It is good that you are reading about periodontitis. Periodontitis is infection of structures surrounding the teeth and usually involves a greater area of the mouth. It is basically a bacterial infection. It is a proven fact that such an infection if left uncontrolled can lead to diabetes, heart disease and various other problems. The only care she requires is to maintain good oral hygiene and follow her dentist's instructions properly. Medicines are of less use in such cases. If active infection is controlled, there are fewer risks of developing other problems.

She won't get diabetes because of periodontitis but due to diabetes , it will worsen her gums condition.

She may get diabetes due to a family history,but periodontitis itself cannot cause diabetes.Get deep scaling done from a dentist.Ask her to avoid excessive intake of sugar.There are no medicines to avoid being diabetic.