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					                                                                                                                 Oral presentation March 7, 2002                                                           9:15 a.m.

                                                                                Changes of the condylar morphology in patients
                                           Eberhard-Karls-Universität           wearing implant retained prosthodontics
                                           Universitätsklinikum Tübingen
                                                                                 IADR 80th General Session in San Diego, March 6-9, 2002
                                                                              Lachmann Sa, Engel Eb, Gomez-Roman Gb, Axmann Dc, Weber Hd

   I. Introduction and aim of study                                                                                     2. Development of condylar changes
                                                                                                                       Logistic regression models underline this risk for initially healthy condyles to develop
                                                                                                                       pathological changes over time (odds ratios 2 to 14). Pathologic articular findings polarize in two
   Radiologic long-term follow-up investigations of the mandibular condyle are rare. From a                            groups: on the one hand there are findings that show virtually no tendency to return to the
   methodological point of view, the role of rotational panoramic radiography (RPR) in the                             radiologically healthy state (flattening, fracture). On the other hand those findings generally
   diagnosis of degenerative temporomandibular joint (TMJ) disorders is subject to controversy.                        associated with active osteoarthrotic lesions trend to decrease in severity (erosion, osteophyte).
   While some authors doubt its clinical relevance others recommend its application in the screening                   Due to the high percentage of lesions that arise from initially asymptomatic condyles the overall
   for TMJ hard tissue pathology. The reliability of RPR findings over time with regard to the fate                    number of affected cases doubles in each group of findings (figures 7,8.)
   of the condylar morphology after insertion of implant retained dental prostheses were the topic of
   interest in this investigation.                                                                                     3. Associations between clinical features and radiological findings
                                                                                                                       None of the logistic regression models applied could reveal a statistical influence of age, gender,
                                                                                                                       type of prosthodontic restoration or time span between the two radiographs to changes in the
                                                                                                                       condylar morphology. The only exception is condylar asymmetry, which was more pronounced
                                                                                                                       in patients with removable prosthodontics.

                                                                                                                                                                                                                            Patterns of change in different findings over time

                                                                                                                                                                                                                                                 No finding on both images     Finding unchanged
                                                                                                                                                                                                                                                 Increase in severity          Decrease in severity
                                                                                                                                                                                                                          No. of patients

                        97-05-30                                                             98-06-16


 Fig. 1                                                                       Fig. 2                                                                                                                                            50

                                                                                                                                                                                                                                            Fl                Er          Os         Sc        Fr         As
   II. Patients and methods                                                                                          Fig. 7                                                                                             Fig. 8

   A prospective follow-up investigation of condylar flattenings, erosion, osteophytes, sclerosis,                     IV. Conclusion
   condylar fractures, and condylar asymmetry with preoperative and control panoramic
   radiographs was performed in 223 patients receiving osseointegrated fixed or removable dentures
   (figures 1,2, 4 and 9). The mean age of the patients at the beginning of the study was about 55                     The results from the investigated patient group suggest the following conclusions:
   years with an average observation time of 5 years.                                                                  1. The condylar morphology remains fairly stable on RPRs taken at different occasions.
   Findings were classified in 3 categories (0-2) as either being absent (0), being slight (1) or severe                  However, there are cases in which changes in the form of the condyles can be observed.
   (2) according to the clinical experience of the investigator (fig. 3).                                              2. Virtually investigated types of condylar findings (flattening, erosion, osteophytes, sclerosis,
   The statistical analysis included explorative data analysis, к-statistics, analysis of variance and                    asymmetry) may be subject to change with fractures as the only exceptions to this rule.
   logistic regression. To guarantee statistical independence of functional associations between one                   3. Changes are expected to occur in patients with a) healthy condyles, b) signs of active
   side from the other a worst case scenario for the initially more severely affected condyle (sum of                     osteoarthrotic lesions.
   all finding scores) was performed. The joint with the higher sum was included in the analysis.                      4. Changes in healthy condyles contribute to an overall increase in articular findings over the
   In cases of equal values on both sides the right condyle was chosen. Intra- and interobserver                          investigated period of time.
   variance had been evaluated previously.                                                                             5. Active lesions usually show a decrease in severity over time.
                                                                                                                       6. There is no evidence of associations to prosthodontic treatment modalities or general
                                                                                                                          anamnestic patient data like age or gender.

