The value of antibiotic prophylaxis for gastrointestinal (GI) procedures has been debated for many years. Previously, antibiotic prophylaxis was recommended for many GI procedures in patients with high-risk cardiac conditions to protect against infective endocarditis. However, practices have substantially changed, in part due to the low incidence of infective endocarditis following GI procedures and the lack of randomized trials supporting the benefit of antibiotic prophylaxis. Furthermore, the indiscriminate use of antibiotics can be associated with the development of resistant organisms, Clostridium difficile colitis, unnecessary expense, and drug toxicity. (See "Clostridium difficile in adults: Epidemiology, microbiology, and pathophysiology", section on 'Antibiotic use' .)
It has been my personal experience that doctors and dentists are still unsure of what to do about antibiotic prophylaxis in joint replacement patients. My dentist is sticking to the antibiotic protocol. I believe he doesn't want to change what seems to be working -- at least in my case. He may be considering each patient's individual case, which would seem reasonable. If the patient is immunocompromised, has an autoimmune condition , or a higher risk of infection for any reason, it would seem to make sense to go forward with antibiotic use prior to dental procedures.