http://www.nature.com/bdj/journal/v186/n10/full/4800155a.html

Many implant surgeons recommend that, to avoid mandibular nerve injury, a 2-mm radiographic space above the mandibular canal should remain after implant placement. 10

There does not seem to be a recommended safe distance to avoid remote nerve compression, which may be defined as nerve compression by an intermediating vector. It is important to consider the cause of an altered sensation after implant placement. This is a case report of a delayed onset paresthesia of partial distribution of the mental nerve, occurring 2 months after dental implant placement in site 20,
with a discussion and speculations as to etiology."

http://www.implantdent.org/pt/re/id/abstract.00008505-200211040-00010.htm;jsessionid=JxrJgt5n939gNn7lSBwGdkyvhhYy7hkNL1QQ9S3W83dnCY6Yjz5G!126031263!181195629!8091!-1

CONCLUSIONS: Transient nerve injury rarely results in legal action. Maximum effort should be devoted to accurately determining the appropriate implant length in the mandible.

http://www.ncbi.nlm.nih.gov/pubmed/12074458?ordinalpos=1&itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DiscoveryPanel.Pubmed_Discovery_RA&linkpos=2&log$=relatedarticles&logdbfrom=pubmed

THE COLUMBUS DISPATCH
Just because a wisdom tooth is there doesn't mean it needs to go.

That's the basis of an effort to stop surgeons from removing third molars that haven't caused a problem and aren't about to.

Leading the charge is Dr. Jay W. Friedman, a retired Los Angeles dentist who published a paper on the topic in the American Journal of Public Health and wrote a statement recently adopted by the American Public Health Association.

Friedman says that useless removals are exceedingly common and cost patients, insurers and society far too much money and time. An estimated 10 million wisdom teeth are extracted from about 5 million Americans each year.

Other dental and surgical trade groups are considering their own positions.

"It's a patient's decision," said Dr. Thomas B. Dodson, a surgeon who lobbied against Friedman's efforts and directs the Center of Applied Clinical Investigation at Massachusetts General Hospital.

Dodson, who has a master's degree in public health, belongs to both the public health group and the American Association of Oral and Maxillofacial Surgeons.

There's no good data on how to predict which teeth will stay put without incident and which will require removal, he said. "They are predictably unpredictable."

That said, his group and Friedman present vastly different numbers.

The surgeons group says that 85 percent of wisdom teeth eventually will need removal; Friedman says 60 percent to 80 percent of extractions aren't necessary.

An independent analysis published this year by the Cochrane Collaboration, a nonprofit group that analyzes the effects of health care, found insignificant evidence to support or undercut routine removal.

Dodson said eliminating prophylactic removal of wisdom teeth would cause pain and suffering down the road and also carries its own costs because those teeth have to be monitored.

Dr. Mark H.K. Greer, who practices dentistry in Hawaii and is president of the American Association of Public Health Dentistry, said his group shares some of the concerns of the Public Health Association and is expected to formalize its stance this year.

Greer said he wants to see more research into the benefits and harm, and his group might call on the federal government to delve into the topic.

He said he appreciates oral surgeons' perspective, but the decision isn't simple and should be based on need. He also said he wants to see better education of patients about their options.

The American Dental Association doesn't have a position but sets guidelines for removal, including when wisdom teeth partially erupt, when there is a chance they will damage adjacent teeth, or when a fluid-filled sac forms around a tooth.

Friedman estimates that Americans would save $2.2 billion a year if dentists and surgeons removed wisdom teeth only when necessary.

He disputes some of the arguments by surgeons about better outcomes in younger patients.

"With any surgical procedure, you want to be fairly certain that you have a good reason for it," Friedman said. "It really is an outrageous situation."

The trouble with that perspective, oral surgeons say, is that wisdom teeth that have yet to cause a problem might one day lead to swelling, cavities and -- much more rarely -- serious problems, including infections and even tumor growth within the sac around the tooth.

