Korean J Orthod.  2021 May;51(3):179-188. 10.4041/kjod.2021.51.3.179.

Evaluation of strategic uprighting of the mandibular molars using an orthodontic miniplate and a nickel-titanium reverse curve arch wire: Preliminary cephalometric study

• Park JH
• Choo H
• Choi JY
• Chung KR
• Kim SH

• KMID: 2515821
• DOI: http://doi.org/10.4041/kjod.2021.51.3.179

Abstract

Objective
To evaluate the overall treatment effects in terms of the amount of uprighting with changes in the sagittal and vertical positions of mandibular molars after applying an orthodontic miniplate with a nickel-titanium (NiTi) reverse curve arch wire (biocreative reverse curve [BRC] system).
Methods
A total of 30 female patients (mean age, 25.99 ± 8.96 years) were treated with the BRC system (mean BRC time, 10.3 ± 4.07 months). An I-shaped C-tube miniplate (Jin Biomed) was placed at the labial aspect for the alveolar bone of the mandibular incisors. A 0.017 × 0.025-inch NiTi reverse curve arch wire was engaged at the C-tube mini-plate anteriorly and the first and second premolars and molars posteriorly in the mandibular arch. Pre- and post-BRC lateral cephalograms were analyzed. A paired t-test was used to analyze the treatment effects of BRC.
Results
The mandibular second molars were intrusively uprighted successfully by the BRC system. Distal uprighting with a controlled vertical dimension was noted on the first molars when they remained engaged in the BRC and the distal ends of the arch wire were laid on the second molars. The mandibular first and second premolars showed a slight extrusion. The changes in the mandibular incisors were unremarkable, while the mandibular molar angulation improved significantly. The lower occlusal plane rotated counterclockwise (MP-LOP: 1.13° ± 2.60°).
Conclusions
The BRC system can provide very effective molar uprighting without compromising the position of the mandibular anterior teeth.

Keyword

Molar uprighting; C-tube miniplate; Biocreative reverse curve; Intrusion

Figure

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  Figure 1 Schematic illustration of the biocreative reverse curve system. The C-tube miniplate is installed on the labial side of the anterior teeth in the symphysis area. The brackets are bonded on the mandibular posterior target teeth. A 0.017 × 0.025-inch reverse curve of Spee nickel-titanium arch wire is raised by the C-tube and the intrusive upright force would be induced to the molars. A, Frontal view. B, Lateral view. C, Occlusal view.

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  Figure 2 Reference points and lines used for cephalometric analysis. Dentoalveolar (containing occlusal plane) measurements. LC, mandibular lingual cortex.

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  Figure 3 Intraoral photographs of the case. A, Pretreatment. B, 6 months after biocreative reverse curve (BRC) procedure. C, 13 months after BRC procedure. D, Post-treatment (treatment periods: 21 months).

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  Figure 4 Lateral cephalograms and superimposed tracings of the case. A, Pretreatment. B, Right after biocreative reverse curve procedure. C, Post-treatment. D, Superimposition tracings from pretreatment (black) to posttreatment (gray).

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  Figure 5 The progress of force-moment system change with the biocreative reverse curve system (non-equilibrium state). A, Initial state. B, Progress state.

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  Figure 6 Overall treatment results of the biocreative reverse curve system (as referenced by the mean value in Table 2). L1, lower incisor (distalized: 0.48 mm, extruded: 0.44 mm); L4, first premolar (distalized: 0.94 mm, extruded: 0.75 mm, uprighted: 0.63°); L5, second premolar (distalized: 0.59 mm, extruded: 0.58 mm, uprighted: 1.46°); L6, first molar (distalized: 1.01 mm, uprighted: 7.29°); L7, second molar (distalized: 0.53 mm, intruded: 1.42 mm, uprighted: 10.83°).

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  Figure 7 Three-dimensional tooth movement on cone-beam computed tomograms of the case. A, B, Initial state of the lower right and left molars, respectively (upper: sagittal, lower: frontal view). C, D, Final state of the lower right and left molars, respectively (upper: sagittal, lower: frontal view). L6, lower first molar; L7, lower second molar.

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