   Condylar findings
                                                                                                                                                   88-08-19                                                                                                    93-12-15
   Flattening                                    0-2
   Erosion                                       0-2
   Osteophyte                                    0-2
   Sclerosis                                     0-2

   Condylar fracture                             yes/no

   Condylar asymmetry                       0-3%, 3-6%, >6%                                                                                        95-02-06                                                                                                    00-06-19
                 Score                       0     1     2
 Fig. 3                                                                            Fig. 4

   III. Results
                                                                                                                     Fig. 9a
   1. Degree of agreement between radiographs
   The morphology of the condyles does in the majority of cases (66%) not change at all (κ=0.47,
   p<0.001, figures 5 and 6 give an example for erosions). The reliability of diagnosing the same
   state of condylar morphology on the second radiograph as expressed by Cohen’s Kappa (κ) is
   0.48 and varies from 0.37 (osteophytes) to 0.60 (flattening). If only patients are analyzed whose
   joints were affected already on the first image, the reliability increases to 0.61 (sclerosis) and to               88-08-19                                              93-12-15                                                  95-02-06                                             00-06-19
   0.91 (flattening). While these values show a high degree of reliability for pathological findings,
   the reliability is reduced in cases of asymptomatic condylar morphology. Changes are strongly                     Fig. 9b
   restricted to one side of the stomatognathic system.
   The condylar asymmetry (AI) does not show a statistically significant trend of change over time.
   The AI of patients with flattenings (AI=13.8%), signs of condylar fractures (AI=18.7%) or                           V. Discussion
   erosions (AI=15.0%) is higher than the mean asymmetry (10.8%, p=0.007).
                                                                                                                       RPR reliability with regard to condylar morphology per se were not addressed in the design of
                                                                                                                       this study. Clinical variables such as insertion of prosthodontic restorations and the time lapse
                          223 right condyles, erosion                                                                  between both radiographs also may influence TMJ changes. Further research needs to be done to
                                                                                  Right condyle                        evaluate the reliability of RPRs taken at the same occasion, eliminating the other mentioned
   1st image
                                                                                                                       clinical variables. Also the clinical relevance of the findings was not addressed in this study since
                          0                 1             2                   Changes in erosive findings              at the radiological follow-up date no functional examination of the stomatognathic system had
       No. of             206               8             9
       patients                                                                                                        been performed. Thus therapeutic consequences need to be drawn with caution.
                                                                                  No change       196
   2nd image
                    0     1     2     0     1    2    0   1    2
       No. of       183   15    8     3     5    0    1   0    8                  Increase        23
       patients                                                                                                        VI. References
   Score of   2nd   image       0     1     2                                     Decrease        4
       No. of patients          187   20    16                                                                         1. Engel E, Lachmann S, Axmann D. The prevalence of radiologic TMJ findings and self-reported orofacial pain in a patient group wearing implant dentures. Int J Prosthodont 14: 120-6, 2001.
                                                                                                                       2. Habets LL, Bezuur JN, Naeije M, Hansson TL. The orthopantomogram, an aid in the diagnosis of temporomandibular joint problems. II The vertical symmetry. J Oral Rehabil 15: 465-71,
                                                                                                                       3. John M, Pullinger AG. Pantomographie - ein diagnostisches Verfahren für knöcherne Veränderungen des Kiefergelenkes? Dtsch Zahnärztl Z 52: 553-7, 1997.
 Fig. 5                                                              Fig. 6                                            4. Könönen M, Kilpinen E. Comparison of three different radiographic methods in screening of temporomandibular joint involvements in patients with psoriatric arthritis. Acta Odont Scand 48:
                                                                                                                       271-7, 1990.
                                                                                                                       5. Lachmann S. Zur Häufigkeit von Kiefergelenkerkrankungen in einer zahnärztlichen Spezialsprechstunde. Eine klinisch-röntgenologische Systematik. In: Abteilung für Röntgendiagnostik in
                                                                                                                       der Klinik für Zahn-, Mund- und Kieferkrankheiten. Hamburg-Eppendorf: Universität Hamburg, 2000. dent, Assistant professor                         Department of Prosthodontics, University of Tübingen         6. Peltola J. Radiographic structural findings in the mandibular condyles of orthodontically treated children and young adults. Thesis. In: Departments of Dental Radiology, Paedodontics and
                                                                                                                       Orthodontics, University of Helsinki. 1995.
bPD Dr. med dent, Assistant professor                     Osianderstr. 2-8, 72076 Tübingen, Germany                    7. Ruf S, Pancherz H. Is orthopantomography reliable for TMJ diagnosis? An experiment on a dry skull. J Orofacial Pain 9: 365-74, 1995. Reprint: Not in File
                                                                                                                       8. Türp JC, Vach W, Strub JR, Harbich K, Alt KW. Erkennung von mandibulären Asymmetrien auf der Panoramaschichtaufnahme. Schweiz Monatsschr Zahnmed 105: 755-9, 1995.
cDr.rer nat, Biometrical statistician                     Requests to: Dr. Stefan Lachmann                             9. Engel E, Seeger P. Intra- und interindividuelle Reliabilität der bildgebenden Kiefergelenksdiagnostik. Eine Studie mit Panoramaschicht- und Magnetresonanztomographischen Aufnahmen
                                                                                                                       von Patienten einer Funktionssprechstunde. Unpublished data, in preparation.
dProf. Dr. med dent, Director                             e-mail: