K M Thieme

Universitätsmedizin Göttingen, Göttingen, Lower Saxony, Germany

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Publications (19)24.04 Total impact

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    ABSTRACT: Due to its complexity, there is currently an incomplete understanding of temporomandibular joint (TMJ) function, especially in relation to the morphological interplay of the condyle and the disc as well as the disc, the Os temporale and the lateral pterygoid muscle. This also holds true for synovial flow and synovial pumps, the existence of which we postulate and for which we present a theory of their mechanism. In view of the complexity of mandibular movements and the morphology and function of the TMJ, we need to know how precisely a reconstruction of the TMJ, if necessary, must be adapted to nature. An analysis of the morphology of the functional states of the mandible, as well as the synovial pump system, should at least provide a basis for moulding reconstructions.
    Annals of anatomy = Anatomischer Anzeiger: official organ of the Anatomische Gesellschaft 10/2011; 194(2):200-7. · 1.96 Impact Factor
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    ABSTRACT: One way of determining the direction of growth of the mandible is to consider the temporomandibular joint and movement of the mandible as a four-joint gear system, regarding growth then as an extension of the gear system. Our aim was to examine any correlations between the type of biomechanical growth extension and change in the maxilomandibular relation after Class II therapy. A total of 130 lateral cephalograms-before and after orthodontic treatment-were available from 65 adolescent class II patients with open bite or deep bite. The two lateral cephalograms from each patient were superimposed on the occlusal plane. Cephalometric values and the vertical base point deviation were determined from biomechanical analyses, together with three distances and three angles. No correlation between the cephalometric data and distances or angles were observed. Although there were no significant differences in the distances, we did note significant differences in all three angles (p < 0.05). If gear system extension during growth is considered, this can be interpreted as meaning that the occlusal plane of those patients with an initially open bite dropped during treatment, but that it rose in patients with an initially deep bite.
    Fortschritte der Kieferorthopädie 10/2011; 72(5):358-70. · 0.89 Impact Factor
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    ABSTRACT: The aim of the study was to establish whether juveniles with a Class II malocclusion change the neuromuscular control of mandibular movements during the course of orthodontic treatment with removable functional appliances (RFAs). Neuromuscular control can be indirectly evaluated by recording cyclic planar mandibular movements which were freely carried out by the patients (28 girls, 14 boys, aged 11.1 ± 1.1 years at the start of treatment) and measured with an ultrasonic device before, during, and after Class II functional appliance therapy, with either an activator or a bite jumping plate. The cyclic movements represented simultaneous rotations of the mandible around a maxillary and mandibular fixed axis (MFHA) and could be characterized by μ(α)-diagrams (μ = swing angle of MFHA, α = mouth opening angle) and path length (L) of the MFHA. The μ(α)-diagrams clearly divided into four parts: movement representing protrusion, mouth opening, and two parts of backward closing as known from Posselt diagrams. Parameters from the Posselt and μ(α)-diagrams were checked by one-factor analysis of variance on a 5 per cent significance level for group dependency. For one-third of the patients investigated, no significant changes were seen in any parameter pre- or post-therapy. However, patients showing an initially large mouth opening capacity or a very short condylar path changed their neuromuscular control to that of Class I subjects. Analysis of μ(α)-diagrams provides the possibility of assessing changes in the neuromuscular control of the mandible during Class II treatment.
    The European Journal of Orthodontics 01/2011; 33(6):628-35. · 1.08 Impact Factor
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    ABSTRACT: The motion patterns of mandibular points were recorded in vivo in closed, free movements of the mandible parallel to the sagittal-vertical plane. The points ran along loops which were valued by their area and length. All points whose loops included the same area under regarding the sense of circulation formed a straight line. Lines belonging to different areas were parallel. When the absolute areas of the oops were plotted for particular points a hollow depression with two minima resulted. The point that showed the lowest minimum in the depression corresponded to the position of the neuromuscular mandibular axis of rotation. The points running along equal loop lengths formed elliptical lines with a minimum below the condyle. The lines of constant loop area and loop length were overlaid with lateral radiographs, to match the patterns of motion with anatomical structures. The mandibular axis of rotation lay mostly cranial anterior of the condyle whereas the point with the shortest path lay mainly below this axis point, inside the bony structures. The row of teeth in the maxilla was found to be located below the line of minimal loop lengths. The cervical spine was arranged along the depression of the minimal absolute areas.
    Journal of physiology and pharmacology: an official journal of the Polish Physiological Society 12/2008; 59 Suppl 5:75-80. · 2.48 Impact Factor
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    ABSTRACT: Morphological parameters of the temporomandibular joint (TMJ) of Cercopithecus mona were analyzed by sagittal medial/lateral slicing of the entire joint. The slice contours of the osseous structures of the joint surfaces were approximated by circles. In this manner, the main parameter of the protrusive cranial border guidance, the protrusive dimeric Link chain (DLC), could be measured. In each joint, all slices yielded protrusive DLCs which were nearly parallel to each other. In medial/lateral direction all parts of the joints participate in force transmission in initial protrusive cranial border function.
    Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(4):336-8. · 1.96 Impact Factor
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    ABSTRACT: The primary aim of the study was to reveal whether the free opening movement of the mandible can be determined by only 2 rotational axes as suggested in recent literature. For this purpose, the free opening movement of the mandible was registered in 20 asymptomatic patients using an ultrasonic measuring system. Subsequently, the locations of the instantaneous centers of rotation (ICR) were determined directly from the raw data. In a second approach, the same data were used to construct a mandibular and maxillar rotational axis according to the dimeric link chain (DLC) concept. On the basis of the angular velocities around these 2 axes, the positions of the ICR were calculated in the sagittal-vertical plane. Calculating the ICR by the DLC method provides similar results to that of the conventional approaches. It can be concluded that the DLC method is a valid approach and that considering the planar mandibular movement as a movement with 2 degrees of freedom is justified.
    Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(4):390-2. · 1.96 Impact Factor
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    ABSTRACT: Examinations of the curvature morphology of the temporomandibular joints (TMJs) in macerated human skulls yielded that in initial protrusive cranial border motion, parts of the condylar articulating surfaces are only functional under force transmission. These areas were found on the lateral-central side of the condyle. In contrast to the Cercopithecus mona, a monkey species, the human TMJ apparently possesses a distinctly higher spatial performance range.
    Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(4):339-41. · 1.96 Impact Factor
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    ABSTRACT: For the physiological intact stomatognathic system, the three main functional states (occlusat articular functions, free mandibular movements, and ideal bolus function) were biomechanically discussed concerning the structure of movement, rolling-gliding characteristics, and force transfer in the temporomandibular joint (TMJ). In all three cases, rolling is not possible in the TMJ since the instantaneous rotational axis is positioned outside of the joint-rolling is not necessary because the TMJ is not loaded by appreciable forces. In the aged stomatognathic system with a lost discus and considerable Loads in the TMJ, however, the attrition of the joint is eased by rolling movement at the articulating surfaces. The destruction of the discus can be seen as a physiological adaptation which brings back the joint to an original odontogen condition.
    Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(4):393-6. · 1.96 Impact Factor
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    ABSTRACT: In former works, we had proved that test persons with sound temporomandibular joints (TMJs) used a mandibularly fixed hinge axis (MFHA) and were able to pilot the mandible by solely two kinematical degrees of freedom. We wondered if we could evaluate the MFHA the same way for patients who had problems with their TMJs. Actually, the MFHA could be determined likewise. The results could provide information on the reason for the distortion of the movement of the TMJs, which cannot be yielded by X-ray radiographs.
    Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(4):384-6. · 1.96 Impact Factor
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    ABSTRACT: The motion patterns of mandibular points were recorded in vivo in closed free movements of the mandible in the sagittal-vertical plane. The points ran along closed loops, which were evaluated by their area and length. All points whose loops showed areas of the same size regarding the sense of circulation formed straight lines. When the absolute area of the loops was taken into account, a valley with two minima was found in the function "absolute area versus position of the point", the point which showed the deepest minimum tallied with the position of the neuromuscular mandibular rotation axis. The points with loop lengths of same size formed elliptical lines, the perimeter of which was minimal for a point below the condyle. Morphological relations: the row of teeth in the upper jaw was found to be located below the line of minimal path lengths on the straight lines with constant areas, and the cervical spine was found to be arranged along the valley of the minimal absolute areas where the path lengths have their maximum.
    Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(4):387-9. · 1.96 Impact Factor
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    ABSTRACT: The subject of this study was to analyse how functional parameters of stomatognathic systems are influenced by growth. For this purpose, two cephalometric radiographs of 65 patients with class-II-relation treated with functional appliances were superimposed on the occlusal plane. The two patient groups consisted of 32 open bite and 33 deep bite cases. The direction of the condylar growth significantly differed for both cases. Nevertheless the hypothesis could be confirmed that the original functional structure was hardly affected by growth.
    Annals of Anatomy - Anatomischer Anzeiger 02/2007; 189(4):404-6. · 1.96 Impact Factor
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    ABSTRACT: Starting with the physical definition of the concept "mobile hinge axis", which only allows 2 degrees of freedom for planar mandibular movement, it will be shown that the hinge axis of the temporomandibular joint cannot be found with a small mouth-opening rotation, as is usual but erroneous. By recording cyclic mandibular movements with a measuring system which itself possesses 6 degrees of freedom, the mobile hinge axis can be found. However, there are patients which do not use a mobile hinge axis, which is indicative of latent functional disturbances of the neuromuscular system.
