June 27, 2022

Inappropriate non-extraction treatment harms facial profile?

The extraction/non-extraction debate has been going on for many years. I cannot see this ending because it is impossible to carry out randomised trials into this question. Nevertheless, this new paper may give us beneficial information.

The extraction debate still rages in orthodontics, and claims are being made about the benefits and harms of both approaches. Many of these are made without any firm evidence. I have covered this extensively in blog posts. Our conclusion is that the extraction/non-extraction decision usually does not harm the profile. But it is more likely to be due to the treatment mechanics. I feel this is a reasonable approach and suggest that this is the viewpoint of most sensible orthodontists. Therefore, I was interested in coming across this new paper about a study on the effects of non-extraction treatment.

What did they ask?

They wanted to answer.

“Are there any differences in the dental, skeletal and soft-tissue effects of non-extraction and premolar extraction in patients ideally planned for premolar extraction”.

What did they do?

The team did a cross-sectional study on patients who had been treated by a group of post-graduate residents. The methodology they used was not conventional, and I will have a go at explaining this. I will discuss this in much more detail later in this post.

  • Firstly, they did a sample size calculation that suggested that they needed to include the records of 40 patients in the study. They based this on a meaningful difference in post-treatment ABO-OGS scores.
  • They identified a sample of patients initially planned for premolar extraction treatment. The decision to extract was based on pre-treatment profile, tooth position, and crowding.
  • Then they used purposive sampling to identify two groups of patients from this sample. These were an extraction group (PME) and a non-extraction group (NE). The NE group was advised to have extractions, but they preferred to have a non-extraction treatment.
  • A supervision orthodontist decided that the treatment was complete when they were satisfied with the aesthetic and functional outcome.
  • They collected pre- and post-treatment cephalograms and study models for ABO-OGS analysis. Then they constructed silhouettes from the cephalograms. These were then shown to a panel of 3 orthodontists with a minimum of 3 years of experience. The raters scored the improvement of the profiles on a visual analogue score using the anchors of “worse” and “great improvement”.
  • Finally, they found that the data was not normally distributed. As a result, they used non-parametric tests for data analysis.

I hope that you have managed to follow these steps.

What did they find?

These were the main findings.

There were no differences between the groups for any of the outcomes at the start of treatment.

I found it challenging to identify the post-treatment data. If I may lapse into the North of England language, I thought that the data presentation was “a right muddle.” This was mostly because the authors spread it between the results and the discussion. They also included many within-group measurements, which was confusing. As a result, I have concentrated on the post-treatment between-group differences. I hope that I have got this right.

ABO-OGS scores at the end of treatment

The median score for the NE group was 23.00 and 16.00 for the PME group. This was statistically and clinically significant.

Profile scores

The profile change score for the extraction group was 65.8, and for the non-extraction group, this was 35.8. Again, this difference was statistically and clinically significant. Unfortunately, I could not find any post-treatment comparisons of the scores.

Cephalometric measurements.

The non extraction treatment proclined the upper and lower incisors by about 10-15 degrees more than the PME group.

Their final conclusions were:

“The NE approach in these cases resulted in a detrimental effect on the nasio-labial angle, increased ABO-OGS scores and decrease in facial profile improvement scores”.

What did I think?

This was a tricky paper to read and interpret. I could not help feeling that it would have improved from input from the referees. I thought this was a shame because the authors have conducted an interesting study.

It is worth us looking at the study methodology first. As we know,  we cannot randomise orthodontic patients to extraction and non-extraction treatment. Instead, the authors have used an interesting approach. This is called a preference study, in which the patient expresses a preference for an intervention. In medical research, studies using this approach report on both randomised and preference groups. This gives reassurance about biases that may occur within the preference group. However, this team was unable to do this. As a result, we must assume there is some bias in the study simply because the non-extraction group declined extractions.

When I looked at the results, I thought they were very interesting and tended to agree with clinical opinion/impressions. They also agreed with the findings of Johnston’s earlier work on the extraction/non-extraction decision.  However, his study looked at a sample of borderline extraction patients.  In this respect, I was somewhat concerned that the current authors did not provide detailed information on the sample of cases that they studied. Although, they did point out that they were clear extraction cases.

Final thoughts

We need to consider whether the biases in this study influence the findings to the degree that we can discount them. I feel that this is not the case. I think that this study provides us with some information that suggests adopting the non-extraction approach in cases that are clearly extraction can cause some harm. Finally, I know that not everyone will agree with this, so let’s have a good discussion.

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Have your say!

  1. In my experience, many orthodontists are reluctant to address facial changes associated with orthodontic treatments – so asking these specialists (or even lay people) to ‘eyeball’ changes is beset with issues at the outset – partly because of innate reflexes, such as facial recognition and facial perception. In any case, this was a hot topic several years ago but the discussions were often emotive and/or ‘political’ rather than evidence-based. My view is that craniofacial differences prior to treatment may be accentuated following orthodontic treatments that elect non-extraction or extraction protocols. Robust diagnosis and treatment planning, which may include predictive modeling using AI algorithms and deep learning, might be a way forward?

