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In an article published in the American Journal of Public Health (September 2007, Vol 97, No. 9), Jay Friedman provides a thought provoking treatise on the reasonableness of third molar extraction.

He begins by revealing what the American Association of Oral and Maxillofacial Surgeons (AAOMS) state as their policy regarding third molar extraction: “if there is insufficient anatomical space to accommodate normal eruption…..removal of such teeth at an early age is a valid and sound treatment rationale based on medical necessity.”

On their web site the AAOMS states that “it isn't wise to wait until your wisdom teeth start to bother you. In general, earlier removal of wisdom teeth results in a less complicated healing process. The AAOMS/OMSF study strongly recommends that wisdom teeth be removed by the time the patient is a young adult in order to prevent future problems and to ensure optimal healing” http://www.aaoms.org/wisdom_teeth.php

In a rebuttal to this idea, Dr Friedman begins his article by stating that “10 million teeth classified as impactions (teeth that fail to erupt into normal position but remain fully or partially embedded and covered by jawbone or gum tissue) are removed every year in the USA from mostly healthy young people” He further states that “third-molar surgery is a multibillion-dollar industry that generates significant income for the dental profession, particularly oral and maxillofacial surgeons. It is driven by misinformation and myths that have been exposed before but that continue to be promulgated by the profession”

The myths that are then explored in his article include the idea that third molars have a high predilection for pathology, that early removal of third molars is less traumatic than late removal, that pressure from erupting third molars causes anterior tooth crowding, that the risk of pathology associated with third molars increases with age, and that there is little risk associated with extraction of impacted molars. Each myth is exposed by citing the scientific literature that suggests that these traditional ideas are at best inaccurate and at worse, patently false.

In terms of risk from third molar extraction, the article pays particular attention to paresthesias arising from impacted procedures. It notes that “reports on the incidence of mandibular (lower jaw) nerve paresthesia vary from a low of 1.3% for temporary and 0.33% for permanent paresthesia to a high of 4.4% for temporary and 1% for permanent paresthesia” It adds that “if 3.5 million lower third molars are removed from 3.5 million persons by oral and maxillofacial surgeons, the incidence of permanent paresthesia ranges from a low of more than 11500 to a high of 35000”

The author also uses posted extraction numbers and the percentage of paresthesias to calculate the numbers for iatrogenic nerve damage, stating that “between 57000 and 175000 persons in the United States have been afflicted with permanent paresthesia over the past 10 years as a consequence of unnecessary prophylactic third molar extractions” It should be pointed out that other authors have reported even higher incidences of lingual nerve paresthesias following third molar extraction. Bataineh (Bataineh AB. Sensory nerve impairment following mandibular third molar surgery, J Oral Maxillofac Surg 2001;9:1012–7) provides just one example. In his study of 30 reports following third molar extraction, he calculates an incidence of lingual nerve paresthesia of between 0-23% and 0.4% to 8.4% for mandibular nerve paresthesia.

The economics of third molar extraction that are outlined by Dr Friedman are particularly gripping. He notes that there are approximately 5400 Oral Surgeons in the United States and cites an article authored by PA Moore published in General Dentistry, 2006, detailing dental therapeutic practice patterns in the US which suggests that each maxillofacial surgeon in private practice averages 53 third-molar extraction cases a month. Many of these are impacted teeth that demand a higher fee than that associated with extraction of those that are fully erupted. Dr Freidman argues that eliminating a proportion of the unnecessary extractions would result in an annual savings to patients of “more than $1.9 billion dollars or $2.2 billion if extractions by general practitioners are included”

The article also describes a model for a reduction in third molar extractions that can be found in the British system. The British National Institute for Clinical Excellence provided recommendations that were adopted by the National Health Service. It is stated that “the practice of prophylactic removal of pathology-free impacted third molars should be discontinued” and “there is no reliable evidence to support a health benefit to patients from the prophylactic removal of pathology free impacted teeth” The conditions that are listed which warrant extraction include non-restorable dental caries, infection with cellulitis, pericoronitis that reoccurs post conservative management, fractures, and pulpal infection.

Dr Friedman concludes that “The evidence is compelling that prophylactic extraction of third molars is a significant public health hazard. It is a silent epidemic of iatrogenic injury that warrants avoidance of the extraction of any third molar in the absence of a pathologic condition or a specific problem”

Dr Friedman is not the only author who has questioned the practice of prophylactic removal of third molars. In his article published in Oral Surg Oral Med Oral Pathol Oral Radiol Endod, 2006 (102:448-52), Dr WL Adeyemo critically examines the literature assessing the relationship between impacted third molars and disease including cysts, tumors and fracture. As he points out, proponents of the prophylactic removal of impacted third molars have relied heavily on the argument that these teeth may become diseased if left in place. However, as Dr Adeyemo points out, a close look at the literature clearly disputes this idea.

