According to Wikipedia, the definition of wisdom is as follows: “Wisdom, sapience, or sagacity is the ability to think and act using knowledge, experience, understanding, common sense and insight.”
So that got me thinking, are we using our wisdom when it comes to the third molars? Are we all thinking along the same lines as specialist professionals, or do we have ‘specialisation bias’ based on our dental nurturing?
There is no doubt that guidelines help us all think in the same way: to have some consistency and uniformity. However, it is all based on the notion that the guidelines hold weight and for the guideline to be robust and longstanding it should be regularly updated and of course look at the bigger picture.
The National Institute of Heath and Care Excellence (NICE), first published in March 2000, called for an end to prophylactic removal of wisdom teeth in the national health service (NHS).
NICE argued that based on available evidence, there was no clinical indication of 44 per cent of third molar removals. This would evaluate to a financial saving of approximately £5m for the NHS at the time.
These initial guidelines started a ‘watch and wait’ approach and a reluctance to be proactive in removal of wisdom teeth. This led to problems occurring later and doctors/surgeons having to deal with more complex extractions.
Most of us practising dentists have trained in the NHS one time or another and, whether we like it or not, there must have been a subconscious bias in our thought process. There certainly was in mine until I started to have more insight. What you see is what you know.
A Cochrane review in 2016 concluded lack of evidence for the NICE guidelines at their time of publication. It noted that the emphasis of the NICE guidelines was based on the risks of surgery, but ignored future pathology.
From my own professional bias, I believe the NICE guidelines also ignore a huge topic, the treatment of occlusal problems.
Here are the reasons I believe wisdom teeth should be removed:
- Pain, infection, caries, fracture, pathology.
- Mesioangular impacting on the second molars. Remove them to prevent distal surface caries (DSC), especially impactions on lower second molars.
- Over-erupted upper third molars which are non-functional and will not have an opposing tooth/prosthesis.
- Unhygienic and non-functional.
- Lack of space in the arch: third molars will remain in partial erupted position.
- Pure distalisation of second molars for occlusal correction, vertical control, particularly in anterior open bite cases.
- Class 3 cases where the overbite is reduced and lower third molars will most likely cause further reduction in overbite due to mesial drift (clinical observation shows this to be true).
- Orthognathic surgical cases where levelling of the curve of Spee is required and wisdom tooth in line of surgical cuts.
- When upper third molars are causing the upper second molars to rotate/ tip such that there is an occlusal interference with the palatal cusps of upper second molars. This leads to an unstable bite / CO-CR discrepancy.
These, along with tooth wear, are signs not to ignore. Below are real cases with my take on the third molars. I appreciate there are many factors to consider in each case, but I cannot put full history and records in this article so we will be mainly looking at the panoramic radiographs.
I certainly do not expect that everyone will agree 100 per cent with my thought process, however, I hope there is some logic to the conclusions for each case.
Case 1
A 48-year-old female was seeking Invisalign treatment. There is one remaining third molar (lower left). It is over-erupted. Invisalign would not intrude this tooth mechanically. The lower left first and second molars have been root filled. If the patient were to lose one of these teeth, she stated she would not have fixed orthodontics so will likely have a bridge/implant. The extraction would be straight forward/conical root. The upper left second molar will not be non-functional. Lower second molars will need up righting as part of the orthodontic plan. The patient was asymptomatic, but I believe the lower left third molar should be removed to achieve treatment goals and long-term stability.
Case 2
A 45-year-old female patient had started to get pain in the lower right quadrant. A horizontal impacted lower right third molar is causing distal surface caries on the lower right second molar. This needs urgent attention. The upper right third molar will be non-functional. There is lack of space and the third molar on the left should be strongly considered for removal. The upper left second molar has a large restoration so if the patient may have future orthodontics the upper left wisdom tooth could be maintained. This should be discussed with the patient. Early remove of third molars – especially lower right – would have avoided this situation.
Case 3
A 24-year-old female wants to correct relapse with Invisalgn. The left third molars have been removed and the upper and lower right third molars remain. The overbite is reduced. The occlusion is class two on the right (side of third molars). There is lower incisor labial recession (the lower incisor is forward out of bone). The lower right third molar is partially erupted, and hard to clean. The lower right third molar is mesiangular and impacting on the second molar. The upper right third molar is non-functional. The upper and lower right wisdom teeth are asymptomatic but should be removed for treatment goals and long-term occlusal stability, prevent future pathology/caries. Mechanically, it is not possible to upright the upper and lower right molars with the wisdom teeth in position.
Case 4
A 32-year-old female wanted lingual bracing for alignment. She had a wide arch and all the third molars had erupted but crowding exists. There was a lack of space. The upper third molars were distally inclined, indicating crowding. The lower right third molar was mesioangular and would not be uprighted orthodontically. The posterior segments need uprighting. There was lower incisor crowding with flared and tipped lower incisors. I requested removal of all four asymptomatic third molars before orthodontic treatment starts. The lowers third molars were removed and upper third molars were left by surgeon. The post-treatment radiograph shows overrupted upper third molars. I would still recommend their removal.
Case 5
A 33-year-old male patient concerned about his anterior open bite. He has had previous orthodontic treatment with four premolars removed as teenager. Re-treatment is required. The posterior teeth will need uprighting. There was premature contcats on the posterior teeth/COCR slide. Tooth wear was evident and there was lower incisor crowding. Although the third molars were erupted and functional, they would require removal to correct the bite and improve the occlusal function. Intrusion of the third molars could be done with bone anchor miniplates but predictability is not certain in this case. Also, as this is a re-treatment we want to be sure. NICE guidelines would not allow this, but I believe the third molars need to go to achieve occlusal treatment goals. I requested removal of all asymptomatic third molars for orthodontics.
Case 6
A 25-year-old female is seeking invisalign treatment. The lower third molars have erupted. The upper third molars are yet to erupt, however, they are impacting on the second molars and causing distal rotation of these teeth. Likely this will casuse poster interferences. This situation will not improve if left. There is lower incisor crowding. The orthodontic alignment will involve arch expansion and uprighting of lower molars with some distalisation. The lower third molars are in the way from a mechanical perspective. She has a narrow arch and too many teeth in a small mouth. All four asymptomatic third molars should be removed before orthodontics for predictability in achievig goals and long-term stability.
Case 7
A 16-year-old female post orthodotnics patient attended for a retainer check. She has impacted lower third molars with mesioangular position against the second lower second molars. There is a high risk of DSC. The upper third molars are pushing on the roots of upper second molars. This has the potential to cause rotations and change of torque of the upper econd molars leading to occlusal interferences. There is the potential for periodontal/hygiene issues. There is no chance the third molars to improve in position and erupt naturally. The patient had started with lower incisor crowding and the lower incisors were proclined to compensate for the skeletal class two relationship. Therefore, there was a greater chance of relapse. I would suggest to refer for removal of all third molars now when roots not fully formed. This could potentially be easier to remove.
Conclusion
From just a few examples you can see the wide range of situations where third molars would be considered for removal. The guidelines for removal of third molars should be broader and should incorporate the occlusal challenges that we face. We need to look at the bigger picture. In my opinion, early removal of third molars has greater advantages than disadvantages and should be strongly considered in many cases. The use of 3D imaging has created a far safer diagnostic environment for the surgeon and this tool should now be commonplace for such procedures.