I’m getting my wisdom teeth out this week. My hygienist and two oral surgeons recommended extraction, but you know what? Did I trust them? Well, sorta.
My grandpa was a dentist who specialized in facial pain, and saw lots of patients with damaged nerves, including by wisdom tooth extraction, so he thought you might as well leave them in if you aren’t having any problems. And I don’t have any problems yet—the surgeons just thought they might come up down the line. So I was wary.
RCTs
My first step was to try to look at the literature. Well, almost 85% of Americans get their wisdom teeth extracted at some point—must mean there’s a vast and well-supported literature on it, right?
While symptomatic or diseased impacted wisdom teeth should be recommended for removal, current evidence neither refutes nor confirms the practice of prophylactic removal of asymptomatic, disease-free wisdom teeth.1
Hmm, not so premising. Maybe we should try another meta-analysis? I mean that one mentioned something about Swedes, not sure I should trust it. What about this one?
Ghaeminia H, Perry J, Nienhuijs MEL, Toedtling V, Tummers M, Hoppenreijs TJM, Van der Sanden WJM, Mettes TG. Surgical removal versus retention for the management of asymptomatic disease‐free impacted wisdom teeth. Cochrane Database of Systematic Reviews 2016
This will definitely help, right? Here, eight Dutch (so at least not Swedish) researchers searched six major medical databases for randomized controlled trials (RCTs) or quasi‐RCTs—in any language, whether published, ongoing, or unpublished, and found a grand total of…two.
No eligible studies in this review reported the effects of removal compared with retention of asymptomatic disease‐free impacted wisdom teeth on health‐related quality of life.2
So we have no RCT evidence, which seems a little rough.
But this doesn’t necessarily mean I’m fine. There must be a reason so many people get them out? One scary paper goes through all the terrible things that can happen if you don’t get them out, and concludes:
There may always be a debate regarding the removal of asymptomatic wisdom teeth but, on scientific review of many related articles, one becomes acutely aware that asymptomatic often does not mean there is no disease present when discussing retained wisdom teeth or third molars.3
Even if it’s not clear whether I should get them out, these researchers seem to promise that I’ll definitely have problems if I keep them. What would these problems look like, though? And how likely are they? And what about the problems with getting the extraction, like punching a hole to my sinuses or making my lips permanently numb?
The Spreadsheet
So I did my usual thing, and spent too much time making a spreadsheet.
At the top are all the risks I could find4 of removal, and below are all the risks of keeping the wisdom teeth. The columns contain:
- my best guess at likelihood from the literature (see below for sources)
- how long the problem is likely to last
- and my guesstimate of how much money that discomfort is worth to me (aka how much I would pay to not have it)
Seems pretty clear that I should keep them. But then I was looking at prices of dental procedures after I get kicked off my parent’s insurance next year, and a conservative 40% likelihood of getting them taken out later,5 multiplied by the cost if my insurance has double the current copay(which seems likely), raises the cost of keeping them by $1800 * 2 * .4 = $1440, which tips the scale in favor of taking them out.
But really, my wisdom teeth aren’t asymptomatic. They’ve been accumulating gunk and sometimes feel a little icky. While I don’t have high confidence that I’m making the right choice, it seems like there is not much evidence either way, so I’ll be letting someone hammer away at my mouth on Thursday.
Want to try your own numbers? Click here to make your own copy of the spreadsheet.