With respect to cyst and tumor development he cites 12 articles that suggest that the incidence of these conditions is quite low. Among those articles are those of DA Keith (Br Dent J, 1973) reporting an incidence of 1.6% for dentigerous cysts, Alattar, et al (Oral Surg, 1980) suggesting a 1-1.4% incidence, Shear and Shigh (Comm Dent Oral Epidemiol, 1978) reporting an incidence of 0.001 and 0.0002 percent in a black and white South African population, and GűYen, et al (Int J Oral Maxillofac Surg 2000) reporting a 2.31% incidence of cyst formation. The article details an even lower incidence of pathologies such as ameloblastoma, epidermoid carcinoma, and odontogenic carcinoma arising from impacted wisdom teeth. Dr Adeyemo concludes that given these statistics, there is little justification for prophylactic extraction of third molars.

The data regarding the risk of mandibular fracture in the presence of impacted third molars is more complex. As the author suggests, for young adults involved in contact sports there is an increased chance of mandibular fracture following blunt force trauma to the jaw if the lower third molars are present. As he states: “There is incontrovertible evidence in the literature regarding the proneness of the mandibular angle to being fractured in the presence of ILTMs” But as he further reports, this isn’t the full story as there is also greater chance of condylar fracture if the third molars have been removed.

Two studies are cited in support of his thoughts on the matter: a retrospective study by Iida et al (Influence of the incompletely erupted lower third molar on mandibular angle and condylar fractures. J Trauma, 2004) that found that mandibular angle fracture was highest in a group with incompletely erupted mandibular third molars and that condylar fracture was higher in the group without thirds, and a study by Zhu S-J, et al (Relationship between the presence of unerupted mandibular third molars and fractures of the mandibular condyle. Int J Oral Maxillofac Surg, 2005). The implication of these findings is that the presence of lower third molars may prevent condylar fractures, a far more difficult problem to treat that mandibular angle fractures.

Dr WL Adeyemo also concludes that in light of the evidence “prophylactic extraction of impacted lower third molars in the absence of specific medical and surgical conditions should be discontinued” He further states that “Extraction of impacted third molars should be limited to those teeth with well-defined medical, surgical, or pathologic indications”

Since these articles were written additional reports have underscored the risk of third molar extraction. Contar, et al, recently looked at the incidence of complications and the relationship to surgical difficulty. Their findings are detailed in the journal Med Oral Patol Oral Cir Bucal, 2010 (Jan1;15(1):e74-8 – Complications in third molar removal: a retrospective study of 588 patients). What they found was that in 59 cases (3.47%) there were complications such as root tip fracture, paresthesia, alveolar osteitis, temporomandibular joint discomfort, and oroantral fistula formation. Surgical difficulty was correlated with these complications.

Another recently published study suggests that the risk of complication increases depending on the skill level of the surgeon. Lower skill is associated with higher risk (Jerjes W, Risk factors associated with injury to the inferior alveolar and lingual nerves following third molar surgery-revisited. Oral Surg Oral Med Oral Pathol Oral Radiol Endod. 2010 Mar;109(3):335-45. Epub 2010 Jan 22). These authors also report that in 3236 patients reporting IAN and lingual nerve injury the prevalence figures were 1.5% and 1.8% at one month, 1.4% and 1.6% at six months, and 0.6% and 1.1% at 18 months - values that are much lower than those reported previously.

Since the articles cited above were published “the ADA has recommended additional research to determine if there is an evidence-basis for prophylactic third molar extractions”, notes Dr Friedman in an email interview with the HUB. With respect to policy change within the Oral Surgical Associations he reports that “Previous to the current emphasis on third molars as a cause of periodontal disease, prophylactic extraction of third molars was recommended to prevent serious pathology such as cysts and tumors. Since there are few tumors, cysts, and other pathology that derive from third molars, the oral surgeons now urge extractions to prevent periodontal disease and associated system diseases” (See the AAOMS press release - http://www.aaoms.org/docs/media/third_molars/press_release.pdf).

Further, Dr Friedman points out that to his knowledge there is no new data suggesting that the incidence of disease associated with third molars has increased. He does point out, however, that “most of the new data is contained in studies paid for by AAOMS and published in the Journal of Oral and Maxillofacial Surgery. None of the studies suggest a change in incidence of related disease, but rather evidence of related periodontal disease that had previously been unrecognized or ignored”.

In the AAOMs press release 10/19/2010 they state that “It is critical that both patients and healthcare providers fully understand how harmful retaining these wisdom teeth can be,” Dr. Rafetto, a spokesperson for the AAOMS says “Inaction can have serious long-term health consequences, including increased systemic inflammation which can lead to cardiovascular disease and preterm birth” This is a statement that appears to stretch the science considerably.

Submitted by Jeff Burgess DDS MSD
Editor in Chief