Osseous changes and condyle position in TMJ tomograms: impact of RDC/TMD clinical diagnoses on agreement between expected and actual findings

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1 Osseous changes and condyle position in TMJ tomograms: impact of RDC/TMD clinical diagnoses on agreement between expected and actual findings Mie Wiese, DDS, a Ann Wenzel, DrOdont, PhD, DDS, b Hanne Hintze, DrOdont, PhD, DDS, c Arne Petersson, OdontDr, DDS, d Kerstin Knutsson, OdontDr, DDS, e Merete Bakke, DrOdont, PhD, DDS, f Thomas List, OdontDr, DDS, g and Peter Svensson, DrOdont, PhD, DDS, h Copenhagen and Aarhus, Denmark, and Malmö, Sweden UNIVERSITY OF AARHUS, UNIVERSITY OF COPENHAGEN, AND MALMÖ UNIVERSITY Objective. The objective of this study was to evaluate the impact of clinical TMJ diagnosis, gender, and age on the agreement between expected and actual radiographic findings. Study design. A total of 204 patients with TMJ symptoms were examined using the Research Diagnostic Criteria (RDC/ TMD). Expected radiographic findings were recorded. TMJ tomograms in closed and open mouth position were assessed for osseous changes and condyle position. Expected and actual findings were compared. Logistic regression analyses were performed with agreement on radiographic findings as the dependent variable and with clinical RDC/ TMD diagnoses, gender and age as the independent variables. Results. The number of radiographic findings was mostly underestimated. A clinical diagnosis of osteoarthritis and age increased the chance of overestimating osseous changes. Disc displacement and age decreased the chance of agreement on certain condyle positions. Conclusion. Tomography often revealed unexpected findings. It was not possible to select particular patient groups who would benefit more or less from a radiographic examination. (Oral Surg Oral Med Oral Pathol Oral Radiol Endod 2008;106:e52-e63) Radiographs may be included in the examination of patients suffering from temporomandibular disorders (TMD), and corrected lateral tomography is considered a PhD student, Department of Oral Radiology, School of Dentistry, Faculty of Health Sciences, University of Aarhus, and Department of Radiology, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. b Professor, Department of Oral Radiology, School of Dentistry, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark. c Associate Professor, Department of Oral Radiology, School of Dentistry, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark. d Professor, Department of Oral and Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden. e Associate Professor, Department of Oral and Maxillofacial Radiology, Faculty of Odontology, Malmö University, Malmö, Sweden. f Associate Professor, Department of Oral Medicine, Clinical Oral Physiology, Oral Pathology & Anatomy, School of Dentistry, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. g Professor, Department of Stomatognathic Physiology, Faculty of Odontology, Malmö University, Malmö, Sweden. h Professor, Department of Clinical Oral Physiology, School of Dentistry, Faculty of Health Sciences, University of Aarhus, Aarhus, Denmark. Received for publication Nov 14, 2007; returned for revision Jan 30, 2008; accepted for publication Mar 15, /$ - see front matter 2008 Mosby, Inc. All rights reserved. doi: /j.tripleo to be an accurate radiographic technique 1 with high diagnostic accuracy for assessment of the osseous components of the temporomandibular joint (TMJ). 2 Cone beam computed tomography (CBCT) has lately become an alternative to conventional tomography, as it is possible to produce high-quality 3-dimensional (3D) images of the TMJ with a lower radiation dose compared to conventional CT. 3 However, in a recent study 4 the diagnostic accuracy of CBCT for detection of morphological osseous changes in the TMJ was found not to differ from that achieved with conventional crosssectional tomography. Guidelines for imaging of the TMJ have been suggested, 5,6 but indications for a radiographic examination are still not well defined. A radiographic examination may serve not only to provide new information but also to confirm or rule out expected pathological findings based on the clinical examination. Radiographic changes are preceded by changes in the articular cartilage that are not visualized in radiographs, and osseous changes that are manifest enough to be detected in radiographs take time to develop. Thus, clinical signs and symptoms may be poorly linked to the radiographic findings. A number of studies have pertained to relate various clinical signs of TMD to radiographic changes of the TMJ However, previous studies have used different clinical examination protocols as well as different radiographic e52

