Lingual sheaths on molar bands are used to hold wires from removable Nance appliances, transpalatal expanders, lower lingual arches, and other appliances. Each sheath usually has an indentation on the distal end that serves as a catch to prevent the archwire from slipping out. However, frequent insertion, removal, and manipulation of the wire causes the dimple to flatten and allows the archwire to loosen or fall out. Even tying the wire in with a stainless steel ligature is not a failsafe method, and the ligature can be irritating to the tongue and soft tissues.
With the following technique, the clinician can adjust the lingual sheath at every appointment. The only tool needed is a band seater* with a plunger that is pulled back toward the handle and let go, pushing the tip forward.
When a lingual wire be comes loose (A), place the tip of the band seater in the groove on the distal end of the sheath (B). Place a finger or thumb on the buccal side of the molar for support while gently pulling back the plunger. Release the plunger so that the tip of the band seater slightly collapses the wall of the sheath. Repeat the procedure until the wire fits snugly (C).
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If the lingual wire is part of a retainer and no more adjustments are needed, place the tip of the band seater on the mesial end of the sheath and push in that side while the wire is fully seated. This will collapse the entire sheath around the wire to prevent it from being dislodged between visits.
FOOTNOTES
- *RMO, Inc., P.O. Box 17085, Denver, CO 80217.