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Grosch K, Meister J, Raval SD, Fouda AM, Bourauel C. Comparative evaluation of different debonding and reconditioning methods for orthodontic ceramic brackets regarding effectiveness for reuse : An in vitro study. J Orofac Orthop 2023:10.1007/s00056-023-00469-z. [PMID: 37318554 DOI: 10.1007/s00056-023-00469-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 04/02/2023] [Indexed: 06/16/2023]
Abstract
PURPOSE To investigate the reusability of ceramic brackets in terms of shear bond strength, friction behavior, slot dimension, fracture strength, and color stability. METHODS A total of 90 conventionally debonded and 30 by an Er:YAG laser debonded ceramic brackets were collected. All the used brackets were inspected under a stereomicroscope at 18 × magnification and sorted according to their adhesive remnant index (ARI). Five groups were formed (n = 10): (1) new brackets as a control group, (2) flamed and sandblasted, (3) flamed and acid bathed, (4) laser-reconditioned, and (5) laser-debonded brackets. The bracket groups were tested regarding different properties such as shear bond strength, friction behavior, slot size, fracture strength, and color stability. Analysis of variance (ANOVA) and nonparametric Kruskal-Wallis tests were used for statistical analysis (significance level: p < 0.05). RESULTS Shear bond strength values of the acid reconditioned brackets were significantly lower (8.0 ± 3.1 MPa) compared to the control group (12.9 ± 2.9 MPa). Laser-reconditioned (32.8 ± 2.7%) and laser-debonded (30.9 ± 2.4%) brackets showed the lowest force loss due to friction (control group 38.3 ± 3.0%). No significant differences were observed between groups regarding slot size and fracture strength. All groups had color differences of [Formula: see text]< 10. Scanning electron microscope images and ARI scores indicated that most of the residues on the bracket bases were removed. CONCLUSION All reconditioning methods yielded adequate results regarding bracket properties. Yet, focusing on the need to protect the enamel and the bracket base, laser debonding seems to be the most suitable method for reconditioning ceramic brackets.
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Affiliation(s)
- Katharina Grosch
- Department of Oral Technology, Center of Dentomaxillofacial Medicine, University Hospital Bonn, Bonn, Germany.
| | - Jörg Meister
- Department of Periodontology, Operative and Preventive Dentistry, Center of Dentomaxillofacial Medicine, University Hospital Bonn, Bonn, Germany
- Center of Applied Medical Laser Research and Biomedical Optics (AMLaReBO), University Hospital Bonn, Bonn, Germany
| | | | - Ahmed Mahmoud Fouda
- Department of Oral Technology, Center of Dentomaxillofacial Medicine, University Hospital Bonn, Bonn, Germany
| | - Christoph Bourauel
- Department of Oral Technology, Center of Dentomaxillofacial Medicine, University Hospital Bonn, Bonn, Germany
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Sezici YL, Önçağ MG. Conventional and self-ligating lingual orthodontic treatment outcomes in Class I nonextraction patients: A comparative study with the American Board of Orthodontics Objective Grading System. Am J Orthod Dentofacial Orthop 2023; 163:e106-e114. [PMID: 36737396 DOI: 10.1016/j.ajodo.2022.10.021] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 10/01/2022] [Accepted: 10/01/2022] [Indexed: 02/04/2023]
Abstract
INTRODUCTION This study aimed to assess and compare the duration and outcomes of orthodontic treatment with conventional and self-ligating lingual fixed appliances with the American Board of Orthodontics (ABO) Objective Grading System. METHODS Thirty consecutive patients with a complete dentition and Angle Class I malocclusion treated with a conventional lingual bracket system (STb; Ormco, Glendora, Calif) or self-ligating lingual bracket system (GC Experience-L; GC Orthodontics, Breckerfeld, Germany) were included. The occlusal outcome was assessed with the ABO instrument. The treatment duration and ABO scores of the 2 groups were recorded. Statistical analyses were evaluated using independent-sample t tests. RESULTS The conventional group had a mean treatment time of 2.10 ± 0.69 years, and the self-ligating group had a treatment duration of 1.68 ± 0.48 years (P >0.05). The mean posttreatment ABO scores in the conventional group were 20.23 ± 5.13, and the mean posttreatment ABO scores in the self-ligating group were 21.00 ± 5.66. No difference was found between the groups regarding the criteria of ABO (P >0.05). The highest scores were given in the assessment of buccolingual inclinations in both conventional and self-ligating lingual bracket groups. CONCLUSIONS The design of the lingual appliances used in this study did not influence the treatment duration and the total ABO scores in treating patients with a Class I relationship in this sample. Both types of lingual brackets were especially deficient in correcting buccolingual inclinations. The strengths were their ability to close spaces and correct anterior rotations and overjet regardless of the bracket types.