2 Volume 106, Number 2 Wiese et al. e53 examination techniques, and no conclusions have been drawn regarding which radiographic findings may be predicted from a clinical examination of the TMJ and surrounding structures. The Research Diagnostic Criteria for Temporomandibular disorders RDC/TMD 13 is an internationally used diagnostic system that has been shown to be reliable for diagnosing TMD. 14,15 In a recent study based on RDC/TMD, coarse crepitus of the TMJ as well as increasing age and gender (women) were found to be associated with an increased risk of degenerative changes in TMJ tomograms, whereas no pain-related variables were associated with radiographic findings. 16 To select patients who will benefit most from a radiographic examination, not only clinical signs and symptoms associated with increased risk of radiographic findings must be identified, but also patient subgroups where unexpected information may be revealed by the radiographic examination. A previous study by Pullinger and White 17 evaluated the efficacy of TMJ tomograms in terms of expected versus actual findings and found that tomograms did add new information as regards a high number of unexpected osseous findings as well as positional changes of the condyle. The impact of various clinical TMJ diagnoses, gender, and age on the orofacial pain specialist s ability to correctly predict the radiographic appearance of the TMJ in tomograms based on the RDC/TMD examination protocol is, however, unknown. This article is part of a study on the impact of radiography on diagnosis and management of TMD patients using the RDC/TMD. The purpose of this part of the study was to evaluate the impact of clinical TMJ diagnosis, gender, and age on the agreement between expected and actual radiographic osseous changes and position of the condyle in TMJ tomograms. The nullhypothesis to be tested was that clinical TMJ diagnosis, gender, and age are not associated with agreement between expected and actual radiographic findings. MATERIALS AND METHODS The study included 204 consecutive patients (48 men, 156 women) referred during 2004 to 2006 to 1 of 3 centers: University of Aarhus (51%), University of Copenhagen (24%), Denmark, and Malmö University, Sweden (25%). Inclusion criteria were age older than 18 years, TMJ pain complaints, sounds (clicking or crepitation) from the TMJ, or changes in the range of mandibular motion. Exclusion criteria were recent trauma to the jaw and, to avoid bias, previous treatment for TMD at the department where the patient paid the visit. The mean age was 38 years (SD 16) for men and 41 years (SD 16) for women, ranging from 18 to 90 years. The women-to-men ratio was 4:1. The age and Table I. Diagnostic classification (only diagnoses occurring in the patient sample are shown) Diagnosis Ia Myofascial pain (RDC/TMD. I.a.) 13 Diagnosis Ib Myofascial pain with limited opening (RDC/TMD. I.b.) 13 Diagnosis IIa Disc displacement with reduction (RDC/TMD. II.a.) 13 Diagnosis IIb Disc displacement without reduction with limited opening (RDC/TMD. II.b.) 13 Diagnosis IIc Disc displacement without reduction, without limited opening (RDC/TMD. II.c.) 13 Diagnosis IIIa Arthralgia (RDC/TMD. III.a.) 13 Diagnosis IIIb Osteoarthritis of the TMJ (RDC/TMD. III.b.) 13 Diagnosis IIIc Osteoarthrosis of the TMJ (RDC/TMD. III.c.) 13 Diagnosis 04 Temporomandibular joint dislocation (AAOP modified from ICD9.CM 830.1) 18 Diagnosis 05 Rheumatoid arthritits (RA) (ARA criteria 1987) 19 gender distribution has been described in detail in a previous paper. 16 The study was approved by the Danish regional ethical committee and was classified as a quality control study. The clinical assessment included detailed questionnaires providing information on the patient s health status, psychosocial dysfunction and onset, and duration and characteristics of pain as well as clinical examination assessing the presence and location of pain, the presence of joint sounds, and measurement of the range of mandibular motion using the RDC/TMD. The examination was performed by 1 of 6 trained orofacial pain specialists who were calibrated by thoroughly going through the RDC/TMD procedure and hereafter together applying the procedure on TMD patients. The clinical diagnoses were made according to the guidelines of the RDC/TMD protocol and guidelines of the American Academy of Orofacial Pain 18 and the American Rheumatism Association. 19 The diagnostic classification is shown in Table I. The orofacial pain specialists were asked to arrive at a clinical diagnosis without the aid of radiographs, and furthermore they were asked to fill in a score sheet describing their expected radiographic findings for the right and the left TMJ in each patient. The score sheet was established after a consensus meeting between orofacial pain specialists and radiologists and it was possible to select from the following predefined parameters (each were scored as yes/no): the presence of flattening, osteophyte, sclerosis, and erosive changes in the TMJ using the following definitions: flattening loss of convexity/concavity of the joint outlines; osteophyte a local outgrowth of bone arising from the mineralized surface; sclerosis increased radiopacity of the spongy bone or thickening of the compact bone; erosion a local area of rarefaction in the layer of compact bone. 16,20,21 The localization of

