Three-dimensional finite element analysis on torque performance of lingual brackets with slot in different directions / 医用生物力学

Objective To analyze the torque performance of lingual brackets with slots in different directions and the influence pattern of arch wires with different sizes and materials on torque of these lingual brackets. Methods The finite element models of the anterior maxilla lingual brackets with vertical and horizontal slot were constructed, including three kinds of materials (stainless steel, beta-titanium, nickel-titanium) and two sizes of arch wires (0.43 mm×0.56 mm, 0.41 mm×0.56 mm), so as to compare and analyze their mechanical properties after the application of torque load on the left upper central incisors with a rotation angle of ±20°. Results With the increase in elastic modulus of the arch wire, torque moments of lingual brackets with horizontal and vertical slot both increased gradually. Torque performance of lingual brackets was affected more by the sizes and materials of arch wires than the directions of slots. The lingual bracket with vertical slot produced 1-2 times of torque force than that with horizontal slot under the same degree of torque angle. The effect of arch wire sizes was smaller than that of arch wire materials, while the synergistic change in sizes and materials of arch wires had the largest influence on torque performance of lingual brackets. Conclusion The lingual brackets with different slot directions, sizes and materials of arch wires will influence the torque performance of lingual brackets. In clinical application, slot directions of lingual brackets as well as sizes and materials of arch wires should be adjusted properly according to the required torque force.

Three-dimensional finite element analysis on torque performance of lingual brackets with slot in different directions / 医用生物力学

Objective Objective To analyze the torque performance of lingual brackets with slots in different directions and the influence pattern of arch wires with different sizes and materials on torque of these lingual brackets.Methods The finite element models of the anterior maxilla lingual brackets with vertical and horizontal slot were constructed,using 3 kinds of materials (stainless steel,beta-titanium,nickel-titanium) and two sizes of arch wires (0.43 mm x 0.56 mm,0.41 mm x 0.56 mm),so as to compare and analyze their mechanical properties after the application of torque load on the left upper central incisors with a rotation angle of ±20°.Results With the increase in elastic modulus of the arch wire,torque moments of lingual brackets with horizontal and vertical slot both increased gradually.Torque performance of lingual brackets was affected more by the sizes and materials of arch wires than the directions of slots.The lingual bracket with vertical slot produced 1-2 times of torque force than that with horizontal slot under the same degree of torque angle.The effect of arch wire sizes was smaller than that of arch wire materials,while the synergistic change in sizes and materials of arch wires had the largest influence on torque performance of lingual brackets.Conclusions The torque performance of lingual bracket will be influenced with its different slot directions,the sizes and materials of arch wires.In clinical application,slot directions of lingual brackets as well as sizes and materials of arch wires should be adjusted properly according to the required torque force.

Three-dimensional finite element analysis on torque performance of lingual brackets with slot in different directions / 医用生物力学

Objective Objective To analyze the torque performance of lingual brackets with slots in different directions and the influence pattern of arch wires with different sizes and materials on torque of these lingual brackets.Methods The finite element models of the anterior maxilla lingual brackets with vertical and horizontal slot were constructed,using 3 kinds of materials (stainless steel,beta-titanium,nickel-titanium) and two sizes of arch wires (0.43 mm x 0.56 mm,0.41 mm x 0.56 mm),so as to compare and analyze their mechanical properties after the application of torque load on the left upper central incisors with a rotation angle of ±20°.Results With the increase in elastic modulus of the arch wire,torque moments of lingual brackets with horizontal and vertical slot both increased gradually.Torque performance of lingual brackets was affected more by the sizes and materials of arch wires than the directions of slots.The lingual bracket with vertical slot produced 1-2 times of torque force than that with horizontal slot under the same degree of torque angle.The effect of arch wire sizes was smaller than that of arch wire materials,while the synergistic change in sizes and materials of arch wires had the largest influence on torque performance of lingual brackets.Conclusions The torque performance of lingual bracket will be influenced with its different slot directions,the sizes and materials of arch wires.In clinical application,slot directions of lingual brackets as well as sizes and materials of arch wires should be adjusted properly according to the required torque force.

Three-dimensional finite element analysis on torque performance of lingual brackets with slot in different directions / 医用生物力学

Objective Objective To analyze the torque performance of lingual brackets with slots in different directions and the influence pattern of arch wires with different sizes and materials on torque of these lingual brackets.Methods The finite element models of the anterior maxilla lingual brackets with vertical and horizontal slot were constructed,using 3 kinds of materials (stainless steel,beta-titanium,nickel-titanium) and two sizes of arch wires (0.43 mm x 0.56 mm,0.41 mm x 0.56 mm),so as to compare and analyze their mechanical properties after the application of torque load on the left upper central incisors with a rotation angle of ±20°.Results With the increase in elastic modulus of the arch wire,torque moments of lingual brackets with horizontal and vertical slot both increased gradually.Torque performance of lingual brackets was affected more by the sizes and materials of arch wires than the directions of slots.The lingual bracket with vertical slot produced 1-2 times of torque force than that with horizontal slot under the same degree of torque angle.The effect of arch wire sizes was smaller than that of arch wire materials,while the synergistic change in sizes and materials of arch wires had the largest influence on torque performance of lingual brackets.Conclusions The torque performance of lingual bracket will be influenced with its different slot directions,the sizes and materials of arch wires.In clinical application,slot directions of lingual brackets as well as sizes and materials of arch wires should be adjusted properly according to the required torque force.

