Prophylactic Removal of Third Molars by Dr. Jay B. Reznick

Categories: Oral Surgery;
Prophylactic Removal of Third Molars 

Do later risks outweigh early cost savings?

by Dr. Jay B. Reznick

Whenever we do a consultation for removal of wisdom teeth, we discuss with the patient the potential risks and complications of the surgery. We try to do a thorough job so the patient can make the best-informed decision about their treatment course. But how much time do we spend discussing the risks of not removing third molars, especially when that patient is younger than 25 years old?

We know the hazards include development of caries, infection, periodontal problems, bone loss, development of cysts and other pathology, fracture of the mandible and damage to adjacent teeth. But how common are these risks, and how heavily should they weigh in our recommendations to our patients?

So, that brings up the age-old question: Should asymptomatic third molars be prophylactically removed? As Assael eloquently put it, it depends on how you ask the question, who is asking the question, and who is providing the answer.1 Insurance carriers and public health systems tend to argue against their removal; we clinicians generally argue in favor of prophylactic surgery with the goal of preventing disease and minimizing the surgical morbidity to our patients. What does the literature say about this question, and how does our personal clinical experience influence whether we recommend removal of asymptomatic third molars or not?

The case against removal
Those who argue against preventive surgery have two basic arguments. First, the incidence of complications from retained third molars—including pain, infection, caries, bone loss, periodontal issues, development of cysts and tumors, and mandible fracture—is so low that prophylactic removal for those reasons is not warranted. The second relates to the financial cost, recovery time and risk of significant complications such as permanent paresthesia.

Stanley et al. evaluated 11,598 cases of impacted third molars in patients older than 20 using panoramic radiographs. Their study showed the incidence of cyst development around third molars to be 0.25%. Internal resorption was visible in 0.13%, 0.72% had periodontal bone loss behind the second molar, and caries were seen in 0.72%.2

Friedman (a retired dentist who is opposed to prophylactic third-molar removal and frequently is an advocate for third-party payers) states that internal resorption is present in 0.85% of asymptomatic wisdom teeth; 1.65% are associated with the development of cysts; 4.72% show periodontal bone loss; and 4.78% show resorption on the distal of second molars. He equates this to the incidence of appendicitis and cholecystitis (10%–12%) in the adult population and argues that prophylactic appendectomies and cholecystectomies are not the standard of care. When including an approximately 8% incidence of pericoronitis, Friedman still argues that a 20% incidence of pathology around third molars, across all age groups, is not justification for their routine removal, because of the risk of postoperative sequalae such as pain, swelling, infection, days lost from work or school, paresthesia and mandible fracture.3

A frequently cited study is the Cochrane database review of randomized clinical trials that compared removal versus retention of asymptomatic, disease-free impacted third molars in adolescents and in adults ages 24–84.4 Studies included those from the United Kingdom (public sector dental care) and the United States (private sector). The review concluded there was insufficient evidence to determine whether impacted asymptomatic wisdom teeth should be removed, and suggested that decisions should be individualized.

In 2000, the National Institute of Clinical Excellence, using data from the U.K. National Health Service, issued guidance to NHS dentists on the management of third molars. The institute stated that up to 40% of wisdom teeth had been removed without clinical indication and that prophylactic removal should not be performed; treatment should be limited to patients with evidence of disease. This reduced the number of third-molar removals by more than 30% compared to the 1990s, and saved the NHS more than £5 million per year in treatment costs.

However, by the last half of the 2000s, the number of patients getting third molars removed doubled compared to the 1990s. By 2010, wisdom tooth removal was at its highest level in 20 years. What caused this dramatic increase was not that prophylactic removal was becoming more common; it was that older patients in their 20s and 30s were now presenting with symptomatic and pathological third molars requiring removal. The article concluded that any financial savings to the NHS was only short-term, and that NHS expenditure for third molar surgery became greater than before the introduction of NICE guidelines.5,6

The case for removal
Most of us in clinical practice would tend to agree that if a third molar will not fully erupt, will come into full function, and may compromise adjacent teeth and not be able to be kept caries- and infection-free for the life of the patient, it should be removed—preferably before the patient turns 25 or becomes symptomatic. We need to remember that “asymptomatic” does not mean “disease-free” (Fig. 1). About 25% of patients who deny any symptoms around their third molars have inflammatory periodontal disease around those teeth.7
Prophylactic Removal of Third Molars
Fig. 1

