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Biomedical subjects

D Kubein-Meesenburg

Publications and source records attributed to D Kubein-Meesenburg.

At least 19 recordsLinked to original sources
PubMed2001

Functional improvement of the mandibular neuromuscular guidance by orthodontic-surgical treatment.

The primary aim of the study was to reveal whether adult patients with skeletal mandibular retrognathism combined with a dental Class II relationship without craniomandibular pain show a characteristic pattern of free mandibular movements compared to patients with a Class I skeletal and dental morphology. The secondary aim was to investigate whether these characteristic structures are subject to change following combined orthodontic-surgical treatment. Free mandibular movements were measured with an ultrasound device and analyzed with computer software developed by the authors. In all patients examined, 2 maxillarily and mandibularly fixed axes were found. These axes have no direct relation to the temporomandibular joints, are positioned above and anterior to the joints and maintain a constant distance. This gear system is referred to as a neuromuscularly determined dimeric link chain. The position of the mandible is defined by the rotational angle mu and the inclination angle alpha around the axes of the dimeric link chain. This dimeric link chain of free movements of patients with Class I skeletal and dental relationship functions according to the principle of least action: The angular velocities around the 2 axes show a constant ratio within the different segments of motion, and in the mu-alpha diagrams the segments of mandibular movements are represented by straight lines, the shortest paths between 2 positions. Individual cases and statistical data show that the structure of mandibular movements of patients with skeletal mandibular retrognathism combines with a dental Class II relationship without craniomadibular pain differs significantly from that of patients with Class I alignment. Mandibular retrognathism and a Class II relationship are accompanied by marked coordination disturbances in the rotary movements around the maxillary and mandibular neuromuscular axes. Following orthodontic-surgical treatment to restore ideal alignment of the occlusal, articular, and skeletal structures, the patients showed a similar pattern in the structure of mandibular movements to that of patients with Class I sketal and dental relationships. Thus, combined orthodontic-surgical treatment leads to measurable functional hamonization not only of the skeletal and dental structures but also of the neuromuscular guidance system.

Adult↗
PubMed2000

Bending vibrations of the femur and the oscillatory behavior of a cemented femoral hip endoprosthesis.

The paper presents a novel method for recording amplitude and phase of 6D-vibrations of a spatial pendulum over a wide frequency range (10 Hz up to 20 kHz). The six degrees of freedom of the pendulum mass were monitored by three electrodynamic stereo pickups. At rest, the tips of the needles and the pendulum's center of mass defined the reference system with respect to which the oscillations of the mass were recorded in terms of their amplitudes and phases. Its small dimensions, constant transfer characteristics, linearity, high dynamics, and virtual lack of reaction onto the moving system over the entire frequency range provided the advantages of the measuring system. This method was used to analyze the spatial 6D-vibrations of the head of a cemented femoral hip endoprosthesis when the femur was stimulated to bending vibrations. The head of the prosthesis carried out axial rotational vibrations at every frequency used to stimulate the femur. The amplitudes of the axial rotations of the cortical bone were small in comparison to the ones of the prosthesis head, indicating that axial rotational vibrations following femur bending vibrations mainly stressed the spongiosa and the cement layer. This was observed over the entire frequency range, including at the low frequencies relevant for gait. Over the low-frequency range, as well as at some of the higher resonance frequencies, stationary instantaneous helical axes characterized the vibrations. The measurements suggest the mechanism that the interface "implant-bone" may already be stressed by axial torsional loads when the femur is loaded by bending impacts that are known to occur during walking.

Biomechanical Phenomena↗
PubMed2000

Harmonization of free mandibular movements by orthodontic-surgical treatment of patients with mandibular retrognathism.

