In our last info letter we discussed how to distalize molars with a kick back utility arch (KBUA) anchored to TADs. Not everybody likes bending utility arches and some prefer to stay with a straight wire system. The technique presented today uses a straight wire, either round SS 0.020’’ or a rectangular SS 0.016 x 0.022’’ and a compressed 150 g Niti coil (manufacturers normally identify 150 g coils as Medium force but it may vary with different manufacturers…know what you use). The coil is activated simply by compressing it a bracket width and is reactivated every 4 weeks by using either crimpable stops, gurin locks or a blob of resin until the molar crown has reached a super Cl I or even a slight Cl III position. Be carefull to take an x-ray when you think you have reached the over corrected position because part of the movement will be crown tipping. The amount of tipping will vary from case to case, but the roots, if needed, have to be corrected to get stability (uprighting molars roots will be described in an other info-letter).
Now that we have described the distalizing method, let’s let’s talk anchorage. We have to plan for anchorage to avoid flaring of the front teeth. Anchorage can be Cl II elastics to the lower arch (either full strap up with a big SS wire if the case is advanced or if the molar movement is done at the start of treatment just place a clear vacuum splint to the lower arch with windows in the molar area to allow placement bonded buccal buttons to the molars for the attachment of the Cl II elastics). If there is little or no cooperation, TADs can be placed mesial to the segment needing distalization and the anterior teeth can be attached to the TADs with a metal ligature. Try to place the metal ligature as parallel as possible to the base archwire to minimize side effects and use an extension arm if necessary (see picture).
For those who want to know about these prefabricated posts, they come from Ormco VectorTAS Crimpable Posts = 601-0040 (packs of 6).
Dr. Michel Champagne