Does this new study suggest that adenoidectomy effects facial development?
We are seeing an increasing number of studies examining the effects of breathing on skeletal growth and other important factors. These developments are good news for those of us seeking evidence on these relationships. This new paper in the high-impact AJO-DDO examined the effects of removing adenoids on respiration, craniofacial development, and posture.
A team from Istanbul, Turkey, did this research
Meral Gurkan, et al
AJO-DDO advance access: https://doi.org/10.1016/j.ajodo.2025.09.029
What did they ask?
They did this study to
“Assess changes in respiratory patterns, craniofacial development, and head and neck and overall body posture in children who have undergone early adenoidectomy and those who have not”.
They provided an extensive, yet, traditional literature review on this subject. Importantly, they noted that mouth breathing is traditionally associated with a distinct craniofacial appearance (adenoids facies). They drew attention to a comprehensive review published in 2025, which showed that mouth breathing induces craniofacial morphological changes and significant alterations in mandibular, lingual, and palatal positioning. However, this was published in a predatory journal. The conclusions of this study are very different from those of a recent paper on a similar subject, published in the AJO in 2025.
I guess at this point you are sensing the direction that this blog post is taking!
What did they ask?
They wanted to
“Evaluate children presenting with respiratory obstruction because of adenoid hypertrophy”.
What did they do?
To answer this question, they conducted a retrospective cross-sectional study. They looked at three distinct groups of participants.
- Group 1 were patients who were diagnosed with adenoid hypertrophy who presented at a later stage and were planned for removal of their adenoids.
- Group 2 were patients with respiratory obstruction because of adenoid hypertrophy who had undergone early surgery and completed 3 years post-operative follow-up.
- Group 3 comprised subjects with no pathology or systemic disease causing respiratory obstruction, and they exhibited normal nasal breathing.
They evaluated all the groups at one time point. All the children in the study were aged 6 to 10 years. The median age of each group was 8 years.
They used the following outcome measures:
- The NOSE scale. This consists of five questions that assess patients’ respiratory symptoms.
- Peak nasal inspiratory flow (PNIF). This provided quantitative data on respiration.
- The head and neck posture.
- A comprehensive orthodontic clinical examinations, including:
- Radiographic records
- Panoramic radiographs
- Lateral cephalogram and analysis
- PA head and hand/wrist X-rays
- Tooth measurement from dental casts
They did a power analysis using the gonial ratio (S-Go/N-Me %) from a similar study. The clinically significant difference they aimed to detect was 0.4%. As a result, we can assume that the gonial ratio is the primary outcome of the study.
What did they find?
The team carried out an extensive analysis of their data. I felt that these were the main points.
When they examined differences in the outcome measures between the groups, they found no differences in any of the postural measurements.
They conducted univariate analyses of 32 Cephalometric measurements. This increases the likelihood of achieving statistical significance and potential false positives. They found statistically significant differences in 7 out of the 32 cephalometric measurements. But these were very small, and I felt that they were not clinically significant.
There were no differences in the dental cast measurements.
However, the later adenoidectomy group had greater nasal obstruction (NOSE score) and lower PNIF. But, the NOSE scores were all within normal limits.
Their overall conclusion was that.
“Early adenoidectomy improves respiratory and craniofacial growth, resembling normal breathing. Delayed surgery leads to persistent mouth breathing and negative growth outcomes”.
What did I think?
This was an interesting study that aimed to answer a clinically relevant question. However, it is also a good example of how a cursory reading of an abstract and a paper can lead to misinterpretation of the results and conclusions.
The authors collected a large amount of data on 34 outcome measures and ran simple univariate statistics between the groups. This increases the chance of false positives. They then concentrated their discussion and conclusion on these differences. However, this did not include their primary outcome of gonial ratio, which was not different between the groups.
This was a traditional cephalometric trawl looking for statistical significance and concentrating the discussion on the “significant” measures totally ignoring the other 25 “non significant” outcomes.
When I examined the cephalometric data, most statistically significant differences between the groups were small. I did not find any clinically significant differences. The authors’ discussion and conclusions were based on statistical significance rather than effect size. However, they noted that we should interpret the study cautiously, given the small effect sizes. Nevertheess, this was not reflected in their conclusions.
I think it is also very relevant to consider the findings in this paper alongside a recent systematic review. I have posted about this review previously. In this systematic review, the authors identified an effect of adenoid removal on skeletal parameters, but it was very small and likely not statistically significant.
It was also interesting to see that they based their sample size on a small difference in gonial ratio. I presume that this was the primary outcome of the study. However, when they analysed this outcome, there were no differences between the groups for genial ratio. This raises questions about the study’s power.
My conclusions.
The data in this study support the conclusions of the previous systematic review. As a result, I feel that this study would have benefited from closer statistical refereeing and less emphasis on statistical rather than clinical significance.
Some readers may feel that I am being to critical and this post represents my confirmation bias. This is not the case I have simply carried out a critical appraisal.
I also realise that I have now done several posts on breathing. However, it appears that research is increasing in this area and it is important that we appraise it. Next week I am doing a post about aligners.
Emeritus Professor of Orthodontics, University of Manchester, UK.
Kevin:
If this study is so weak, then why have you chosen to highlight it? Isn’t that confirmation of selective reporting/bias? You downplay their study that was published in a “predatory” journal (whatever that means) but it makes me wonder if the dragon at the gate of holy orthodontics turned it away to keep the messaging consistent with control over the narrative? It’s interesting that you refer to the AJODO as the AJO. Does dentofacial orthopedics exist in your orthodontic world view?