By the time a person is 16 to 18 years old, a surgeon usually can tell whether there is room for a wisdom tooth to come in, said Dr. William R. Kaye, an associate professor of and clinical director for oral and maxillofacial surgery at the Ohio State University College of Dentistry.

If there isn't room, it's time to consider taking out the teeth, Kaye said.

Surgery is usually easier the sooner it's done, both from the surgeon's perspective and the patient's, he said.

"Do we know for sure that every wisdom tooth needs to come out? No, we don't," Kaye said. "But we sure know the ones that we wish would have come out."

http://www.columbusdispatch.com/live/content/local_news/stories/2009/03/23/UNWISE.ART_ART_03-23-09_A1_43DAR59.html?sid=101

Dr. Dodson's argument is pretty weak, imo. He mentions that there would be costs involved in leaving the teeth in because they would have to be monitored. Wouldn't the wisdom teeth just be monitored along with the rest of a person's teeth at regular checkups? That cost of monitoring surely wouldn't come close to the exorbitant costs of extraction and subsequent possible injuries/complications/meds following surgery.

Dodson says that "it's a patient's decision" ultimately. A poster just described on the forum how she was pressured into having her wisdom tooth extraction by her dentist because she was told of all the things that could go wrong with the tooth in the future. We trust what our dentists say to us. Same old question...how can we make an informed decision without being given complete and true information about the risks involved? Patients need to be informed of both sides of the issue, imo, with equal attention made to both sides.

Recently, studies have been done the United States on an alternative to complete removal of the wisdom tooth--the coronectomy.

Coronectomy
The procedure known as “coronectomy” (corona=crown; -ectomy=to cut out) involves removing the “crown”, the top or biting portion of the tooth, while leaving the roots in place. The purpose is to decrease the possibility of damaging the nerve when the roots are removed.

What happens to the root?
The expectation after removing the top of the tooth is that the root will remain in place and eventually cover with bone. Roots encased in bone can remain buried in the jaw for years, and rarely cause problems.
The literature and my personal experience has shown that in a significant percentage of cases, these roots begin to drift upward, away from the nerve, before being covered with bone. In my experience, this has been clinically insignificant.

What else could happen to the root?
It would be possible for the root to drift to the surface of the jaw. If this root irritated the tissue or the adjacent tooth, or otherwise became symptomatic, it would necessitate removal. Even though a second surgery would need to be performed, the possibility of nerve damage should be negligible, since the root would have migrated away from it's original resting place next to the nerve. Since the purpose of the coronectomy is to avoid this damage, this goal would have been accomplished, even though a second surgical procedure was necessary to remove the remaining portion of the tooth.

The root tip could also become infected in the post-operative phase and necessitate removal. Antibiotics are normally given pre-operatively or at the time of surgery, as well as post-operatively, to minimize this risk.
http://www.ivoralsurg.com/procedures/coronectomy.html

A 3D digital X-ray is the dental equivalent of a CT scan. Dentists call it CBCT, or cone beam computed tomography. CBCT fully reveals your jawbone structure, and also guides the actual surgery with precision that is far superior to 2D dental office X-rays.”

http://knol.google.com/k/murry-shohat/dental-implants/2srzofgvr8kjr/4?domain=knol.google.com&locale=en#

"General dentists were less polarized. Half refer out 80% or more. On the other hand, one in four (24%) treat most extractions, referring less than 20% of cases."

"Read the dentists' comments (on the link below) for more insight into their thoughts on referring patients out to oral surgeons."

http://www.thewealthydentist.com/SurveyResults/36_WisdomToothReferrals_Results.htm#Comments

"Excellent results from increasingly popular but expensive dental implant surgery can be assured. Technology that your dentist should be telling you about will preclude nerve injuries, permanent numbness, involuntary drooling, perforated sinuses, incorrect tooth angles and broken jawbones. Here’s why and how to protect yourself."

http://www.scribd.com/doc/9943517/Dental-Implants