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Biomedical subjects

W Bauer

Publications and source records attributed to W Bauer.

At least 37 records · Page 2Linked to original sources
PubMed1996

Mandibular incisors, alveolar bone, and symphysis after orthodontic treatment. A retrospective study.

The mandible of a deceased 19-year-old young woman who had been treated with an edgewise appliance was removed during autopsy. The overall tooth movements during the 19 months of treatment were reconstructed (treatment documents) and compared with the macroscopic, radiologic, and micromorphologic findings of the incisor/alveolar bone/symphysis complex of the dry mandible. The initial lateral cephalogram revealed an extremely narrow and high symphysis, with an incisor position straight above the thin bone. During treatment, the incisors had been moved to lingual (lingual root torque) and derotated. Morphologic evaluation of the dry mandible revealed lingual (oral) aspects of the roots reaching some millimeters out of the lingual alveolar bone and largely without cortical plate covering. Lateral dental contact radiographs of any bone/incisor segment showed the sagittal alveolar bone width to be smaller than the labiolingual (orobuccal) diameter of the incisor roots. A comparison of the approximate pretherapeutic alveolar bone height, which was assessed by measuring the distance from the cementoenamel junction to the most coronal margin of any root resorption in scanning electron microscopy, with that of the specimen showed a calculated bone loss on the lingual aspect extending from 2.3 to 6.9 mm. On the labial (buccal) aspect, bone loss was far less pronounced. These results suggest that in the case of a narrow and high symphysis, pronounced sagittal incisor movements and derotation during routine orthodontic treatment with a fixed appliance may be critical and lead to progressive bone loss of lingual and labial cortical plates.

Adult↗
PubMed1996

[Disk displacement of the temporomandibular joint: correlation of magnetic resonance tomography and clinical findings].

PURPOSE: To evaluate the value of magnetic resonance imaging (MRI) in symptomatic patients with different degrees of internal derangement. MATERIAL AND METHODS: We prospectively investigated 117 temporomandibular joints (TMJ) of 59 symptomatic patients and 31 asymptomatic volunteers and correlated this with clinical parameters. RESULTS: There was a positive correlation between the degree of internal derangement and deformity of the disc, maximal mouth opening, signal intensity of the posterior band, thickness of the bilaminar zone, proliferative bony changes, size of the condyle and reduced translation movement of the condyle, which in addition moved upward and backward. Patients most often complained of pain which was dependent on the degree of disc displacement and condylar changes. Clinical parameters were found to be inaccurate in predicting disc displacement. CONCLUSION: Patients with internal derangement of the temporomandibular joint may be asymptomatic. Patients history may give the only pointer to the disorder.

Adult↗
PubMed1996

[Conservative versus surgical therapy of unilateral fractures of the collum mandibulae--anatomic and functional results with special reference to computer-assisted 3-dimensional axiographic registration of condylar paths].

A clinical, radiographic and computer-assisted axiographic follow-up was carried out on 60 patients who had been treated for unilateral subcondylar fractures. These were patients of the Department of oral, maxillofacial and facial plastic surgery of the Medical Faculty of the University of Technology in Aachen, Germany. After surgical reduction of the condyle with fixation by osteosynthesis where results were positive, 27 patients exhibited a shortening of the condyle paths on the side operated on by up to 16.4%. Although conservative therapy produced slighter straightening of the condyle with more or less strongly marked condylar deformations in two-thirds of the cases, functionally more positive results were obtained by markedly slighter limitation of the condyle paths on the traumatized side. These results would appear to indicate operative therapy of unilateral subcondylar fractures in the case of luxation fractures, condylar dislocation in excess of 50 degrees, and in those cases where intermaxillary immobilization is not feasible. In the remaining cases, conservative treatment is preferred, due to it showing functionally more positive results.

Adult↗
PubMed1995

[Findings in the panoramic tomogram in orthodontic patients with functional disorders].

In our study of 107 patients, for whom data derived from clinical functional analysis, axiography and, in part magnet resonance imaging, were present, we were able to show that in routine orthodontic diagnosis the use of panoramic X-ray in the normal course of a general examination of the mandibular joint can also provide important indications of the presence of cranio-mandibular disorders. The panoramic X-ray revealed that in patients with Angle class II and front deep and open bite there were significantly mor changes in the form of the condyles. A definite morphologic finding of a retracted fovea pterygoidea was found frequently in patients with anterior disk replacement with or without reduction. Lastly, the panoramic X-ray showed that a change in form of the condyles, with in some cases a serious arthrosis, occurs significantly most frequent in patients with anterior displacement without reduction.

Adolescent↗
PubMed1995

Computer simulation of occlusal discrepancies resulting from different mounting techniques.

The effect of arbitrary mounting of maxillary casts on occlusal relationships was investigated in this study. Maxillary casts of 31 volunteers were mounted on an articulator by use of two split cast bases. This mounting was done first with the arbitrary face bow and second with a hinge bow. Three reference points were defined and measured on each maxillary cast with a three-dimensional digitizer. The measurements were taken from the arbitrarily mounted cast and from the cast mounted according to the hinge axis. Opening and closing movements that were transferred according to the hinge axis. Opening and closing movements that were transferred from the articulator to the mouth of the patient were simulated by a computer based on measurements of the reference points. The results revealed that the use of an arbitrary face bow causes a deviation of the hinge-axis points from the precise axis of more than 5 mm in 77% of the cases. Resulting occlusal errors depended on the angles between the arbitrary and precise axes and the direction of the axis shifts. The occlusal error is roughly proportional to the shift or tilting of the hinge axis in millimeters or degrees. For a given deviation of the arbitrary and precise axes, the occlusal error is proportional to the record height. For a record height of 2 mm or more, an occlusal error of more than 0.1 mm will occur. An average occlusal error of more than 0.1 mm would most likely lead to the necessity of extensive selective grinding of occlusal discrepancies in the patient's mouth.

Adult↗
PubMed1995

Gingival invagination area after space closure: a histologic study.

The aim of this study was to show the micromorphologic findings (epithelium, connective tissue, bone) in a region of pronounced gingival invagination after space closure by analyzing a maxilla taken in autopsy from a 19-year-old woman who was orthodontically treated. The dental records were also at our disposal. The second left premolar was congenitally absent. This area displayed before therapeutic horizontal bone atrophy. For space closure, the first upper left molar was moved mesially with a fixed appliance. After space closure, pronounced gingival invagination was diagnosed. The lateral segments of the specimen were prepared histologically in the horizontal plane. The microscopic observations revealed deep epithelial proliferation, hyperkeratinization, and one isolated keratin pearl in the connective tissue. Irrespective of location, the broad connective tissue layer showed disparate characteristics. Cell-rich, loose connective tissue with low fiber density were dominant in the subepithelial layer. The epiperiosteal layer displayed multiple tough fibers, some running parallel, some with reticular meshing, permeated with many blood vessels. Very few inflammatory cells were detected in the soft tissue. The bone had been resorbed in the mesiopalatal area of the molar (tooth movement direction) apart from one small isolated bony islet. These observations suggest that inflammatory influences were unlikely for marginal bone loss mesiopalatal to the tooth.

Adult↗