3 e54 Wiese et al. August 2008 the morphological change was not specified to the individual joint components (condyle, mandibular fossa, and articular tubercle), but the joint was assessed as one structure. The condyle-to-mandibular fossa relation (condyle-to-fossa) in closed position and condyle-to-top of the articular tubercle relation (condyleto-tubercle) in maximum open position was classified as being central, anterior, or posterior in the horizontal direction. For the closed position, the condyle-to-fossa relation in the vertical direction was additionally classified as being central, superior, or inferior. After the clinical examination and completion of the score sheet, the patient s right and left TMJ was examined radiographically by individually corrected lateral TMJ tomography using conventional film in a Cranex Tome or a Scanora tomographic x-ray unit (Soredex, Helsinki, Finland), which make use of the exact same radiographic technique. The examination consisted of 4 lateral sections in closed position and 4 lateral sections in maximum open position of each TMJ. The section layer thickness was 4 mm. A mouth prop was used to stabilize the maximum open mouth position during the exposure. Experienced radiographers performed all examinations. The tomograms of each patient were evaluated by 1 examiner from a panel of 5 calibrated oral radiologists, who were blinded to the clinical diagnosis as well as the orofacial pain specialist s description of the expected radiographic osseous changes and position of the condyle. The radiologist s findings were considered the gold standard. In connection with the calibration of the radiologists, an atlas containing examples of morphological changes in TMJ tomograms was developed. The radiologists could confer with this atlas while evaluating the tomograms if they were in doubt how manifest a change should be to be recorded. The tomograms were evaluated using the same scoring system as used by the orofacial pain specialists except that all TMJ components were assessed individually (condyle, mandibular fossa, and articular tubercle). The films were evaluated on a light box with an x-ray magnifying viewer. Data Analysis A finding in one or more of the TMJ components was calculated as an actual finding for the joint. was defined as concordance between the orofacial pain specialist s expected and the oral radiologist s actual finding on TMJ tomograms, i.e., either a true positive finding or a true negative finding. on any type of change was defined as a true positive finding of one or more osseous changes regardless of the number and type of radiographic change (e.g., flattening was expected and sclerosis and erosion were the actual findings), or a true negative finding, that is, a correct expectation of no changes at all. Sensitivity was defined as the percentage of joints with expected radiographic osseous changes out of all joints with radiographic changes (the number of true positive findings divided by the total number of positive findings). Specificity was defined as the percentage of joints with no expected radiographic osseous changes out of all joints with no radiographic changes (the number of true negative findings divided by the total number of negative findings). To estimate if certain clinical diagnoses or patient characteristics were associated with agreement on osseous change, individual logistic regression analyses were performed with agreement/nonagreement on flattening, osteophyte, sclerosis, erosion, and any type of change in the right or left TMJ as the dependent variables and with the clinical RDC/TMD group I diagnoses of myofacial pain (Ia and Ib), group II diagnoses of disc displacements (IIa, IIb, and IIc), as well as the individual group III diagnoses of arthralgia (IIIa), osteoarthritis (IIIb), and osteoarthrosis (IIIc) of the right or left TMJ together with gender and age as the independent variables. With the purpose of estimating whether possible associations were a result of under- or overestimating the number of expected osseous changes, further logistic regression analyses were performed for those independent variables that were found to be consistent and statistically significant in the above-mentioned analysis for both the right and the left TMJ. Two separate logistic regression analyses were thus performed. First, only joints with actual radiographic changes were selected, and the dependent variables were true positive/ false negative findings of flattening, osteophyte, sclerosis, erosion, and any type of change. Second, only joints with no actual radiographic changes were selected, and the dependent variables were true negative/ false positive findings of flattening, osteophyte, sclerosis, erosion, and any type of change. Further, the clinical RDC/TMD group I, II, and the individual group III diagnoses, gender, and age were included in the analysis with the dependent variables agreement/nonagreement on the condyle-to-tubercle relation in open position and on the condyle-to-fossa relation in the horizontal and vertical direction in closed position. The statistical analyses were performed using the SPSS package, GLM version 10.0 for Windows (SPSS Inc., Chicago, IL). The level of statistical significance was P.05. RESULTS The number of the clinical TMJ diagnoses is shown in Fig. 1. The most frequent diagnoses were myofascial

4 Volume 106, Number 2 Wiese et al. e55 Fig. 1. Number of clinical TMJ diagnoses before radiographic examination. More than one diagnosis can occur in the same joint or patient. pain (Ia and Ib) followed by arthralgia (IIIa) and disc displacement with reduction (IIa). The prevalence of diagnoses and combinations of diagnoses in this patient sample has been described in more detail in a previous paper. 16 between expected and actual radiographic osseous changes Fig. 2 shows expected and actual radiographic osseous changes in the TMJ. The most frequent actual finding was flattening, which occurred in about 39% of the TMJs. Osteophyte and erosion was found in approximately 18% of the TMJs, and sclerosis occurred in only 9% of the TMJs. Almost half of the TMJs (49%) had some kind of radiographic osseous change. A detailed description of the distribution of radiographic findings in right, left, and both TMJs as well as combinations of radiographic findings in the patients can be found in a previous paper. 16 In general, the orofacial pain specialists underestimated the number of radiographic changes, and therefore the specificity, i.e., the ability to correctly identify TMJs with no radiographic osseous changes based on the clinical examination was relatively high ( ). The sensitivity, i.e., the ability to correctly identify TMJs with radiographic osseous changes based on the clinical examination was rather low ( ) for osteophyte, erosion, and sclerosis. For flattening and any type of change, i.e., when agreement was accepted even if the orofacial pain specialist expected another type or number of changes than what was actually found in the radiographs, the sensitivity was a little higher ( ). Associations between clinical RDC/TMD diagnoses, patient s gender and age, and agreement on osseous radiographic changes The results of the logistic regression analyses are found in Table II. For women, a lower chance of agreement on erosion was found compared with men (odds ratio [OR] 0.35), and a decreased chance of agreement on osteophyte and sclerosis was found with increasing age (OR 0.96 per year). For TMJs with a clinical diagnosis of osteoarthritis (IIIb), the chance of agreement on any type of change was 3 times higher (OR 3.10) than for TMJs not diagnosed with osteoarthritis, but the chances of agreement on erosion, osteophyte, and sclerosis were smaller (OR 0.36) for TMJs clinically diagnosed with osteoarthritis compared to those that were not. Furthermore, a 3 times higher chance of agreement on osteophyte was found with a clinical diagnosis of arthralgia (IIIa) compared to those without (OR 3.66), whereas a clinical diagnosis of osteoarthrosis (IIIc) was associated with a much lower chance of agreement on osteophyte (OR 0.17). Some of these associations, however, were inconsistent and found only for the right or the left TMJ. Age and a clinical diagnosis of osteoarthritis were the most consistent findings. Associations between these clinical variables and true positive and true negative radiographic findings separately were therefore further analyzed. With ascending age, the chance of a true positive finding of flattening as well as the chance of correctly expecting any type of change increased (OR 1.03 per year;.01 P.05). The chance of a true negative

5 e56 Wiese et al. August Number of TMJs False positive True negative False negative True positive Actual radiographic changes Flattening, sens=0.54 No flattening, spec=0.86 Osteophyte, sens=0.14 No osteophyte, spec=0.94 Sclerosis, sens=0.17 No sclerosis, spec=0.91 Erosion, sens=0.40 No erosion, spec=0.90 Any-type-of-change, sens=0.47 No changes, spec=0.86 Fig. 2. Expected versus actual radiographic osseous changes in the right and left TMJ. Sensitivity (sens) and specificity (spec) for the ability to expect a radiographic change. A particular type of change can occur either alone or in combination with other changes.

