Odontogenesis

We obtained data from two convenience samples (Figure 1, page 1186). The first sample consisted of 732 adults at three academic health centers in the Research Diagnostic Criteria for TMD (RDC-TMD) Validation Project whom we characterized by using the expanded RDC-TMD assessment protocol.^{10 (link)} Case status was based on consensus by two dentists at each site (among them Y.M.G. and R.O. at the University at Buffalo, N.Y., E.S. at the University of Minnesota, Minneapolis, and E.L.T. at the University of Washington, Seattle) using calibrated technique.^{10 (link)} We recruited putative control participants on the basis of absence of pain in the facial area during the preceding six months. At the time of participants’ enrollment, we evaluated them according to history, clinical examination and panoramic radiographic findings to exclude people with any possibility of odontogenic pain. We used this first sample for initial item development. Among the participants with TMD, we included 65 in a reliability assessment, with an interval of two to seven days between survey administrations to evaluate temporal stability.^{11 (link)}For validity testing, we divided the 732 participants into four groups. We defined the target group, those having pain-related TMD, as those having a diagnosis of pain-related TMD (that is, myofascial pain, arthralgia or both) (as described by Schiffman and colleagues^{10 (link)}). We identified two comparison groups without pain. One of them consisted of healthy control participants, defined as not meeting criteria for a diagnosis of TMD; exclusion criteria at enrollment permitted only low-severity headaches (per International Classification of Headache Disorders, second edition [ICHD-II], criteria^{12 (link)}) that were not affected by masticatory function. The second comparison group consisted of those with a nonpainful TMJ disorder, defined as a TMJ disorder (such as disk displacement or osteoarthrosis) identified via magnetic resonance imaging or computed tomography, and this group served as a comparison for reporting of masticatory system symptoms. Participants in this latter group may have had jaw pain symptoms, but we required that those symptoms be insufficient to meet criteria for a diagnosis of TMD pain. We identified a third comparison group—those with headache in the temple region—by means of an algorithm from the ICHD-II criteria.^{12 (link)} This group was a subset of the healthy control participants and those with nonpainful TMJ disorders, and we selected it on the basis of the absence of a diagnosis of TMD pain. Consequently, these participants represented those with regional headache without TMD pain and served as a comparison for pain symptom reporting. To create groups with similar sample sizes, we randomly selected a subset of the participants with pain-related TMD and retained it for analyses.
Another pain group, that with odontalgia, consisted of 80 participants whose chief complaint was toothache and odontogenic disease confirmed by means of clinical examination and radiographs. We did not determine the presence or absence of TMD in this group owing to logistic limitations, so we used these data for secondary analyses to determine the false-positive rate associated with a competitive pain condition.

The criterion examiners, using questionnaires and a semi-structured interview, reviewed the medical history and pain characteristics in order to rule out possible non-TMD pain conditions and to exclude individuals with co-morbid conditions (see exclusion criterion in Table 1). Participants reporting a history consistent with migraine were not excluded. However, if a participant presented for evaluation while having an active migraine headache, the subject was rescheduled at a later date for the clinical examination. In addition, panoramic radiography and a clinical exam, including assessment for warmth, swelling and redness of the tissue, were used to rule out odontogenic, soft tissue, and hard tissue pathology. Other pathology not targeted for inclusion in the project was ruled out with TMJ MRI and CT. In establishing the reference standard diagnoses, the criterion examiners considered self-report of pain in the last month; effect of jaw function, movement, parafunction and rest on the reported pain over the past month; replication of the reported pain on provocation using clinical tests (see Table 2); and the TMJ CT and MRI studies. The criterion examiners also considered both common and uncommon TMD conditions that were operationalized by the consensus of the criterion examiners (see Table 3).
The criterion examiners performed their evaluations within the following procedural framework. Each of two CEs interviewed and examined each participant blinded to each other’s findings. Using all available clinical information including the imaging studies with the radiologist’s interpretations, they independently rendered their criterion diagnoses. They then compared their findings and, if either CE differed with the other’s findings or diagnoses, the participant was reexamined by both of them to resolve the area of disagreement. If either CE disagreed with the radiologist’s interpretation, the radiologist was consulted for further review of the images with the CEs. The reference standard diagnoses were then established by consensus between the CEs. The study’s requirement of a consensus between 2 independent examiners was designed to reduce the likelihood of diagnostic error. The estimated absolute error associated with a single exam is reported in the Results section.