Thanks, I chose to post about it because there is a risk that it will be quoted and I wanted to draw attention to it and let readers make up their own minds about its conclusions. I’m surprised that you do not know what a predatory journal is, I suggest that you look it up. I’m not sure of your point about the AJO. This was a little careless of me to miss out the DO but as you may know in the UK we tend to refer to this journal as the AJO.
The Wilmslow Boy strikes again!
BTW – by predatory journals you mean those that permit open access to worldwide peer review unlike subscription-based, select club journals, such as the AJODO, where non-subscribers can only read the Abstract?
Rather than a logical critique of the paper we get ‘nit-picking’
We all know that some publications are very poor quality and some are called ‘predatory’. And we also know what Kevin was referring to with AJO.
The twisting of language and the use of tortuous, complicated terms seems a common thread among protagonists of intensive intervention approaches, and strong clinical proof is often still away in the future.
The term epigenetic orthodontics was introduced to the dental profession a while ago. Someone was proposing what they did was special and almost by inference that they used epigenetics and other orthodontists don’t. By definition, all orthodontics that moves teeth is epigenetic.
So you reached the same conclusion that I did in 2009, Dr Cordato. Due to continued demand, the book is to be republished this Spring –
Dear Prof Singh
It was an easy conclusion to reach.
The explanation of Moss’s theory of functional matrix was the only value I found in the book.
I did enjoy a few instances in the book of post treatment images where there were fewer teeth than what the patient started out with; all the while the text was extolling non-extraction approaches. I smiled, almost laughed.
having had my adenoids remeved in my v early teens, with a family history of increased LFH/Cl III, I cannot say it had any affect in my case study of one
The adenoids were removed as i was a competitive swimmer to increase my air flow (VO2 /Max)…. I made squad but not the Olympics or commenweath games, so is that a double negative ?
🙂
I give a yearly seminar on predatory journals to trainees. Some of them have had papers published in such journals and I warn them strongly against this. Predatory journals are entities that exist for one reason – to make money from young and (I hope) naive young academics who are desperate to publish anything to include on their CVs. Such journals are a threat to the integrity of science and will publish anything for money.
What is worrying is the amount of pseudoscience in medicine that gets published online, along with crank therapies and conspiracy theories, especially about vaccines, which are used to justify the ravings of self-appointed “experts”, and these are likely to result in patient deaths.
Do your utmost to alert everyone to the danger of predatory journals – the motto of the Royal Society is ” Nulla in Verbo” – “Don’t take anyone’s word for it” – the equivalent of taking advice from some random person online.
Truth about those journals! It’s so frustrating that people don’t evaluate who the reviewers are or what the impact score is.
Living in rural Africa for years, I saw children die every week from preventable diseases. So even in dental school, I was the one that people always tapped to talk to parents about vaccines. Seeing a child die of tetanus is NOT a pretty thing.
Niall:
Could you please provide the evidence that supports your claims of “Predatory journals are entities that exist for one reason – to make money from young and (I hope) naive young academics who are desperate to publish anything to include on their CVs. Such journals are a threat to the integrity of science and will publish anything for money”.
I think that these publications are no different from other established journals, some of which have extortionate page charges, effectively forming a monopoly. These new publishers will be subject to user review and peer review – so the unscrupulous ones will be weeded out over time (as is the case with something like the International Journal of Adult Orthodontics and Orthognathic Surgery, which no longer exists).
Thanks for your comments. I am sorry but I think that you are wrong to add support to predatory journals. it is well known that these journals run a poorly refereed pay to publish model. You must know this. I would go so far to say that no serious academic should publish in these journals. I certainly would not think about it.
I don’t have the article handy but I’m remembering from ENT colleagues that the Pediatric Otorhinolaryngology literature looked at this before and found the effects were clinically significant if under 6 years of age. It’s interesting that this study was looking above that age (looking at 6-10 year olds) given the ENT community shows effects under 6. Of course, the algorithm to get where it’s clinically approved to remove them by the ENT is a whole pathway as well. Thoughts? Hopefully literature will get stronger interdisciplinary interaction.
I perform procedural sedations regularly on children (ages 2-6). It seems that most airway problems are attributed to patients with a Mallampati score of 2+-4.(The Mallampati classification (or score) is a pre-operative, visual assessment of the oral cavity used by healthcare professionals to predict the ease of endotracheal intubation and assess the risk of obstructive sleep apnea (OSA). It ranks airway difficulty from Class I (easiest) to Class IV (most difficult) based on the visibility of soft palate structures, pillars, and the uvula.)
Moreover, the Brodsky score of 2+-4 also affects the airway tremendously. (The Brodsky grading scale measures tonsillar hypertrophy (size) on a 0–4 scale based on the percentage of the oropharyngeal airway they occupy. It is widely used to assess airway obstruction and sleep-related breathing disorders.)
If the patient snores, had a sleep study with apnea and/or has OSA, Brodsky score >2, Mallampati score >2, the child is NOT a candidate for procedural sedation. If the adenoids are large, the airway is even affected further. Hopefully, by puberty the adenoids and the tonsils should decrease in size. My experience is such that the Mallampati score usually stays the same through adolescence. Other than the adenoids, all the other measures can be evaluated very inexpensively by visual inspection. I once referred a patient to my ENT colleague who sounded (breathing) like a herd of horses as she walked into my operatory. The pediatrician was upset that I referred her to the ENT before the Pediatrician. The ENT said: ” Murphy, you’ve been looking at tonsils and tongues your whole career! You know when there is a problem!
One thing confuses me here. Is AJO-DO considered as a predatory journal?!? That’s big news to me, if I’m not misunderstanding the blog and the discussion here :-S
Thanks for the comment. No the AJO is not a predatory journal.