Search PubMed⌕ Search

Biomedical subjects

L W Kobes

Publications and source records attributed to L W Kobes.

At least 19 recordsLinked to original sources
PubMed1998

Study on the surface of resins that burn without residues in the lost-wax procedure.

STATEMENT OF PROBLEM: When compared with waxes and prefabricated components made of dental alloys, processing resins is difficult and often results in a less accurate fit. The exact linear dimension is hard to realize, as the materials required for a dental casting are adjusted to dental waxes, and usually there are no special processing instructions for these resins. PURPOSE: The surface structure of 16 residue-free burning resins was determined to find which could enlarge the range of application for waxes in the dental casting technique. MATERIAL AND METHODS: A total of 480 specimens (30 castings for each of 16 resins) were marked with an individually cut pyramid, which left an impression in the resin. This was distinctly visible in the metal after casting in "the lost form." The surfaces of these 480 specimens were measured in three dimensions with a positioning aid "before casting in resin" and "after casting in metal" by the Perthometer micrometer. All specimens were treated identically by the lost-wax process by using the rotation symmetry of the muffle. The differences in the surface data before casting in resin and after casting in metal characterize the quality of the particular resin. RESULTS: Surface roughness differed between the 16 resins in the range of micrometer. CONCLUSIONS: With the dental casting technique, it is recommended that some resins replace waxes or wax-resin compositions.

Dental Alloys↗
PubMed1992

Long-term electromyography as a possible diagnostic aid for detecting craniomandibular dysfunctions.

As there is a positive correlation between oral parafunctional habits and craniomandibular disorders, objective electromyographic findings on parafunctional jaw activities could be very interesting for the diagnosis and management of craniomandibular disorders. The described pocket-sized and battery-operated electromyographic measuring device fulfils the essential requirements for monitoring and recording parafunctional activity in a chosen time period. It is easy to handle and can therefore be operated by a trained patient. At the end of the registration the collected data are transferred to a computer for statistical or graphical analysis. With this device, long-term electromyography on patients in their usual environment is possible. Further studies on parafunctional behaviours applying long-term electromyography could increase the understanding of craniomandibular disorders.

Adult↗
PubMed1991

[Functional craniomandibular disorders and ENT-symptoms].

Complaints in the otolaryngologic region, that cannot be referred to an otolaryngological pathologic process, are often caused by or combined with craniomandibular dysfunctions. As a rule these complaints are not the result of direct mechanical irritation of the articular tissues, but the effect of neuromuscular incoordination and spasms. Consequently the term "Costen's syndrome" is obsolete and should be used no more. In many cases the interaction of otolaryngological symptoms and craniomandibular disorders can only be proved ex iuvantibus. Occlusal equilibration combined with physical and physiotherapeutic treatment are approved methods to normalize neuromuscular function and eliminate muscle tension and pain.

Deglutition Disorders↗
PubMed1990

[Economic aspects of use of alternative dental alloys].

A cost calculation for different types of dental alloys was carried through all stages of production. Recycling and scrap material values were included. Results showed that over an estimated 20 years of usage, the higher annual cost for bridges cast with a high gold alloy in relation to those with lower gold content alloys is not that significant that from the patients point of view the lower alloys should the choice. Due to the system of health insurance, this cost calculation from the production point of view looks different for the organizations that are reimbursing the patient for his expenses, as these organizations are not entitled to the scrap value of old restorations.

Cost-Benefit Analysis↗
PubMed1989

[Influence of occlusion on head posture during prolonged phases of clenching].

The influence of divergent splint-adjusted maximum intercuspation on head posture during prolonged phases of clenching was studied in five subjects. During clenching in maximum intercuspation profound changes of head posture were observed, if intercuspation was not harmonized with an upright posture of head and body. Since the interrelation between occlusion and head posture is established a comprehensive approach of orthopedic, physiotherapeutic, and dental measures, in particular for the therapy of myoarthropathy patients with cervical spine symptoms seems appropriate. Occlusal corrections and determination of occlusal relations must always be made or at least checked in the upright relaxed patient with the head straight.

Bruxism↗
PubMed1989

[Is the T-scan system a relevant diagnostic method for occlusal control?].

The T-Scan system has recently been introduced to the market as a computer-aided device for direct monitoring and documentation of individual occlusal patterns. To receive first assessments of diagnostic relevance of this method, sensitivity and planar resolution capacities of the T-Scan system was tested in an in-vitro study, that showed a lack in the resolution capacity and an excessive variation in sensor sensitivity. Therefore the clinical use of the system is very limited.

Dental Occlusion, Balanced↗
PubMed1989

[Comparative analytic occlusal study of clinical use of T-scan systems].

Occlusal corrections are dependent on a precise registration. The T-Scan system has recently been presented to the market as an innovative, computer-aided device, capable of providing exact information regarding position, strength and frequency of occlusal contacts. The diagnostic validity of this technique was tested in a comparing study on 16 patients. The occlusal situation of these patients was analyzed by use of the T-Scan system and the markings compared with those obtained from UV-sensitive articulation foil. The results show that the diagnostic possibilities of the T-Scan system are very much limited. The use oft he T-Scan system as the only means of occlusal analysis cannot be recommended. The main reason for this is an often misleading reproduction of occlusal contacts, caused by the T-Scan-sensor-foil being too thick and too inflexible and therefore creating an uncontrollable shift of the mandibula when closing the bite. However, the T-Scan system seems to be a valuable tool for education of both students and patients, as the on-screen coulour display of occlusal mechanisms are really impressive.

Dental Occlusion, Balanced↗
PubMed1979

[Stability of temporomandibular joint relations in the edentulous].

Loss of teeth causes a change in the relationship of the mandibular condyles to the articular fossa of the temporal bone. The movement of the joint is pathologically restricted by the relation of the articular disc. The study showed that the function of the masseter muscles could be normalized with a modified Shore bite path plate. This normalized function was expressed by a change in jaw relation. The theoretical foundation was discussed and the results of preliminary investigations were presented.

Humans↗
PubMed1979

[Possibilities and limits of prosthetic rehabilitation of the reduced dentition].

The initial findings are crucial for determining the time and the extent of possible prosthetic treatment. The patients to be fitted with a prosthesis are divided into several groups, on the basis of the present state and the reaction of the masticatory organ to external irritation, into resistant and insufficient states. The topography (not the number) of abutment teeth, the relationship of the edentulous parts of the jaw to the number of remaining teeth, the extent and the course of future prosthetic surfaces, the possibility of the equilibrium and distribution of force, the antagonistic relationship of the teeth with each other and hygienic factors limit the prosthetic possibilities. The free-end saddle represents a particular problem in the fitting of a dental prosthesis; its variant forms are discussed and, on the basis of many years of successful controls, the possibility and the limitations for the fitting of prostheses were pointed out.

Biomechanical Phenomena↗