Uprighting Impacted Molars
The management of impacted molars used to be a difficult problem. Separating wires and threaded pins (requiring restorations) have been advocated. Uncertainty and delay characterized these approaches.
In 1971, I demonstrated a technique for uprighting impacted lower second molars using direct bonding technique. Recently, a new direct bonding material has become available which greatly facilitates the technique. This adhesive undergoes a very rapid initial set, which can be crucial to success, since it is essential that the initial polymerization occur without any contamination by moisture. In the second molar region, this can be very challenging. Materials requiring the use of ultraviolet lights can be difficult to protect from moisture until initial polymerization occurs.
The availability of a rapidly polymerizing bonding material has routinized a predictably successful method of bonding uprighting levers to the exposed occlusal surface of partially impacted molars. Right and left uprighting levers of several lengths can be prefabricated for added efficiency.
The Technique
The technique has been used in over fifty cases and the average length of time required for uprighting has been three months (Fig. 1).
The levers are fashioned from .020 wire, beginning with a small loop for retention in the bonding material. The wire is carried buccally, then gingivally, in close contact with the tooth to reduce the likelihood of interfering with occlusion. The wire is then carried forward, ending in a hook in the cuspid/first bicuspid embrasure (Fig. 2).
It is important to allow space for the hook to move distally as the tooth uprights. It may be necessary to equilibrate the opposing molar if it has overerupted .
After the lever is formed, the impacted tooth is isolated with cotton rolls and its occlusal surface is etched according to accepted technique.
Then a brush is moistened with the adhesive liquid and brought to the adhesive powder to form a bead. The moistened bead is touched to the prepared enamel surface and protected against moisture for fifteen seconds as the initial polymerization occurs.
Next, the lever is placed in position with the small loop set into the adhesive material (Fig. 3).
Additional adhesive mixture is added to cover the loop. (Fig. 4).
The final set occurs in about five minutes, after which the lever can be activated by hooking it on
the base archwire (Fig. 5).
A loop plier can be used to increase the activation before hooking onto the archwire. At subsequent appointments, the wire is unhooked, activated, and rehooked until the tooth is in proper position. Frequently, equilibration of the opposing molar is necessary as the tooth uprights.
Sometimes, as the tooth erupts, a space develops between the uprighting molar and the tooth anterior to it. If this occurs, or if buccolingual correction is necessary, the tooth should be banded to accomplish space closure or buccolingual correction.
Occasionally, it is desirable to tie back the hook with an elastic ligature to promote distal crown movement of the impacted tooth. This is true when the crown is locked under the distal edge of the first molar band. Although this is generally not necessary, if there is no improvement in four weeks, ligation should be considered.
When the uprighting is completed, a slowly turning #4 round bur is useful in removing the adhesive without cutting the enamel.
