Bernd Koos

Bio: Bernd Koos is an academic researcher from University of Tübingen. The author has contributed to research in topics: Medicine & Craniofacial. The author has an hindex of 14, co-authored 48 publications receiving 669 citations. Previous affiliations of Bernd Koos include University of Kiel.

Precision of an instrumentation-based method of analyzing occlusion and its resulting distribution of forces in the dental arch.

Abstract: In practice, analysis of occlusion is reduced to depicting it with color-marking foils. Precise analysis that incorporates time resolution and plots the distribution of forces within the occlusion is not possible in the everyday clinical situation with the usual methods. T-Scan® III is a computer-assisted dental occlusion analyzer that depicts occlusion by means of pressure-sensitive foils. The aim of our study was to test the accuracy and reliability of this method. The study population comprised 42 subjects (23 male and 19 female, aged 20–30, median age 26 years). The measurements were performed using the TScan® III from Tekscan Inc., South Boston, MA, USA. Six recordings with two foils were made for each subject and a total of 30 masticatory cycles were registered. Statistical analysis referred to the method’s measurement accuracy and reliability, as well as the influence of changing the foil and repositioning the T-Scan® III during the repeated measurements. The percentage distribution of forces per tooth ranged from 0 to 41%. The mean measurement per tooth was 6.9% of the maximum total force exerted. The measurement error was 1%, the 1.96-fold measurement error calculated according to Bland & Altman (accuracy) was 2% and the 2.77-fold measurement error (reliability) was 2.8%. Neither changing the foil nor the repeated measuring had any statistically significant influences on the measured value. The measuring technique studied is superior to the usual methods, particularly with regard to force analysis per tooth. The level of accuracy is acceptable and no interference arising from change of foil or repeated measuring was detected. The method presented in this study therefore enhances routine diagnostics with marking foils. A combination of this method with marking foils would be ideal because the pressure-sensitive foils in this system do not produce any contact markings intraorally. This combination enables the contacts depicted on the computer to be assigned intraorally with even greater precision.

Precision of an Instrumentation-based Method of Analyzing Occlusion and its Resulting Distribution of Forces in the Dental Arch Präzision eines instrumentellen Analyseverfahrens der Okklusion und ihrer resultierenden Kraftverteilung im Zahnbogen

Abstract: Background and Objective: In practice, analysis of occlusion is reduced to depicting it with color-marking foils. Precise analysis that incorporates time resolution and plots the distribution of forces within the occlusion is not possible in the everyday clinical situation with the usual methods. T-Scan® III is a computer-assisted dental occlusion analyzer that depicts occlusion by means of pressure-sensitive foils. The aim of our study was to test the accuracy and reliability of this method. Subjects and Methods: The study population comprised 42 subjects (23 male and 19 female, aged 20–30, median age 26 years). The measurements were performed using the TScan ® III from Tekscan Inc., South Boston, MA, USA. Six recordings with two foils were made for each subject and a total of 30 masticatory cycles were registered. Statistical analysis referred to the method’s measurement accuracy and reliability, as well as the influence of changing the foil and repositioning the T-Scan ® III during the repeated measurements. Results: The percentage distribution of forces per tooth ranged from 0 to 41%. The mean measurement per tooth was 6.9% of the maximum total force exerted. The measurement error was 1%, the 1.96-fold measurement error calculated according to Bland & Altman (accuracy) was 2% and the 2.77-fold measurement error (reliability) was 2.8%. Neither changing the foil nor the repeated measuring had any statistically significant influences on the measured value. Zusammenfassung

Reliability of clinical symptoms in diagnosing temporomandibular joint arthritis in juvenile idiopathic arthritis.

Abstract: Objective. Temporomandibular joint (TMJ) arthritis, commonly considered oligoarthritic/asymptomatic, occurs frequently in children with juvenile idiopathic arthritis (JIA), and gadolinium-enhanced magnetic resonance imaging (Gd-MRI) has proved to be a sensitive diagnostic tool in this context. We compared the reliability of clinical examinations to Gd-MRI results in diagnosing the condition. Methods. Patients with JIA (134 consecutive) underwent routine clinical and Gd-MRI examinations. The clinical items examined were clicking, tenderness (TMJ/adjacent muscles), and mouth-opening capacity. Blinded MRI reading focused on inflammation (synovitis/hypertrophy). After statistical power analysis, the clinical findings for 134 healthy controls were included. Contingency analysis was used to determine the sensitivity, specificity, and frequency of clinical symptoms (JIA/healthy controls); Cohen’s κ was used to establish the interrater reliability. Results. Statistically significant differences were observed between JIA and healthy control groups with regard to the concise screening items (power analysis > 0.95), whereas no differences in mouth-opening capacity were noted. In 80% of the patients with JIA, Gd-MRI revealed signs of TMJ arthritis, with positive correlations between concise screening items and Gd-MRI results. The average specificity was 0.81, but the sensitivity was low, at 0.42. Combining items led to a marked increase in the sensitivity (0.73). There was a high rate of both false-negative and false-positive results (corresponding to clinical underdiagnosis or overdiagnosis of TMJ arthritis). Conclusion. Despite a relatively high specificity, clinical examination alone does not seem sufficiently sensitive to adequately detect TMJ arthritis. Thus, a relatively high number of cases will be missed or overdiagnosed, potentially leading to undertreatment or overtreatment. Gd-MRI may support correct diagnosis, thereby helping to prevent undertreatment or overtreatment.

Toward Establishing a Standardized Magnetic Resonance Imaging Scoring System for Temporomandibular Joints in Juvenile Idiopathic Arthritis.

