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