    Reference: Singh GD Maldonado L, Thind BS. Changes in the soft tissue facial profile following orthodontic extractions: A geometric morphometric study. Funct. Orthod. 22(1):34-40, 2005.

  2. Interesting study, hard to find comparability. Al Class I with 4 premolar extraction? Class II? Class III. Anteroposterior discrepancy severity? Biprotrusion severity/presence? Amount of IPR? Amount of crowding. Treatment time… so many variables.

  3. One point worth remembering, when comparing exo to non-exo, is that the ABO-OGS scoring is unconsciously and inherently skewed to favor extraction cases due to four less teeth, and the resulting reduction in the potential to lose points across those teeth. This should have been accounted for, or adjusted when comparing the scores between the two groups.
    With that said, I do not disagree at all with the conclusions of this paper.
    In the last few years, I have come across increasingly more egregious examples of Proclinodontics and Homunculation, with clear-cut exo cases being mistreated by blowing the teeth out.
    I am surely not the only one that has encountered this.
    Matter-of-fact, a famous proponent of a Virtual Orthodontic Residency program is quite proud of using aligners to treat severe crowding & bimax protrusion by positioning the roots out of the alveolus.
    One of the biggest clinical challenges today IMO, both among new grads and experienced practitioners, is the inability or unwillingness to recognize and successfully treat subjects that either present with incisor/lip protrusion before Tx, or develop protrusion during Tx.
    Too many simply ignore well-established concepts of facial balance, stability, incisor positioning goals, the Holdaway ratio, root:alveolar relationships etc, all in the name of ethnicity, aging or some other such bullshittery.
    The end result is what the authors noted in their study. While legions are tripping over themselves to recreate the original folly of Charles Tweed, they seemingly lack the realization and fortitude it took to correct those oversights.

  4. The cases which required extraction but were treated non extraction proclined the upper and lower incisors significantly. Surely this causes potential perio problems later on and upsets the soft tissue equilibrium? Unless permanently retained, these would simply relapse into a position of soft tissue equilibrium? I only treated non-extraction in mild crowding cases, where the incisors weren’t already proclined. I know of colleagues who treated almost everything non extraction then sometime later ..re-treated…then later again ….re-treated! An interesting paper though.

    • I’m curious about your mention of “potential pero problems later”. Just a couple days ago I did (admittedly superficial) search for research on this and from the handful of studies I looked at none found any negative effects on the perio from proclining lower incisors! I was surprised…most only followed up about 5 years, and the only one that did find negative sequelae found lingual recession on corrected incisors in Class 3 cases. Any comments?

  5. With proper control of anchorage, there should be minimal if any undesired effect on the face from extractions.There are numerous articles that indicate the effect of extractions on the face; with thick lips showing no effect, thin lips showing the most effect, and average lips showing minimal effect.

  6. THIS ARTICLE DOES NOT MENTION ANYTHING ABOUT BIOMECHANICS, GEOMETRY, FORCES, AND ENGINEERING. Nor does this study mention anything about the biomechanical force coupling between the morphology of the anterior-posterior atlanto-occipital joint and the anterior-posterior curve of spee between the mandible and maxilla. The movement of the atlanto-occipital joint moves the skull and maxilla up and down while chewing with the mandible COMPRESSES food against the maxillary dentition, forming the anterior-posterior curve of spee to geometrically and biomechanically pair in symbiotic relation with balanced forces.

    Extracting premolars causes the anterior segment of the maxilla to progressively collapse down and backwards. Even if the best mechanical technique is used, the geometry of the anterior-posterior curve of spee is altered such that the segment anterior to extractions is flattened or a posterior segment is curved convex downwards(correct) and the anterior segment is curved concave downwards with anterior vertical excess(flawed). Either result is geometrically and biomechanically ANTAGONISTIC to the anterior-posterior geometry and biomechanics of the atlanto-occipital joint, inducing strain upon the masticatory system and the A-O joint and its ligaments. BOTH CONSEQUENCES ARE EXTREMELY DANGEROUS-
    It is predictable that the tongue force will increase, as it is cramped and pushes forwards against a retracted anterior segment, and with nowhere to go the tongue will push the skull forwards over the AO joint, shearing ligaments : DANGEROUS.


    At this point, aesthetics are only opinion, and the function claimed by extraction orthodontists, remains unproven bias without any chewing study by gastroenterologists and neurosurgeons.

    You can’t argue against geometry and biomechaincal principles which have been proven over thousands of years.

    -Math and Physics Professor

    • Interesting comments Corinne and I would like to discuss this further

      Do you have an email contact?

      You can create a temporary one for privacy if need be

      All the best,

      Arthur MD DDS

    • This is QUITE BIZARRE.

