To extract teeth or not; the constant orthodontic dilemma?
One of the most important decisions that we take in orthodontic treatment planning is whether we need to extract teeth or not. This post is about a recent study that evaluated aspects of this decision.
I find it surprising that after many years of research, and practice, that I have limited evidence to use in the decision to extract teeth as part of my treatment. As a result, the decision that I may take about extractions is mostly based upon clinical experience. At this point, I would also like to point out that there is no evidence that extractions cause harm. I have discussed this before.
The Angle Orthodontist published this paper. This is an open access journal and you can download the whole paper.
Niousha Saghafi et al.
Angle Orthodontist: Advanced access.
In their introduction, they pointed out that most of the controversy about the extraction decision was concerned with borderline cases. Previous studies studies have showed marked inconsistencies for this type of case.
They did this study to find out if the experience of the operator had an effect on the extraction decision for borderline cases. They also wanted to find out if gender and place of education had an effect.
What did they do?
They carried out a study in several “steps”.
They took a sample of treated cases from the graduate clinic records. They used the following inclusion criteria
- Complete records
- Orthognathic profile
- Class I molars and canines
- Crowding of between 4-8mm
They initially identified 8 cases and used them in a pilot study. The investigators put these into a computer survey and showed these cases to 16 Faculty members and 15 residents and asked them to state whether they would extract or not? They then used this data to identify a final sample of three cases in which the examiners could not agree on the extraction decision. These were defined as borderline cases.
This was an ambitious data collection exercise. They sent a survey to a large sample of 2005 orthodontists who were active members of the AAO. The first part of the survey gathered demographic information on the orthodontists. In the second part, they sent the case records to the orthodontists and asked them to record their treatment decisions. Finally, they asked them whether their decisions to extract had reduced over time.
What did they find?
They got a response rate of 253/2005 (13%). Of the respondents 28% had less than 5 years experience, 32% were in the 5-15 years experience group and 40% had greater than 15 years experience.
When they looked at the non responders they found that more clinicians in the least experienced groups responded. Importantly, clinicians with more than 15 years experience were less likely to respond.
Finally, there was a different response rate for each case.
They presented a large amount of relevant data. So that I can be brief I have extracted the relevant data into this table.
|Less than 15 years||54 (15%)||285 (85%)|
|Greater than 15 years||75 (27%)||193 (73%)|
This showed that most clinicians preferred a non extraction approach.
Their overall conclusion was
“More clinicians with greater than 15 years experience preferred extractions than clinicians with less experience”.
Finally, 24% of the respondents believed that extraction rates had decreased. This was due to change in treatment philosophy (48%), aesthetic beliefs (31%) and patient choice (21%).
What did I think?
I thought that this was a simple study that attempted to answer a difficult question. However, we need to consider whether the investigators achieved their aims. I think that they did, to a degree. As with all studies, there are some shortcomings. We need to evaluate whether these are so great that the findings do not add to our knowledge. This is my interpretation of these issues.
Firstly, they used case vignettes. Some would suggest that this is not a “real world” situation as it does not reflect the clinical assessment. Nevertheless, orthodontists are perfectly capable of coming to decisions based on full records. As a result, I feel that the use of cases was both satisfactory and practical.
My major concern is with the low response rate (13%). I think that we have to consider whether the sample of respondents may not be representative of a population of “typical” orthodontists. This is a considerable limitation and I wonder if we can conclude that the findings are only relevant to the respondents.
Finally, the authors pointed out there was not an equal number of extraction/non-extraction decisions made by the orthodontists. This may mean that outside of Seattle, the cases were not really borderline! But I am not familiar with USA orthodontic demographics and perhaps I am being a little mischievous?
If I consider these issues, I still feel that it was interesting that the older practitioners were more willing to extract. This may be due to their clinical experience in treating more extraction cases than the younger practitioners. As a result, they were not concerned about taking a this decision because they could manage space closure. Alternatively, younger practitioners may be more influenced by their recent training. This may be based on the current trend to treat more cases on a non-extraction basis.
I also think that it is important to remember that there is limited research on the need for extractions in borderline cases. We know that no harm is done by extractions, if the mechanics are correct. We also know that non-extraction Class I treatment is easy. Perhaps the younger orthodontists are taking the easy option for them and their patients. There is, of course, nothing wrong with this approach.
In order to finish, I need to put forward a word of caution. This is needed before all the non-extraction at all costs, breathing consultants, jaw expanders and orthodontic oral physicians get excited. This paper was based on borderline cases. There is no doubt that some cases are clearly non-extraction and others are extraction. The orthodontist who never extracts may be causing the same amount of harm that they accuse those who routinely extracting.
And so the wheel keeps turning….