According to estimates, approximately 1 million wisdom teeth are removed annually in Germany, making the removal of third molars one of the most common oral surgery procedures. Is this high number justified?

Unfortunately, there are no clear guidelines worldwide regarding when and whether prophylactic removal of third molars is indicated. A recent review therefore attempted, for the first time, to compare the outcomes of a watch-and-wait approach vs prophylactic removal of third molars. The criteria for including studies in the meta-analysis were strict. Of the original 765 studies on wisdom tooth extraction, only 27 ultimately made it into the statistical analysis. The review examined both the positive and negative consequences of third molar extraction.

Caries Prevention and Third Molars

If third molars have erupted fully or partially, maintaining adequate oral hygiene to keep them clean requires intensive effort. Experience shows that many patients are unable to do so due to the difficulty in accessing these areas. This leads to chronic plaque buildup around the wisdom teeth, which can result in inflammation and tooth decay. This is reflected in the review’s findings. It was found that caries occurred more frequently distal to the second molars when the third molars had erupted. Furthermore, it was determined that not only the immediately adjacent teeth but also all teeth were affected. If caries was present on the wisdom teeth, there was a higher risk for caries in the rest of the dentition. Thus, it stands to reason that removing third molars can have a caries-preventive effect.

Protection of the Second Molars Against Inflammation

Various studies have examined not only the development of caries but also the development of gingivitis and periodontitis in the presence of wisdom teeth. The review found that, on average, the outcomes were as follows:

• Following extraction, especially of partially affected wisdom teeth, probing depths and clinical attachment loss in the second molars decreased.
• Following extraction of even fully erupted wisdom teeth, probing depths and the plaque index in the second molars decreased.
• Probing depths and the plaque index of the second molars were significantly higher when wisdom teeth were present, particularly in the upper jaw.

Impact on Bacteria in the Oral Cavity

In addition to clinical changes, the review also identified microbiological changes following wisdom tooth extractions. The number of certain gram-negative bacteria, gram-negative rods, and spirochetes at the second and third molars was determined. These play a crucial role in the development of periodontitis. After wisdom tooth extraction, their numbers were significantly lower.

Similar to the findings regarding periodontal pocket depth, measurable effects were also observed in saliva. Following the removal of the third molars, the number of lactobacilli and Streptococcus mutans decreased significantly. This suggests a reduced risk for dental caries following wisdom tooth extraction because S mutans causes caries and lactobacilli serve as a marker for caries activity.

Crowding Caused by Third Molars?

The most common reason dentists recommend wisdom tooth extraction is likely related to orthodontics. Many orthodontists recommend removing third molars to prevent crowding after treatment is completed. However, the data included in the review did not confirm this. From the authors’ perspective, prophylactic removal of third molars is not indicated for orthodontic reasons.

Economic Risks for Extraction

Although the data regarding the preventive effects of wisdom tooth extraction on caries and periodontitis support its use, the authors of the study do not recommend it without reservation. They emphasized the risks and potential consequences of this surgical procedure, which include nerve damage, postoperative pain, infections, and bacteremia. According to the data, bacteremia occurs in approximately 60% of cases and should not be overlooked. From an economic perspective, prophylactic wisdom tooth extraction is not recommended because the follow-up costs are, on average, significantly higher than those associated with a watch-and-wait approach.

Conclusion

There are good reasons to recommend removing third molars. First and foremost, leaving wisdom teeth in place increases the risk for caries, gingivitis, and periodontitis in the adjacent teeth and, in some cases, throughout the entire dentition. This is likely due to the fact that cleaning them is significantly more difficult because of their location. However, there are currently no data available to justify the removal of wisdom teeth from an orthodontic perspective. From an economic standpoint as well, the data support leaving wisdom teeth in place. Therefore, the decision should be made on an individual basis, considering the consequences of this often traumatic procedure as well as its risks.

This story was translated from Coliquio, part of the Medscape Professional Network.