Spreadsheet Sources
Removal
| Risk | Literature Review |
|---|---|
| Nerve damage | Study: if the nerve is in very close contact the risk may be as high as 9%. The risk to the lingual nerve is less than 0.5%. It may take up to 18 months for this to recover. Rarely the nerve may not recover fully and you may be left with small patches of numbness to your lip or chin. Taste is rarely affected. Lit review: .7% for partially erupted, 1.7 for horizontal (IDN, for LN deficits 2/2.8%) - inferior dental nerve (IDN) and lingual nerve (LN) - Twice as bad with Lingual split technique Inzidenz, Risikofaktoren und Verlauf von Sensibilitätsstörungen nach operativer Weisheitszahnentfernung. Mund-, Kiefer- Und Gesichtschirurgie, 4(2), 99–104, 10.1007/s100060050178: N=1100, Dysesthesia of the inferior alveolar nerve occurred with an incidence of 3.57%. The lingual nerve was injured in 2.1% of patients Dysesthesia of the inferior alveolar nerve persisted in 0.91%, and of the lingual nerve in 0.37%. Risk factors: - Alveolaris - Age: every decade goes up 1 unit of seen/expected aka 100% more than average - aka 10% increase per year - Cutting up the tooth: many parts>none>two parts- N. lingualis- sedation worst of local anesthesia or ITN (Intrathecal narcotics) - More experience is better (8/3.1) /(4/10.3) = 6.6x safer for >10yrs than <3yrs Links between anaesthetic modality and nerve damage during lower third molar surgery, British Dental Journal - No link with anesthetic modality, N=400 - (7.5%) were associated with altered sensation at one week with three procedures (0.49%) showing persistent symptoms at six months Early extraction: a silver bullet to avoid nerve injury in lower third molar removal? - ScienceDirect - 2/810 = 0.0025 *100 = 0.25% incidence of 6 month nerve damage Nerve morbidity following wisdom tooth removal under local and general anaesthesia - ScienceDirect - More risk when procedure >15m |
| Infection | Minimized by proper care |
| Weakening of the Jaw | Can cause significant weakening of the jaw with the resultant possibility of jaw fracture |
| Death | Review: extraction (41% of deaths), “mostly seen in patients with compromised health condition” This study found one case |
| Dry socket | Painful, clears up within days or weeks |
| Root tip fracture | Nature: “Several histological studies in animals and humans have shown vital root fragments are well tolerated by the oral environment, healing enclosed in a layer of cementum with bone eventually filling the extraction socket.“But necrotic ones are worse |
Keeping
| Risk | Literature Review |
|---|---|
| Caries: in wisdom tooth & 2º molars | This study only had one partially erupted horizontal third molar (=wisdom) but found caries in the 2nd molar Study with N=224: “The prevalence of caries affecting the distal aspect of the second molar was 38% (n = 85) in this population. In 18% of patients there was evidence of early enamel caries. Fifty-eight percent of caries was managed with restorative treatment but 11% of patients required second molar extraction and 13% of patients required the removal of the second and third molars. The prevalence of distal caries was significantly higher in patients with partially erupted wisdom teeth positioned below the amelocemental junction (P <0.05) of the adjacent second molar … However there was no difference in dental health when comparing this group to the remaining study population (P = 0.354)." - 60% of second molars caries for my category - Of people with caries - 58% Root canal - 13% Removal of 2. - 11% Removal of 2 & 3 (n=10…) Suggestion: rigorous caries risk assessment, biannual bitewing radiographs, individualized preventative measures and timely assessment of third molars Study: newer data now demonstrate that 22% to 33% of young adults with wisdom teeth erupted to the occlusal plane will be affected by occlusal dental caries. It also appears that the age group older than 25 years will be more at risk. |
| Periodontal disease | Study:The prevalence of periodontal inflammatory disease on the distal of the maxillary and mandibular second molars was decreased from 77% before surgery to 23% following removal of the wisdom tooth. there is a significant relationship between periodontal disease and systemic health. surprisingly high percentage (25%) of people with asymptomatic wisdom teeth had periodontal disease Unclear whether it helps because extraction also -> problems |
| Cysts | This study indicates that prophylactic third molar surgery for teeth with high and strongly elevated ‘position scores’ is appropriate in order to prevent cyst formation or mandibular angle fractures in a population at risk for facial trauma 1% to 6% incidence. Other articles claim that this cyst development has been greatly exaggerated or overemphasized.“Such cysts can become large and expand the cortical bone, sometimes causing mild discomfort but rarely numbness. If pain is a presenting symptom, the dentigerous cyst is most likely secondarily infected. The dentigerous cyst is treated with curettement with little if any recurrences anticipated” |
| Keratocystic odontogenic tumor (KOT) | “8% to 10% of all odontogenic cysts” |
| Tumor benign | “There are 2 malignant variants, which are exceedingly rare.” |
Dodson TB, Susarla SM. Impacted wisdom teeth. BMJ Clin Evid. 2014 Aug 29;2014:1302. PMID: 25170946; PMCID: PMC4148832. ↩︎ ↩︎
Ghaeminia H, Perry J, Nienhuijs MEL, Toedtling V, Tummers M, Hoppenreijs TJM, Van der Sanden WJM, Mettes TG. Surgical removal versus retention for the management of asymptomatic disease‐free impacted wisdom teeth. Cochrane Database of Systematic Reviews 2016, Issue 8. Art. No.: CD003879. DOI: 10.1002/14651858.CD003879.pub4. Accessed 24 October 2022. ↩︎
McCoy JM. Complications of retention: Pathology associated with retained third molars. Atlas of the Oral and Maxillofacial Surgery Clinics. 2012;20(2):177-195. doi:10.1016/j.cxom.2012.06.002. ↩︎
I didn’t look that hard, so take this with a grain of salt. I bet there are plenty of other terrible things that can happen either way. ↩︎
“Between 30% and 60% of people who retain their asymptomatic wisdom teeth proceed to extraction of one or more of them between 4 to 12 years after their first visit.” 1 ↩︎