In this lecture, the speaker explains the nasolabial (nose‑lip) angle as a simple yet powerful diagnostic criterion for assessing maxillary position in orthodontic patients. An ideal angle is about 100°, with a normal range of 90‑110°. Class II patients typically exhibit an overly obtuse angle, indicating a retruded maxilla. The speaker argues that traditional orthodontic interventions—headgear or extractions with retraction—tend to increase this angle further, worsening facial aesthetics and airway patency. Through several clinical examples—a mother and daughter with peg lateral incisors, and a young boy with Class II Division I malocclusion—the speaker demonstrates how orthotropic treatment (forward development of the maxilla and mandible) reduces the nasolabial angle toward the ideal range (e.g., from 140° to 118°, and from 135° to 105°) and simultaneously improves airway space and chin prominence. The talk references James McNamara’s 1981 study, which found that most Class II cases have a retruded maxilla and mandibular retrusion, supporting the forward‑growth approach. John Mew’s long‑standing advocacy for maxillary forward development is also highlighted. The segment concludes that the nasolabial angle is an easy, accurate measure of maxillary position and should guide treatment planning toward forward growth rather than restrictive methods.
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Welcome back. This segment is entitled Diagnostic Criteria: Nasolabial Angle. Here is the nasolabial angle. In an ideal situation, it would be around 100 degrees, and the range of normal is considered from 90 to 110. The nose lift angle is almost always too obtuse in Class II patients. Traditional orthodontics with a headgear Or removal of teeth and retraction makes the number, which is already too large, even larger. What this means is that orthodontic treatment to develop the upper and lower jaws forward is preferable to headgear wear and/or removal of teeth if improved facial aesthetics is the goal, and certainly if we're wanting to optimize the airway for our patients. It is the goal. So, let's look at a patient. Or 2 patients, actually, here. This is a mother and her daughter. The mother was missing an upper lateral incisor and had a peg lateral incisor. She underwent orthodontic treatment in which the peg lateral incisor was extracted, and the space for that tooth was closed, and the missing lateral incisor space was closed. She also had lower bicuspid teeth removed and was retracted back. So, this results in a 140-degree nose-lip angle, which is a very, very, very large number. Makes her have very flat cheeks and a very empty look to her face. Her daughter had the exact same problem orthodontically with a peg lateral incisor and a missing lateral, but we opened space to put a veneer for the peg lateral and for an implant for the missing lateral. We didn't take out any teeth in the mandible, and we used orthotropics to develop the face forward, resulting in a 118-degree nose-lip angle, which, whereas it's not ideal, it's a whole lot better than what she had. than her mother. And you can see the dramatic difference in the facial balance associated with this. So, let's look at a typical Class II case. Here's a young boy who has a Class II Division I malocclusion with a very large overjet. And you can see the progression of treatment here from the beginning to the finish using orthotropics. But let's break this down a little bit and show it to you in pieces. Okay. He starts out with a 135-degree nose-lip angle, which really says his maxilla is too far back. It needs to be moved forward. Now, this boy had a number of orthodontic opinions to have headgear and/or have teeth extracted to retract his front teeth back. His mother thought better of that and had us do orthotropics. Here you can see what we do with orthotropics. We advance the upper incisors, About 8 to 10 millimeters, and you can see the space between the permanent lateral and the primary cuspid in this case. We've created an even larger overjet. We then developed the mandible forward with an appliance which negates the headgear effect, and you can see the nice forward development of the mandible which has occurred. You can also see the dramatically improved nose-lip angle, which is now 105 degrees, which is considered inside the ideal range. Now, you can see also that the mandible has come forward rather dramatically. His chin is much more prominent, which is a wonderful thing both aesthetically and functionally. You're going to see that in a moment. You then contrast that with a more traditional treatment of wearing a headgear. And here in this example, the child wearing the headgear has a 135-degree nose-lip angle, just like our patient. And I put on a drinking straw here, for that's what the kind of an airway that child is going to have, unfortunately. So, here we see the patient that we treated. This is an old x-ray, and I've lined in the airway where— so you can see it well. But you can see on the left, pretreatment, the very large overjet, and on the right, there's no overjet remaining, but you can see the dramatic improvement in the airway achieved in this particular case with orthotropic treatment. Let's go back to the literature of 1981 and talk about Class II malocclusion. Dr. James McNamara, one of the most famous orthodontists in the world, from the University of Michigan, did this study. And what he found was rather interesting. He found that only a small percentage of cases in the study exhibited maxillary skeletal protrusion relative to cranial and cranial base structures. On the average, the maxilla was in a neutral position. It was more often in a retruded than protruded position. In reality, if you look at these patients today with the modern diagnostic criteria we're using, you'll find that virtually all Class II patients have the maxilla too far back. He further stated that mandibular skeletal retrusion was the most common single characteristic of the Class II sample. So, obviously, it would make sense to try to develop the mandible forward than retract everything. Finally, he stated that maxillary skeletal protrusion is not a common finding. In fact, more cases of maxillary retrusion were observed. Thus, it appears that in designing the ideal treatment regime, those approaches which might alter the amount and direction of mandibular growth could be more appropriate in many cases than those which restrict maxillary development. John Mew, of course, has recognized for many years, even prior to 1981, that the maxilla needs to be developed forward. And then the mandible will develop forward. And with the child you just saw, you can see the results both aesthetically and in terms of his airway, how excellent the result can be if this is done. So, there you have the second diagnostic criteria, the nasolabial angle. It's very easy to see, and it accurately measures the position of the maxilla in the face.
