WISDOM TEETH REMOVAL SURGERY

I am a financial advisor. This is financial advice.

Something I find rather medieval is how many people believe in the necessity of wisdom tooth removal surgery. People seem to have a perception that the procedure is 'standard practice' and that their teeth will get crowded and crooked and cause all sorts of complications if they don't remove their wisdom teeth. This is flatly unsupported:
-Contrary to popular public perception, 'expert consensus' does not endorse the procedure [1 & 2].
-Various literature reviews looking for support for the procedure in terms of effects on health outcomes and teeth crowding have turned up empty-handed [3, 4, 5, 6, & 7].
-The two best pieces of evidence on the topic (an RCT and a longitudinal study) both find null results for the causal effect of impacted teeth on crowding [8 & 9].

These findings go against the common intuition of many, but they are sensible: Wisdom teeth are lodged in rather-soft tissue and aren’t rooted in place very firmly; they don’t exert enough force to push established teeth out of the way. My guess is that people think otherwise because of the teething pains they experience and because they observe that people with impacted wisdom teeth develop progressively more crowded teeth overtime. Such anecdotes are however mistaken due to a lack of perspective; the longitudinal evidence doesn’t suggest that these peoples’ teeth become crowded to any greater degree than those who undergo the surgery [9].

Also interesting is the fact that many supposedly ‘impacted’ wisdom teeth seem to eventually grow in normally (erupt); even mesioangular impactions (the wisdom teeth growing in at an angle, pic related) often naturally reorient themselves to a normal, vertical orientation [10]:

Apart from the paper’s own evidence, here's an interesting paragraph where it cites some other stuff:

“However, third molars may be beneficial for orthodontic and restorative treatment. A number of authors have shown that they become upright throughout development as their angulation improve [17, 26–28]. Additionally, mesial migration of the molars due to interproximal attrition or extraction therapy increases the eruption space and reduces the frequency of the third molar impaction [18, 19, 29, 30].”

This raises an interesting question: Assuming that impacted wisdom teeth are even a problem to care about, why don’t we just do medical interventions to help them grow in normally? Should it be that these removals are done due to the perverse profit incentives of the medical industry, would this not be even stronger incentive to milk recurring payments out of patients over a longer time period via attempts to use braces to assist the eruption of their wisdom teeth?

These were the questions on the practice which interested me, though they aren’t necessarily everything to consider about the procedure. As with any surgery, there are risks, and so there’s a cost-benefit analysis to be done here. The APHA policy statement from earlier [2] actually has a nice review on this and smacks down some common arguments for the procedure.

Finally, as a bit of speculation, I'd like to point out that correlation is not causation and to put forward three hypotheses which, as far as I'm aware, are untested:

1. People who suffer from severe teeth crowding are more likely to undergo wisdom tooth removal, and there would be a positive correlation between teeth crowding and wisdom tooth impaction if the meme surgery weren't so widely recommended.

2. Causality goes from teeth crowding -> wisdom tooth impaction; teeth crowding prevents wisdom teeth from erupting naturally.

3. Unrelated to the two above: Wisdom teeth are meant to be backup molars in case you loose a tooth, and they’re designed to be permanently impacted without issue in the case that none are lost (I give less weight to this idea now that I know that wisdom teeth (even supposedly 'impacted' ones) often develop normally when left to their own devices).

All told, I’d go so far as to say that cases where there are imminent risks from thing like infection are the only ones where the urgency involved can justify the procedure on medical grounds, but then again, that would also apply to every single other tooth in our mouths.

References:

[1] Lindauer, S. J., Laskin, D. M., Tüfekçi, E., Taylor, R. S., Cushing, B. J., & Best, A. M. (2007). Orthodontists’ and surgeons’ opinions on the role of third molars as a cause of dental crowding. American Journal of orthodontics and dentofacial orthopedics, 132(1), 43-48. Retrieved from https://sci-hub.ru/https://doi.org/10.1016/j.ajodo.2005.07.026

[2] The American Public Health Association. (2008). Opposition to Prophylactic Removal of Third Molars (Wisdom Teeth). Policy Number 20085. Retrieved from https://www.apha.org/policies-and-advocacy/public-health-policy-statements/policy-database/2014/07/24/14/29/opposition-to-prophylactic-removal-of-third-molars-wisdom-teeth

[3] Mettes, T. D. G., Ghaeminia, H., Nienhuijs, M. E., Perry, J., van der Sanden, W. J., & Plasschaert, A. (2012). Surgical removal versus retention for the management of asymptomatic impacted wisdom teeth. Cochrane Database of Systematic Reviews, (6). Retrieved from https://sci-hub.ru/https://doi.org/10.1002/14651858.CD003879.pub5

[4] Zawawi, K. H., & Melis, M. (2014). The role of mandibular third molars on lower anterior teeth crowding and relapse after orthodontic treatment: a systematic review. The Scientific World Journal, 2014. Retrieved from https://sci-hub.ru/https://doi.org/10.1155/2014/615429

[5] Genest-Beucher, S., Graillon, N., Bruneau, S., Benzaquen, M., & Guyot, L. (2018). Does mandibular third molar have an impact on dental mandibular anterior crowding? A literature review. Journal of stomatology, oral and maxillofacial surgery, 119(3), 204-207. Retrieved from https://sci-hub.ru/https://doi.org/10.1016/j.jormas.2018.03.005

[6] Costa, M. G. D., Pazzini, C. A., Pantuzo, M. C. G., Jorge, M. L. R., & Marques, L. S. (2013). Is there justification for prophylactic extraction of third molars? A systematic review. Brazilian oral research, 27, 183-188. Retrieved from https://sci-hub.ru/https://doi.org/10.1590/s1806-83242013000100024

[7] Vitkūnaitė, B. (2019). Evaluation of impacted lower third molars angulation effect on dental arch crowding. Systematic literature review. Retrieved from https://www.lsmuni.lt/cris/bitstream/20.500.12512/101434/1/Batrice%20VitkunaiteMT%20BVit%2004.30.pdf

[8] Harradine, N. W., Pearson, M. H., & Toth, B. (1998). The effect of extraction of third molars on late lower incisor crowding: a randomized controlled trial. British Journal of Orthodontics, 25(2), 117-122. Retrieved from https://sci-hub.ru/https://doi.org/10.1093/ortho.25.2.117

[9] Žigante, M., Pavlic, A., Morelato, L., Vandevska-Radunovic, V., & Spalj, S. (2021). Presence and Maturation Dynamics of Mandibular Third Molars and Their Influence on Late Mandibular Incisor Crowding: Longitudinal Study. doi: 10.21203/rs.3.rs-538924/v1 Retrieved from https://assets.researchsquare.com/files/rs-538924/v1/6bb1cd29-efcf-4b04-843f-4b4c4f6ab32d.pdf?c=1631883672

[10] Camargo, I. B., Sobrinho, J. B., de Souza Andrade, E. S., & Van Sickels, J. E. (2016). Correlational study of impacted and non-functional lower third molar position with occurrence of pathologies. Progress in orthodontics, 17(1), 1-9. Retrieved from https://sci-hub.ru/https://doi.org/10.1186/s40510-016-0139-8