Outside-In Dentofacial Diagnosis by Dr. Chad Foster

by Dr. Chad Foster

As orthodontists, we take great pride in our knowledge of all things teeth. Quite literally, our world revolves around teeth! This knowledge serves us well and is crucial in our occlusal and functional treatment goals. However, is it possible that there are certain cases in which our “tooth-centric” minds can steer us wrong? Digging deeper into our dental evaluations, can our loyalty to traditional quantification of norms and numbers come at the expense of aesthetics? Is it possible that our expertise biases us to not see the forest for the trees?

We’re excellent at zooming our attention in on the teeth, formulating a plan, then justifying that plan against any evidence that may contradict it as we move from inside to out. Once a person’s mind is made up, the evidence needed to reverse course is substantially more than if all evidence had been given equal appreciation from the beginning. Think about it: When presented with the typical orthodontic eight-photo layout, what do we tend to evaluate first? If you’re like me, it has always been the teeth.

I’d like to describe a quick and easy diagnostic tool that has helped me in this regard. The “outside–in dentofacial diagnosis” process has been championed by Dr. David Sarver for many years, and his terminology of macro-, mini- and microaesthetics will be used in this discussion. It is not a philosophy or a complicated process; it is not intended to replace your current methodology of treatment. It can be an adjunct to all treatment styles, from Tweed to Damon and everything beyond and between. It is simply a quick tool that hopefully allows us to shift our paradigms of how we evaluate the face and smile with our “tooth-centric” minds.

This tool is about acknowledging your first impressions. The dentofacial structures are observed starting from outside in: first face, then smile, then teeth—moving from macroaesthetics to microaesthetics. The goal is to avoid confirmation bias in evaluating the face and smile after the clinician has first evaluated the teeth.

Here’s how it goes: When first evaluating a patient, the facial front and facial profile photos are appreciated first before looking at anything else. No looking at the teeth! What impressions do you take away from these photos? What are your observations of the overall facial shape, facial thirds, facial symmetry, midface, musculature, nose, lips and chin? How would you subjectively grade the quality of the overlying related soft tissues? Without knowing, what age would you estimate the patient to be?

Next, observe the facial front smiling photo and appreciate the smile. What impressions do you have about symmetry, lip mobility and “smile window” dimensions? What about gingival show, maxillary anterior tooth display, smile arc and the overall width of tooth display? Even without seeing intraoral photos, what observations are made at this “social” distance regarding the general size and shape of the anterior teeth, “dark triangle” embrasures, crowding, spacing and anything else specific to the teeth themselves?

Finally, dive into your evaluation of the intraoral photos and the rest of your typical diagnostic process, including finer aesthetic issues. Again, these photos are very purposefully evaluated after the facial and smile photos.

Case #1: 20-year-old woman

Macroaesthetic (facial) observations
From facial front and facial profile photos (Fig. 1a)

The facial front photo shows nice lips—full, with a good vermilion display and cupid’s bow. Mild excessive nasal dorsum and the nose seems to project forward just slightly more than ideal. However, in the facial profile photo, the lips strike me as a little less full in the A–P dimension. While I wouldn’t grade the nasolabial angle as truly obtuse, it is more obtuse than I would have expected from my initial impression of the lips on the facial front photo. Relative to the nose and chin, if the lips were to be even slightly retracted from where they currently are, it would be unfavorable aesthetically. In my opinion, there is not much forgiveness there. As far as my impression of facial thirds, I would grade her as having a short lower-third facial height and she shows an overall round appearance of her face with well-developed masseters.

Miniaesthetic (smile) observations
From facial front smiling photo (Fig. 1a)

When evaluating the facial front smiling photo, her “smile window” really stands out—large in both height and width. Her teeth are beautifully large and the centrals show “barrel shape” with convex lateral contours. The transverse tooth display seems deficient and definitely not in harmony with the size of her teeth or the size of her “smile window.” The posterior teeth seem to disappear behind the canines, lacking proper aesthetic gradation. Upper central incisors show about 80% of their height. We know that with normal aging, loss of elasticity in the upper lip will tend to decrease this vertical incisor show over time. A more ideal vertical show of these beautiful maxillary anterior teeth would be closer to 100%. Lastly, her smile arc appears a bit on the flat side.

Microaesthetic (teeth) observations
From intraoral photos (Fig. 1a)

Generalized large teeth—particularly upper incisors, which seem disproportionately large. Upper incisors are barrel-shaped and lower incisors triangular, both lending themselves to less-than-ideal embrasures when properly aligned. Archforms are a bit narrow and tapered, secondary to generalized lingual inclination of posterior teeth.

