Letís talk about prosthetic joints and dentistry
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By George Malkemus  January 25, 2013 12:00 am

A joint replacement involves the removal of a damaged joint that is replaced with an artificial joint, called prosthesis. Seventy percent of joint replacements are performed because arthritis has caused the joint to stiffen and become painful to the point where normal daily activities are no longer possible. If the joint does not respond to conservative treatment such as medication, weight loss, activity restriction and use of walking aids such as a cane, joint replacement is considered appropriate and necessary.

The most common joints replaced are hips and knees. More than 770,000 Americans have successful hip or knee replacement surgery each year.  There is ongoing work on elbow, shoulder and ankle replacement.  Joint replacement has a long history.  Total hip replacements date back to the 1700s. Today, hip and knee replacements are highly successful because of improved and less invasive surgery techniques and the improvement in material components, in particular the metal titanium that replaced stainless steel.  Titanium has an amazing biocompatible feature; bone actually grows into the metal and fuses to the titanium implant.  Dental implants are also made out of titanium. The jawbone fuses to the dental implant root replacement. 
Infections in replacements
Infections have always been a problem with joint replacement surgery.  During the 1950s, the infection rate after hip joint replacement surgery was close to 12 percent.  By the 1970s, the rate of infection after hip surgery had been reduced to less than 2 percent.  The reduction was because of two important changes:

1. Treatment with antibiotics just before the hip joint replacement surgery.

2. The use of laminar airflow systems in the operating room. This reduced the most common post-operative infections in the prosthetic joints, which occur during the first three months after surgery and are caused by wound contamination in the operating room.   Infections occurring after three months are less common and thought to be caused by either wound contamination or the spread of bacteria through the blood circulatory system from an infected site in another part of the body. One possible source of infection comes from the mouth through the gums.

Periodontal disease and joint infections
Gum disease, called periodontal disease, plays a role in numerous disease conditions throughout the body, including heart disease, strokes, ulcers and adverse pregnancy outcomes such as low birth weight and preterm births. Diabetes is also affected and increased by periodontal disease, which alters blood sugar control in diabetics.  Bacteria that build up between the tooth and gum can enter into the bloodstream when gums bleed. These bacteria can travel throughout the body and cause serious health problems. Also, periodontal disease is an inflammatory disease and affects other diseases that are affected by inflammation such as diabetes.

Since the 1970s, there has been concern the source of the late infection in prosthetic joints was coming from periodontal disease. To prevent this possibility, antibiotics were given to prosthetic joint patients before dental treatment. Taking antibiotics before any medical or dental treatment is called antibiotic prophylaxis. 

The theory was bacteria found in bleeding, infected gums traveled from the mouth, through the blood stream to the prosthetic joint, where circulation is reduced, and then eddied out in the joint area and started an infection.

It was thought taking antibiotics would prevent this from happening. Though there was no scientific basis for this theory, giving antibiotics before dental treatment to patients who had prosthetic joints became the norm during the 1980s and 1990s. During this time, antibiotics were given routinely even for dental patients with metal pins, plates, and screws, and also even for prosthesis without metal, including breast implants.

Subsequent studies have shown antibiotic prophylaxis is not usually needed for most dental patients.  Prosthetic infections are almost exclusively caused by staphylococci.  These bacteria are not found in the mouth.  Also, individuals with periodontal disease are at a continual risk for infection spread, not just when they see the dentist. What is important is for all individuals to keep their gums in good health.   Statistical research has shown that there is a much greater risk of allergic anaphylactic shock from antibiotic use than there is risk of prosthetic infection during a dental procedure.  Finally, bacteria resistance has become a concern with antibiotic over use.

2003 and 2009 Guidelines
In 2003, new guidelines were designed by a collaboration of the Infectious Diseases Society of America (IDSA), the America Dental Association (ADA), and the American Academy of Orthopaedic Surgeons (AAOS).  According to the guidelines, “antibiotic prophylaxis was not recommended for patients with pins, plates or screws, or for otherwise healthy patients with total joint replacements.  Patients at greater risk because of specific medical conditions should be considered candidates for prophylaxis.  These included patients whose prostheses were less than two years old or those who had “high-risk” conditions like inflammatory arthropathies (rheumatoid arthritis, systemic lupus erythematous), drug-induced or radiation-induced immunosuppression, previous joint infection, malnourishment, hemophilia, human immunodeficiency virus infection, insulin-dependent diabetes or malignancy.”

There is still controversy related to antibiotic prophylaxis use during dental treatment. In 2009, the AAOS issued guidelines to orthopedists, which recommended taking antibiotics before dental treatment even in healthy individuals with joint replacements two years later.  This is even after the 2003 guidelines were issued, which state, “The risk/benefit and cost/effectiveness ratios fail to justify the administration of routine antibiotic prophylaxis.”

Present guidelines from 2012

In 2012, ADA and the AAOS released the first co-developed evidence-based guideline on the Prevention of Orthopedic Implant Infection in Patients Undergoing Dental Procedures. The systematic review of the literature found no direct evidence that dental procedures cause orthopaedic implant infections.

The guidelines include three recommendations:
1. The practitioner might consider discontinuing the practice of routinely prescribing prophylactic antibiotics for patients with hip and knee prosthetic joint implants undergoing dental procedures. Patient preference should have a substantial influencing role.

 2. We are unable to recommend for or against the use of topical oral antimicrobials in patients with prosthetic joint implants or other orthopaedic implants undergoing dental procedures. Patient preference should have a substantial influencing role.
3. Patients with prosthetic joint implants or other orthopaedic implants should maintain appropriate oral hygiene. 

Basically the 2012 guidelines say that there is no evidence showing dental treatment causes prosthetic implant infection, but that there is also no evidence showing dental treatment does not cause prosthetic implant infection, so patients are left to decide for themselves.  Sounds like a compromise cop out to me.  However, both the ADA and the AAOS agree that it is important for patients to keep their mouths clean. Good!

I do not believe that most prosthetic patients need to take antibiotics before dental treatment, but I give them the information and let them decide.  I have some patients that routinely take antibiotics for their dental treatment and others that decline.
The most important recommendation is to keep one’s gums in good health.  Periodontal disease can be prevented with good oral health habits, such as brushing and flossing, and regular professional cleanings.
Enjoy life and keep smiling.

George Malkemus has had a Family and Cosmetic Dental Practice in Rohnert Park for over 27 years at 2 Padre Parkway, Suite 200. Call 585-8595, or email info@ malkemusdds.com.  Visit Dr. Malkemus’ Web site at http://www.malkemusdds.com.

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