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Harikrishnan P, Magesh V. Finite element analysis of tie wings rotation: A new phenomenon in orthodontic bracket-archwire contact assembly during simulated torque. Proc Inst Mech Eng H 2022; 236:1626-1634. [DOI: 10.1177/09544119221122013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In orthodontics, the torque generated forces from the rectangular archwires refine the teeth position. Literature shows only linear deformation in brackets during torqueing. The objective of this study was to evaluate a new phenomenon of tie wings rotation, an angular deformation in Stainless Steel (SS) brackets with SS and Beta-Titanium (β-Ti) archwires at various angles of twist. Maxillary central incisor SS 0.457 mm × 0.635 mm and 0.558 mm × 0.711 mm brackets, SS and β-Ti archwires of 0.431 mm × 0.635 mm and 0.533 mm × 0.635 mm sizes were used. Finite element analysis was performed in various bracket-archwire assemblies for simulated torque. Palatal root torque was applied and the gingival tie wings rotation was measured at selected points, from 5° to 30° angles of twist. The tie wings rotation for 30° twist with SS 0.533 mm × 0.635 mm archwire in 0.558 mm bracket ranged from 1.32° to 2.55° and with SS 0.431 mm × 0.635 mm archwire in 0.457 mm bracket from 0.71° to 1.73°. Similarly, with β-Ti 0.533 mm × 0.635 mm archwire in 0.558 mm bracket and β-Ti 0.431 mm × 0.635 mm archwire in 0.457 mm bracket, the tie wings rotation ranged from 0.73° to 1.38° and 0.39° to 0.93° respectively. The tie wings rotation were present in all the FE models. Higher archwire size, stiffness, and angles of twist showed increased rotation. Thus, clinicians should be aware of this tie wings rotation during torqueing as an additional factor for torque loss.
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Affiliation(s)
- Pandurangan Harikrishnan
- Department of Orthodontics, Faculty of Dental Sciences, SGT University, Gurugram, Haryana, India
- Teeth “N” Jaws Center, Nungambakkam, Chennai, Tamil Nadu, India
| | - Varadaraju Magesh
- Department of Mechanical Engineering, College of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu, Tamil Nadu, India
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Friction Force Adjustment by an Innovative Covering System Applied with Superelastic NiTi Brackets and Wires-An In-Vitro Study. MATERIALS 2022; 15:ma15124248. [PMID: 35744316 PMCID: PMC9230937 DOI: 10.3390/ma15124248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 05/24/2022] [Accepted: 06/13/2022] [Indexed: 11/27/2022]
Abstract
The aim of this study was the investigation of polymeric coverings to adjust frictional forces between V-shaped wires and brackets, both made of superelastic NiTi. Adjustment of frictional forces is relevant for certain stages during orthodontic therapy. Coverings able to generate frictional forces when assembled to such brackets are additively manufactured. Six different internal widths of coverings were examined in three different environments: dry condition at room temperature (RT) or body temperature (BT), or artificial saliva (AS) at RT. The different coverings significantly affected the frictional forces for all media (p < 0.001). A correlation between internal width of the covering and resulting frictional forces was found. BT and dry environment showed the lowest friction forces for all samples. The highest force was found for two covering types at RT in AS, while the remaining four covering types showed the highest values in dry environment (p < 0.001). Friction could, therefore, be adjusted by variation of bracket covering clipped onto brackets, which is useful for orthodontic therapy. Coverings delivering higher friction provide dental anchorage, while coverings with lower friction can be used for tooth movement or purely esthetic reasons. It was shown that the variation of covering width may be used for adjustment of frictional forces.
