April 6, 2001
SAN ANTONIO (San Antonio Express-News) -
Dentists have puzzled for years over the lopsided
numbers of women who experience pain and problems
with their jaw muscles and joints.
Temporomandibular disorders, or TMDs, as they
are called, afflict an estimated 12 million
Americans, and are two to five times more common
in women than in men.
Researchers have questioned the role sex
hormones may play in the development of the
condition. An earlier study, in fact, suggested
there was a link between TMDs and women taking
hormone replacements or birth control pills.
But a new study from the University of Texas
Health Science Center appears to refute that
finding. Researchers found women who were taking
hormone replacements or birth control pills did
not have a higher rate of TMDs than women who did
not use those medications.
``We found absolutely no link between taking
estrogen and having the signs and symptoms of
TMD,'' said John P. Hatch, a professor of
orthodontics and psychology and director of the
university's Facial Pain Clinic.
The study was published last month in the
Journal of the American Dental Association.
The temporomandibular joint is in front of the
ear, between the temporal bone of the head and the
lower jaw. Symptoms of TMDs can include pain in
the face or joint, limited jaw movement, grinding
or clenching of jaws and headaches.
Hatch and his colleagues looked at 510 San
Antonio women, ages 37 to 82, who were enrolled in
a large, ongoing dental study. The women were
examined for evidence of jaw disorders and were
asked to bring their prescription pill containers
to the clinic so researchers could note if the
medications contained estrogen.
Hatch said most of the 174 subjects taking
estrogen were women on hormone replacement
therapy, but a few were using birth control pills.
``The implication for the practicing dentist is
that the patient who is taking estrogen is nothing
to be alarmed about,'' he said. ``They really are
not at significant risk for TMD. There may be some
risk there for some people, but in general, it
shouldn't be a major concern to the practicing
dentist at this time.''
Col. Edward F. Wright, a Wilford Hall Medical
Center dentist and the Air Force's top expert on
TMDs, said Hatch's research was sound and
appropriate conclusions were drawn.
``Based on that study, I would give that advice
to patients - that hormone replacement therapy
does not cause an increase in TMD symptoms,'' he
said.
Hatch noted the earlier study relied on
insurance company records and found that women who
got prescriptions for estrogen were more likely to
also seek referrals to jaw pain specialists. But
the subjects of that study were not selected at
random, Hatch said, and there was no follow-up to
confirm that the women were diagnosed with TMDs.
The San Antonio Express-News.
