In school we were taught to treat impacted first permanent molars by extracting the first primary molars and fabricating a distal shoe appliance and cementing this to the second primary molar. I did this on one or two occasions. In my experience this was a rare occurrence. In the middle 1980s I had more experience and knowledge. Studying Functional Jaw Orthopedics (FJO) had given me a better understanding of how to treat this problem. The technique employing a, distal shoe, was inferior compared to my "new appliance". The distal shoe technique did nothing to improve the position and orientation of the first permanent molar, required minor surgery and resulted in premature loss of the first primary molar and results in crowding of the teeth anterior to it. None of this happens when employing my adapted removeable sagittal appliance therapy. With this appliance, no surgery, no extraction, and a "normal" eruption of the first permanent molar, regarding position and orientation.
Technique: First recognition of the problem, next, a. distal marginal ridge is exposed. Bond a trapezoidal shaped resin, cleat, on the distal marginal ridge, next ; make impression. next, fabricate modified sagittal appliance with expansion screw. next place appliance, instruct pt, turn expansion screw one turn every third day until the molar is free from the ledge of the distal part of the first primary molar. Next; restore first primary molar as necessary Next; cut away acrylic from appliance to make room for eruption of the permanent molar. next; when the first permanent molar has erupted so that it can no longer get 'stuck' on the primary molar, remove appliance and wait.
If the first primary molar is still covered by gingiva, cut an area of overlying gingival tissue away from the distal marginal ridge. Place IRM on the ridge. Next appt, remove IRM and bond resin on to the ridge and proceed as above. No place for drawing here but you can use your imagination. If questions, just write. Be happy to go into as much detail as required.
The year I first did this,( 1985) I treated 5 children. Two were local, one from Wilkes-Barre, one Philadelphia
( parents just moved into Bloomsburg area), and one from Millville, None since. :)) Like I said, it is not that common.