The aim of the following study was to investigate whether adult patients with mandibular retrognathism combined with a dental Class II relationship without craniomandibular pain show a characteristic structure of free mandibular movements caused by the neuromuscular system compared to patients with neutral skeletal and dental relationships. The authors also analyzed whether these characteristic structures changed following orthodontic-surgical treatment. To record the spatial movement of the mandible, an ultrasound measurement system was chosen and diagnostic software was developed for computer analysis of the recorded movements based on physical and biomechanical concepts. Clinically complaint-free, adult patients with mandibular retrognathism and distal bite exhibited a structure of mandibular movement that was markedly displaced as compared to patients with neutral skeletal and dental alignment. After completion of orthodontic and surgical treatment, it is apparent that the entire neuromuscular system of movement was transformed from one characterized by massive dysco-ordination to one of harmonized, coordinated motion, as is seen in patients with nonpathologic, neutral relation.

Adolescent↗
PubMed1999

[Results of the application of the Goettingen concept for three-dimensional repositioning of the maxilla in orthognathic surgery].

During orthodontic-surgical treatment, a three-dimensional repositioning of the maxilla is needed after Le Fort I osteotomy. The preoperatively planned and desired position of the maxilla could often not be implemented satisfactorily in the surgical procedure. Several authors described deviations of up to 15 mm in the vertical dimension and 5 mm in the sagittal dimension between the planned and the achieved position. In order to avoid this error, the "model-repositioning instrument" for three-dimensionally controlled cast surgery and the "three-dimensional doublesplint method" in combination with a surgical facebow for actual surgery were developed. A group of 20 adult patients with severe dentofacial deformities were treated according to the Goettingen concept for combined orthodontic-surgical treatment with condylar position control with a surgical facebow. For each patient the position of three marked reference points on the maxillary dental arch under pre- and postoperative conditions was evaluated using superimposed tracings of lateral radiographs. These values were compared with the performed movements of the dental maxillary arch during cast surgery. It can be shown that with the new developments the planned position of the maxillary dental arch could be transferred from cast surgery to actual surgery with an accuracy of +/- 1 mm vertically and sagittally.

Adult↗
PubMed1999

Functional conditions of the mandible: theory and physiology.

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.

Biomechanical Phenomena↗
PubMed1999

Masticatory musculature under altered occlusal relationships--a model study with experimental animals.

In a study with experimental animals, the occlusal relationships of male Wistar rats were altered by the bilateral extraction of lateral teeth; the bolus function was eliminated by feeding a soft diet. Both steps led to relief of strain on the temporomandibular joint and thus also in the muscular system itself. The masticatory muscles adapted to the new experimental conditions. We observed a reduction in muscle dry weight and a shift in muscle fiber composition in favour of the IIb fibers, which indicates that less masticatory strength was required. Adaptation thus occurred equally on the macroscopic and microscopic levels.

Acclimatization↗
PubMed1999

Functional condition of the mandible: physical structures of free mandibular movement.

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.

Biomechanical Phenomena↗
PubMed1999

Alteration of the functional condition of the mandible during clinical treatment.

Free mandibular movements and their neuromuscular guidance were measured with an ultrasonic device and analyzed with computer software developed by the authors. In all patients examined, we found maxillarly- and mandibularly-fixed axes which maintain a constant distance. This guidance system is named a neuromuscularly-determined dimeric link chain. The position of the mandible is defined by the 2 rotational angles (mu, alpha) around the axes of the dimeric link chain. This dimeric link chain of free movements normally functions according to the principle of least action. The angular velocities around the 2 axes show a constant ratio during the different segments of motion. In the mu-alpha-diagrams, the segments of movements of the mandible are represented by straight lines, the shortest path between 2 positions. Individual cases and statistical data show that the structure of mandibular movements of patients with skeletal mandibular retrognathism combined with dental class-II-relationship without craniomandibular pain significantly differs from the structure in patients with neutral alignment. Mandibular retrognathism and class-II-relationship are accompanied by marked coordination disturbances of rotations around the maxillary and mandibular neuromuscular axes. Following orthodontic-surgical treatment that restored ideal alignment of the occlusal, articular, and skeletal structures, the patients examined showed a similar pattern in the structure of mandibular movements to that of patients with neutral skeletal and dental relationships. Thus, combined orthodontic-surgical treatment leads to measurable functional harmonization not only of the skeletal and dental structures, but also of the neuromuscular guidance system.