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Comparative investigation of fully customized lingual bracket systems and conventional labial appliances: Analysis of forces/moments and final tooth positions. Am J Orthod Dentofacial Orthop 2022; 162:348-359.e2. [DOI: 10.1016/j.ajodo.2021.03.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 03/03/2021] [Accepted: 03/03/2021] [Indexed: 11/20/2022]
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Sharp IG, Minick G, Carey C, Shellhart CW, Tilliss T. Assessment of simulated vs actual orthodontic tooth movement with a customized fixed lingual appliance using untreated posterior teeth for registration and digital superimposition: A retrospective study. Am J Orthod Dentofacial Orthop 2022; 161:272-280. [DOI: 10.1016/j.ajodo.2021.02.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 02/01/2021] [Accepted: 02/01/2021] [Indexed: 11/01/2022]
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Kyprianou C, Chatzigianni A, Daratsianos N, Bourauel C. Vertical and Orovestibular Forces Generated by Beta-Titanium and Stainless-Steel Rectangular Wires in Labial and Fully Customized Lingual Bracket Systems. MATERIALS (BASEL, SWITZERLAND) 2021; 14:5632. [PMID: 34640028 PMCID: PMC8510413 DOI: 10.3390/ma14195632] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 09/17/2021] [Accepted: 09/20/2021] [Indexed: 12/02/2022]
Abstract
This study aimed to investigate the force values exerted from rectangular wires when combined with conventional labial and fully customized lingual appliances under predefined, idealized activation. Fully customized lingual brackets of two brands Incognito™ (3M Unitek, Monrovia, CA, USA) and WIN (DW Lingual Systems, Bad Essen, Germany) and labial brackets of another brand, discovery® MIM and discovery® smart systems (Dentaurum, Ispringen, Germany), were chosen. Stainless-steel and beta-titanium wires of 0.018" × 0.025" were examined. For IncognitoTM, 0.0182" × 0.025" beta-titanium wires were tested. Intrusion/extrusion and orovestibular movements were performed in a range of 0.2 mm, and the forces were recorded for each 0.1 mm of the movement. Mean values and standard deviations were calculated for all measurements, and ANOVA was performed for statistical analysis. Slight differences were observed between the forces generated from beta-titanium and stainless-steel wires. The same wire generated in some cases 5-53% higher forces with the lingual appliance due to the vertical orientation of the long walls during intrusion/extrusion and increased wire stiffness at the anterior region. Beta-titanium and stainless-steel 0.018" × 0.025" wires can generate similar force values during the final stages of the orthodontic therapy; thus, possibly only one of the two alloys could be used in each orthodontic wire sequence.
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Affiliation(s)
- Chrystalla Kyprianou
- Department of Oral Medical Technology, School of Dentistry, Faculty of Medicine, University of Bonn, 53111 Bonn, Germany;
| | - Athina Chatzigianni
- Department of Orthodontics, School of Health Sciences, Faculty of Dentistry, Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece;
| | - Nikolaos Daratsianos
- Department of Orthodontics, School of Dentistry, Faculty of Medicine, University of Bonn, 53111 Bonn, Germany;
| | - Christoph Bourauel
- Department of Oral Medical Technology, School of Dentistry, Faculty of Medicine, University of Bonn, 53111 Bonn, Germany;
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Harikrishnan P, Magesh V. Comparative finite element analysis of bracket deformation in tie wings and slot region during simulated torque. Am J Orthod Dentofacial Orthop 2021; 160:588-593. [PMID: 34373152 DOI: 10.1016/j.ajodo.2021.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 01/01/2021] [Accepted: 01/01/2021] [Indexed: 10/20/2022]
Abstract
INTRODUCTION Torque in orthodontics is the activation of the archwire for the third-order movement of teeth. During this force transfer mechanism from the twisted archwire, the bracket is prone to deformation. This study aimed to compare the deformation in tie wings and the slot region of the bracket during torque using finite element analysis. METHODS Three-dimensionally modeled 0.017 × 0.025-in and 0.019 × 0.025-in stainless steel (SS) and titanium molybdenum alloy archwires were assembled in 0.018-in and 0.022-in solid modeled SS edgewise brackets, respectively. The finite element model of the bracket-archwire combinations was developed with contact boundary conditions. The deformation between tie wings and the slot was analyzed for various angles of twist. RESULTS For SS archwires at 30° angle of twist, the tie wings deformation in 0.018-in and 0.022-in brackets were 48.67 μm and 34.87 μm, respectively. The slot deformations of 0.018-in and 0.022-in brackets were 66.33 μm and 45.69 μm, respectively. Similarly, the amount of deformation in the bracket-titanium molybdenum alloy archwire combinations were also presented. CONCLUSIONS The slot deformation was more than the tie wings deformation as the slot walls bear the immediate torque force. Thus, orthodontic researchers should know that the torque-relevant bracket deformation should ideally be evaluated in the slot region rather than the tie wings.
