George A. Malkemus, DDS: OSTEOPOROSIS AND OSTEONECROSIS

A current complex dental issue is the concern about the bisphosphonates in osteoporosis medications causing "osteonecrosis," a rare condition in which healthy jawbone dies (osteo, Latin for bone, and necrosis, Latin for death or dying). Oral bisphosphonate medications are commonly taken to prevent or treat osteoporosis or Paget’s disease. The use of intravenous bisphosphonates for certain cancer patients has been linked to osteonecrosis as well. The occurrence of osteonecrosis is rare, but a serious condition.

OSTEOPOROSIS

Osteoporosis ("porous bones", from Greek: οστούν/ostoun meaning "bone" and πόρος/poros meaning "pore") is a serious skeletal disorder that weakens bones and increases the risk of developing fractures. It affects about 10 million Americans, 8 million of them women. Another 34 million are at risk of developing osteoporosis. This disorder affects more women than cancer, heart disease and stroke combined. Many patients are treated with a group of prescription drugs called "oral bisphosphonates." Examples include alendronate (Fosamax, Merck & Co., Whitehouse Station, N.J.), risedronate (Actonel, Procter & Gamble, Cincinnati) and ibandronate (Boniva, Roche, Nutley, N.J.).

Calcium is an important element needed throughout the body for muscle and tissue functions. Calcium blood, muscle, and tissue levels have to be specifically maintained. Bone calcium is used to maintain this balance by storing and releasing calcium as needed. Bone calcium is constantly being eaten away and rebuilt within the skeletal bone. In fact, there is a complete human skeleton turn over every 3 years. Osteoporosis is a disease in which the boney release of calcium is greater than the rebuilding of bone, causing defects and reducing the density of bone. Bisposphonate drugs patch the boney defects and therefore increase the bone density.

Correct amounts of daily calcium intake are necessary through diet and or supplements. 1500 mg per day is the normal level for healthy individuals. Vitamin D is necessary for calcium absorption, either through sunlight or supplements. During winter months, it is impossible to receive enough vitamin D through sunlight north of San Jose, CA.

RISK FACTORS FOR OSTEOPOROSIS

The most important risk factors for osteoporosis are aging in both men and women. In women, the decrease in estrogen following menopause is correlated with a rapid reduction in bone mineral density, while in men, a decrease in testosterone levels has a comparable (but less pronounced) effect. Also, those with a family history of fracture or osteoporosis are at a much greater risk for osteoporosis. There are many other risks factors for having osteoporosis. Some are as follows: excessive alcohol use, tobacco smoking, poor nutrition, high dietary protein intake, low weight-bearing inactivity, many medications [particularly steroids and anticonvulsants], diabetes, and auto immune diseases.

If you have any of the risk factors for osteoporosis, have a discussion with your physician and consider having bone density tests.

OSTEOPOROSIS AND BONE FRACTURES

The risks of osteoporosis, especially the development of bone fractures, are serious. Fractures of the spinal column and hip are the most common osteoporosis problems, and hip fractures can be life threatening. The National Osteoporosis Foundation reports that an average of 24 percent of patients 50 years and older with hip fractures die within one year of their injury. One in five patients with a hip fracture ends up in a nursing home. Six months after experiencing a hip fracture, only 15 percent of patients are able to walk across a room without help. A woman’s risk of experiencing a hip fracture is equal to her combined risk of developing breast and ovarian cancers.

It is estimated that alendronate may reduce by 40 percent the risk of experiencing a hip fracture in patients with osteoporosis. Thus, it is possible that the drug could prevent more than 100,000 hip fractures and tens of thousands of deaths each year. Given the risks associated with osteoporosis and the proven benefits of oral bisphosphonate therapy, you should never stop taking these medications before discussing the matter fully with your physician.

OSTEONECROSIS OF THE JAW

Jaw complications linked to the use of bisphosphonate medications are a growing concern. The drugs have been associated with osteonecrosis of the jaws (ONJ), an uncommon but potentially serious condition that can cause severe destruction of the jawbones. News reports have alarmed and confused many patients who receive these drugs to prevent or treat osteoporosis.

Most cases of ONJ have been seen in patients with cancer who receive treatment with intravenous bisphosphonates, which absorb differently from oral bisphosphonates. Intravenous bisphosphonate medications are use in cancer therapy to reduce bone pain and hypercalcemia (abnormally high calcium levels in the blood), associated with metastatic breast cancer, prostate cancer and multiple myeloma.

The true risk posed by oral bisphosphonates remains uncertain, but researchers agree that it appears to be very small.

Most cases of osteonecrosis of the jaw associated with bisphosphonates are diagnosed after procedures such as tooth extraction. However, the condition can develop spontaneously. Also, invasive dental procedures, such as extractions or other surgery that affects the bone, can worsen this condition. Patients receiving intravenous bisphosphonate therapy should avoid invasive dental procedures if possible. The risk of developing osteonecrosis of the jaw after dental surgery in patients using oral bisphosphonates appears to be low.

Symptoms of osteonecrosis include, but are not limited to, the following:

– Pain, swelling or infection of the gums or jaw;

– Gums that are not healing;

– Loose teeth;

– Numbness or a heavy feeling in the jaw;

– Drainage;

– Exposed bone.

Because osteonecrosis of the jaw is rare, researchers cannot yet predict who will develop it. To diagnose the condition, clinicians may use X-rays or test for infection (taking microbial cultures). Treatments may include antibiotics, oral rinses and removable mouth appliances. Minor dental work may be necessary to remove injured tissue and reduce sharp edges of damaged bone. Surgery typically is avoided because it may worsen the condition.

The consensus is that if you are taking bisphosphonate medications for osteoporosis or cancer, then good oral hygiene along with regular dental care is the best way to lower your risk of developing osteonecrosis.

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