Extractin orthodontic treatment, Dental Education Lecture

Four extraction ortho is presented to the patient's mother. She does not agree lower bicuspid extraction. Her reasoning is that the lower teeth are not so crowded (Fig.2). Closer look shows that the lower incisors are somewhat lingually inclined. The patient is scared when the upper bicuspids are extracted (Fig.1). The final result will be most likely canine Class I and molar Class II (1,2).

Dr. Ness replies: Actually, what orthodontic training does the mother have? How does she know what amount of crowding warrants extraction? How does she know upper bicuspid extraction only is a treatment option. Who is the dentist here?

By doing this, you will have a constricting maxillary arch and an expanding mandibular arch. After spaces are closed, there is a good chance you will end up with molar class II in posterior crossbite.

Upper bi only ext is appropriate when there is NO crowding in the lower arch, or even space.

I don't recommend this plan at all. But, your patient knows more than both of us.

Sorry for the sarcasm, but that scenario irritates me. Take charge of your patients. Doug Ness

I mentioned you when I presented the treatment plan. The mother respected the idea of yours. I did mention that the lower bi may need to be extracted after arch wire sequence. We may waste about 6 months. I want to learn the lesson.

I love your passion for dentistry. Thanks. These are two cases of upper bi ext (1,2).

I have done many. But the decision lies in lower arch crowding. Zero to 1mm only. Any crowding will need IPR.

When the patient returns, you will be surprised to find the alignment (Fig.3). The UR 3 has started distal drifting (Fig.4,6), while the UL 3 needs distal retraction (Fig.5), either power chain (Fig.7) or closed coil spring. Take photos either prior to change of wires (if oral hygiene is not bad) or after (Fig.3-7, 16x16 ss wires, 4.5 months post bracketing). Check overjet before retraction. In fact, the overjet allows to retract the upper anteriors.

Three weeks later, UL3 and 5 have approximated each other (Fig.8). The long axis of UR3 (Fig.9 white line) is off. After changing to 16x22 wires, power chain x2 is placed between UL 3 and 5, while power chain x3 (without twist) is between UR 3 and 5. The purpose of the latter is to change the axis of UR3. The patient is coming back in 3 weeks. Use a unilateral child cheek retractor for photography.

Eighteen months post banding, anterior over bite and over jet and posterior interdigitation are within normal limit except UR5 rotation. For correction of the latter, two lingual buttons are placed with power chain (Fig.10). The lingual button at UR3 dislodges in a few days. It is placed at UR2; Fig.11 is taken 1 month post placement.