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Thursday, June 17, 2010

Should Wisdom Teeth Be Removed as a Prophylactic Measure?


As a dentist, I have come across several patients who have voiced doubts about removing their wisdom teeth surgically or routinely. “Do I really need the surgery?” is often the query that needs to be answered in a convincing manner. Why do dentists recommend removing wisdom teeth, and should they be removed simply as a prophylactic measure even when they are not really causing any trouble? This topic is being debated heatedly among the dental fraternity today, giving reasons for and against that have confused many.

 Lower Molar Impaction.JPG 
Photo of Lower Molar Impaction causing Pericoronal Infection.

Before we get into the technicalities of the debate, let me explain more about wisdom teeth. The “third molars” or the last molars are commonly referred to as the “Wisdom Teeth” because they erupt in the oral cavity anytime between the ages of 17-25 or older that marks the age of maturity. Most adults will have all four wisdom teeth in their oral cavity, while there may be an absence of one or more of them in others. At times, it is found that all four wisdom teeth are absent (I am a perfect example of this case). Most commonly it is seen that the wisdom teeth affect other teeth as they are erupting into the oral cavity – becoming impacted.

X Ray impacted tooth.JPG

Photo shows: X-Ray of Lower molar horizontal impaction causing root resorption of second molar.

The definition of an impacted tooth according to Archer - “A tooth which is completely or partially un-erupted and is positioned against another tooth, bone or soft tissue, so that its further eruption is unlikely, described according to its anatomic position."

Why do impactions occur? Well, there are numerous theories that try to explain why such impactions occur. According to the Orthodontic Theory by Durbeck - “Jaws develop in a downward and forward direction. Growth of the jaw and movement of teeth occurs in forward direction, anything that interferes with such movement will cause an impaction (small jaw -- decreased space)."
Other reasons attributed are local infections, inflammations, malocclusion, trauma and early loss of teeth. Other theories attribute it to use-disuse, heredity, nutritional habits and/or endocrinal secretions.

Many a times, the third molars (wisdom teeth) erupt into their proper position and may not cause any trouble during the entire lifetime of the person. In such a case, they are treated much like any other teeth that may be present in the oral cavity. However, if these teeth decay, cause repeated periodontal problems, occlusal problems or pain in the temperomandibular joint, then the dentist generally advocates removing them.

Maintaining dental hygiene by brushing and flossing, in the case of third molars (fully erupted or partially erupted), can be a little difficult due to the normal anatomical space behind the tooth where food particles get lodged and cannot be easily removed. This becomes a potential source of infection, which can turn into acute cellulites and become life threatening if not treated in time with appropriate antibiotics.

At times, the third molars do not erupt completely into their correct position due to any number of reasons, like, for example, lack of space. They may also be positioned either horizontally, vertically, away or toward the neighboring tooth (Distal or Mesial). Such teeth are said to be impacted and may cause damage to the neighboring teeth or become a potential source of infection due to the creation of “periodontal pockets." They may also put pressure on the roots of the adjacent teeth, thereby causing the roots to resorb or push the adjacent teeth from its position to cause malocclusion or misalignment. Such patients turn up with pain and other discomforts associated with the third molars, and are advised to remove their third molars surgically, after taking appropriate X-rays and investigating the case thoroughly.

  mandibular impaction.JPG mandibular impaction1.JPG                                           mandibular impaction2.JPG
Pic1. Lower third molar Vertical impaction

Pic 2. Lower Third Molar Mesioangular impaction

Pic 3. Lower Third Molar Horizontal Impaction

Photographs and illustrations courtesy: Dr. Anisha. K. Maria Professor in Oral and Maxillofacial Surgery Dept. (Modern Dental College and Research Hospital. Indore)

Generally, fully erupted third molars that are properly aligned can be extracted easily like any other teeth, provided there are no other pathological factors, and this can easily be ruled out by taking an X-ray before the extraction. However, partially erupted, or impacted, teeth need to be removed surgically, as stated above.

Treatment Controversy:
It is a common practice, in developed countries, to remove the third molars as a preventive or prophylactic treatment despite sufficient scientific data to support it. There have been numerous studies and research conducted to evaluate the effect of preventive removal of asymptomatic wisdom teeth. However, the research showed no evidence to either support or to refute this practice. (Refer: The Cochrane Collaboration Interventions for treating asymptomatic impacted wisdom teeth in adolescents and adults.)

The National Institute for Health and Clinical Excellence, in UK, the authority that appraises the cost-effectiveness of treatments for the National Health Service, “recommends that impacted wisdom teeth that are free from disease should not be operated on.” (Refer: - http://guidance.nice.org.uk/TA1/Guidance/pdf/English)

Whereas, in the U.S., the American Association of Oral and Maxillofacial Surgeons “recommends that all wisdom teeth should be removed at an early age as a prophylactic measure.” (Refer: - http://www.aaoms.org/wisdom_teeth.php)
Interestingly, there are studies to show that “dentists graduated from different countries or even different dental schools in the same country may have different clinical decisions regarding third molar removal for the same clinical condition.” (Refer: - Journal of Oral and Maxillofacial Surgery Volume 65, Issue 4, April 2007, Pages 658-662 / Decision Making of Israeli, East European, and South American Dental School Graduates in Third Molar Surgery: Is There a Difference?

However, there is also a strong opposition to the prophylactic removal of third molars, one of them being the American Public Health Association that “recommends against prophylactic removal of asymptomatic, non-pathological wisdom teeth, including wisdom teeth that are un-erupted or impacted.”

Q: Should molars be routinely removed? A: American dentists have come to call wisdom teeth 'teeth of misfortune'. This is because the cure is often worse than the 'disease.'”  (Read: - http://www.wddty.com/wisdom-teeth-and-statin-drugs.html) (Why should I have my wisdom teeth removed?)

Other arguments are that the third molars or wisdom teeth are vestigial molars that used to help our ancestors in grinding down plant tissue. Our ancestors had larger jaws with more teeth, but as the human diets changed, smaller jaws evolved. Other findings suggest that the changing diet has played a more significant role, than genetics, in the development of the jaw size in human beings.

Therefore, one can say that not all the third molars need to be removed surgically. Each case needs to be studied independently, and the pros and cons weighed carefully before making the decision to remove it or not. If a tooth is not troublesome, then it can be left alone, till such time that it does cause any symptoms of discomfort or pain. It is also best to remove third molars surgically, if need be, during the younger ages to middle age as the healing capacity of the tissues is much better then, than in an older person.

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Original article posted on Xomba

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