“To extract or not to extract?” – This question is the most controversial and common question asked when treatment planning an orthodontic case. This is often debated in cases involving moderate crowding, when correction of a Class 2 or Class 3 is required and we must understand each approach may lead to very different outcomes.
Treating practitioners are usually divided into two groups – a group that favours the extraction approach and the group that favours the non-extraction approach. It must be understood that neither approach is correct. Based on experience, scientific evidence and knowledge of orthodontic principles my mantra is “Never say never and never say always!” There are many factors to consider when diagnosing and treatment planning cases.
It is claimed that non extraction treatment results in a broader smile with reduced buccal corridors, unobstructed airways and better facial aesthetics. However, in certain situations, non-extraction therapy may result in gum recession with patients who exhibit thin tissue biotype and lack labial bone and a convex facial profile. The “Non extractionist” will also tell you all patients having had extractions finish with a very “flat” facial profile with a retracted upper lip.
On the other hand the “extractionists” claim a more stable occlusion is acquired when extracting, preserving soft tissue in thin or average lower anterior tissue biotype.
With 30 years’ experience as an Orthodontist, I could show you hundreds of my finished cases with both extraction and non-extraction treatment plans and I guarantee no one can tell by looking at their facial profiles if teeth were extracted or not. This is proven when I share my before and after photos of cases throughout my OrthoED Mini Masters program and Drs debate how the patient was treated.
Many factors must be considered when diagnosing patients to extract or not to extract and is determined case by case – as an entire problem list and options need to be formulated. These include but are not limited to:
- Soft tissue convexity and incisor protrusion
- Upper and lower lip protrusion
- Upper lip thickness
- Canine relationship
- Nasolabial angle and the E-place
- Dimitrios Konstantonis (2012)
There are many reasons for this controversy which started with Edward Angle in the early 1900s and have completed full circles many times over the last 100 years.
- Facial Profile
The major concern in choosing between extraction and non-extraction treatment modality is the effect it has on the soft tissue profile of the patient. Non extractionists believe that extractions result in “dish in” of the face, whilst extractionists claim without extractions in certain cases the periodontal health will be compromised and the profile will appear full.
Studies conducted by Rushing et al in 1995, Stephens et al in 2005 and Erdinc et al in 2007, support the fact general dentists and orthodontists were unable to distinguish between the facial profiles of subjects treated with or without extraction treatment plans.
Extractions in patients with fuller profiles, does not necessarily cause a “dish in” of the face and in fact, invariably result in better aesthetics than non-extraction treatment. Hence, clinicians must plan cases suitably to avoid over retraction of the anterior segments leading to unfavourable profile changes.
- Extraction and TMJ Disorders
- Extraction treatment in combination with use of headgear was accused of causing TMJ disc derangement, however, there is no direct relationship between TMD and any orthodontic treatment.
- Buccal Corridors
- Few orthodontists are of the belief that extracting maxillary premolars leads to narrowing of the dental arch, resulting in unaesthetic broader buccal corridors. However, other important factors must be considered such as obtaining sufficient buccal crown torque of the posterior teeth and imparticular the upper canines and first premolars to gain a pleasant aesthetic outcome.
- Stability and Risk of Impaction
- Adhering to a non-extraction protocol would not always be the best for many patients. Since the patients most likely to experience ineffective orthodontic treatment are those with crowding and protrusion, a non-extraction approach may not provide optimum aesthetics function, periodontal health and stability in such cases.
- Casetta et al 2013 showed an increased prevalence of mandibular second molar impactions my be correlated with the increasing fame of non-extraction therapy.
- Turkuz et al in a Turkish population in 2013 demonstrated 81.8% of patients who did not undergo extractions had impacted third molars, compared to 63.6% of the patients who underwent premolar extractions.
- Saysel et al in 2005 found angulation of third molars to be more favourable as well as increased third molar eruption space, following extraction treatment.
Contemporary Extraction Guidelines can generally be adopted but other factors will need to take part in the decision making.
- 4mm of arch length discrepancy – extraction rarely indicated
- 5-9mm of arch length discrepancy – non-extraction (posterior expansion)/extraction
- 10mm or more of arch length discrepance – extraction almost always required to obtain enough space
(Proffit WR, Fields Jr HW, Sarver DM. Contemporary orthodontics. Elsevier Health Sciences; 2006)
In summary, the option to treat with or without extraction should be made objectively for each case based on strong evidence with equal attention on the soft tissue paradigm and performing a thorough diagnosis, detailed problem list and a full assessment of risk analysis. A sound knowledge of orthodontic principles and a well educated understanding of the required occlusal outcome is essential.