We all have experience seeing the consequences of third-molar retention, including caries, bone loss, infection and other pathology around nonerupted or partially erupted wisdom teeth. We also appreciate the increased morbidity of treating these patients past 30 years of age. Multiple studies confirm that the risk of complications and morbidity associated with surgical removal of third molars increases with age.4,8,9

Even when third molars are fully erupted, they are frequently more difficult to clean because of their location at the back of the mouth. As a patient ages, the likelihood of caries and periodontal pathology increases. Garaas et al. reviewed the data on 6,793 patients who participated in the Dental Atherosclerosis Risk in Communities study. The average age of the subjects of this study was 62 years and all subjects had at least one visible third molar. Only 2% of the subjects had third molars that remained free of caries or periodontal disease.10

Erupted third molars also have a negative impact on the periodontal health of the adjacent second molars, especially in middle-age and older adults. The risk of periodontal pockets of at least 5 mm around a second molar is 1.5–2 times greater when an erupted third molar tooth is present.11,12 When an impacted third molar—especially a mesioangular or horizontal impaction—is in close proximity to the distal root of the second molar, it is not uncommon for there to be significant bone loss, which increases as the patient ages (Figs. 2a and 2b).
Prophylactic Removal of Third Molars
Fig. 2a
Prophylactic Removal of Third Molars
Fig. 2b

Nunn et al. followed 416 men at the Veterans Affairs dental clinic in Boston for 25 years and found that the lowest incidence of second molar pathology occurred when the third molar was absent.13 In a study by Moss et al. with middleage and older subjects, not only was the prevalence of second molar periodontitis higher, but there was more severe periodontal disease in teeth more anterior in the mouth.14

Pericoronitis is another risk of retained third molars (Fig. 3). This condition, which can cause significant pain and morbidity for patients,15 is frequently the presenting complaint of patients when they seek care. About 25%–30% of impacted third molars are extracted because of acute or chronic periocoronitis.16 If not treated in a timely manner, infection can spread through the soft tissues into the fascial spaces, resulting in a possibly life-threatening situation, requiring hospitalization and aggressive treatment (Fig. 4).

Prophylactic Removal of Third Molars
Fig .3
Prophylactic Removal of Third Molars
Fig. 4

The development of cysts and tumors around retained, unerupted wisdom teeth is also a factor to be considered when discussing prophylactic removal of third molars. Although rare in comparison to the incidence and prevalence of infections, periodontal disease and caries, these lesions can result in significant morbidity, destruction of bone and adjacent teeth, and increase the risk of serious complications such as mandible fracture (Fig. 5) and permanent paresthesia.
Prophylactic Removal of Third Molars
Fig. 5

The majority of pathological findings are cystic, including dentigerous cysts (Fig. 6) and more aggressive odontogenic keratocysts. A smaller percentage are solid tumors, most commonly ameloblastoma (Figs. 7a and 7b). These lesions are seen radiographically in approximately 1%–2% percent of patients with impacted third molars.17 The prevalence of cysts and tumors was seen to increase after the age of 50 years, especially in males, reaching 18.6% in patients in their seventh decade in a review of 20,802 third molars in a single institution.18
Prophylactic Removal of Third Molars
Fig. 6
Prophylactic Removal of Third Molars
Fig. 7a
Prophylactic Removal of Third Molars
Fig. 7b

One of the greatest risks of not removing asymptomatic third molars is that they will eventually need to be removed when the patient is in middle age or beyond (Fig. 8). Bouloux et al. reviewed seven studies that followed patients with retained third molars up to 18 years. The mean age at the beginning of the studies was 25. The researchers found that the incidence rate for third-molar removal was on average 3% per year, and that after 18 years, 64% of patients who had been initially asymptomatic developed pathology that resulted in the necessary removal of at least one wisdom tooth because of periodontal infection, caries, pericoronitis and other causes.19 Increasing age is associated with a higher risk of persistent postoperative pain, swelling, prolonged recovery and iatrogenic injury to the mandibular nerve and mandible fracture. These risks increase dramatically beyond age 35.20
Prophylactic Removal of Third Molars
Fig. 8

