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Biomedical subjects

W Engelke

Publications and source records attributed to W Engelke.

At least 19 recordsLinked to original sources
PubMed1992

[The importance of electromagnetic articulography in studying tongue motor function in the framework of an orthodontic diagnosis].

Objective data are required for assessing the influence of movements of the tongue on the position of the teeth. Electromagnetic articulography (EMA) makes it possible to track movements of the tongue using the principle of inductive distance measurement. A helmet made of light but robust acrylic material serves as a carrier for three transmitter coils; these latter are located in front of the forehead, in front of the chin, and at the back of the neck. Receiver coils are fixed to the tip of the tongue and at various points on the dorsum of the tongue. The distance between the receiver coils and the transmitter coils is calculated in real time by means of a personal computer. The movement trajectories are displayed on the computer screen in different colors in X-Y coordinates. The movements of the tongue are recorded in patients with correctly positioned front teeth and compared with those in patients with a frontal open bite. The significance of electromagnetic articulography for dental research and functional treatment is demonstrated.

Adolescent↗
PubMed1992

An experimental study of new diagnostic methods for the examination of osseous lesions in the temporomandibular joint.

Digital subtraction radiography, tomosynthesis, bone uptake of radionuclide, and arthroscopy were evaluated for detection and quantification of bony lesions induced unilaterally in the condyles of six dogs. A stereotaxic head-holder facilitated acquisition of reproducible radiographs suitable for subtraction and for circular tomosynthesis. Bone uptake of technetium-99m methylene diphosphonate was measured with a hand-held collimated miniature detector. Arthroscopy was performed with an arthroscope of 2.4 mm diameter. Bone defect mass determined by subtraction radiography correlated highly (r = 0.92, p less than 0.001) with the calcium content of removed bone measured by atomic spectroscopy. Both subtraction radiography and tomosynthesis indicated reshaping of the condyle into a more anterior position over a 10-week follow-up period. Radionuclide uptake was significantly elevated (p less than 0.04) from 2 to 10 weeks after surgery and correlated (r = 0.73, p less than 0.05) with regained bone mass measured by subtraction radiography. Arthroscopy revealed progressive degeneration of cartilage with denudation in the fossa. Both radiographic techniques demonstrated the lesions and bone remodeling, but only subtraction provided quantitative results. Radionuclide uptake predicted quantitatively future bone mass changes, and arthroscopy revealed cartilage and soft tissue status not otherwise observable.

Animals↗
PubMed1992

[The follow-up of the orthodontic treatment of facial cleft patients with the Göttingen computer-supported documentation system].

The care of patients with cleft lip, alveolus, and palate demands supervision of the development and progress over a long period of time. It also requires a standardized and systematic basic documentation. In our cleft center the documentation is summarized on one sheet of paper with DIN-A4 formation (297 x 210 mm). The use of electronic data processing improves the documentation. The storage of general and medical data has been supplemented by a personal computer system, PC-System. Five years after developing of this computer aided documentation system several patients are shown as examples for the application of this system for longterm control patients with cleft lip, alveolus, and palate.

Child↗
PubMed1991

Assessment of bone remodeling in the temporomandibular joint by serial uptake measurement of technetium 99m-labeled methylene diphosphonate with a cadmium telluride probe.

Regional uptake of technetium 99m-labeled methylene diphosphonate was measured serially over time to follow the healing course of surgically generated lesions, induced unilaterally in the condyles of beagles. A small portable cadmium telluride probe was used for radiation detection, with and without a gold collimator attached. Radioactivity was measured at six periarticular sites on both the operated and the contralateral control sides and expressed as a ratio with respect to a reference site over the sagittal suture. The use of a collimator was crucial to separate the activity associated with bone mineralization in the condylar head from that arising in the adjoining bones. The uptake in the condylar region increased 2 weeks after surgery and remained at a constant level above the presurgery baseline (p less than 0.05) until termination of the study (10 weeks). Postmortem histologic examinations confirmed the high bone turnover level by revealing newly formed bone as well as the presence of osteoclasts. The time course of nuclide uptake in the temporomandibular joint is different from the general pattern of rise and fall of activity displayed in other bones and indicates the persistence of bone remodeling processes during a prolonged period of at least 10 weeks.