Adult↗
PubMed1999

Interpretation of the vertical and longitudinal growth of the human skull.

Our model describes asymptotic growth as a time-dependent process which expresses a quantitative change in individual morphological factors. The development and growth of the face are intimately connected with the cranial base, which undergoes only minor changes between the ages of 0 to 25 years. The difference in growth of the neuro- and viscerocranium is evident in that the dimensions and angles of the viscerocranium undergo greater changes than those of the neurocranium. The anterior cranial base lengthens until the end of normal growth via bone apposition at the nasion. This elongates the cranial base. The nasion influences the sagittal maxillary relationships. The posterior cranial base shows a constant growth rate up to ca. 15 years of age. The face and dentition develop along the nasion-gonion and sella-gnathion distance, which demonstrates the greatest absolute growth rate. During growth, the viscerocranium increases principally in height.

Adolescent↗
PubMed1998

Techniques for achieving three-dimensional positioning of the maxilla applied in conjunction with the Göttingen concept.

Three-dimensional repositioning of the maxilla is possible after Le Fort I osteotomy. However, the preoperatively planned and desired position of the maxillary dental arch often cannot be sufficiently achieved during actual surgery, and deviations in the sagittal and vertical dimensions are common. To reduce these errors, the model-repositioning instrument was developed for model surgery in conjunction with the Göttingen concept for orthodontic-surgical treatment with condylar position control. This instrument allows a controlled three-dimensional positioning of jaw segments with three reference points directly on the teeth. The three-dimensional double-splint method combined with a surgical facebow was developed for a controlled three-dimensional positioning of the maxilla during surgery. This instrument and method were applied during treatment of 20 adult patients, and the position of the maxilla before and after surgery was analyzed. It was found that the planned position of the maxillary dental arch could be transferred from model surgery to actual surgery with an accuracy of +/- 1 mm sagittally and vertically. Thus, the application of the Göttingen concept for three-dimensional positioning of the maxilla results in an improvement of accuracy compared with other methods. Furthermore, use of these procedures is easier and less time-consuming during model and actual surgery than are other procedures.

Adult↗
PubMed1992

Changes in mandibular mobility after different procedures of orthognathic surgery.

A prospective study including 63 adult Class II and Class III patients was carried out in order to examine short- and long-term effects of four different treatment methods on mandibular mobility. The patients were treated either (Group A, control-group) orthodontically alone or (Group B) by a LeFort I-osteotomy, a (Group C) mandibular advancement or (Group D) a two-jaw surgery/mandibular set-back. In the surgery-groups (B, C, and D) maximum opening, protrusion and lateral excursions were measured 2 days pre-operatively (T0), and 3, 8, 14.5, and 25.5 months post-operatively (T1-T4). In the control-group (A) at T0 and T4 was measured, only. Significantly differing effects of the four treatment methods on mandibular mobility were detected. (A) Orthodontic treatment alone, (B) maxillary advancement by LeFort I osteotomy, and (D) two-jaw surgery/mandibular set-back osteotomy did not influence mandibular mobility permanently. Temporary decreases in groups B and D (P less than or equal to 0.05) were observed, however. In contrast, permanent reductions after (C) mandibular advancement took place (P less than or equal to 0.001). Longitudinal survey showed that in all surgery groups recoveries were limited to a short period of 3-14.5 months, depending on the movement. Surprisingly, a closer similarity between the LeFort-I group (B) and the two-jaw surgery group (D), rather than between the sagittal-split groups (C and D), was seen indicating that the problem of reduced mobility after orthognathic surgery can be limited to Class II therapy. It was concluded that in Class III therapy, the application of rigid fixation in combination with a method of maintaining condyle-position, thereby dispensing with maxillomandibular fixation, prevents permanent reductions in mobility and guarantees a rapid recovery to pre-operative mobility levels.

Adolescent↗
PubMed1992

Application of the condylar positioning appliance in mandibular sagittal split osteotomies with rigid skeletal fixation.

