A classmate of mine work heads a prison dental service, and she's been working there for at least 10-15 years. She doesn't worry. The only personal "risk" I would speculate about would be from a higher prevalence of blood-transmitted diseases like hepatitis, HIV, and so on since it is a prison, - lot's of former drug addicts, gang-bangers, and other people that probably have a low health IQ. But of course, with perfect adherence to universal infection control rules, you should be ok.