Adult↗
PubMed1991

Studies on focal alveolar bone healing with technetium (Tc)-99m labeled methylene diphosphonate and gold-collimated cadmium telluride probe.

The benefit of using a collimator for a miniaturized cadmium telluride probe was evaluated by monitoring the bone-healing processes for 13 weeks after the induction of small iatrogenic alveolar bone lesions in one side of the mandible in beagles. Technetium (Tc)-99m labeled methylene diphosphonate (200 to 300 MBq, 5.1 to 8.1 mCi, in a solution of 0.5 to 1 ml, intravenously) was used as a bone-seeking radiopharmaceutical. The radioactivity over the bone lesion (L) and the contralateral normal site (C) in the mandible were measured between 1.5 and 2 hours after injection of the tracer, and the activity ratio L/C served as an index of relative bone uptake. A study of six dogs revealed that the healing response to a hemispheric bone defect of 2 mm diameter in the cortical bone could not be detected by an uncollimated probe, and in a repeated study in two dogs the use of a gold collimator (5 mm in diameter, 5 mm in length) did not increase the L/C ratio significantly. A second study in six dogs with 5 mm lesions showed that although systematic trends in the time courses of the L/C ratio obtained both with and without the collimator could be demonstrated, the L/C ratio of collimated versus uncollimated measurements was significantly (p less than 0.005) increased. In three of the latter six dogs, abscesses developed after 9 weeks, leading to a second increase (p less than 0.05) of the L/C ratio with collimation compared with the noninflammation group; without collimation no significant (p greater than 0.15) difference between the two groups could be demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Process↗
PubMed1991

Condylar movements in clicking joints before and after arthrography.

The aim of this study was to investigate whether anaesthesia and contrast medium injection alter the biomechanics of the TMJ, thus influencing the arthrographic diagnosis in patients with anterior disc displacement with reduction. Opening and closing movements were recorded in nine patients by means of an opto-electronic motion recorder (Jaws 3D) before anaesthesia, after anaesthesia and after arthrography. The system computed the trajectories of a condylar point in the sagittal, frontal and horizontal plane. Data were analysed for changes in the position of the clicks, for the amount of condylar translation and for changes of the trajectories between recording conditions. The results indicated that arthrography had a significant effect on the position of the opening clicks in all nine patients. After injection, the clicks occurred on average 1.6 mm later than before injection. This was probably due to the excursive movements required for defusion of the contrast medium in the joint. The other parameters examined were not affected by the joint anaesthesia and the arthrographic procedure. The interventions influenced the shape and the incline of the sagittal condylar movement in three of the nine patients. In conclusion, arthrography altered the joint biomechanics, but not sufficiently to invalidate the arthrographic diagnosis.

Adult↗
PubMed1991

Delayed endodontic and prosthetic treatment of two traumatized incisors.

This case report describes the delayed endodontic and prosthetic treatment of two maxillary central incisors in a 16-year-old patient. Both teeth had been traumatized eight years previously. The examination revealed arrested root formation with wide open apices, periapical inflammation and inflammatory resorption. Endodontic treatment with calcium hydroxide led to formation of hard tissue barriers in both teeth so that definite obturation could be performed. One tooth was lost due to a deep crown-root-fracture and replaced by an intraosseous implant, whereas the other incisor was retained for nearly four years.

Adolescent↗
PubMed1991

[Motor activity of the point of the tongue in forming dento-alveolar consonants].

Electromagnetic articulography, a new tool for the study of articulatory movements, was used for the examination of apical tongue dorsum movements during the production of repeated VCV sequences. In our study of 16 normal German speakers, the trajectories of three apicolingual consonants, /t/, /s/ and /ss/, in an aCa sequence were assessed for inclination and length of the articulatory movement trajectories. A clear differentiation in length and direction of articulatory movements for the VCV utterances/ata/, /asa/ and /ass a/ was revealed. Variation in the direction of initial movement starting from the resting position was interpreted as effect of coarticulation.

Electromagnetic Fields↗
PubMed1991

[Electromagnetic articulography: a new method for studying the motor function of the velum palatinum].