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Affiliation(s)
| | - Varadaraju Magesh
- Department of Mechanical Engineering, College of Engineering and Technology, SRM Institute of Science and Technology, Kattankulathur, Tamil Nadu, India
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Implications of pretreatment incisor inclinations for the achievement of cephalometric normal values-a study on two patient collectives. J Orofac Orthop 2021; 83:181-194. [PMID: 34232329 DOI: 10.1007/s00056-021-00320-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2020] [Accepted: 05/10/2021] [Indexed: 10/20/2022]
Abstract
PURPOSE The objective was to clarify whether standardized multibracket therapies-differing only in finishing-wire dimensions (0.016 × 0.022 inch vs. 0.017 × 0.025 inch CNA [Connecticut New Archwire]) and excluding any extraction treatment or additional appliances other than intermaxillary elastics-can produce normal incisor inclinations starting from different baseline inclinations. METHODS We analyzed pre- and posttreatment cephalograms of 156 patients (age: 15.6 ± 1.3 years) treated with Roth system (0.018 inch slot). Each archwire group (n = 89 or 67) was divided into subjects with initially retroclined, orthograde, or proclined upper and/or lower incisors (U1, L1). For the resultant 12 subgroups, descriptive statistics were compiled relative to five reference planes (NL, ML, NA, NB, BOP), followed by multiple intragroup (Kolmogoroff-Smirnoff and Wilcoxon signed-rank test) and intergroup (Kruskal-Wallis and Mann-Whitney U test) comparisons relative to NL or ML. RESULTS The following intra- (1, 2) and intergroup (3, 4) differences were statistically significant (p ≤ 0.05) in both archwire groups: (1) post- vs. pretreatment inclinations in the subgroups initially retroclined U1, retroclined L1 and orthograde U1, but without normal values being achieved (subgroups retroclined U1, L1) or preserved (subgroup orthograde U1); (2) observed vs. expected alterations for the subgroups initially orthograde and proclined U1 and L1; (3) posttreatment inclinations for the subgroups initially retroclined vs. orthograde L1 and proclined L1; (4) observed alterations for the subgroups initially retroclined vs. proclined U1 and L1, but neither retroclined nor proclined vs. orthograde. Archwire thickness influenced the outcome to only a limited extent under the special circumstances of this study. CONCLUSION The bracket/archwire combinations evaluated did not lead to normal incisor inclinations in most cases. Posttreatment values did significantly depend on the pretreatment situation. Most frequently, alterations were protrusive in direction, which notably even included incisors that showed norm values at the outset of treatment. It can be concluded that bracket torque will influence but not dominate incisor inclinations.
