Tooth decay and agriculture are thought to be related because research has shown that tooth decay was not very common in humans until the practice of agriculture became more widespread. A major cause of tooth decay is the bacterium Streptococcus mutans, and it is closely related to the bacterium Streptococcus ratti, which is found in the mouths of rats. Researchers believe that the development of agriculture might have caused humans to have closer contact with rats and their related bacterium that can lead to tooth decay.
More about tooth decay:
The prevention and treatment of tooth decay is thought to date to ancient Egypt, the first civilization considered to have practiced dentistry.
Some researchers believe that the increase of tooth decay is linked more closely to the increase in sugar and flour in the human diet.
Stress also has been found to increase the likelihood of tooth decay, because people tend to grind their teeth when they are stressed. Grinding the teeth can cause cracks into which bacteria can seep. The cracks also are difficult to clean.