Canine Retraction With Temporary Anchorage Devices
Condition: Class II Malocclusion; Class III Malocclusion; Crowding, Tooth; Bimaxillary Protrusion
MeSH terms: Prognathism; Malocclusion; Malocclusion, Angle Class II; Overbite; Malocclusion, Angle Class III
Study type: Interventional

Summary: 
      Various malocclusions require the extraction of the first premolars and retraction of the
      canines with the need for maximum anchorage. If the canines are pulled into the extraction
      space using the molar teeth for support, unwanted tooth movement occurs. This study aims to
      evaluate the effect of temporary anchorage devices and power arms, which are auxiliary
      orthodontic appliances in reducing undesirable tooth movements.
    

Detailed description: 
      In orthodontic patients who require overjet correction, increased facial convexity, or relief
      of severe crowding, dental extraction followed by canine retraction is indicated. In
      conventional orthodontic treatment, the molars are used for anchorage and reinforced with
      intra-oral or extra-oral appliances. Although effective, this produces unwanted side effects
      where the molars move mesially and rotate, taking up some of the extraction space. As the
      canines move into the extraction space they tip backward requiring further uprighting. Power
      arms are vertical metal extensions placed in the canine brackets. They direct the force to
      the center of resistance of the tooth to allow bodily movement and prevent canine tipping.
      Temporary anchorage devices (TADs) are minimally invasive, small screws, inserted in the jaw
      bones to act as anchorage units instead of the molars.

      This study aims to evaluate the effect of the TADs and power arms on the efficiency of canine
      retraction including the rate of canine retraction and canine tipping as well as mesial molar
      drift and rotation.

      The null hypothesis is that the use of the power arm and the TADs have no effect on the
      canine retraction rate.

      This study is a single-arm, single-center study. Twenty quadrants in 10 adult patients will
      be selected from the Orthodontic Outpatient Clinic at the Future University in Egypt.

      Orthodontic records will be collected including study models, intra- and extra-oral
      photographs and cone beam computed tomograms.

      Molars will be banded and Roth 0.22" brackets will be bonded to the canine and second
      premolars. Power arms, 8mmin length, will be inserted in the vertical slots of the canine
      brackets.

      The dental arches will be leveled and aligned using consecutive archwires. TADs will be
      inserted between the second premolars and first molars. The first premolars will then be
      extracted and canines will be retracted within a week. Canines will be retracted along 0.016"
      X 0.22" stainless steel archwires using 150 g of force applied by an elastomeric chain. The
      elastic chain will be replaced every 4 weeks.

      After 6 months of canine retraction, the orthodontic records will be collected for
      comparison.
    

Intervention name(s): canine retraction
Intervention type(s): Procedure
Intervention description(s): Canine retraction using elastomeric chains activated every 4 weeks, using power arms to direct force through the center of resistance and TADs for direct anchorage.
Intervention model: Single Group Assignment
Masking: None (Open Label)
Primary purpose: Treatment