Use of intermaxillary elastics in orthodontic practice, easy, cheap and effective. Kleber Meireles. Episode 75. January 21st 2021

Join me as I summaries Kleber’s lecture on the use of intermaxillary elastics in orthodontics, topics of force magnitude, side effects and how to counter them, use of a sliding jig and stability are described.

Force magnitude more important than the size of the elastics

• Large variation forces used by orthodontists in Kurol 1996
• Use a gauge on every patient
• Excessive = damage to PDL and RR
• Force required
  • Retraction of upper incisors = 250g each side Oesterle 2012 / 350 g Proffit
  • Individual

Class 2 elastics effects

• Distalise anterior teeth
• Mesial of lower posterior teeth
• Extrusion of upper anterior teeth
• Extrusion of lower posterior teeth
• Rotate occlusal plane clockwise
• Retrusive upper lip
• Protrusive lower lip

How to avoid side effects

• Case selection: avoid high angle cases
• Avoid upper arch retraction on round wire
• Reduce vertical vector
  • Increase horizontal distance mesial of U2s and L7s
  • Change the vertical vector by using a sliding jig
    • Slidingjig movesvector from above the brackets upper, to below the bracket, lower arch force from below the bracket to above the bracket
    • Sliding jig – directs upper arch forces to the molars – more efficient than to archwire only or canine

Class 2 subdivision

• Class 2 one side, class 1 other side.
• Of dental origin, no skeletal
• Usually cant on class 2 side, with arch up on the RHS
• Class 2 elastic on effected side
• Distalisation on URQ with sliding jig
• Retraction of the arch – on rectangular SS – 350g

Torque

• Can be lost upper incisors
• Place torque into the archwire during the retraction – not after retraction

Finishing

• Triangular elastics

Class 2 elastic stability

• Patient may posture: assess displaced mandible / CR
• Tooth movement:
  • Bony formation may not be complete
  • PDL may not be reorganised
    • REQUIRE 3 months of wear for stability, bone growth and PDL