There are three basic methods forensic scientists use to confirm the identity of an individual.
Fingerprints have been used the longest and have become a very reliable method of identification. It makes one assumption: fingerprints are like snowflakes, in that there are no two that are exactly alike. But some naysayers are now saying that that theory may be flawed since we have not seen all fingerprints in the world (the rest of that theory can be discussed another day). Around 2000, DNA became, and is now, considered the gold standard for identification. That is in spite of its unsuccessful attempt to prove O.J. Simpson’s guilt in his murder trial (also reserved for another day!)
There are several types of DNA, but suffice it to say, that its reliability is unquestioned, especially since it is the only scientific method able to quantify the accuracy of its determination. There is one major drawback. The microscopic evidence is very sensitive to the elements. It is easily destroyed and can be lost within days if a body, for example, is left in a lake. The same holds true for fingerprints.
3) Dental Characteristic Comparison
Like the other methods, dental characteristic comparison requires comparing a known sample to an unknown sample. We must have dental records and x-rays of an individual who authorities think it might be. The saving grace for dentistry is that the human teeth are virtually indestructible when it comes to durability. Most all petroleum based fires will not burn the hardened outer covering of teeth, referred to as enamel. The restorations in the teeth are also durable and will withstand all environmental decomposition, even surviving underwater or underground with little or no change.
Authorities claim that there are upwards of 8000 missing and unidentified persons in the U.S. Most of these individuals have been to a dentist during their lifetime. Once a person is reported missing by their families, missing persons divisions of local agencies request x-rays and records of the last treating dentist. From these records, each restoration or missing tooth is charted in a national central computerized database. If any body has been recovered anywhere in the country, and its dental restorations have been reported to the database, then the computer can sort this information quickly and provide a positive ID. The problem is that so many of the 8000 have not had their dental data entered in the computer. Unless the database is complete and accurate, it may not successfully provide an answer regarding the identity.