The researchers found that year-of-death determinations based on nails were accurate to within three years.
The generally poor post-mortem preservation of soft tissues would be a limiting factor to this approach.
All the people whose tissues were tested for the study were residents of the United States.
Atmospheric dispersion tends to create uniform levels of carbon-14 around the globe, and researchers believe that these would be reflected in human tissues regardless of location.
Now, new applications for the technique are emerging in forensics, thanks to research funded by NIJ and other organizations.
In recent years, forensic scientists have started to apply carbon-14 dating to cases in which law enforcement agencies hope to find out the age of a skeleton or other unidentified human remains.
Since then they have been dropping back toward natural levels.
There might have been a settlement around the castle or the surrounding areas in previous periods, the head of Istanbul Archeology Museums Zeynep Kızıltan said.
The excavation works in Aydos Castle, which consists of an area of approximately 26 to 27,000 square meters, have been carried out since 2016.
Radiocarbon levels in teeth formed before then contained less radiocarbon than expected, so when applied to teeth formed during that period, the method was less precise.
To determine year of death, the researchers used radiocarbon levels in soft tissues.