Can wisdom teeth replace 2nd molars?

Question

I went to a dentist because my 2nd molar needed a filling. Just out of curiosity I asked him if a wisdom tooth can replace a lost 2nd molar. Suddenly he looked at me like I killed somebody and said loudly "NO!". Then there was another occasion where I went to a dentist with my nephew. I asked the same question and got the same answer.

Well then I did some research on my own and did find out that this might be a controversial topic. So the main belief is that they can't replace 2nd molars except if the patient is very young (max 14 years). It's important how much root of the wisdom tooth has already formed.

There are other sites where I do find claims that it can be done up to age 25.

Then I thought about it. If it would be possible dentist would not want you to know because:

1. Wisdom teeth removal are by far the most common surgeries done by dentists. So this is a big market

2. If the wisdom teeth could replace molars that would make some implants useless. But implants, bridges etc. are a big market too.

Then there is also another question that comes out of this: Why are wisdom teeth routinely removed? Even if they can't replace the molars through growing into the free space a dentist can pull out the tooth by himself and put it into the free space. So you wont have the costs of an implant and this teeth might fit perfectly like it has always been there. Nothing artificial.

A very good source about this topic that I did find: http://www.orthodontic.ca/caseevaluation/2ndmolarreplacement.pdf

Answer 1

See A prospective study on transplantation of third molars with complete root formation Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology vol. 97, pp. 231–238.

A total of 50 third molars with completely developed roots were autotransplanted to replace a lost first or second molar in the same number of admitted patients.

The study was prospective and comprised 50 transplanted teeth in 50 patients consecutively admitted for eventual autotransplantation after extraction of a molar tooth because of caries, periodontal infection, root fracture, or iatrogenic injury from root canal reamers. If the probability of removing the transplant without severe injuries to the root cement was judged to be good and if the transplant had a suitable shape and dimension for the recipient site, the patient was included in the study. The patients, with an average age of 36.7 years, range 21-66

The cumulative survival rate during 4 years' follow-up was 81.4%. In all, 7 transplants were lost during the follow-up time, 4 of them due to marginal periodontal pathosis and the other 3 due to root resorption.