Another argument in favor of prophylactic removal of third molars relates to the cost, time and radiation exposure of lifelong “active surveillance.” Because the incidence of third-molar pathology increases with each year that surgical management is delayed, a reasonable approach would be to reevaluate patients on a biannual schedule. These clinical visits to monitor third-molar status require patients taking time off work to be seen, as well a biannual radiographic imaging of each retained tooth. This would not be necessary had the patient had their wisdom teeth removed in adolescence.20 The socioeconomic costs of this approach are not insignificant, especially when at least 60% of patients will ultimately need to undergo surgical management because of pathology, when the risks are greater and their medical history will likely be more complex.6

And finally, some personal thoughts on the subject. I remember throughout my residency hearing multiple times the adage “Let sleeping dogs lie” in relation to asymptomatic wisdom teeth. I was told it was repeated often by an attending surgeon who retired just before I started my OMFS training. It seems like our philosophy has changed over the past 50 years; we are now routinely seeing patients up to their 80s who have had that sleeping dog wake up, and that puppy is not happy (Fig. 9)!
Prophylactic Removal of Third Molars
Fig. 9

It made me think about what has changed over that time and why we now recommend prophylactic removal of all impacted third molars. The first change was the replacement of the chisel and mallet with the high-speed, high-torque surgical handpiece. This began with the introduction of the pneumatic Hall drill in 1964, which allowed impacted teeth to be removed more easily and with a much lighter touch. The surgical handpiece gradually replaced the traditional technique in training programs.21 Many doctors trained in the use of the chisel and mallet for removing impacted teeth contend that this method is less traumatic to bone and soft tissues and is actually faster than using a handpiece.22

The other advancement was in the field of ambulatory anesthesia. Intravenous thiopental (Pentothal) was replaced with methohexital (Brevital), and then by propofol (Diprivan) in 1989. Propofol has been found to be a safer anesthetic drug than the barbiturates and is associated with a more rapid recovery and lower incidence of nausea, vomiting and cognitive impairment.23 In ambulatory office anesthesia, we have noted a near-elimination of postoperative shivers (“Brevital shakes”) and intraoperative laryngospasm. In addition, we now use intravenous midazolam and fentanyl rather than diazepam and meperidine in our balanced anesthetic techniques. Both drugs offer faster onset and recovery.

We also have seen a revolution in the monitoring equipment used during sedation and general anesthesia. Pulse oximeters became commonplace starting about 1987, and end-tidal CO2 monitors became standard over the past decade. Before these devices were available, the only ways to monitor a patient’s ventilation and oxygenation status was via precordial stethoscope and monitoring the color of their lips. The combination of safer anesthetic drugs and better and more complete monitoring of patients in our offices has allowed us to deliver sedation and anesthesia in a much safer setting.

I propose that the shift in thinking that favors prophylactic removal of asymptomatic third molars in the adolescent years, rather than waiting until they are problematic, is a result of patients living longer lives and living long enough to develop significant medical issues. We have all had these patients present to our offices with decayed, infected, pathologic third molars we wish had been removed decades earlier. We currently have the ability to provide a less traumatic procedure under general anesthesia more safely and smoothly.

“Letting sleeping dogs lie” has been replaced because of our increased knowledge and the use of technology to give our patients a better overall experience and better health.