      • We agree: This is quite bizarre. The title of this article implies that preserving all 32 teeth could cause damage to the facial profile. All of the beautiful, successful movie stars, from Schwarzenegger to Margo Robbie to Julia Roberts, who have never had extractions for orthodontics, have an optimal profile, posture, and strength.

  7. good evening. I think that the aesthetic profile should not be damaged with the extractions carried out without forgetting the tongue which will be stuck by such a decision if it has a large volume. yet the alternative for extractions is to be avoided when the masticatory muscles have greater forces. The choice to extract or not to extract will depend on the result of the predictable treatment according to the fixed aesthetic and functional objectives.

  8. Why are we still beating a dead horse?

  9. It is incredible that this is still being discussed and probably will until domesday. Irrespective of Dr Catene’s interesting and complicated comments there are 2 reasons for removing teeth,one to de-crowd and, two, to retract (usually uppers when proclined). If worried about facial profile changes then presumably it’s the latter group you’re interested in. If the teeth are angled forwards and outside the lip and the molars are class 2 then extract to retract. If the teeth are normally angled and it is a skeletal problem then don’t. Understand limitations due to the skeleton in all dimensions and the neutral space, you should be ok. Not sure that we need to invoke all sorts of complicated theories or create a new panic about taking teeth out. I haven’t seen or heard of an epidemic of sunken faces, shearing a-o joints or exploding tmjs, maybe I’m just not looking hard enough.

    • WOW ! SCARY! If biomechanics are too “COMPLICATED” for any dentist to understand, and dentists avoid a complicated study, opting for simplistic,subjective, aesthetic, biased opinions, then they should find another profession, such as modern art, where they are free to creatively “sculpt” and paint faces with extractions on canvasses without any consequence to the heath/safety of citizens. A lack of an exploratory survey into AO joint and TMJ damage does not make it safe to extract. Only medical and scientific geniuses should be doing studies, and making safety judgements-and probably they would be outside of dentistry in applied physics / mechanics etc. In a dentally ethical world, orthos would be obeying the biomechanical directives of independent, no-conflict of interest(no money motives) researchers and scientists.
      But, who has heard of any dental, research, ethics program from any ortho website?
      Dentists are trying to miss the ethical point: Medical specialists are seeing the damages to multiple body systems caused by extractions. And, there is a need for preventive methods, from biomimicry chewing methods to tongue posturing, breathing techniques, and chewing to stimulate more bone growth to accommodate 32 teeth without malocclusion or any need for ortho or oral surgery. Of course, this would not make money for ortho, but it would be preventive, natural, safe, and guided by rigorous, scientific research.

      The Karen Badt Survey reveals a SEVERE Epidemic of health damage caused by extractions-significant enough to ban extractions until rigorous medical research is completed!

    1.Myth: Extractions are needed to “de-crowd”. Fact: the maxilla and mandible of modern humans needs more chewing stimulation to reach full growth potential with space for every adult tooth. Dentists have a moral duty to educate all children about the correct ways to hold and chew food to stimulate more bone growth and optimal alignment. Orthopaedics has already proven that all bone responds to forces.
    (Parents research online all the time with their children).
    2.Myth: Extractions are needed to retract in presence of proclined incisors. Fact: the incisors are proclined because the lung tree, airway, and spine needs the tongue to move the incisors into a proclined angle because the child did not sufficiently chew to stimulate enough arch growth for the tongue to pass along the palate and for incisors to erupt more vertically. Also, NOT placing a round fruit against the incisors while chewing allows them to procline. NOT placing the tongue upwards enough along the palate to push the palate forwards, instead of proclining the incisors forwards, can cause proclining. Correcting ALL of this is FIRST a matter of education! Intervention with appliances is only for when educated children don’t bother to try to learn correct habits -In our observation, most children are eager to learn.

    Best Regards, Serenna, -mother of 4 children, who faced with expensive ortho proposals for 2 kids, decided to be more vigilant about correcting oral habits-and it has paid of with our oldest two -8 and 11 years.

  11. YOUR ORTHODONTIC PROFESSION IS CONTINUING TO MISS THE ETHICAL, SCIENTIFIC POINT: There are plenty of airway centric dentists and orthodontists, who have NEVER extracted a single tooth from a child BY STARTING TO STIMULATE MAXIMUM, FORWARD AND WIDE BONE GROWTH OF THE MAXILLA AND MANDIBLE AS SOON AS TODDLERS CAN CHEW! They do this by teaching parents and children to use BOTH HANDS to chew ROUND FRUITS and VEGETABLES, tough charcuterie, raw cheese, and nutrient dense foods that generate more masticatory force and require greater neuro-proprioception, while providing nutrition for bone growth. Most often this FREE advice and method provides enough space for all teeth to erupt into perfect alignment without any ortho, or with a very quick, 2 month, simple refinement only for aesthetic Hollywood perfectionists.

    AND, that is precisely why ortho suppresses all FREE, ethical and scientific efforts to share this natural approach, and avoids studies to explore the full potential of chewing to solve all ortho “problems”.

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