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Clinical Diagnosis
Often clinical cases
for inclusion in an RCT are defined according to validated diagnostic
categories (e.g. Diabetes, Type I; Endometrial Cancer, Stage II;
Gingivitis).
Historically, an important
obstacle to case definition by clinical diagnosis of TMD (e.g.
Myofascial pain; Ostearthritis of the TMJ) has been the absence
of any reliable and valid scheme for diagnosing TMD patients according
to operational criteria, although even modest lack of agreement
in diagnostic criteria can lead to serious misclassification of
TMD cases (LeResche
et al., 1991).
A carefully developed
and acknowledged clinically useful diagnostic scheme for TMD,
the Guidelines for Classification, Assessment and Management of
TMD (The American Academy of Craniomandibular
Disorders, 1990), still lacks suitable operational criteria
to allow adequate evaluation of its reliability and validity or
to allow its use in rigorous RCTs investigating TMD.
In an attempt to address
these shortcomings, research diagnostic criteria for temporomandibular
disorders (RDC/TMD) have been developed and made available to
researchers and clinicians for scientific evaluation (Dworkin
and LeResche, 1992). The RDC/TMD was developed by a team of
international clinical research experts gathered together (with
NIDCR support) to develop, to the largest extent possible, an
empirically-based and operationalized system for diagnosing and
classifying RDC/TMD, based on the best available scientific data,
within the context of a biopsychosocial model.
The RDC/TMD uses a
dual axis system that allows:
- On
Axis I - a physical diagnosis based on pathophysiology; coordinated
with
- On Axis II - an
assessment of TMD-pain and related parafunctional behaviors,
psychological distress and psychosocial dysfunction
The RDC/TMD uses clinical
examination and history-gathering methods with scientifically
demonstrated reliability for gathering clinical signs of TMD,
and which also include assessment of behavioral, psychological
and psychosocial factors. The complete RDC/TMD publication is
available at a web-site created by a consortium of world-wide
researchers using the RDC/TMD http://rdc-tmdinternational.org,
which includes:
- The
complete RDC/TMD Axis I examination;
- The Axis II questionnaire;
- Detailed specifications
for conducting an RDC/TMD clinical examination;
- Operationally defined
criteria for an Axis I diagnosis of the most common forms of
TMD;
- Empirically-derived
normative values for classifying patients on Axis II parameters
of depression, somatization and grade of chronic pain; and
- The rationale and
background for developing the RDC/TMD.
Two recent RCTs used
RDC/TMD Axis II criteria for graded chronic pain as the critical
component of the TMD case definition (see Figure
5.1. for a schematic design of the RCTs) (Dworkin
et al., 2002h; Dworkin
et al., 2002b).
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