 Hello everyone, welcome back to another session on dentistry and more. So we are continuing our dental age estimation methods. So far we finished the dimensions method, the Gustavson method, the role of Palatal Roge and the role of third molar. Today we have the role of dental DNA. So as we all know teeth can resist extreme conditions. So teeth are an excellent source of DNA. So actually what happens once we get the DNA, we conduct a PCR method that is polymerase chain reaction which allows amplification of highly degraded DNA. So once we get the teeth and we get DNA we can do the PCR polymerase chain reaction and we can do amplification of this highly degraded DNA. So this facilitates the comparison with a non-biological anti-motum sample of the person such as we can get the person's DNA from the hair, from a comb, epithelial cells, from a toothbrush or babsy specimen. So we can take the DNA and compare it with this. The advantages are DNA pattern can be compared to the parents or siblings, thus facilitating a positive identification. So basically we have two types of DNA that is nuclear DNA, nuclear DNA that is genomic DNA. This is located in the nucleus of a cell and commonly used in nuclear studies. The second DNA is mitochondrial DNA and this is present in the mitochondria of cells. So how do we extract the dental DNA? So the tooth pulp is considered as the best source of dental DNA. So this dental DNA can be extracted and can be used for personal identification using HLA DQ amplification method. Next we have cytogenic grinding, cytogenic grinding. The technique is cooling the whole tooth to extremely low temperature using liquid nitrogen then mechanically grind it to very fine powder then we get sufficient amount of DNA. We can use intact, curious as well as a root filled tooth. First we cool the tooth to extremely low temperature then we grind to a fine powder. But the main problem of cytogenic grinding is tooth needs to be completely crushed. So according to Trivedi, Trivedi what he suggested was less destruction method for DNA isolation unlike cytogenic grinding. So he suggested opening of the root canals scraping the pulp area with a nosed medical needle then subsequently flushing the tissue debris and use the material for DNA isolation. First root canal be opened then scrape the pulp area with a needle then flesh the tissue debris and use it for the extraction of DNA. So this retains the morphology and physiology of the tooth unlike the cytogenic grinding. This was done by Trivedi et al. So likewise we can get the DNA and use the DNA for person's identification comparing it with the person's parents siblings or person's anti-mortem DNA where we get it from the toothbrush specimen or even from the hair or the it can be extracted from the hair in the comb what the person used before. So likewise we can estimate the age or person's identification using dental DNA. So that's all about dental DNA and its role in forensic dentistry. I'll come up with the histologic method of age estimation or the histology tooth histology and its role in dental age estimation. Thank you.