6 Volume 106, Number 2 Wiese et al. e57 Table II. Associations between clinical variables (gender, age, and diagnoses) and agreement between expected and actual radiographic findings of degenerative changes in the TMJ Variables, category osteophyte sclerosis OR CI (P) erosion any-type-of-change Gender: (Men) Women Right TMJ (.04) Left TMJ Age: (18) 18 (per year) Right TMJ (.01) Left TMJ (.01) (.01) Diagnosis IIIa: (No) Right TMJ Left TMJ (.01) Diagnosis IIIb: (No) Right TMJ (.01) (.01) (.01) (.04) Left TMJ (.04) (.01) Diagnosis IIIc: (No) Right TMJ Left TMJ (.03) The reference groups for the independent variables are those presented in parenthesis. Empty spaces represent nonsignificant associations OR, odds ratio; CI, 95% confidence interval; P, P value. finding of any type of change increased with ascending age (OR 1.03 per year;.01 P.03), while the chance of a true negative finding of flattening, osteophyte, sclerosis, and erosion decreased with ascending age (0.92 OR 0.97 per year;.01 P.02). However, for flattening, sclerosis, and erosion a statistically significant association was found only for either the right or the left TMJ. A very high chance of a true positive finding of flattening and sclerosis was found for a clinical diagnosis of osteoarthritis (IIIb), which was more than 20 times higher than for TMJs not clinically diagnosed with osteoarthritis (20.64 OR 29.74;.01 P.04). However, for sclerosis, this association was found only for the left TMJ. For a clinical diagnosis of osteoarthritis, a decreased chance of a true negative finding of flattening, erosion, osteophyte, and sclerosis was found (0.01 OR 0.11; P.01). This was a consistent finding and highly statistically significant for both the right and the left TMJs. between expected and actual radiographic position of the condyle The expected versus the actual condyle-to-fossa position is illustrated in Fig. 3. In most TMJs, the condyle was positioned centrally both in the horizontal and vertical direction. In the horizontal direction the most prevalent position next to the central was a posterior position, and in the vertical direction it was an inferior position. A detailed view of the different combinations of position in the horizontal and the vertical direction and the distribution on right, left, and both TMJs may be seen in Wiese et al. 16 In the majority of the cases, the orofacial pain specialists expected the condyle to be positioned centrally in both the horizontal and the vertical direction. Therefore, the percentage of agreement was high for TMJs positioned centrally in the horizontal direction (agreement in 91% of the cases) and for TMJs positioned centrally in the vertical direction (agreement in 89% of the cases). When the condyle was posteriorly positioned in the horizontal direction, agreement was found in about one third of the cases, and it was observed in only one fifth of the cases when the condyle was superiorly positioned in the vertical direction. The agreement was extremely low when the condyle was anteriorly positioned in the horizontal direction (agreement in 4% of the cases) or inferiorly positioned in the vertical direction (agreement in 1% of the cases). Fig. 4 shows the expected versus the actual condyleto-tubercle relation in the open mouth position. The condyle was positioned under the top of the articular tubercle in the majority of the TMJs (49%). The frequency of an anterior and a posterior position was almost identical: 24% and 27% of the TMJs, respectively. In most cases, the orofacial pain specialists expected the condyle to be positioned under the top of the articular tubercle. The highest agreement was therefore found when the condyle was actually positioned under the top of the articular tubercle (agreement in

7 e58 Wiese et al. August 2008 Fig. 3. Expected versus actual condyle-to-fossa relation in the right and left TMJ in closed position expressed as a horizontal relation (central, anterior, posterior) and a vertical relation (central, superior, inferior). The percentage in brackets represents the agreement between the expected and actual radiographic position. Fig. 4. Expected versus actual radiographic condyle-to-tubercle relation in the right and left TMJ in maximal open position (total number of TMJs 407, one radiograph missing). The percentage in brackets represents the agreement between the expected and actual radiographic position.

