Diabetes causes blood vessels to gradually clot, leading to poor circulation of nutrients and blood. This condition causes the bones surrounding the teeth and gums to weaken, making teeth more susceptible to infections.
Diabetes also increases the amount of sugar in saliva, the main food source of harmful bacteria in the mouth. Leading to the teeth of the infected person will easily accumulate plaque, gingivitis and gradually develop periodontal disease.
For more details, check out the following infographic!