Pre-ortho tomos

[Grace Petrikowski]

TO: ORADLIST at listserv.ucla.edu


In response to Ken Abramovitch:

I have not seen anything in the literature to suggest that TMJ tomos should
be a standard of care for routine orthodontic cases.  In addition, there is
no evidence in the ortho literature to suggest that orthodontic treatment
actually prevents/cures TMJ problems.  The push for tomos in otherwise
normal patients stems from a medico-legal fear on the part of the
orthodontists, since some patients develop TMJ symptoms during or after
treatment.  It is argued that pre-treatment tomos serve as a baseline for
comparison later on if TMJ problems develop.  However, there is no proof
that these patients wouldn't have developed problems anyhow, even if they
hadn't undergone ortho treatment.

Obviously, pre-treatment tomos are indicated if there is a positive history
or evidence of various arthridites or if clinical findings/history otherwise
suggest imaging is prudent.  One may argue that information gained from
routine tomos aids in informed consent for treatment but the likelihood of
detecting a *significant* abnormality in an otherwise routine patient is
very low.  In a study looking at TMJ radiographic findings (tomos) in almost
500 consecutive children and adolescents prior to orthodontic treatment, we
found positional, functional or osseous abnormalities in less than 10% of
patients and abnormalities found consisted of remodeling which was not
judged severe in any of the cases.  No patients in this sample had signs of
degenerative changes.  (Petrikowski CG, Grace MGA.  Temporomandibular joint
radiographic findings in adolescents.  Cranio 1996;14:30-36).  Furthermore,
even if abnormalities are found, the orthodontist will likely proceed with
treatment anyhow, leading to the question of what purpose the tomographs
really served.

Taking radiographs for treatment planning is based not only on standards of
practice but also professional judgement.  There are arguements for and
against routine TMJ tomos prior to orthodontic treatment but I am not
convinced that the evidence to date supports including TMJ tomos as a
standard of care for all ortho patients.

Grace Petrikowski  DDS, MSc, FRCD(C)
Faculty of Dentistry, University of Toronto
124 Edward Street
Toronto, ON  Canada  M5G 1G6
gpetrikows at dental.utoronto.ca