8 Volume 106, Number 2 Wiese et al. e59 67% of the cases). When the condyle was positioned posteriorly, agreement was found in less than half of the cases (42%), but for condyles positioned anteriorly, agreement was seen in only about one fourth of the cases. Associations between clinical RDC/TMD diagnoses, patient s gender and age, and agreement on position of the condyle Associations between clinical RDC/TMD diagnoses, gender and age, and agreement on position of the condyle in closed and open position are presented in Table III. A statistically significant association between the clinical variables and agreement on position of the condyle in open position was found only for the diagnoses of myofascial pain (Ia, Ib), which decreased the chance of agreement (OR 0.26). This association, however, was found only for the left TMJ. For the closed mouth position, ascending age was found to be associated with a decreased chance of agreement on a central and anterior position in the horizontal direction (OR 0.97), but this was found only for either the right or the left TMJ. Furthermore, with ascending age a decreased chance of agreement on central position in the vertical direction was observed (OR 0.98). The chance of agreement on a central position in the vertical direction was observed to be twice as high for women compared with men (OR 2.12). A clinical diagnosis of disc displacement (IIa, IIb, IIc) was found to be associated with a decreased chance of agreement on a posterior position in the horizontal direction and a superior position in the vertical direction compared to TMJs without disc displacement (OR 0.30). The chance of agreement on an inferior position in the vertical direction decreased with a diagnosis of myofascial pain (Ia, Ib) (OR 0.30), but a statistically significant association was found only for the left TMJ. Finally, arthralgia (IIIa) was associated with a decreased chance of agreement on an inferior position in the vertical direction for the right TMJ (OR 0.41). DISCUSSION Methodological considerations In the traditional definition of sensitivity and specificity, a gold standard, which expresses the true presence and absence of disease, is needed. An assessment of the true appearance of the TMJ, as would be available from autopsy material 22 or dry skulls, 4,21 may be optimal as a gold standard for osseous changes in the joint, but this is obviously not possible in a clinical study assessing clinical signs and symptoms in patients. In the present study, the radiographic finding by the oral radiologist was defined as the gold standard, and calibration sessions between the radiologists had been carried out to minimize interobserver variation. Furthermore, an atlas with examples of morphological changes in TMJ tomograms was available during the evaluation of the radiographs. The orofacial pain specialists were all trained, experienced clinicians. They were thoroughly calibrated in RDC/TMD examination and diagnoses, but it is possible that there could still be differences between observers related to expectancy of radiographic findings after the clinical examination. We believe, however, that these potential differences between the orofacial pain specialists reflect observers generally, as expectancy differences without doubt exist in reality. Since a rather large number of variables were tested in the logistic regression model, the results should be interpreted with caution, and we considered only consistent results with low P values to be conclusive. Prediction of changes in TMJ tomograms In this study, lateral corrected cross-sectional tomography did provide information of the osseous components of the TMJ not expected by the orofacial pain specialists. Overall, there was poor agreement between expected and actual radiographic findings. The sensitivity was low for most of the osseous changes, whereas the specificity was relatively high, which means that the orofacial pain specialists in general underestimated the number of osseous changes. The sensitivity was higher for an expectation of any type of change, although it did not exceed 50%. These results lend support to the notion that it is difficult to predict the outcome of the radiographic examination on the basis of the clinical examination. We showed that some clinical diagnoses were indeed associated with an increased or decreased chance of agreement, whereas others were not, or the finding was not consistent in both joints. The reason for these inconsistent findings could be that for those diagnostic groups too few actual changes were present in one of the joints. In consequence