Is my dentist right?

Hi:
I had a bad pain about 12 years before in my mandibular second premolar. Then I was in the second year of med school and I was so busy that I tolerated the worst pain ever for some exams. After a while it became painless and i thought the problem was nothing. After a while a fistula appeared and I realized it was a abscess. I went to our family dentist and he said anytime I had the time I could come and do something for that but it is not an emergency. Right now I can feel the discomfort. I went to the dentist and he said that because its chronic the success rate is 50% and I may have no problem for many years ahead! But I know that such a sack of pus may cause many problems. I wonder if his opinion is accurate. Please help me. I try to attach a part of my OPG that contains this tooth. Please give me your opinion.
[IMG]http://i44.tinypic.com/6prxhx.jpg[/IMG]
It is not sensitive to heat or cold. It is a little tender. It's motility is 2 of 10. Some pus comes out of the fistula sometimes. The tooth has no hole. It seems some trauma caused it not a tooth decay. The discomfort level is constant.
What should I do? Should I change my dentist? Should I go to a periodontist? Please help me
Benign