1. Assael LA. Indications for Elective Therapeutic Third Molar Removal: The Evidence Is In. Editorial J Oral Maxillofac Surg 63: 1691–1692, 2005.
2. Stanley HR, Alattar M, Collet WK. Pathological Sequelae of Neglected Impacted Third Molars. J Oral Pathol 17(3): 113–117, 1988.
3. Friedman JW. The Prophylactic Extraction of Third Molars: A Public Health Hazard. Am J Public Health 97(9); 1554–1559, 2007.
4. Hossein G, Perry J, Nienhuijs MEL, Toedtling V, Timmers M, Hoppenreijs TJM, Van der Sanden WJ, Mettes TG. Chochrane Database Syst Rev 2020 May 4; 5(5).
5. National Institute for Clinical Excellence. Guidance on the Extraction of Wisdom Teeth. London. NICE 2000.
6. Renton T, Al-Haboubi M, Pau A, Shepherd J, Gallagher JE. What Has Been the United Kingdom’s Experience with Retention of Third Molars? J Oral Maxillofac Surg 70: 48–57 Suppl 1, 2012.
7. Blakely GH, Marciani RD, Haug RD, et al. Periodontal Pathology Associated with Asymptomatic Third Molars. J Oral Maxillofac Surg 60: 1227–1233, 2001.
8. Bui CH, Seldin EB, Dodson TB. Types, Frequencies, and Risk Factors for Complications After Third Molar Extraction. J Oral Maxillofac Surg 61: 1379, 2003.
9. Bouloux GF, Steed MB, Perciaccante VJ. Complications of Third Molar Surgery. Oral Surg Clinics No Am 19(1): 1–13, 2007.
10. Garaas R, Moss KL, Fisjer EL, Wilson G, Offenbacher S, Beck JD, White RP. Prevalence of Visible Third Molars with Caries Experience or Periodontal Pathology in Middle-Aged and Older Americans. J Oral Maxillofacial Surg 69(2): 463–70, 2011.
11. Smart GJ. Third Molars May Have a Negative Impact on Periodontal Health. Evidence-Based Dentistry 6: 95, 2005.
12. Elter JR, Offenbacher S, White RP, Beck JD. Third Molars Associated with Periodontal Pathology in Older Americans. J Oral Maxillofac Surg 63(2): 179–184, 2005.
13. Nunn ME, Fish MD, Garcia RI, Kaye EK, Figueroa R, Gohel A, Ito M, Lee HJ, Williams DE, Miyamoto T. Retained Asymptomatic Third Molars and Risk for Second Molar Pathology. J Dent Res 92(12): 1095–1099, 2013.
14. Moss KL, Oh ES, Fisher E, Beck JD, O enbacher S, White RP. Third Molars and Periodontal Pathological Findings in Middle-Age and Older Americans. J Oral Maxillofac Surg 67: 2592–2598, 2009.
15. McNutt M, Partrick M, Shugars DA, Phillips C, White RP. Impact of Symptomatic Pericoronitis on Health-Related Quality of Life. J Oral Maxillofac Surg 66: 2482–2487, 2008.
16. Rakprasitikul S. Pathological Changes in the Pericoronal Tissues of Unerupted Third Molars. Quintessence Int 32(8): 633–638, 2001.
17. Patil S, Halgatti V, Khandelwal S, Santosh BS, Maheshwari S. Prevalence of Cysts and Tumors Around the Retained and Unerupted Third Molars in the Indian Population. J Oral Biol Craniofacial Res 4: 82–87, 2014.
18. Shin S-M, Choi EJ, Moon S-Y. Prevalence of Pathologies Related to Impacted Mandibular Third Molars. SpringerPlus 5: 915–919, 2016.
19. Bouloux GF, Busaidy KF, Beirne OR, Chiang S-K, Dodson TB. What Is the Risk of Future Extraction of Asymptomatic Third Molars? A Systematic Review. J Oral Maxillofac Surg 73: 806–811, 2015.
20. Vranckx M, Fieuws S, Jacobs R, Politis C. Prophylactic vs. Symptomatic Third Molar Removal: Effects on Patient Postoperative Morbidity. J Evid Base Dent Pract 21(3): 1–13, 2021.
21. Alpert B. The Evolution of Oral and Maxillofacial Surgery Over the Past 100+ Years—With an Emphasis on the Role of Fluoride and the High-Speed Handpiece. J Oral Maxillofac Surg 76: 1611–1615, 2018.
22. Chien AT, Stehle NE, Karian BK. The Use of Chisels in the Extraction of Mandibular Third Molars: A Technique That May Prevent the Aerosolization of Severe Acute Respiratory Syndrome Coronavirus 2. J Oral Maxillofac Surg 79(6): 1199–1206, 2021.
23. White PF. Propofol: Its Role in Changing the Practice of Anesthesia. Anesthesiology 109: 1132–1136.

Author Bio
Dr. Jay B. Reznick Jay B. Reznick, DMD, MD, is a diplomate of the American Board of Oral and Maxillofacial Surgery. Reznick earned an undergraduate biology degree from University of California, Berkeley, a dental degree from Tufts University and an MD degree from the University of Southern California. He interned in general surgery at Huntington Memorial Hospital in Pasadena, California, and trained in oral and maxillofacial surgery at LAC + USC Medical Center. Reznick is a consultant to a number of manufacturers and suppliers of dental and surgical instruments and equipment, and is on the editorial advisory boards of a number of dental journals. He is the director of the Southern California Center for Oral and Facial Surgery in Tarzana, California.

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