    Annals of Anatomy - Anatomischer Anzeiger 02/1999; 181(1):41-4. · 1.96 Impact Factor
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    ABSTRACT: The functional conditions of the mandible are differentiated according to the number of kinematic degrees of freedom assigned to each mandibular movement. One degree of freedom: pro- and retrusive occlusal border movement. The interplay of the TMJs with the occluding teeth determines a compulsory course which corresponds to a 4-bar-chain guidance. 2 degrees of freedom: free sagittal mouth movement without tooth contact. Using graphic recordings of cyclic mandibular movements, the mobile hinge axis is identified as a mandibularly fixed line which is not directly categorized as a part of an anatomical structure. In the maxillary coordinate system, its movement describes a cylinder; sagittally, it describes a circle. The mandibular positions are clearly identifiable with 2 angles. The in vivo measurements show that neuromuscularly healthy systems supply the mandible with anticipatory guidance. 3 degrees of freedom: bolus function. The articular space in the TMJ is utilized.
    Annals of Anatomy - Anatomischer Anzeiger 02/1999; 181(1):27-32. · 1.96 Impact Factor
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    ABSTRACT: The manifold mandibular movements of oral aperture can be modelled by movements of couples in neuromuscular gear systems. These systems consist of the dimeric link chain of the neuromuscular hinge axis (rocking arm) and a neuromuscularly enforced cyclic trajectory of a well-defined point of the mandible. The neuromuscular hinge axis is the common constant of all gear systems whereas the position of the cyclic trajectory at the fixed plane (maxilla) is closely related to the specific path of the entire rigid body mandible. The presented theory is inferred by measurements of the mandible's movement that take all six degrees of freedom into account.
    Deutsche Stomatologie (Berlin, Germany: 1990) 02/1991; 41(9):332-6.
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    ABSTRACT: Measurements of the mandible's movements which take its six degrees of freedom into account show that the conventional concept of a condylar hinge axis does not hold: on principle the structure of motion of the condylar hinge axis is not different from that of the incisal edge. The spaces of movement which are related to the condylar hinge axis and the incisal edge are factually enforced by a hinge axis of the neuromuscular system. This neuromuscular hinge axis cannot directly be related to anatomical structures although in the sagittal-vertical plane it reduces the number of the degrees of freedom from three to two.
    Deutsche Stomatologie (Berlin, Germany: 1990) 02/1991; 41(8):279-83.
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    ABSTRACT: In orthognathic surgery the Le Fort I osteotomy changes the structure of motion of the mandible. This structure and its changes could reliably and quantitatively be described if it was evaluated by a projection of the mandibular movement upon a couple's movement in a gearing system. The comparison of Le Fort I cases with orthodontically treated class-I-cases shows significant differences.
    Deutsche Stomatologie (Berlin, Germany: 1990) 02/1991; 41(11):420-3.
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    ABSTRACT: The free movements of mandibular, oral apertures can be related to the couples' movements of neuromuscular throttle cranks which reveal a common specific property: a double dead position of the mandible (couple). As the neuromuscular system uses the same cyclic path of a well-defined mandibular point for the opening and the closing process of a specific mandibular movement, the mandible can follow the same or two different trajectories although the positive drive works on. The different movements of oral aperture are related to the geometrical positions of the cranks at the fixed plane. Geometrical properties and measures of the gear systems of eleven class-I-patients are reported and discussed.
    Deutsche Stomatologie (Berlin, Germany: 1990) 02/1991; 41(10):383-5.
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    ABSTRACT: Movements of the mandible are recorded in vivo by a measuring system (MT 1602) that takes all 6 degrees of freedom of a rigid body into account. Class-I-patients were asked to move their mandible in the sagittal-vertical plane. The evaluation of the measurements yields an almost plane mandibular movement that only uses 2 degrees of freedom although a general plane movement normally possesses 3 degrees and although the human temporomandibular joint (TMJ) has a certain space of motion. This quantitative reduction of the degrees of freedom by one is produced by a neuro-muscularly guided dimeric link chain that cannot directly be related to anatomical landmarks. The diverse types of mandibular motion of a sound patient differ in the constant ratio of the angular velocities around the 2 axes of the dimeric link chain. Therefore, the paths of the individual mandibular points are epicycloids or hypocycloids. Patients with disorders of the TMJ and the neuromuscular feedback system do no longer show this constancy of the angular velocities' ratio. Besides that, we theoretically derive and empirically prove the fact that common axiographs do not record the "path of the hinge axis" of the TMJ, on principle. In this context we discuss some--in dentistry and anatomy widespread--fundamental misconceptions of the rigid body's kinematics.
    Anatomischer Anzeiger 02/1991; 173(5):249-64.
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