In this lecture, Dr. William M. Hang challenges the conventional orthodontic teaching that extracting four teeth to upright the remaining dentition over basal bone prevents gingival recession. He presents clinical anecdotes of patients who, despite having four, eight, or even twelve teeth removed, still exhibit significant recession, sometimes requiring grafts. He questions the logic of extracting more teeth to solve the problem and highlights that many severe recession cases in middle‑aged patients stem from the four‑tooth extraction protocol. Hang then cites two key peer‑reviewed studies—Birte Melsen’s work from Aarhus, Denmark, and Artun’s adolescent advancement study—both concluding that substantial labial movement of mandibular incisors does not markedly increase recession risk. He uses these findings to support his 20‑year clinical experience that aggressive extractions are unnecessary. The talk also critiques the over‑reliance on Invisalign’s treatment planning, arguing that clinicians may compromise tongue space and re‑approximate teeth unnecessarily to satisfy the software, rather than following evidence‑based biomechanics. Overall, the presentation blends case evidence, literature review, and professional opinion to argue for preserving teeth and limiting extractions while still achieving stable, recession‑free outcomes.
Chapters
So, we've been taught that we have to take 4 teeth out to get the teeth upright over basal bone so that the cases will be more stable. And here's a guy who's a chiropractor in this town, and his dad's a dentist, and he had 4 teeth taken out. And these are his teeth. Anyone notice a problem that may be a problem here? You're supposed to take out 4 teeth, right? So the teeth are more upright over basal bone to avoid recession. But do you think this may be a problem in this guy's life? Maybe? Really? Okay. So, maybe in this case, taking the 4 teeth out and getting them over basal bone wasn't helpful. Well, if taking out 4 teeth isn't enough, let's take out 8. Alright. Here's a cuspid and a first molar and a cuspid and a first molar. How many people have had 8 teeth taken out in their head? How many of you ever seen a case like this? No. Now fortunately this is a really old case. You can see some really old braces on here with old bands. But look at that. My, oh my. The teeth are upright over basal bone to prevent recession. But there is still recession. Of course, he gets a tire patch graft to go on here, but he's still got that recession going on. What do you think? Suppose we ought to take out the molars too? I mean, if he's still getting recession, 8 teeth are gone, what's the matter with 12? Go look at your cases. Some of the worst recession that you have in your patients in their 40s and 50s is on patients who've had 4 teeth taken out. So, from the refereed literature, this is really nice to have this article come around to give credence to what I was doing for more than 20 years. From one of the best orthodontic programs in the world, Aarhus, Denmark, Birte Melsen here. Everybody knows her in Europe and in the United States. After massive labial movement incisors, The whole thing is about, gee, do you really get recession or not? And the answer is, gingival recession of mandibular incisors did not significantly increase during orthodontic treatment. After treatment, fewer than 10% of subjects had gingival recession greater than 2 millimeters, and at follow-up, 5% of the pre-existing gingival recession had improved. Blah, blah, blah. The point is, it's okay. And yet, how many of you do Invisalign here? I do. How many of you, how many of you reapproximate the teeth when you do because you're afraid to advance them or Invisalign tells you that you shouldn't? Why do you let Invisalign rule your life and you reduce the tongue space potentially by doing so? If one article isn't enough, how about another? Periodontal status of mandibular incisors after pronounced orthodontic advancement during adolescence. This is from Artun. Adolescent orthodontic patients with dental alveolar retrusion may be treated with pronounced advancement of the mandibular incisors without increasing the risk of recession. Recession that occurs during the period of active treatment is not progressive.
