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References

Kuroda S, Yamada K, Deguchi T, Kyung HM, Takano-Yamamoto T. Class II malocclusion treated with miniscrew anchorage: comparison with traditional orthodontic mechanics outcomes. Am J Orthod Dentofacial Orthop. 2009; 135:302-309
Yamada K, Kuroda S, Deguchi T, Takano-Yamamoto T, Yamashiro T. Distal movement of maxillary molars using miniscrew anchorage in the buccal interradicular region. Angle Orthod. 2009; 79:78-84
Lim SM, Hong RK. Distal movement of maxillary molars using a lever-arm and miniimplant system. Angle Orthod. 2008; 78:167-175
Graber TM, Vanarsdall RL., 3rd edn. St Louis: Mosby; 2000

Tricks of the trade: molar distalization with double loop archwire distalizer

From Volume 11, Issue 4, October 2018 | Pages 155-157

Authors

Arunachalam Sivakumar

MDS, MOrth RCS(Ed)

Reader, Department of Orthodontics, Manipal College of Dental Sciences

Articles by Arunachalam Sivakumar

Jitendra Sharan

MDS, PhD

Department of Orthodontics, All India Institute of Medical Sciences, Bhubaneswar, India. New Delhi

Articles by Jitendra Sharan

Vanishri S Nayak

MSc

Senior Grade Lecturer, Kasturba Medical College, Manipal, India

Articles by Vanishri S Nayak

Article

Loops are an integral part of orthodontic mechanotherapy. They deliver a predictable force system for an efficient tooth movement in the required direction. A simple, yet effective double loop archwire distalizer has been developed for molar distal movement. It can be used for bilateral or unilateral distalization in the maxillary or mandibular arch. This appliance has been found to be very useful, simple to apply, and easy to handle at the chairside.

Molar distalization for gaining space in the dental arch is a popular strategy among orthodontists. A number of clinical and research reports have demonstrated the efficiency of intra-oral molar distalizing appliances supported with miniscrews in the contemporary practice.1,2-3 This article showcases a simple tactic utilizing archwire loops for maxillary second molar distal movement. After a preliminary alignment and levelling, a continuous archwire set-up is designed with double loop archwire distalizer. When the double loop archwire distalizer is used to move the molar tooth distally, the activity of the loops invites anchorage loss in the mesial direction too. To prevent this, a miniscrew could be inserted buccally between the second premolar and first molar, although other sites may be appropriate.

Fabrication

  • Fabricate double loop archwire distalizer from 0.020” special+ Australian wire, which has excellent resilience and resistance to permanent deformation. The double loop assembly consists of an open vertical loop (4–5 mm wide and 6–7 mm high) and a short omega loop (Figure 1).
  • Make the mesial leg of the open vertical loop flush with the distal aspect of the convertible first molar tube. Continue the distal leg to form a short omega loop that is bent at a distance of about 2 mm beyond the mesial end of the second molar tube (Figures 1 and 2a).
  • Form a 20° bend down at the distal leg of the open vertical loop (Figure 2b).
  • Activate the set up by engaging the omega loop to the second molar tube (Figures 2c and 3a–c). The force delivered by the activated loop moves the maxillary second molar distally (Figures 2d and 3d–f).
  • If additional tooth movement is desired, reactivate the ‘double loop’ by opening the omega loop with a bird beak plier at the subsequent appointment (Figure 4).
    • Figure 1. Basic design of double loop distalizer. L2 should be longer than L1 by at least 2 mm to permit effective activation.
    Figure 2. Schematic representation of activation of double loop distalizer. (a) Initial position of double loop distalizer in maxillary arch. (b) Distal leg of open vertical loop bent down 20°. (c) Activation of double loop distalizer generating moment and force. (d) Space opening from initial activation.
    Figure 3. (a–c) At the start of distalization (main buccal tube on the first molar is of open type to receive the archwire and is secured with steel ligature). (d–f) After 3 months of treatment with a double loop distalizer.
    Figure 4. (a, b) Opening the short omega loop activates the open vertical loop. (c) Completion of distalization of maxillary second molar.

    Discussion

    The engagement of the omega loop into the tube of the second molar compresses the open vertical loop, and so the deactivation of the open loop distally drives the second molar. The 20° bend produces a moment that counteracts the tipping movement created by the force of the appliance, and closing the open vertical loop would place it further at an angle that in itself generates an activation moment in the desired direction. Thus the molar undergoes a translatory movement instead of tipping (Figures 2c, d). Further, the activation of the double loop archwire distalizer conforms to the biomechanical principle, as outlined by the Bauschinger effect, which states that the range of activation of a loop is always greatest in the direction of the last bend.4 Furthermore, a double loop archwire distalizer is a fail-safe design.