Considerations in treatment planning

The significant crowding here justifies consideration of a four-premolar extraction pattern. I also think that a non-extraction treatment, properly executed, has the potential for a great outcome as well. In my opinion, these opposing plans come with their own set of compromises.

Macroaesthetic considerations in treatment planning

Consideration of how potential treatment options could affect the lower-third facial height strikes me as very important in this case. I believe any decrease at all for this patient would negatively affect facial aesthetics. A four-premolar extraction plan could potentially have more of a tendency for this than a non-extraction plan. Even if the lower-third facial height were maintained with proper mechanics in the extraction plan, she would still end treatment with four fewer teeth supporting occlusal load, and there are also no third molars present. Long term, I would have concern for how the aging process will affect this round-faced patient with well-developed masseters. In this extraction scenario, I would forecast some degree of continued overclosure/loss of vertical. In any small amount in this case, now or in the future, I would see this as detriment to facial aesthetics.

In diagnosis, I judged that any degree of lip retraction would negatively affect facial aesthetics. An extraction plan—particularly when also combined with arch expansion and IPR, both of which would benefit aesthetics—would have the potential for some degree of upper anterior retraction, even if minimizing anchorage. A thought with this consideration in mind might be extraction of second bicuspids. While this might reduce the chance of anterior retraction, it also increases the likelihood of decreasing the mandibular plane angle and losing vertical in the lower facial third.

Miniaesthetic considerations in treatment planning

Increasing the transverse display of teeth within the “smile window” would be a great benefit to smile aesthetics. If the non-extraction plan is possible, this plan provides a better opportunity to maximize this versus the extraction plan.

If mechanics are not well controlled, the non-extraction plan poses a risk of significantly proclining the upper incisors. This would be bad for a few reasons:

• This potential proclination would have a tendency to further decrease the already less-than-ideal full vertical show of the maxillary incisors within the “smile window,” particularly the centrals.
• In the same way, the proclination would have a tendency to further flatten the smile arc.

An extraction plan, by way of favoring retraction, might have better potential for gains in incisor vertical show and smile arc in this regard.

Microaesthetic considerations in treatment planning

Significant IPR of the upper and lower incisors would improve the aesthetic contours and contact angles of these teeth as well as provide needed space, which would greatly help the non-extraction plan.

Decision on extractions

The concern for lower-third facial height in the present and long term and the narrow arch in the “smile window” were the two biggest factors that led me to begin treatment with a non-extraction plan. In “borderline” non-extraction plans like this one, extractions may still be opted for after initial alignment, before the pano/repo appointment.

Treatment outcome

The non-extraction plan was seen through, and total treatment time was 20 months. Significant arch expansion was achieved via self-ligating appliances (Alpine brackets, Rocky Mountain Orthodontics) used in combination with light-force NiTi “extra wide” wires. “Extra wide” wires have a shape slightly wider than that of the Damon or universal shape. In cases like these, after initial placement of a 0.14 NiTi extra wide, I will advance to and typically leave the patient in 20x20 extra wide NiTi wires for at least six to eight months to maximize dental expansion under very light forces. By the time we advance to finishing wires, most often 18x25 TMA, there is little to no further need for expansion.

Significant interproximal reduction—approximately 0.7mm per contact point L3–3 and 0.9mm per contact point U3–3—served the purpose of gaining space for alignment and also was a microaesthetic benefit to the individual teeth.

Class 2 elastics were used at different times during treatment, both for occlusal correction and also to benefit mild tipping of the occlusal plane to benefit maxillary incisor vertical show and smile arc. “Shorty” Class 2 elastics (U4s to L6s) are shown in the initial appliance placement photos. Alpine brackets were also repositioned midway through treatment to benefit smile arc; upper anteriors were placed more gingival, and lower anteriors more incisal. No upper incisor brackets were “flipped” during this treatment.

The severe crowding aligned with a very mild increase in upper proclination and more significant increase in lower anterior proclination, which was expected. As seen on the up-close lateral smiling photo (Fig. 2), the upper anteriors show an aesthetically acceptable angle of proclination. Additionally, there is no visible evidence of periodontal thinning or recession at the end of her treatment, and retention records through 12 months post-treatment have shown the same.

Beautiful upper anterior vertical display and smile arc were achieved (Figs. 3a–3c, and Figs. 4a, 4b and 5). The dental expansion truly projects her beautiful teeth within her smile window. The slightly more rectangular (rather than barrel) shape of the upper incisors as well as the more linear contact angles also add to the final aesthetic result, which speaks for itself.