Frictional property comparisons of conventional and self-ligating lingual brackets according to tooth displacement during initial leveling and alignment: an in vitro mechanical study / 대한치과교정학회지

OBJECTIVE: We evaluated the effects of tooth displacement on frictional force when conventional ligating lingual brackets (CL-LBs), CL-LBs with a narrow bracket width, and self-ligating lingual brackets (SL-LBs) were used with initial leveling and alignment wires. METHODS: CL-LBs (7th Generation), CL-LBs with a narrow bracket width (STb), and SL-LBs (In-Ovation L) were tested under three tooth displacement conditions: no displacement (control); a 2-mm palatal displacement (PD) of the maxillary right lateral incisor (MXLI); and a 2-mm gingival displacement (GD) of the maxillary right canine (MXC) (nine groups, n = 7 per group). A stereolithographic typodont system and artificial saliva were used. Static and kinetic frictional forces (SFF and KFF, respectively) were measured while drawing a 0.013-inch copper-nickel-titanium archwire through brackets at 0.5 mm/min for 5 minutes at 36.5℃. RESULTS: The In-Ovation L exhibited lower SFF under control conditions and lower KFF under all displacement conditions than the 7th Generation and STb (all p < 0.001). No significant difference in SFF existed between the In-Ovation L and STb for a 2-mm GD of the MXC and 2-mm PD of the MXLI. A 2-mm GD of the MXC produced higher SFF and KFF than a 2-mm PD of the MXLI in all brackets (all p < 0.001). CONCLUSIONS: CL-LBs with narrow bracket widths exhibited higher KFF than SL-LBs under tooth displacement conditions. CL-LBs and ligation methods should be developed to produce SFF and KFF as low as those in SL-LBs during the initial and leveling stage.

Indirect Bonding With Various Bracket System In Lingual Orthodontics.

The indirect bonding technique is pivotal for success in lingual orthodontics. There are different laboratory techniques available for indirect positioning and bonding of lingual brackets. The HIRO system is one of the most used and easy to perform. At the early stages of the 80's, most of the practitioners and the patients have been seduced by lingual But the difficulties of the technique have rapidly given a disappointment. Today ten years later the authors present the progress which have been realized: the evolution of the brackets, the accuracy of their placement in the lab procedures, the making of the wire, the increase in patient's comfort. So this article attempts to review some of the advantages, disadvantages, bracket systems and laboratory procedures of lingual orthodontics.

Lingual Orthodontics - An Overview.

Esthetics is one of the major goals in orthodontic treatment Lingual orthodontics is the only orthodontic technique which is really invisible and permits the patient to have a beautiful smile not only after, but also during treatment and allowing a realistic control of the results.This article reviews the development, advantages and disadvantages, bonding techniques, biomechanics, and treatment procedures of the lingual appliance The aim of this article is to give a broad view of Lingual Orthodontics concepts and treatment in a simplified way, to encourage the orthodontist to use this important treatment modality regularly in their practice.

Incisor inclination indicator for anterior torque control during retraction in lingual orthodontic treatment / 대한치과교정학회지

A device called incisor inclination indicator to control the axial inclinations of the incisors in the diagnostic setup is introduced. It is used to control the retraction of the maxillary and mandibular incisors. In this article, we describe the use of the incisor inclination indicator to prescribe adequate torque into the anterior lingual brackets and evaluate the results of treatment in a bimaxillary dentoalveolar protrusion case that underwent orthodontic treatment with the pretorqued anterior lingual brackets. Retraction of the maxillary and mandibular incisors was achieved with careful control of the axial inclination. It is indicated that the use of the incisor inclination indicator is an effective adjunctive laboratory procedure for anterior torque control during retraction in lingual orthodontic treatment.

The positioning errors in bonding lingual brackets / 대한치과교정학회지

The purpose of this study was to evaluate the positioning errors according to the method of bonding lingual brackets. Dental models of twenty orthodontic patients with malocclusion were selected for this study. The positioning errors were measured on each model that brackets were bonded to. Three different bonding methods were used. For the first method, the bracket was bonded intimately to the lingual surface of the model. For the second method, the bracket was bonded intimately to the lingual surface after setting up using articulator. The passive bracketing, bonding the bracket ligated first to ideal archwire, was used after setting up as the last method. The results were as follows: 1. The brackets bonded without setting up showed greater angulation errors in the upper 1st premolar and the lower canine than those in other bonding methods. The brackets bonded without passive bracketing showed greater positioning errors in upper central incisor, lower 1st and 2nd premolars. 2. The brackets bonded without setting up showed greater torque error in lower 2nd premolar than those in other bonding methods. The brackets bonded without passive bracketing showed greater torque errors in all upper teeth, lower 1st and 2nd premolars. 3. The brackets bonded without passive bracketing showed greater rotation errors between upper central incisors, lower central incisors, lower lateral and central incisor, lower canine and lateral incisor. 4. The brackets bonded without setting up showed greater in-out errors between upper canine and lateral incisor than those in other bonding methods. The brackets bonded without passive bracketing showed greater in-out errors between upper central incisors, upper central and lateral incisors, upper 1st and 2nd premolars, lower lateral and central incisors, lower canine and lateral incisor. These results suggest that there is a large amount of positioning error in lingual brackets even by an indirect bonding technique, and it may be reduced by passive bracketing.