of this, these findings should not be seen as conclusive, and therefore focus was drawn toward the more consistent findings in the following. When all TMJs were considered, both those with and without osseous changes, an OR less than 1 was generally found for the individual osseous changes while an OR greater than 1 was found for agreement on any type of change (Table II). This is logical since the definition of agreement on any type of change is reached even if several changes are expected, but only one is actually present. Furthermore, the decreased chance of agreement for the individual osseous changes could be explained by a larger proportion of TMJs with no changes than TMJs with the individual osseous

9 Table III. Associations between clinical variables (gender, age, and diagnoses) and agreement between expected and actual radiographic position of the condyle Variables, category open position posterior closed position horizontal relation central closed position horizontal relation anterior OR CI (P) closed position horizontal relation posterior closed position vertical relation central closed position vertical relation superior closed position vertical relation inferior Gender: (Men) Women Right TMJ Left TMJ (.03) Age: (18) 18 (per year) Right TMJ (.02) (.03) Left TMJ (.02) (.01) Diagnoses group I: (No) Right TMJ Left TMJ (.01) (.01) Diagnoses group II: (No) Right TMJ (.01) (.01) Left TMJ (.01) (.01) Diagnosis IIIa: (No) Right TMJ (.01) Left TMJ The reference groups for the independent variables are those presented in brackets. Empty spaces represent nonsignificant associations. OR, odds ratio; CI, 95% confidence interval; P, P value. OOOOE e60 Wiese et al. August 2008

10 Volume 106, Number 2 Wiese et al. e61 changes in this patient group, whereas the proportion of TMJs with actual radiographic osseous changes make up a relatively larger part of the group when all types of changes are considered. When only TMJs with actual osseous changes were considered, a strong chance of agreement on flattening and sclerosis was found (OR 30) for patients who were clinically diagnosed with osteoarthritis. However, when considering only TMJs with no actual osseous changes the odds ratio for patients with a clinical diagnosis of osteoarthritis was low ( ). This means that for patients with this diagnosis, the orofacial pain specialists most often expected to find osseous changes in the joints, thereby correctly identifying TMJs that had actual osseous changes, but rarely identifying the TMJs with no actual changes, i.e., overestimating the number of joints with osseous changes. According to the RDC/TMD the diagnosis of osteoarthritis is applied if arthralgia plus either coarse crepitus or radiographic osseous changes are present, which could be a reason why the number of changes were in general overestimated for patients with clinical signs of osteoarthritis. These findings are in accordance with those observed by Pullinger and White 17 who found that the ability to predict osseous changes in patients diagnosed with osteoarthritis was greater than for patients diagnosed with soft tissue derangements. They furthermore concluded that a high false positive rate was observed for this patient group, which is in concordance with our results. Ascending age was found to be associated with a decreased chance of agreement on osseous changes. For age the chance of agreement (odds ratio) reported is per year. Therefore, the decreased chance of agreement on, e.g., osteophyte in a 50-year-old compared with a 25-year-old is years which equals With ascending age, OR was greater than 1 when only TMJs with actual osseous changes were considered, whereas the odds ratio was less than 1 when only TMJs with no changes were considered. These results signify that for older patients the orofacial pain specialists overestimated the number of osseous changes. Age has been found to be associated with increased risk of radiographic osseous changes, 16 but the results from our study indicate that the orofacial pain specialists probably considered age too strong a risk factor. However, with increasing age of the patient, the OR was greater than 1 for a true negative finding of any type of change. This means that the tendency toward overestimating the number of osseous changes was present only when the orofacial pain specialists tried to specify what type of change they expected, and not when any kind of osseous change counted. Not surprisingly, the orofacial pain specialists could not predict exactly what kind of change to expect; however, it may be of greater importance that the