PubMed Health⌕ Search

Biomedical subjects

D Kubein-Meesenburg

Publications and source records attributed to D Kubein-Meesenburg.

At least 19 recordsLinked to original sources
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↗
PubMed1991

Comparison of 'normal' TMJ-function in Class I, II, and III individuals.

Fifty-seven non-orthodontically treated young adults, judged as either clinically healthy or with only mild symptoms of TMJ-dysfunction, were divided into groups according to their sagittal molar relationship (Class I-, Class II-, and Class III-group). All underwent a standardized clinical and axiographic examination with an axiographic recording device (SAS-SYSTEM). The comparison of the lengths of the axiographical protrusive curves showed significantly higher values in the Class II group than in the Class I (P less than 0.01) and in the Class I group than in the Class III group (P less than 0.001). Analogous differences could be found in clinical protrusive measurements at the incisal point and in lateral excursions. It was concluded that the protrusive condylar movement capacity coincides with the dental sagittal relationship. In opening, significant differences were seen axiographically (Class I v. Class III: P less than 0.001; Class II v. Class III: P less than 0.01), but not clinically. Since axiographic measurements show only condyle translation, but not rotation in contrast to measurements at the incisal point, it can be concluded that the differences in opening are also translatory and not rotational. Measurements of the average change of curvature of axiographic tracings showed significantly less curved protrusive tracings in Class III than in Class I (P less than 0.001) and Class II individuals (P less than 0.01), supporting the concept that in the Class III group condyle movement is restricted to the straight posterior slope of the tubercle.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Positioning control of the upper incisors in orthognathic surgery. Pre-operative planning with the Model Positioning Device and intra-operative application of the Sandwich Splint.

In orthognathic surgery a three-dimensional positioning of the maxilla is possible by means of the Le Fort I osteotomy and subsequent maxillary movement. In treatment planning and at the time of surgery it is very important to achieve an exact positioning of the upper incisors in relation to the upper lip and the rest of the skull. The Model Positioning Device described here allows three-dimensional positioning of the upper incisors in one- or two-jaw surgery. The reference plane is the upper surface of the upper part of a semi-individually adjustable articulator. The application of the Sandwich Splint enables the three-dimensional positioning of the maxilla in relation to the rest of the skull. The Sandwich Splint ensures that the vertical position of the mandible in relation to the rest of the skull above the osteotomy plane is exactly reproducible in the pre- and post-operative situation in both model surgery and at time of surgery. To this mandibular position the maxilla is positioned in three dimensions, as preplanned. The vertical dimension, which is identically reproducible before and after surgery is measured with a caliper. After surgery the mandible can be rotated into the planned new intercuspidation.

Calibration↗
PubMed1991

Elements of a general theory of joints. 5. Basic mechanics of the knee.

In the sagittal plane the interplay of the knee joints, the patellofemoral and the tibiofemoral joint, are depicted as a closed kinematic chain consisting of 3 dimeric link chains. Kinematically the system is without constraint and possesses 3 (abstract) degrees of freedom. Only the application of external forces fixes the single dimeric link chains in mechanically stable positions and thus determines the momentary functional state of the knee. Without external loads the single links can snarl up like those of a bike's chain. The crucial ligaments play a minor role for knee bending. A qualitative analysis of the force distribution within the knee is presented. In the frontal plane the tibiofemoral joint represents a linkquadrangle with positive drive (one abstract degree of freedom) which also becomes mechanically stable by external compressive forces.

Biomechanical Phenomena↗
PubMed1991

Elements of a general theory of joints. 6. General kinematical structure of mandibular movements.

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.

Humans↗
PubMed1991

[Structural arrangement of mandibular neuromuscular guided drive systems].

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.

Biomechanical Phenomena↗
PubMed1991

[Control cycles of mandibular movements as a "slow-reflex" model].

The neuromuscular gearing of mandibular movements is of complex nature. In this Context of a feedback system peripherical afferent stimuli represent the input, where as the efferent motoric stimuli the output. The pyramidal, extrapyramidal system and the influence of the cerebellum is discussed. The mandibular movement follows a slow reflex pattern.

Afferent Pathways↗
PubMed1991

[Posterior guidance of the mandible as a neuromuscular assigned dimeric joint chain].

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.

Biomechanical Phenomena↗
PubMed1991

[The general even mandibular movements as couple movements in neuromuscular guided mechanism].

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.

Biomechanical Phenomena↗
PubMed1991

[Arrangement of neuromuscular movement cycles of free mandibular movements following Le Fort I-operations].

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.

Adult↗
PubMed1991

Elements of a general theory of joints. 4. Coupled joints as simple gear systems.

In the present article the relative motion in the horizontal plane of 2 adjacent lumbar vertebrae (axial rotation of the lumbar spine) and the cranial border movement of the mandible parallel to the vertical-sagittal plane are examined. The interplay of joints is depicted onto the function of a gear system with positive drive. The limits of this projection are described.

Humans↗