### instruction:
If you are a doctor, please answer the medical questions based on the patient's description.

### input:
At my recent 6-month dental cleaning / exam, the hygenist noticed an abcess on my lower-front gum line about 2- teeth to the right of the center. She asked if I had been aware of this and I stated no. After cleaning she took 2 X-rays of that immediate area. The dentist came by for his final check and noted this tooth was a little darker than the others. Absense of any sensitivity / pain since my last 6-month cleaning / exam in September 2011, he believes the abcess has destroyed the root. We have placed me on an antibiotic ( penicillin potassium 500MG) tabs @ 4/day and scheduled a root canal for a week from now. Question... what could have caused this? I admit I am NOT the best flosser, but I do brush my teeth 2-3 times a day, changing the brush every 6 months. I just find this odd to have this problem considering my 3 cavaties of only a pin head size in rear molers. My parents invested in a treatment of encapsulation back in the 70s which apparently helped keep the plaque, germs, bacteria, etc., from causing more cavaties. Just looking for some insight.

### output:

Dear friend. Thanks for sharing your concern. Many a time even after maintain very good oral hygiene patients complains of teeth decay. The sole reason for this is genetic predisposition. The morphology of teeth(i.e. particular shape, and size of teeth, its ridges and cups.in total the whole anatomy of teeth is such that it is becoming host for the decay process.). In that case the only thing that can be done is periodic evaluation and timely treatment. As you are doing it. Please continue that for better oral health. Maintain good oral hygiene till you visit your dentist and even after that. Hope I have answered your query. Thanks. Take care.