During orthodontic-surgical treatment of dentofacial deformities, centric relation of the mandibular condylar head to the fossa articularis must be maintained. Intraoperative application of the condylar positioning appliance, in combination with different surgical splints, allows three-dimensional adjustment of the jaw segments. The condylar positioning appliance can be used in osteotomies of the mandible alone, in isolated Le Fort I osteotomies, or in simultaneous osteotomies of the maxilla and mandible.

Bone Plates↗
PubMed1992

Elements of a general theory of joints. 7. Mechanical structures of the relative motion of adjacent vertebrae.

The mechanical structure of the relative motion of adjacent vertebrae is given by the interplay of the artt. zygapophysiales, the intervertebral disk and the ligaments, respectively. This structure will be described in the 3 main functional planes. Horizontal plane (parallel to the disk): The two artt. zygapophysiales structurally represent a force locked, kinematically contrained four-bar-chain (link quadrangle). It possesses but one degree of freedom. The intervertebral disk does not influence, therefore, the kinematic structure but the extent of the motion. Frontal-coronal plane: The four-bar-chain of the frontal plane seems to be inflexible. Lateral bending is only possible combined with a right or left handed axial rotation. Vertical-sagittal plane: The artt. zygapophysiales work as a single dimeric link chain. The momentary rotational center lies on the common normal of the two articular surfaces. Its position upon that is determined by the geometry of the applied force system according to the "reciprocal theorem of synarthroses". Solely one direction of translation is possible. A translation perpendicular to the intervertebral disk is impossible in the cervical and thoracic region.

Biomechanical Phenomena↗
PubMed1991

[The importance and technic of temporomandibular joint positioning in the sagittal splitting of the mandible].

The rigid fixation of segments in orthognathic surgery offers the advantage of avoiding long-term rigid intermaxillary immobilisation and reducing in-hospital treatment time and the entire clinical course. Nevertheless, it is difficult or even impossible to correct postoperatively osteotomy segments. Therefore the exact transfer of the preoperative position of the condyle to the postoperative situation is essential for the use of this technique and its use in bimaxillary surgery. The presented technique, which has been successful in the cooperation of orthodontics and orthognathic surgery for many years, is a prerequisite for an up-to-date treatment of dentofacial anomalies.

Dental Articulators↗
PubMed1991

[Changes in opening mobility due to surgical advancement of the mandible].

A prospective follow-up study of 21 class-II patients, who were treated with a combination of orthodontics and orthognathic surgery, revealed typical postoperative changes in opening mobility. Their characteristics were: a strong initial loss of mobility and a regeneration period of about one year. Because the increase of mobility could not completely compensate for the initial reduction, a significantly reduced mobility was detected 25.5 months postoperatively. This reduction was considered as clinically acceptable, since former studies showed more unfavorable developments. However, individual changes of mobility are worth of notice. The comparison of condylar-related axiographic measurements with incisal measurements showed that the reduction of the length of axiographic tracings was more prominent than the "clinical-effective" reduction of the combined condylar rotation and translation.

Adult↗
PubMed1991

[Longitudinal changes in the acoustic temporomandibular symptoms due to different procedures of orthognathic surgery].

A longitudinal study of TMJ sounds prior to and after combined orthodontic-orthognathic surgical procedures was carried out. The relative frequency of such sounds two days prior to operation (T0) and three months (T1), eight months (T2), 14.5 months (T3), and 25.5 months (T4) postoperatively remained--treatment-independently--largely unchanged. Chances in frequency between T0 and T4 showed only a nonsignificant tendency to differ in comparison with changes seen after orthodontic treatment (A) only. An analysis of individual changes revealed that after Le Fort I osteotomy (B) and bimaxillary procedures/posterior mandibular repositioning (D), no change in the preoperative sounds is to be expected. In contrast, following mandibular advancement (C) TMJ sounds first disappeared, in particular in the period immediately following operation (T0-T1), but also subsequently reappeared. The difference vis-a-vis group B (Le Fort I osteotomies) was statistically significant (group B vs. group C: p less than or equal to 0.01.

Auscultation↗