Case 2: 31-year-old woman

Macroaesthetic observations
From facial front and facial profile photos (Fig. 6a)

Similar to the first case presented, in regard to this patient’s lower-third facial height, I would grade her as short. She shows an overall round appearance to her face and the appearance of well-developed masseters. The nasolabial angle is acute and her upper lip is everted and forward relative to her lower lip.

Miniaesthetic observations
From facial front smiling photo (Fig. 6a)

The “smile window” is normal in width but seems short in height, which negatively reduces the aesthetic display potential for the teeth. I have noticed that this type of decrease in “smile window” height can be more common in patients with a short lower-third facial height due to the soft tissue (lip) redundancy encroaching on it and thus reducing height. The upper incisor show within the “smile window” is definitely less than ideal at around 50%. The smile arc is flat. Her transverse tooth display seems good, although there is some degree of lingual tapering of her bicuspid area that is noticeable.

Microaesthetic observations
From intraoral photos (Fig. 6a)

Maxillary anterior proclination is obvious and it affects the full vertical show of these teeth. Because of their angulation, they appear shorter despite being very nicely proportioned, full teeth. Contact lines between the maxillary anterior teeth are acceptable, the teeth themselves have favorable shape, and she does not show any dark embrasure spaces, but in my opinion, conservative IPR would still provide a microaesthetic benefit here.

Considerations in treatment planning

I think the significant maxillary dental protrusion and the severe mandibular crowding in this case justify consideration of a four-bicuspid extraction pattern, and I think it could be well treated that way. I also think that a non-extraction treatment, properly executed, has the potential for a great outcome as well. In my opinion, these opposing plans come with their own set of compromises.

Macroaesthetic considerations in treatment planning

I know for sure as it relates to macroaesthetics, miniaesthetics and microaesthetics, anything short of significant retraction/uprighting of the upper incisors will be a failure. It is absolutely a must in this case. Extraction of two bicuspids in the upper arch would surely create enough midarch space to enable this retraction. The extraction option is very predictable in this regard.

A non-extraction plan is more questionable here in regard to if it would be capable of providing enough upper incisor retraction.

In this non-extraction scenario, retraction of the upper incisors would rely mostly on significant dental expansion, significant IPR and negative-torque upper anterior brackets. In her case, the lingual inclination of the maxillary posteriors (particularly the bicuspids) poses an opportunity for such expansion, the large incisor crowns are favorable for IPR, and “flipping” maxillary incisor brackets could provide the needed negative torque.

Considerations of how potential treatment options could affect the lower-third facial height are very similar to the first case. Referencing my original facial observations, any further decrease to the lower-third would be detrimental to overall facial aesthetics. My preference in this case, more so even than in Case #1, would actually be to slightly increase her lower-third facial height, because it would seem to have potential to improve overall facial balance. There is no doubt retraction of maxillary anteriors would improve upper lip eversion, but a slight increase in vertical here would also aid in establishing better lip balance as well. A non-extraction plan, in my opinion, gives a better likelihood of resulting in this increased vertical, if that is what is desired.

The long-term lower-third facial height concerns as they relate to a four-bicuspid extraction plan are very similar to Case #1. Just as in that case, she displays a short lower third, a round face, well developed masseters and absent third molars. My opinion on how aging would tend to further decrease lower-third facial height as a detriment to facial aesthetics would be the same in this case.

Miniaesthetic considerations in treatment planning

As previously mentioned, the height of her “smile window” is short and I would evaluate this as at least partially secondary to soft tissue (lip) redundancy in this case. This lip redundancy is shown not only in the facial photos but also in the cephalometric radiograph. If a non-extraction plan would have a better ability to slightly increase vertical and reduce this redundancy, there could possibly be some improvement in “smile window” height.

Retraction of her very proclined upper anteriors has the potential to both increase the vertical show of her upper incisors (which do not show enough) and also bring better smile arc form to her currently flat anterior occlusal plane. I would be very confident that extraction of bicuspids would be more than enough to satisfy the retraction needed to achieve these goals. The retraction potential in a non-extraction plan would be less, and possibly not enough.

While the transverse tooth display within her smile window does not demand the expansion that was needed in Case #1, some mild expansion would still benefit miniaesthetics. In this case, I would say that the buccal torque needed in the bicuspid segments to achieve this mild expansion could be achieved just as well with either the extraction or non-extraction plans. This is one area in treatment considerations where this case differs significantly from Case #1, which demanded significant expansion for the benefit of aesthetics.

