|Year : 2017 | Volume
| Issue : 3 | Page : 216-217
Bodily alignment of the lateral incisor spring: Blocked-out laterals unraveled
Vishal Dixit1, Sonahita Agarwal2, Sudhir Kapoor3
1 PG Student, Department of Orthodontics and Dentofacial Orthopedics, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India
2 Reader, Department of Orthodontics and Dentofacial Orthopedics, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India
3 Prof. and HOD, Department of Orthodontics and Dentofacial Orthopedics, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh, India
|Date of Submission||09-Apr-2016|
|Date of Acceptance||14-Sep-2016|
|Date of Web Publication||17-Jul-2017|
Department of Orthodontics and Dentofacial Orthopedics, Sardar Patel Post Graduate Institute of Dental and Medical Sciences, Lucknow, Uttar Pradesh
Source of Support: None, Conflict of Interest: None
Introduction: Bodily alignment of teeth that are blocked out of the arch specially in cases of a palatally placed lateral incisor, is often time consuming and difficult. Though several treatment methods are available for accomplishing this, these approaches have some drawbacks. To overcome these shortcomings, the BALI (Bodily Alignment of Lateral Incisor) spring was designed to achieve bodily movement of palatally blocked-out lateral incisors in preadjusted edgewise appliance therapy. Methods: This spring in the form of figure of eight (8) is made with 0.017” X 0.025” TMA wire. It is engaged into the lateral incisor bracket and tied to the base archwire after sufficient space has been created for the blocked-out tooth. Conclusion: The BALI spring is an efficient and versatile auxiliary which can be effectively used for the bodily alignment of palatally placed lateral incisors. It is easy to fabricate and engage, prevents distortion of the archwire and applies light forces to the tooth.
Keywords: Blocked-out lateral, ectopic eruption, lateral incisor
|How to cite this article:|
Dixit V, Agarwal S, Kapoor S. Bodily alignment of the lateral incisor spring: Blocked-out laterals unraveled. J Indian Orthod Soc 2017;51:216-7
|How to cite this URL:|
Dixit V, Agarwal S, Kapoor S. Bodily alignment of the lateral incisor spring: Blocked-out laterals unraveled. J Indian Orthod Soc [serial online] 2017 [cited 2017 Sep 24];51:216-7. Available from: http://www.jios.in/text.asp?2017/51/3/216/210915
| Introduction|| |
Blocked-out lateral incisors are a common occurrence in routine orthodontic practice. Since in such cases both crown and root are placed palatally, the stability of these cases demands not only crown alignment but also ideal root positions. The traditional approaches, using a light round archwire, loose ties using E-chain or ligatures, would produce a simple tipping of the crown into the line of the arch while the root remained largely in the original position in bone or even become more palatally placed. Then, it becomes a daunting task for the orthodontist to move the root through the thick palatal bone. Therefore, to overcome these shortcomings, we have designed the Bodily alignment of the lateral incisor (BALI) spring that will facilitate movement of the lateral incisor bodily.
| Fabrication|| |
This spring is made with 0.017” × 0.025” TMA in the edgewise mode.
- The wire is bent into a rectangular box (incisal box) of length more than the lateral incisor bracket width by 1 mm on each side. Height of the box should be same as that of the lateral incisor bracket height [Figure 1]a
- Another similar rectangular box (Gingival box) is fabricated adjoining the incisal box with the common base. The length will be the same and the height will be half of the bracket height [Figure 1]b
- The completed spring is in the shape of an “8” with two adjoining boxes bent at angle of 150° to each other [Figure 1]c.
|Figure 1: (a) Fabrication of the incisal box, (b) complete BALI spring with incisal and gingival box, (c) angle between two boxes is approximately 150°, (d) On activation of the BALI spring, the clockwise moment|
generated by palatal force of the incisal box and the counterclockwise moment generated by the labial force of the gingival box cancel out each other to bring about bodily movement of the lateral incisor
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| Insertion of the Spring|| |
The middle horizontal arm which is also the common base for both boxes will be inserted into the bracket slot and ligated with a steel ligature of 0.009”. Activation is done by tying a 0.010” steel ligature from the gingival box to the main archwire.
| Biomechanics|| |
When the auxiliary is activated, it exerts a labial force on the tooth as well as a couple. This labial force creates a moment that leads to tipping of the crown labially. A couple is created when the incisal box hits the labial surface of the tooth applying a lingual force on the tooth. This couple creates a counterbalancing moment which cancels the moment created by the labial force [Figure 1]d. This results in the tooth being moved bodily into the line of occlusion. The torque efficiency of this spring could be attributed to the large moment arm (distance between the two forces of the couple) that it provides.
| Clinical Application|| |
A preadjusted edgewise bracket was bonded onto the lateral incisor of a case with palatally blocked-out lateral incisor. The spring was inserted and activated by tying it to the base archwire [Figure 2]a,[Figure 2]b,[Figure 2]c,[Figure 2]d. Reactivation was done after 2 months and the total treatment duration with the spring was approximately 4 months. It was observed that the lateral incisor had moved bodily and come into alignment within the arch [Figure 2]e and [Figure 2]f. BALI spring was used in another similar case with blocked out lateral incisor and the time taken for the lateral to align was around 3 months [Figure 3]a,[Figure 3]b,[Figure 3]c.
|Figure 2: (a and b) Pretreatment intraoral photographs of the patient frontal view and occlusal view, (c and d) insertion and activation of the BALI spring on the lateral incisor bracket lateral view and frontal view, (e and f) postalignment intraoral photographs lateral view and occlusal view|
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|Figure 3: (a) Pretreatment intraoral photograph of the patient frontal view, (b) frontal view of insertion and activation of the BALI spring on the lateral incisor bracket, (c) postalignment intraoral photograph frontal view|
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| Conclusion|| |
This spring is easy to fabricate and engage, applies light forces, prevents distortion of the arch form, and needs only a single activation to accomplish the correction.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Proffit WR, Fields HW. The first stage of comprehensive treatment: Alignment and leveling. In: Contemporary Orthodontics. 4th
ed. St. Louis: C.V. Mosby; 2007. p. 553.
Nair SB, Prakash AT, Shetty KS. Mollenhauer aligning auxiliary for bodily alignment of blocked-out lateral incisors in preadjusted edgewise appliance therapy. J Indian Orthod Soc 2014;48:156-62. [Full text]
Linge L, Linge BO. Patient characteristics and treatment variables associated with apical root resorption during orthodontic treatment. Am J Orthod Dentofacial Orthop 1991;99:35-43.
[Figure 1], [Figure 2], [Figure 3]