A new study of Adolf Hitler's poor dental health has provided an intimate look into the Nazi leader's life, debunking some ideas and supporting others.

French researchers, who were given rare access to fragments of the dictator's teeth and his dentures held in Moscow, have concluded that Hitler was a vegetarian who died in 1945 in Berlin from taking cyanide and a bullet.

"The teeth are authentic, there is no possible doubt," professor Philippe Charlier told AFP.

The study, which Charlier co-authored with four other researchers, was published Friday in the scientific magazine European Journal of Internal Medicine.

The analysis of Hitler's bad teeth and numerous dentures found white tartar deposits and no traces of meat fiber -- the dictator was vegetarian, Charlier said.

"At the moment of his death, Hitler had only four remaining teeth – all four mandibular [lower jaw] incisors," the research team wrote, adding that he also had dental crowns, one bridge and an odd metallic bar.

And in regards to conspiracies that Hitler lived on well after 1945, the researchers say the teeth put those myths to rest.

"Our study proves that Hitler died in 1945. We can stop all the conspiracy theories about Hitler. He did not flee to Argentina in a submarine, he is not in a hidden base in Antarctica or on the dark side of the moon," Charlier said.

If this study confirms the generally accepted view that Hitler died on April 30, 1945, in his Berlin bunker with his companion Eva Braun, it does also shed new light on the exact causes of death, Charlier said.

"We didn't know if he had used an ampule of cyanide to kill himself or whether it was a bullet in the head. It's in all probability both," he said.

The examination of the teeth did not find any traces of powder, which indicates there was not a revolver shot to the mouth, more likely the neck or the forehead.

Equally, bluish deposits seen on his false teeth could indicate a "chemical reaction between the cyanide and the metal of the dentures," the researcher said.

The French team was able to look at a skull fragment presented as being from the Führer, which showed a hole on the left side which was in all probability caused by the passage of a bullet.

The scientists were not authorized to take samples from this fragment.

As it stands, the fragment's morphology was "totally comparable" to radiographies of Hitler's skull taken a year before his death, the research found.

In March and July 2017, Russia's secret service the FSB and the Russian state archives authorized a team of researchers to examine the bones of the dictator, for the first time since 1946.

The research supports the widely-held narrative that Hitler died in a joint suicide as the Nazi regime was falling to complete ruin. As Soviet troops advanced within 500 meters (1,650 feet) of the Führerbunker, the dictator's underground command center, Hitler and his new wife Eva Braun took cyanide capsules and shot themselves. Their bodies were discovered that same day.