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Albertini P, Mazzanti V, Mollica F, Lombardo L, Siciliani G. Comparative analysis of passive play and torque expression in self-ligating and traditional lingual brackets. J Orofac Orthop 2021; 83:13-22. [PMID: 34185103 DOI: 10.1007/s00056-021-00314-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 05/01/2021] [Indexed: 11/25/2022]
Abstract
INTRODUCTION The aim of this study was to determine and compare the play and torque expression of self-ligating and conventionally ligated lingual brackets, with square and rectangular slots, when engaged with archwires of different size, cross section and material. METHODS Passive play and torque expression of 3 types of archwires and 5 types of brackets from four different manufacturers were measured and compared using a dynamometer. Each archwire was tested five times in each bracket; passive play was compared to ideal values, while torque expression was tested at 5, 10 and 20 Nmm as clinically efficacious values. RESULTS Regarding full thickness stainless steel archwires, the lowest passive play was found in STb brackets (2.66 ± 0.89°, Ormco, Glendora, CA, USA), which was statistically significantly lower than for ALIAS brackets (4.44 ± 0.75°, Ormco), In-Ovation L brackets (6.14 ± 3.22°, Dentsply GAC, Bohemia, NY, USA), Harmony brackets (7.76 ± 2.94°, American Orthodontics, Sheboygan, WI, USA) and eBrace brackets (9.46 ± 3.94°, Riton Biomaterial, Guangzhou, China). Increasing the torsional load to the greatest torsional load clinically applicable, there were no statistically significant differences between STb, ALIAS, In-Ovation L and Harmony brackets. CONCLUSIONS STb and ALIAS brackets generated the lowest passive play; STb and In-Ovation L brackets showed the lowest angle of play at the greatest torque expression. These measurements allow to understand the accuracy of lingual systems and at the same time the amount of overcorrections to be applied in the setup in order to obtain high quality orthodontic treatments.
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Affiliation(s)
- Paolo Albertini
- Postgraduate School of Orthodontics, University of Ferrara, via Livatino, 9, 42124, Reggio Emilia, Ferrara, Italy.
| | | | | | - Luca Lombardo
- Postgraduate School of Orthodontics, University of Ferrara, via Livatino, 9, 42124, Reggio Emilia, Ferrara, Italy
| | - Giuseppe Siciliani
- Postgraduate School of Orthodontics, University of Ferrara, via Livatino, 9, 42124, Reggio Emilia, Ferrara, Italy
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Fontinha C, Cattaneo PM, Cornelis MA. How efficient is customized lingual orthodontics? An assessment of treatment outcome. Orthod Craniofac Res 2021; 25:73-81. [PMID: 33998771 DOI: 10.1111/ocr.12494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 05/07/2021] [Accepted: 05/08/2021] [Indexed: 12/01/2022]
Abstract
OBJECTIVE To assess the efficacy of lingual orthodontics by comparing setups and post-treatment casts. SETTING AND SAMPLE POPULATION Thirty-two consecutive patients treated with a customized lingual orthodontic appliance were included in this retrospective study. MATERIALS AND METHODS Initial casts, post-treatment casts and setups were scanned, and the digital models produced were analysed in terms of overjet; overbite; molar and canine relationships; intercanine, interpremolar and intermolar distances; upper and lower arch lengths; midline deviation; bucco-lingual angulation of all teeth and mesio-distal angulation of anterior teeth. Comparisons between setups and post-treatment casts were performed via paired t tests. Relationships between the planned and actual correction were studied using regression analysis. RESULTS Statistically significant differences in bucco-lingual torque between setups and post-treatment casts were found for all upper teeth, except for central incisors. In the lower jaw, statistically significant differences in bucco-lingual torque were found between setups and post-treatment casts for the lower incisors and molars. No statistically significant differences in mesio-distal angulation of anterior teeth were found between setups and post-treatment casts. Upper and lower arch widths did not vary significantly between setups and final casts, except upper inter-second premolar and intermolar distances. CONCLUSION Customized lingual appliances offer efficient control of mesio-distal angulation of all anterior teeth. Significant differences in torque between setups and post-treatment casts were observed for upper lateral incisors, canines, premolars and molars, as well as lower incisors and molars. However, the torque difference was clinically significant (over three degrees) for upper second premolars and molars only.