Microaesthetic considerations in treatment planning

I am partial to conservative aesthetic IPR to anterior teeth in most cases I treat as a benefit to both miniaesthetics and microaesthetics. The exception to this would be in patients who show unfavorably small/narrow incisors to begin with. That is not the case here, and while the tooth shape and contours in this case do not beg for aesthetic IPR like Case #1, I still see it as a benefit here in addition to gaining needed space if a non-extraction plan is chosen.

Decision on extractions

The lower-third facial height and its impact on macroaesthetics and miniaesthetics pushed me to give non-extraction treatment a try here. When I began this case in 2017, I had just begun “flipping” (inverting) upper incisor brackets in certain cases, and by then I had seen enough benefit in those cases to give me hope in this one. I reasoned this negative torque in combination with expansion and IPR might just get us to where we wanted to be. Still, I understood, and made the patient well aware, that we might need to consider changing course to a four-bicuspid extraction plan after initial alignment and reassessment.

Treatment outcome

The non-extraction plan was seen through; total treatment time was 23 months (Figs. 7a–7c, p. 37, and Figs. 8a, 8b and 9).

Significant arch expansion was achieved via self-ligating appliances (Alpine brackets, Rocky Mountain Orthodontics) used in combination with light-force extra wide NiTi wires. More so than for the purpose of aesthetics (although also a benefit), the expansion in this case served a greater purpose: helping to create much-needed arch length. Significant IPR (approximately 0.7mm per contact point L4–4 and 0.7mm per contact point U3–3) also aided greatly in attaining space needed for alignment.

Upper incisor Alpine brackets were “flipped” to create negative torque to upright these teeth. I have learned that the maximum benefit from this technique comes from its use with IPR. Of particular importance is the timing of the IPR and the progression of specific wires.

Like the first case, we began with 14 NiTi extra wide wires. The next wire used in the upper arch was a 16x22 NiTi extra wide wire, used in place of the 20x20 extra wide wire that’s typically my second archwire used after the 14. The 16x22 is undersized in the 0.022 brackets that I use and will not engage the negative torque quite yet. This is intentional. When “flipping” U2–2 in this way, I have found that engaging the negative torque too early, before creating space via IPR, results in less of the desired lingual crown torque effect and actually more unwanted facial root torque. I will stay in the 16x22 NiTi extra wide and perform the pano/repo appointment in this wire. At that appointment, I will also assess how initial alignment has gone in my non-extraction attempt, often with use of additional ceph and photos.

If I decide to go with an extraction plan, my repositions will include unflipping the upper incisor Alpine brackets and going into a 20x20 extra wide NiTi in the upper arch to match the lower. If I decide to stick with the non-extraction plan, I will leave the upper incisors flipped, reposition as needed, and stay in the 16x22 NiTi extra wide. At the next appointment, I will perform the necessary IPR and advance to either a 16x25 SS or a 18x25 SS archwire in the upper arch, depending on how aggressively I would like to engage the negative torque. Through this method, I have been quite impressed at the level of lingual crown torque that accompanies the typical IPR space closure. I think this case is a good example of that technique.

The upper incisors were significantly retracted to a pleasing position. In the lower arch, it was accepted that there would be proclination of the lower incisors in this non-extraction plan. The goal was to try to limit it to an acceptable amount, which is, of course, subjective. In the final photos, the lower anteriors show no evidence of periodontal thinning or recession, and this is consistent in retention records through 12 months posttreatment. Long-term observation of periodontal tissues in these types of non-extraction cases is key to true posttreatment success.

In the microaesthetic and miniaesthetic posttreatment evaluation, ideal alignment, consonant smile arc and aesthetic anterior tooth contacts make an appearance. The vertical show of her beautiful upper incisors has increased from approximately 50% to 90%, and what a difference it makes for her smile! While it is always hard to get a true apples-to-apples comparison with pretreatment and posttreatment facial front smiling photos, it does appear at least that there is a subtle reduction in soft tissue redundancy (particularly the lower lip), likely due in part to the slight increase in lower-third facial height, which has very slightly opened up her “smile window.”

Finally, and in the humble opinion of this “tooth-centric” trained orthodontist, none of the aforementioned dental changes imparted by this treatment are nearly as important to overall aesthetics as the subtle but significant vertical change pictured in the final facial profile photo. The balancing of facial thirds with the slight increase to the lower third provided by this orthodontic treatment has brought a bit more balance to highlight the natural beauty of this woman that speaks for itself.