March 18, 2024

Good news! Extractions do not damage smiles. 

The debate between extraction and non-extraction in orthodontics has been ongoing since the dawn of time. Over the years there have been three main groups with differing views. The first group believed every patient needed teeth extracted, the second group treated everyone without extractions, and the third group, the largest, carefully evaluated each patient’s case and decided whether to extract teeth based on their professional judgement.

After analysing the factors that affect the decision to extract teeth, investigators have found that dental crowding is the most common influence. While this conclusion may seem obvious to most orthodontists, there is still a debate with the proponents of non-extraction treatment who argue that extractions can harm facial profiles and make smiles less attractive, amongst other terrible things. A new study investigated this issue.

A team from Brazil did this study, and the AJO-DDO published the paper.

What did they ask?

They did this study to answer this question.

“Is there a difference in the smile attractiveness between patients treated with and without premolar extractions 36 years after treatment”?

What did they do?

The team did a nice cross-sectional survey study by following these stages. 

  1. They evaluated the records of all the patients treated orthodontically at Bauru Dental School between 1970 and 1980.
  2. The team included patients with Class I or Class II malocclusion treated with and without extractions of 4 first premolars followed by fixed appliances. The main exclusion criterion was the absence of records.
  3. They collected records at the start of treatment (T1), post-treatment (T2) and at long-term follow-up (T3).
  4. Digital study casts were analysed using the PAR index, the Objective Grading System, and the Little Irregularity index.
  5. They made reproducible smile photographs of each patient 36 years after treatment.

To analyse the smile aesthetics, they enrolled a pane of 62 laypeople, 33 dentists and 89 orthodontists from an approach using WhatsApp and other social networks.

The panel members rated the photographs using a numbered scale, with one being the least attractive and 10 being the most attractive smile.

Finally, they analysed the relevant data using univariate statistical analysis.

What did they find?

The team identified a sample of 52 sets of records. Fifteen were treated without extractions, and 37 with extraction treatment. Patients with extractions had a mean post-treatment time of 37.9 years, whereas the non-extraction group had a mean post-treatment time of 34.7 years.­­­

The groups had no significant differences in terms of age, gender, and type of malocclusion before and after treatment. However, the extraction group had a higher post-treatment age. It’s worth noting that there were no differences between the two groups for severity of malocclusion, as measured by the three occlusal indices. Importantly, the extraction group had a higher mandibular LLI at the start of treatment.

There was no difference between the groups when they looked at the attractiveness of the long-term smile.

Their conclusion was.

“There was no difference in the smile attractiveness between non-extraction and extraction treatment”.

What did I think?

Although it may be tempting to criticize this study, it is important to recognize that research on this topic can be difficult and intricate. Therefore, we should appreciate the hard work of this team in finding a group of patients who received orthodontic treatment almost four decades ago.

Let’s start by examining the issues with this study. I am concerned that the authors did not provide us with information on the number of patients who were screened to identify the final sample. It is also essential to provide information on the patient records that were excluded. This is because we need to see if there are any differences between the final and excluded cases that could indicate potential bias. As a result, we must conclude that this paper does have selection bias. Unfortunately, we do not know the amount or direction of the bias.

Collecting these records was an achievement. Using a diverse panel to record relevant patient outcomes was a great step.

Final comments

The findings of this study support other research that suggests extractions are not harmful. Most well-trained orthodontists are aware that it is not the act of extracting teeth that causes harm, but rather the selection of the appropriate techniques. This is certainly the case if the orthodontist overretracts the upper incisors. We can prevent this by careful space closure.

In my opinion, this is another that study that provides us with further reliable evidence suggesting that extractions and good orthodontic mechanics does not do harm.

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Have your say!

  1. Yet another nail in the coffin. There’s so many nails the coffin is now made of nails.

  2. Thanks, Kevin. This sounds like another tambourine percussion, “extractions or not, if the case is misdiagnosed the end result will not be optimal”. Quoting Prof. Lysle Johnston, regardless of individual pre-treatment circumstances, “if the clinician’s intention is to treat all patients with the same approach, diagnosis is irrelevant.” Add to that an inadequate understanding and suboptimal application of mechanics, the outcome can’t be good.

  3. Were these studies looking at the smiles detached from the face, as it seems?

    The most common report in terms of aesthetics of the smile from patients unhappy with the results is that the smile is recessed in relation to the rest of the face. The nose seems bigger in relationship. The nasobial angle is steeper (9 degrees on average according to the literature), an unfavorable aesthetic result in most cases outside of bimaxillary protrusion. Nasolabial folds are reported to be deeper.

    Hence this study–if evaluating floating smiles–is worthless.

    • I wouldn’t say it’s worthless. I think everyone would agree that profiles or 45- degree views would add another dimension to the study and evaluate other aspects (like the ones you mention). However another critique of extractions is narrow arches and dark buccal corridors, and a “floating smile” would be great at evaluating those (maybe even preferred in evaluating those since it eliminates the other factors which could skew the judgement).

  4. Reminds one the simile in Indian classic ‘Mahabharatha’ where age-old Bheeshma was made to lie on a ‘bed of arrows’ (“Shara Shayya) awaiting for an auspicious time of death! We can expect more nails on this coffin of extraction debate, that started early last century. For the time being, it is prudent to call it ‘one more nail’ in the coffin, rather than ‘last’ as you aptly did!

  5. Sorry to chime in here but are many anti-extractionists claiming that extractions damage smiles? Or are they claiming they can (in some cases) damage the face and create smaller dental arches making the tongue more susceptible to descending and increasing the risk of sleep breathing disorders?

    These claims are wildly different to ‘damaging smiles’. I’m not sure I see as much value in this study as some of the readers have commented here.

    And even at that, do the anti-extractionists actually mean the extractions themselves, or the mechanics often accompanied by extraction orthodontics? What is this exactly a ‘nail in the coffin’ for?

  6. I’ve seen way too many adults with ruined profiles (biconcave), return of Class II with OJ and significant crowding in 40 years of clinical practice to take much consolation in these findings.

    While on the topic- Did anyone follow up on the cases Dr. Tweed re-treated with extractions to see what those faces looked like years later?? Are they buried in the Tweed Foundation archives?

  7. Dear Kevin,

    After reading some of the very interesting articles and commentary on your website, I have to say this is the most disappointing one.

    I have witnessed the harms first hand in a very close friend of mine who had 4 wisdom teeth and 4 pre-molars extracted over a 3 year period starting at the age of 25. The loss of facial volume in the lower two thirds of her face was tremendous and she has gone from having a round full face to a drawn-in sunken face and jaw with the appearance of a woman in her 60’s.
    You can look at any number of before and after pictures to see the difference is as clear as night and day. In addition to that she now has problems breathing and eating.

    I find it almost mind boggling that her Orthodontist says there is nothing wrong, as the rest of her friends and family have noted the changes too. Only a blind man could say he can’t see a difference. I appreciate this is only one case, but the impact has been devastating for her. Instead of enjoying her youth, she has instead spent time and money to find a solution in the hope of restoring her appearance which I suspect will be a very difficult task.

    I have tried to help her, but with the exception of a handful of Orthodontists and Maxillofacial surgeons overseas and unobtainable for her, most are unwilling to offer the means to reopen extraction spaces or fit dental implants or provide any pathway back to normality for her. There seems to be a collective ideological stone wall, that is based “we have done no harm” rather than “do no harm”.

    Sadly, this attitude in itself is “doing harm”.

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