Torque Stability of Plastic Brackets Following Multiple Loading and Artificial Material Aging – an In-Vitro Comparison

Möller, Matthias; Klocke, Arndt; Sadat-Khonsari, Reza; Schlegel, V.; Kahl‐Nieke, Bärbel

doi:10.1007/s00056-009-9915-0

Cited by 7 publications

(9 citation statements)

References 23 publications

(50 reference statements)

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“…A comparison between metal, ceramic, and plastic brackets has shown that slot wall rigidity varied according to the material. Low rigidity brackets such as plastic, and to a lesser degree, metallic ones, allowed more play for the wire than rigid ceramic brackets (Harzer, Bourauel, & Gmyrek, 2004;Matsui, Umezaki, Komazawa, Otsuka, & Suda, 2015;Möller, Klocke, Sadat-Khonsari, Schlegel, & Kahl-Nieke, 2009;Morina, Eliades, Pandis, Jäger, & Bourauel, 2008).…”

Section: Introductionmentioning

confidence: 99%

Variability of slot size in orthodontic brackets

Lefebvre

Saadaoui

Olivé

et al. 2019

Clinical & Exp Dental Res

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ObjectiveThe accuracy of the information incorporated into brackets is a determining factor for the efficacy of torque applied to teeth. The aim of this study was to compare the dimensions of a bracket's slots with the nominal values announced by the manufacturer.Materials and methodsA total of 730 maxillary right central brackets manufactured by seven companies (Dentsply Gac, American Orthodontics, Rocky Mountain Orthodontics, GC Orthodontics, 3M Unitek, and Dentaurum) were studied. The sample included 0.018 × 0.025 and 0.022 × 0.028 in., metal and ceramic, conventional and self‐ligating brackets. Images were obtained with an Olympus BX51 optical microscope. Slot dimensions were measured at the base and at the face on both mesial and distal sides using ImageJ software. Data were analyzed using Wilcoxon, sign tests, two‐ and three‐way ANOVA, and Tukey's tests. Intraclass correlation coefficient was employed to assess the intraobserver and interobserver variability. The threshold for statistical significance was p ≤ .05.ResultsStatistical analysis showed that the slot dimensions of 90% to 97% of studied brackets were significantly different from nominal values. In general, slot size was oversized, with a face size larger than the base size. Comparison between mesial and distal sides showed that up to 45% of the brackets were significantly asymmetrical. The manufacturer had a significant effect for base and face widths (p = .0001) and for length (p = .003).ConclusionThis study shows that a large proportion of measured brackets displays dimensional inaccuracies when compared with stated values. Clinically, the slot oversize and the divergence of slot walls cause an increase of wire‐slot play, inducing a loss of torque control. Practitioners cannot fully trust the precision of used appliances and should be aware that adjustments could be needed in the finishing stages of the treatment.

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Section: Introductionmentioning

confidence: 99%

Variability of slot size in orthodontic brackets

Lefebvre

Saadaoui

Olivé

et al. 2019

Clinical & Exp Dental Res

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“…14 This was assumed to have a negative effect in the torque capacity of polycarbonate brackets and led various laboratory studies to suggest that plastic brackets without a metal slot are inappropriate to deliver the desirable amount of torque in clinical conditions. [15][16][17] The problem was considered even greater for plastic brackets filled with ceramic particles, 17 as those examined in our case. However, such an effect was not evident in our study.…”

Section: Discussionmentioning

confidence: 94%

Comparative assessment of clinical performance of esthetic bracket materials

Gkantidis¹,

Zinelis²,

Karamolegkou³

et al. 2012

The Angle Orthodontist

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Objectives: To compare the alterations in esthetic appearance and slot morphology/integrity of two main types of esthetic brackets caused after clinical use. Materials and Methods: Sixteen ceramic (CR) and 16 plastic (PR) central incisor brackets were obtained from 16 young adult patients at the end of treatment in a prospective randomized manner. As controls, 12 ceramic (CC) and 12 plastic (PC) nonused brackets were also examined. Three representative slot width measurements were obtained through micrometric microscopy. Visual inspection of optical microscopy images, surface electron microscopy (SEM), and energydispersive x-ray spectroscopy (EDS) were also performed. Results: Intraoral exposure time varied from 5 to 20 months (mean, 12.4; P 5 .73). Two-way analysis of variance revealed significant differences in slot width among the different materials and a significant interaction between the material effect and its status (P , .001). Bonferroni post hoc tests on material 3 status effect showed significant differences between CC (95% confidence interval [CI]: 434.5, 447.0) vs PC (95% CI: 460.2, 472.8), CC vs CR (95% CI: 453.2, 464.4), and PC vs PR (95% CI: 448.8, 458.9). Interestingly, a significant difference was not detected for CR vs PR. Slot width was correlated with the time under clinical use only for plastic brackets (PR: r 5 2.64, P , .01). Visual inspection of the optical microscopy images did not reveal any major macroscopic morphological disfigurements or significant discolorations. However, a rough and irregular slot wall surface was evident after clinical use (also with SEM), especially in the bottom of the slot. Conclusions: Both bracket types presented adequate clinical performance at least for the time period studied and in terms of esthetic appearance and morphologic integrity. (Angle Orthod. 2012;82:691-697.)

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“…This difference in fracture load values can be explained by difference in material characteristics of the brackets used. [12][13][14][15] In a clinical situation, the torquing moment transferred from the wire to the maxillary central incisor was 1035 to 2373 gfmm. [16][17][18] Therefore, results of this study indicate that all brackets tested have enough resistance to deformation or fracture to incorporate torque to the maxillary central incisor using 0.019 × 0.025˝ SS archwire.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of Different Bracket's Resistance to Torsional Forces from Archwire

Ayesha²,

Sam

et al. 2016

The Journal of Contemporary Dental Practice

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Aim:The present study was aimed to evaluate the resistance to deformation or fracture of brackets of various materials (ceramic, ceramic reinforced with metal slot, and stainless steel brackets) with archwires during application of torque. Materials and methods:The sample size included 30 brackets of maxillary right central incisor with slot dimension of 0.022 × 0.028˝ and made of three materials (10 of each type):(1) Ceramic brackets (cer), (2) ceramic brackets reinforced with stainless steel slot (cer/ss), and (3) stainless steel brackets (metal). Thirty stainless steel archwire segments of 0.019 × 0.025˝ SS 5 cm in length were used. Elastomeric ties were also used in this study.Results: Highest to lowest deformation or fracture torque found is as follows: Stainless steel brackets (5713.2 gfmm), metal ceramic reinforced with metal slot brackets (4080.8 gfmm), and ceramic brackets (3476 gfmm). Conclusion:Stainless steel brackets showed significantly higher values of torsional load than ceramic brackets reinforced with metal slot and ceramic brackets.Clinical significance: Clinically orthodontic treatment is based on specific force applications to the dentition, the maxilla and the mandible. In order to obtain these forces, orthodontic brackets are attached to the teeth. Most commonly used brackets are metal (stainless steel), ceramic, and combination of metal reinforced ceramic brackets. For successful orthodontic treatment, it is necessary to maintain proper torque and avoid torque loss. Torque loss leads to deepening of bite. Torque loss occurs due to many reasons, one of them being bracket failure to withstand applied torque.

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Torque Stability of Plastic Brackets Following Multiple Loading and Artificial Material Aging – an In-Vitro Comparison

Cited by 7 publications

References 23 publications

Variability of slot size in orthodontic brackets

Variability of slot size in orthodontic brackets

Comparative assessment of clinical performance of esthetic bracket materials

Evaluation of Different Bracket's Resistance to Torsional Forces from Archwire

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