orofacial pain specialist can correctly predict whether a degenerative change is present in the TMJ rather than predict which type of individual osseous change may exist. From the present study it was not possible to sort out certain patient groups who would benefit more or less from a radiographic examination in terms of revealing unexpected radiographic findings. Only a clinical diagnosis of osteoarthritis and increasing age of the patient was associated with a higher chance of correctly identifying TMJs with osseous changes, but for these patient groups an overestimation of expected radiographic findings was observed. However, for osteoarthritis patients, clinical findings may be present without radiographic degenerative changes, as there may be differences between onset of pain and development of degenerative changes manifest enough to show on radiographs. The chance of agreement was not influenced by a clinical diagnosis of myofascial pain and disc displacement, but as implied by the diagnostic classification system, findings of degenerative osseous changes in the TMJ are traditionally not associated with these diagnoses. Conclusions regarding the impact of arthralgia and osteoarthrosis on the agreement on radiographic osseous changes could not be drawn. Lateral cross-sectional tomography did provide information on the position of the condyle not expected by the orofacial pain specialists. In general, low agreement was observed for the position of the condyle. Most often, the orofacial pain specialists expected the condyle to be placed centrally in the mandibular fossa in closed position and under the top of the articular tubercle in open position, which was demonstrated by a high degree of agreement for these positions. For positions deviating from those, low agreement was found. With ascending age, a decreased chance of agreement on the position of the condyle was found for a central condyle-to-fossa relation in the vertical direction. In addition to this, a clinical diagnosis of disc displacement decreased the chance of agreement on a posterior position in the horizontal direction as well as a superior position in the vertical direction. In other words, for patients with clinical signs of disc displacement, the orofacial pain specialists were less likely to correctly predict a posterior and a superior condyle-tofossa relation. Difficulty in correctly predicting the position of the condyle in 30% of the patients with clinical signs of derangement or osteoarthritis was also reported by Pullinger and White. 17 The orofacial pain specialist s difficulty in predicting the position of the condyle from the clinical examination may not be surprising since the association between a displaced disc and the position of the condyle is unclear. A noncentric

11 e62 Wiese et al. August 2008 condyle position is not necessarily a sign of pathology since this is often found in asymptomatic subjects. 23,24 However, other studies have demonstrated a relationship between the position of the condyle and a clinical diagnosis of disc displacement Since the clinical significance of the position of the condyle is uncertain, the importance of radiographic information about condyle position may be questionable. Whether the unexpected radiographic findings should influence the indications for a radiographic examination depends on the impact of these findings on the management of the patient. From our results, it follows that if the radiographic findings do in fact have an impact on the treatment offered to the patient, then TMJ tomography is of great value, and patients from all diagnostic groups tested would benefit from a radiographic examination. The impact of radiographic findings on diagnosis and patient management will be addressed in a subsequent article. CONCLUSION TMJ tomography was found to provide additional information beyond that expected from the clinical examination. In general the orofacial pain specialists underestimated the number of radiographic findings, whether it was osseous changes or position of the condyle deviating from a central position. A clinical diagnosis of osteoarthritis as well as increasing age of the patient was found to have an impact on agreement on radiographic osseous changes. An increased chance of agreement was observed for TMJs with actual osseous changes, but the chance of agreement decreased when TMJs with no actual changes were considered, indicating that the chance of overestimating the number of osseous changes is increased when clinical signs of osteoarthritis are present. 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