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PEARLS

Activating a Modified Closing Loop

Common techniques for activating a closing loop are problematic. Cinching the distal end of the archwire can be time-consuming and inaccurate. Tying back an omega loop between the premolars or between the second premolar and first molar is difficult when the interbracket space is narrow. Lacing back the archwire to a hook is possible, but a crimpable hook can come loose, and a soldered hook requires soldering.

Cureton and Storie recommended a technique in which a U-bend was placed in the distal leg of a teardrop closing loop1 (Fig. A). In a further modification of Cureton and Storie's technique, I incorporate a V-bend rather than a U-bend to hold the laceback ligature in a specific location, avoiding the play that can occur with a curved bend.

The V-bend is placed at about one-third the occlusal level of the distal leg of the loop. After activating the loop, a laceback metal ligature or power thread is tied to the posterior anchoring tooth or to a miniscrew, then attached to the loop's V-bend (Fig. B). Alternatively, power chain can be threaded through the V-bend and looped back through the lumen of one of the chain sections, then attached to the anchorage tooth or miniscrew.

This loop modification is simple and fast using a V-bend plier. Without a distal-end bend, the archwire can be removed for regular wire adjustments or the addition of incisor torque, and the same wire can be used during the entire space-closure phase. The amount of activation is easily adjusted by moving the distal leg as needed, then tightening the laceback.

ACKNOWLEDGMENT: The author appreciates the assistance of Dr. Joseph Gafari.

REFERENCES

  • 1.   Cureton, S.L. and Storie, D.: Simplified activation of closing loops, J. Clin. Orthod. 35:490-492, 1998.
  • CHADI
    DR. KASSIR

Dr. Kassir is in the private practice of orthodontics, Center Massoud, Bikfaya Main Road, El Metn, Mount Lebanon, Lebanon. E-mail him at chadikassir489@hotmail.com.

Fig. 1 Adolescent Class II, division patient with favorable growth pattern.
Fig. 2 Class II, division 1 patient with no growth or unfavorable growth pattern.
Fig. 3 A preferable strategy for treating Class II, division 1 patient with no growth remaining or an unfavorable growth pattern may be to extract only the maxillary bicuspids...
Fig. 4 A. Adult Class II patient before treatment. B. Fifteen months later, after maxillary premolar extractions and mandibular interproximal enamel reduction.
Fig. 5 A. 15-year-old male Class II patient before treatment. Different Visualized Treatment Objectives using: B. Tweed Triangle. C. Steiner Analysis. D. APo line. E. A line. F. Radney line. Note how A line and Radney line suggest more facial positions of maxillary and man­dibular incisors.
Fig. 6 ] A. Mandibular arch-length discrepancy measured with Irregularity Index, adding contact-point dis­placements: A(2mm) + B(2mm) + C(3mm) + D(3mm) + E(1mm) = 11mm. B. Mandibular arch-length discrepan­cy measured with occlusogram.
Fig. 7 Typical Steiner Box for mandibular arch, with arch-length discrepancy measured according to Irregularity Index and Visualized Treatment Ob­jective designed using APo line.
Fig. 8 A. Modified Steiner Box, with arch-length discrepancies measured by occlusograms and VTO designed using A line. With mandibular premolar extractions, note additional maxillary space necessitated by retraction of mandibular canines. B. Modified Steiner Box, with arch-length discrepancies measured by occlusograms and VTO designed using A line. Without mandibular premolar extractions, additional maxillary space is not needed.
Fig. 9 After four premolar extractions and anterior retraction, insufficient space remains to correct posterior malocclusion. MPA IV appliance was placed after one year of treatment.

REFERENCES 2

DR. CLARENCE BRYK DDS, MS

DR. CLARENCE BRYK DDS, MS

DR. LARRY W. WHITE DDS, MSD

DR. LARRY W. WHITE DDS, MSD

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