The observation of articulatory movements, particularly of velar movements, is of considerable theoretical and practical interest in evaluating the velopharyngeal function of the cleft palate patient. A new electromagnetic device is presented for tracking the movements of the velum and the tongue simultaneously in correlation with the posterior pharyngeal wall and the hard palate in the midsagittal plane. An inductive measuring principle is used; a miniature transmitting coil is placed at the lower margin of the velum, another coil is used for recording the position of the posterior pharyngeal wall as well as the surface of the hard palate and the movements of the tongue dorsum. The measuring principle is described and the movements of the velum during speech production are demonstrated in cleft palate patients with different speech results.

Electromagnetic Fields↗
PubMed1990

The diagnostic value of subtraction radiography in the assessment of granular hydroxylapatite implants.

Although histologic analysis of osseous changes around hydroxylapatite (HA) implants can be highly accurate, it is of limited use in human beings. Digital subtraction radiography may provide a noninvasive alternative. Ten patients with bony lesions were operated on and nine of the iatrogenic defects were filled with granulated HA. In one patient, the defect was left unfilled for reference. Customized film holders provided standardized radiography. Follow-up images after 4 to 6 months were subtracted from immediately obtained postoperative images, and changes around the implants were noted. From ten pairs of radiographs, eight could be successfully subtracted, whereas two pairs required corrective image transformation before subtraction. Although no bone loss was observed in any of the patients, the implants did not appear to enhance physiologic bone regeneration either. Hence, subtraction radiography holds the potential of clinical utility for the follow-up of HA implants. However, technical improvements are necessary to yield quantitative data.

Adult↗
PubMed1990

How invasive is TMJ double-contrast arthrography in combination with cinematography? Patient discomfort versus known diagnostic gain.

There is no doubt that double-contrast TMJ fluoroscopic tomography enables a differential diagnosis and treatment in internal derangement pathosis. Its indication is, apart from the expected diagnostic gain, also determined by the degree of its invasiveness, and other alternative diagnostics being available (nuclear magnetic resonance). Data on patient discomfort and complications were gathered in 63 arthrotomographies; pain sensations and mandibular mobility, during and after the procedure in particular, were studied. We consider, along with Westesson, the procedure to be less invasive than commonly considered, once the surgeon-radiologist has gained enough experience.

Arthrography↗
PubMed1990

[Are additional filters made of niobium superior to the copper filter in dental radiology?].

At a dental X-ray unit the effect of an additional filter made of niobium has been tested in the molar region of the mandible with respect to dose reduction. It has been compared against the effect of an additional filter made of copper. With regard to the same dose at the film, radiation dose at the surface of the patient proved to be slightly more reduced after application of the copper filter than after application of the niobium filter. Radiographs have been made by exposure of intraoral dental films (Kodak film Ultra Speed D) together with a hydroxyapatite step-wedge. Measurements of optical density resulted in the same values after application of the copper filter and the niobium filter, respectively. Reduced image contrast due to application of one of these additional filters proved to be helpful. In short, an additional copper filter placed in the X-ray beam shows identical or better results when compared against an additional filter made of niobium.

Copper↗
PubMed1990

[Clinical and instrumental examination of tongue motor function].

The examination of tongue motor functions requires a clinical examination of voluntary movements as well an objective evaluation of the intraoral movements during speech, deglutition, mastication and during rest. For a comparison with the simple visual assessment of voluntary movements with the mouth opened, intraoral tongue movements have been studied using various techniques. The use of lateral x-ray palatography and electromagnetic articulography (EMA) for objective intraoral measurement of tongue motor activitiesis described. Case examples are given for simultaneous recording of midsagittal movements of the tongue, the mandible and the velum during swallowing and speaking.

Deglutition↗
PubMed1990

[Extended application potential for Esser's speech-color image transformation in the phoniatrics clinic: initial report].

The SFT system developed by Esser is an electronic device primarily used for visualizing speech sounds in the therapy of severely hearing-impaired patients. This paper discusses first results in the diagnostic and therapeutic application of the SFT on persons with no hearing handicap. The range of application includes the articulation, its malfunctions, speech coordination and voice functions. Observations have shown that SFT representation supplementary to listener judgement permits a clear description of a series of features from the categories mentioned above. Phonetic disorders, speech coordination and certain voice functions can thus also be compared and documented directly. Its application as an optical feedback device in the course of articulatory and voice therapy as well as the adjustment of the SFT system to certain fields of application are discussed.

Articulation Disorders↗