He then accepted a position of Professor of Prosthetic Dentistry and Orthodontics at Chicago Dental Infirmary.
This obturator was self-sustaining and it restored the function of the soft palate and allowed the wearer to speak correctly.
Case presented an article called The question of Extraction in Orthodontia which was followed by discussions by different orthodontists.
Premolar extraction rose to popularity in the 1970s, when up to 60% percent of all patients were routinely treated with the Tweed technique.
At the same time, it was observed in research published in the AJO-DO that this technique led to the retrusion of the jaws, "flattened" profile, and reduced vertical dimension.
Plaintiff Susan Brimm was awarded 1.3 million dollars for the damage caused by this by then standard orthodontic procedure.
In panic about what this jury conclusion would mean for the rising orthodontic specialty's reputation, and to ward off copy-cat lawsuits, the American Association of Orthodontists (AAO) commissioned and paid for research articles that established that the "jaw joint has nothing to do with the teeth."
These research articles are required reading in US orthodontic schools as of 2023, and orthodontists today tend to believe that this commissioned "high quality evidence" disproves that extraction/retraction can cause temporomandibular disorder.
This despite the fact that a 2022 peer-reviewed study on the topic has confirmed that extraction orthodontic treatment changes mandibular kinematics (movement and position) and may be a risk for temporomandibular disorder.