of bracket), but before S mutans, S sanguis bacteria were allowed to adhere. The bacteria were always allowed to adhere for 90 minutes in all the experiments. Adhesion was quantitated by a microbial culture technique by treating the brackets with adhering bacteria with trypsin and enumerating the total viable counts of bacteria recovered after cultivation. There were consistently no differences in the adherence to stainless steel, ceramic, or plastic brackets. The presence of an early salivary pellicle and S sanguis reduced the number of adhering S mutans to all three types of brackets. Adhesion of bacteria to orthodontic brackets depends on several factors. The presence of a salivary pellicle and other bacterial species seem to have a significant effect on the adhesion of S mutans, reducing their numbers and further limiting any differences between types of brackets.

Comparisons of shear bond strength of precoated and uncoated brackets

In an attempt to save chairside time during bonding, orthodontists are using ceramic and metal brackets that have been precoated with the adhesive material. The adhesive used on the precoated brackets is similar in composition to that used for bonding uncoated brackets; the difference is essentially in the percentages of the various ingredients incorporated in the material. The purpose of this study is to determine whether these changes in composition affect the shear bond strength and the site of bond failure when precoated and uncoated ceramic and metal brackets are used. Eighty-five recently extracted human molars were bonded according to the manufacturer's instructions and mounted in phenolic rings. An occlusogingival load was applied to the bracket, producing a shear force at the bracket-tooth interface with a Zwick Universal Test Machine. After debonding, all teeth and brackets were examined under 10× magnification. Any adhesive remaining after bracket removal was assessed with the Adhesive Remnant Index (ARI). The current findings indicated that: (1) Precoated ceramic brackets that used a slightly modified adhesive have similar shear bond strengths as that provided by Transbond XT adhesive on uncoated brackets; (2) precoated metal brackets that used the same adhesive have significantly lower shear bond strength than those obtained with Transbond XT on uncoated brackets. The differences in the bond strength between the ceramic and metal brackets were attributed to the combined effects of the changes in the composition of the adhesives used and in the retention mechanisms incorporated in the bracket bases of the different types of brackets; (3) all bracket/adhesive combinations tested provided clinically acceptable shear bond forces. (Am J Orthod Dentofac Orthop 1997;112:617-21.)

A comparison of shear bond strengths of metal and ceramic brackets

The study measures and compares shear bond strength data obtained from metal, ceramic, and ceramic-filled plastic brackets bonded td human incisor teeth with a heavily filled composite resin. The mean values for groups of different types of brackets were not statistically significant. The site of failure was commonly at the resin/bracket interface except for the ceramic-filled plastic brackets, which frequently showed failure of the bracket itself. One group of ceramic brackets that used no mechanical retention often showed failure to the extent that the bulk of resin remained on the bracket. The findings strongly suggest that ceramic brackets should offer a viable alternative to their metal counterparts because they combine esthetics with a bond strength that is comparable to and as reliable as-their metal counterparts.