Abstract: OBJECTIVES: The temporomandibular joints (TMJs) are frequently affected in children with juvenile idiopathic arthritis (JIA). Early detection is challenging, as major variation is present in scoring TMJ pathology on Magnetic Resonance Imaging (MRI). Consensus-driven development and validation of a MRI scoring system for TMJs has important clinical utility in timely improvement of diagnosis, and serving as an outcome measure. We report on a multi-institutional collaboration towards developing a TMJ MRI scoring system for JIA. METHODS: Seven readers independently assessed MRI scans from 21 patients (42 TMJs, age range 6-16y) using three existing MRI scoring systems from American, German, and Swiss institutions. Reliability scores, scoring system definitions and items were discussed among 10 JIA experts through two rounds of Delphi surveys, nominal group voting, and subsequent consensus meetings to create a novel TMJ MRI scoring system. RESULTS: Average-measure intraclass correlation coefficients (avICC) for the total scores of all three scoring systems were highly reliable at 0.96 each. Osteochondral items showed higher reliability than inflammatory items. An additive system was deemed preferable for assessing minor joint changes over time. Eight items were considered sufficiently reliable and/or important for integration into the consensus scoring system: bone marrow edema and enhancement (avICC=0.57-0.61; %SDD=±45-63% prior to re-defining), condylar flattening (0.95-0.96; ±23-28%), effusions (0.85-0.88; ±25-26%), erosions (0.94; ±20%), synovial enhancement and thickening (previously combined; 0.90-0.91; ±33%), and disk abnormalities (0.90; ±19%). CONCLUSION: A novel TMJ MRI scoring system was developed by consensus. Further iterative refinements and reliability testing are warranted in upcoming studies.

Classification of temporomandibular joint erosion, arthritis, and inflammation in patients with juvenile idiopathic arthritis

Abstract: Juvenile idiopathic arthritis is the most common disease in pediatric rheumatology. It is characterized by chronically progressive joint destruction. The temporomandibular joints (TMJs) are involved in up to 87% of patients and may take an asymptomatic course in 69% of cases. Other than contrast-enhanced magnetic resonance imaging (MRI), there are no reliable screening symptoms or non-invasive procedures available to diagnose the inflammation in its acute form. The goal of this study was to establish an imaging-based classification system for TMJ erosion via MRI and cone-beam computed tomography (CBCT) in an effort to improve indication-specific treatment approaches and to facilitate the comparison of findings. A total of 46 patients were included. Contrast-enhanced MRI and CBCT images obtained during treatment by pediatric rheumatologists and orthodontists were available from 23 patients with juvenile idiopathic arthritis. We devised a classification system combining the findings of both imaging techniques based on this patient sample in comparison with CBCT findings from an age- and gender-matched group of 23 non-arthritis patients, taking into consideration the available literature and administration of contrast medium. Our cohort of 46 patients comprised 60% female and 40% male patients with a mean age of 14 years, providing a total of 92 TMJs for evaluation. We were able to apply the findings efficiently and conveniently to this classification system with no relevant interobserver differences. Mild structural abnormalities were noted in 21% of TMJs in the control group, whereas 83% of TMJs in the arthritis group exhibited severe anomalies, including cases of extreme destruction. Age and gender did not affect the degree of destruction significantly. This is the first classification system to link CBCT and MRI with the use of contrast medium. Contrast-enhanced MRI is an internationally recognized technique that permits acute inflammation to be unequivocally diagnosed. Although structural erosion of the TMJs in our arthritis group was generally severe and significant, we were surprised to observe some cases that were clinically asymptomatic.

Temporomandibular joint diagnostics using CBCT

Abstract: The present review will give an update on temporomandibular joint (TMJ) imaging using CBCT. It will focus on diagnostic accuracy and the value of CBCT compared with other imaging modalities for the evaluation of TMJs in different categories of patients; osteoarthritis (OA), juvenile OA, rheumatoid arthritis and related joint diseases, juvenile idiopathic arthritis and other intra-articular conditions. Finally, sections on other aspects of CBCT research related to the TMJ, clinical decision-making and concluding remarks are added. CBCT has emerged as a cost- and dose-effective imaging modality for the diagnostic assessment of a variety of TMJ conditions. The imaging modality has been found to be superior to conventional radiographical examinations as well as MRI in assessment of the TMJ. However, it should be emphasized that the diagnostic information obtained is limited to the morphology of the osseous joint components, cortical bone integrity and subcortical bone destruction/production. For evaluation of soft-tissue abnormalities, MRI is mandatory. There is an obvious need for research on the impact of CBCT examinations on patient outcome.

Temporomandibular Joint Arthritis in Juvenile Idiopathic Arthritis: The Forgotten Joint

Abstract: Purpose of reviewThis review explores the prevalence, clinical and radiographic signs, and treatment of temporomandibular joint arthritis in children with juvenile idiopathic arthritis. Recent findingsTemporomandibular joint arthritis seems to be a more frequent manifestation in patients with juvenile idiopathic arthritis than previously believed, in part due to the paucity of clinical symptoms and poor sensitivity of conventional radiographs used for diagnosis. Antinuclear antibody positivity, early onset of disease, and presence of systemic or polyarticular disease are all risk factors for temporomandibular joint arthritis but may underpredict temporomandibular joint involvement in juvenile idiopathic arthritis. Magnetic resonance imaging enhanced with gadolinium is currently the gold standard in detection of temporomandibular joint arthritis, and treatment with intra-articular corticosteroids has been shown to be effective and safe, with minimal side effects. SummaryGiven the paucity of clinical symptoms in temporomandibular joint arthritis, detection of temporomandibular joint inflammation using contrast-enhanced magnetic resonance imaging is essential for instituting appropriate therapy in a timely fashion. The use of intra-articular corticosteroids holds promise for control of temporomandibular joint inflammation and prevention of associated morbidities.