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Affiliation(s)
- Clara Fontinha
- Department of Orthodontics, University of Geneva, Geneva, Switzerland.,Private Practice, Geneva, Switzerland.,Private Practice, Lisbon, Portugal
| | - Paolo M Cattaneo
- Section of Orthodontics, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.,Melbourne Dental School, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Vic., Australia
| | - Marie A Cornelis
- Section of Orthodontics, Department of Dentistry and Oral Health, Aarhus University, Aarhus, Denmark.,Melbourne Dental School, Faculty of Medicine, Dentistry and Health Sciences, University of Melbourne, Melbourne, Vic., Australia
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Magesh V, Harikrishnan P, Singh DKJ. Experimental evaluation of orthodontic bracket slot deformation to simulated torque. Proc Inst Mech Eng H 2021; 235:940-946. [PMID: 33962528 DOI: 10.1177/09544119211015086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In orthodontic fixed appliance therapy, the archwire torque used to refine the teeth position during the treatment imparts significant forces inside the bracket slot. The objective of this study was to measure the torque relevant bracket slot deformation in Stainless Steel (SS) brackets during various degree of archwire twist. Standard edgewise brackets 0.018-inch (in.)/0.022-in. each 20 no. and 0.016 × 0.022, 0.017 × 0.025, 0.019 × 0.025, and 0.021 × 0.025 in. archwires each 10 no. were used. A novel experimental setup consisting of loading fixture and torque key mounted on a Vision Measuring System (VMS) were used to measure the brackets slot deformation. The Top Slot and Middle Slot Deformations (TSD and MSD) of the brackets for 35° angle of twist in 0.016 × 0.022 in. archwire in 0.018-in. slot, 0.019 × 0.025 in. archwire in 0.022-in. slot and for 30° angle of twist in 0.017 × 0.025 in. archwire in 0.018-in. slot and 0.021 × 0.025 in. archwire in 0.022-in. slot were measured. Results showed that the mean TSD and MSD were higher when the archwire size, the slot size and the angle of twist were greater. In the evaluated bracket-archwire combinations, the TSD were higher than MSD and the bracket slots were elastically deformed within the clinically required 35° angle of twist in the archwire. Clinicians should be aware of this torque relevant bracket slot deformation which might be a factor for torque loss and suitably incorporate archwire angle of twist.
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Affiliation(s)
- Varadaraju Magesh
- Department of Mechanical Engineering, College of Engineering and Technology, SRM Institute of Science and Technology, Chengalpattu, Tamil Nadu, India
| | | | - Devadhas Kingsly Jeba Singh
- Department of Mechanical Engineering, College of Engineering and Technology, SRM Institute of Science and Technology, Chengalpattu, Tamil Nadu, India
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Harikrishnan P, Magesh V, Ajayan AM, JebaSingh DK. Finite element analysis of torque induced orthodontic bracket slot deformation in various bracket-archwire contact assembly. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2020; 197:105748. [PMID: 32932130 DOI: 10.1016/j.cmpb.2020.105748] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2020] [Accepted: 09/04/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND AND OBJECTIVES Orthodontic fixed appliance therapy involves alignment of teeth through the bracket and archwires. The archwire twist (torque) imparts significant forces inside the bracket slot in refining the teeth position at the end of treatment. The objective of this in- silico study was to evaluate the torque induced bracket slot deformation in the commonly used 0.018 inch (") and 0.022" conventional Stainless Steel (SS) brackets with clinically relevant archwires during various angles of twist. METHODS SS maxillary central incisor brackets of 0.018" width × 0.022" depth (0.457 mm × 0.558 mm) and 0.022" width × 0.028" depth (0.558 mm × 0.711 mm) were used. The SS archwires of 0.016" width × 0.022" depth (0.406 mm × 0.558 mm), 0.017" width × 0.025" depth (0.431 mm × 0.635 mm), 0.019" width × 0.025" depth (0.482 mm × 0.635 mm) and 0.021" width × 0.025" depth (0.533 mm × 0.635 mm) were engaged in the respective bracket slots. The assembled bracket-archwire Finite Element (FE) models were constructed. The archwire torque, the top, middle and bottom slot deformations (TSD, MSD, BSD) were obtained for the bracket-archwire combinations for various angles of archwire twist using FE Analysis (FEA). RESULTS The torque, TSD, MSD and BSD for 30o twist of 0.016" × 0.022" archwire in 0.018" slot were 28.13 Nmm, 35.71 µm, 21.51 µm and 15.67 µm respectively, and for 0.017" × 0.025" archwire were 50.18 Nmm, 54.52 µm, 32.47 µm and 19.11 µm respectively. Similarly for 0.019" × 0.025" archwire in 0.022" slot and 0.021" × 0.025" archwire in 0.022" slot they were 38.82 Nmm, 50.78 µm, 31.47 µm and 16.82 µm, and 60.22 Nmm, 65.22 µm, 36.44 µm and 22.68 µm respectively. CONCLUSIONS The slot deformation was present in both 0.018" and 0.022" brackets which increased as the angle of twist increased. The TSD were higher than the MSD and BSD in all the bracket-archwire combinations. We conclude that there is only elastic deformation of bracket slots upto 30o angle of twist and clinicians could maintain within this torque limits to avoid plastic deformation leading to improper teeth position.
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Affiliation(s)
- Pandurangan Harikrishnan
- Craniofacial Orthodontist, Division of Orthodontics, Teeth "N" Jaws Center, Lake Areaa 1st Cross Street, Nungambakkam, Chennai 600034, Tamil Nadu, India.
| | - Varadaraju Magesh
- Department of mechanical engineering, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu 603203, Tamil Nadu, India.
| | - Akhil Minu Ajayan
- Department of mechanical Engineering, SRM Institute of Science and Technology, Chengalpattu 603203, Tamil Nadu, India.
| | - Devadhas Kingsly JebaSingh
- Department of mechanical engineering, SRM Institute of Science and Technology, Kattankulathur, Chengalpattu 603203, Tamil Nadu, India.
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Torque efficiency of a customized lingual appliance : Performance of wires with three different ligature systems. J Orofac Orthop 2019; 80:304-314. [PMID: 31552447 DOI: 10.1007/s00056-019-00190-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 07/02/2019] [Indexed: 10/26/2022]
Abstract
PURPOSE Torque control in lingual orthodontics is key to obtain optimal esthetic results. The aim of this in vitro experimental study was to verify the efficiency of the ligature-archwire-slot system in torque control using a customized lingual appliance. METHODS An idealized cast with eight extracted human teeth was created and a set of customized lingual brackets was obtained. Tests were performed with the following wires: 0.016″ × 0.022″ nickel-titanium (NiTi), 0.016″ × 0.024″ stainless steel (SS), 0.017″ × 0.025″ βIII titanium (βIIITi), 0.0182″ × 0.0182″ βIIITi, 0.018″ × 0.025″ SS, 0.018″ × 0.025″ NiTi, 0.018″ × 0.025″ βIIITi, and three types of ligatures were tested using a universal testing machine to calculate the efficiency in torque control. A blind statistical analysis was performed. RESULTS Based on post hoc multiple comparisons, differences were found for two of the three ligatures when using the 0.016″ × 0.022″ NiTi wires (p < 0.001 for both ligatures). When considering all ligatures, 0.018″ × 0.025″ SS and 0.018″ × 0.025″ βIIITi were significantly different from all other wires (p < 0.001 in all cases). With a moment of 5 Nmm, the 0.016″ × 0.022″ NiTi wire developed median angles of 26.7, 29.8, and 38.7° with the three ligatures, respectively, while the 0.018″ × 0.025″ SS developed median angles of 12.9, 10.7, and 12.7°, respectively. CONCLUSIONS The ligature type and geometry did not affect the efficiency of torque control, except for the 0.016″ × 0.022″ NiTi wire. The wires generating the greatest moments were the 0.018″ × 0.025″ SS and 0.018″ × 0.025″ βIIITi.
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Coordinating bracket torque and incisor inclination : Part 3: Validity of bracket torque values in achieving norm inclinations. J Orofac Orthop 2018; 79:320-327. [PMID: 29556669 DOI: 10.1007/s00056-018-0132-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2017] [Accepted: 02/15/2018] [Indexed: 10/17/2022]
Abstract
PURPOSE To analyze common values of bracket torque (Andrews, Roth, MBT, Ricketts) for their validity in achieving incisor inclinations that are considered normal by different cephalometric standards. METHODS Using the equations developed in part 1 (eU1(BOP) = 90° - BT(U1) - TCA(U1) + α1 - α2 and eL1(BOP) = 90° - BT(L1) - TCA(L1) + β1 - β2) (abbreviations see part 1) and the mean values (± SD) obtained as statistical measures in parts 1 and 2 of the study (α1 and β1 [1.7° ± 0.7°], α2 [3.6° ± 0.3°], β2 [3.2° ± 0.4°], TCA(U1) [24.6° ± 3.6°] and TCA(L1) [22.9° ± 4.3°]) expected (= theoretically anticipated) values were calculated for upper and lower incisors (U1 and L1) and compared to targeted (= cephalometric norm) values. RESULTS For U1, there was no overlapping between the ranges of expected and targeted values, as the lowest targeted value of (58.3°; Ricketts) was higher than the highest expected value (56.5°; Andrews) relative to the bisected occlusal plane (BOP). Thus all of these torque systems will aim for flatter inclinations than prescribed by any of the norm values. Depending on target values, the various bracket systems fell short by 1.8-5.5° (Andrews), 6.8-10.5° (Roth), 11.8-15.5° (MBT), or 16.8-20.5° (Ricketts). For L1, there was good agreement of the MBT system with the Ricketts and Björk target values (Δ0.1° and Δ-0.8°, respectively), and both the Roth and Ricketts systems came close to the Bergen target value (both Δ2.3°). Depending on target values, the ranges of deviation for L1 were 6.3-13.2° for Andrews (Class II prescription), 2.3°-9.2° for Roth, -3.7 to -3.2° for MBT, and 2.3-9.2° for Ricketts. CONCLUSIONS Common values of upper incisor bracket torque do not have acceptable validity in achieving normal incisor inclinations. A careful selection of lower bracket torque may provide satisfactory matching with some of the targeted norm values.
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Al-Thomali Y, Mohamed RN, Basha S. Torque expression in self-ligating orthodontic brackets and conventionally ligated brackets: A systematic review. J Clin Exp Dent 2017; 9:e123-e128. [PMID: 28149476 PMCID: PMC5268106 DOI: 10.4317/jced.53187] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 05/22/2016] [Indexed: 11/16/2022] Open
Abstract
Background To evaluate the torque expression of self ligating (SL) orthodontic brackets and conventionally ligated brackets and the torque expression in active and passive SL brackets. Material and Methods Our systematic search included MEDLINE, EMBASE, CINAHL, PsychINFO, Scopus, and key journals and review articles; the date of the last search was April 4th 2016. We graded the methodological quality of the studies by means of the Quality Assessment Tool for Quantitative Studies, developed for the Effective Public Health Practice Project (EPHPP). Results In total, 87 studies were identified for screening, and 9 studies were eligible. The quality assessment rated one of the study as being of strong quality, 7 (77.78%) of these studies as being of moderate quality. Three out of 7 studies which compared SL and conventionally ligated brackets showed, conventionally ligated brackets with highest torque expression compared to SL brackets. Badawi showed active SL brackets with highest torque expression compared to passive SL brackets. Major and Brauchli showed no significant differences in torque expression of active and passive SL brackets. Conclusions Conventionally ligated brackets presented with highest torque expression compared to SL brackets. Minor difference was recorded in a torque expression of active and passive SL brackets. Key words:Systematic review, self ligation, torque expression, conventional ligation.
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Affiliation(s)
- Yousef Al-Thomali
- MDS, Dean, Faculty of Dentistry, Department of Orthodontics, Taif University, Taif, KSA
| | - Roshan-Noor Mohamed
- MDS, Assistant Professor, Department of Pediatric Dentistry, Faculty of Dentistry, Taif University, Taif, KSA
| | - Sakeenabi Basha
- MDS, PhD, Assistant Professor, Department of Community Dentistry, Faculty of Dentistry, Taif University, Taif, KSA
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